NSCA Research Summaries
Acute Effect on Power Output of Alternating an Agonist and Antagonist Muscle Exercise During Complex Training
Friday, April 08, 2005
Researchers from Edith Cowan University suggest the alternating of agonist and antagonist muscle exercises may be useful in ballistic power training. The purpose of this study was to determine if a complex training method consisting of alternating agonist and antagonist muscle movement patterns had an acute effect on agonist power output.
Twenty-four experienced college-aged rugby players were randomly and equally assigned to control (Con) and experimental (Antag) groups. After a specific warm-up, participants performed a pretest that consisted of five explosive bench press-style throws set at a 40kg resistance with the Plyometric Power System training device. Following the pretest, participants in the Antag group performed a prone bench pull (load set at 50% of 1RM), explosively, for eight repetitions. Each group had three minutes of recovery before post testing. The repetition with the highest concentric average power output was chosen and recorded for analysis.
Results from the Con group were relatively unchanged, whereas the Antag group saw a significant increase in acute agonist power output. Researchers suggest that the antagonist intervention strategy may reduce breaking phase time in the ensuing agonist muscle movement. In turn, an increase in force, speed, and power may result.
Baker D, and RU Newton. (2005). Acute Effect on Power Output of Alternating an Agonist and Antagonist Muscle Exercise During Complex Training. Journal of Strength and Conditioning Research, 19(1):202 – 205.
Preadolescent Strength Training
Thursday, March 17, 2005
Researchers from the University of Athens in Athens, Greece recently set out to see if strength training has any effect on strength and hormonal levels in preadolescent males?
Nineteen untrained preadolescent males (age 11 – 13) participated in the study. Subjects were randomly assigned to either a strength training group, or a control group. The strength training group performed a resistance training program 3 times a week for 2 months, consisting of 3 sets of 10 repetitions on 6 different exercises. Rest intervals consisted of 1 minute between sets and 3 minutes between exercises. Isokinetic strength, isotonic strength, testosterone, sex hormone binding globulin, and free androgen index were measured before the training program, after training program, and following a 2 month detraining period.
The strength training group showed a 124% increase in mean testosterone concentration and a 75% increase in free androgen index, while the control group showed no change in hormone levels. Results also showed the strength training group had a 17.5% increase in strength after the 2-month training program. But strength gains decreased 9.5% after the detraining period, suggesting that strength changes in youth are reversible and not permanent.
The researchers point out that the strength training program used in this study did not have a negative impact on hormonal regulation in prepubescent boys, as testosterone and sex hormone binding globulin remained within reference value ranges. In addition, the researchers say that a supervised, concentric resistance training program does not appear to be risky for healthy children, as show by zero injuries being reported during this study.
Tsolakis CK, Vagenas GK, Dessypris AG. (2004). Strength adaptations and hormonal responses to resistance training and detraining in preadolescent males. Journal of Strength and Conditioning Reseach, 18(3):625 – 629.
The Relationship Between Balance and Pitching Error in College Baseball Pitchers
Tuesday, March 08, 2005
The authors of a study recently published in The Journal of Strength and Conditioning Research have concluded that the practice of the balance-point position by college baseball players does not reduce pitching error.
Researchers from Saco Bay Orthopaedic and Sports Physical Therapy, SmartCare Physical Therapy, Day-Kimball Hospital and Maxwell, Knowland, and Kluger-ENT Associates investigated the relationship between balance and pitching error in college baseball pitchers. Specifically, the relationship of unilateral stance as well as sensory system input on pitching error was examined.
Sixteen male college baseball players (3 left-handed, 13 right handed) completed the study. Each pitcher threw 20 fastballs at game intensity. Pitching error was measured using a high-speed digital camera and an L-shaped apparatus which allowed researchers to determine ball position on an x-y plane as it crossed home plate. Balance was measured in a unilateral stance (balance-point position) as well as six different tests in the normal stance with a combination of different sensory conditions. Correlations were done between pitching error and velocity and each balance assessment.
Although this study does not support practice of the balance-point position to reduce pitching error, college baseball pitchers and coaches may consider sport specific exercises that eliminate visual and somatosensory inputs to stimulate the vestibular system. However, additional research is needed in order to pinpoint the determinants of pitching error.
Marsh DW, Richard LA, Williams A, Lynch KJ. (2004). The Relationship Between Balance and Pitching Error in College Baseball Pitchers. Journal of Strength and Conditioning Research, 18(3): 441 – 446.
How Much Rest is Needed Between Sets?
Tuesday, February 22, 2005
A University of Kansas study examined the effects of three different rest period lengths on subsequent set performance. Twenty-eight recreational weight trainers participated in this study.
Subjects performed one set of bench press at 75% of their predetermined 1RM to volitional exhaustion. After a randomly assigned rest period of 1-minute, 3-minutes, or 5-minutes, subjects performed another set of bench press at the same percentage of 1rm, to volitional exhaustion.
Results showed significantly fewer repetitions for the second set with all three rest intervals. In addition, the total work performed during the second set was significantly less with the 1-minute rest interval than it was with the 3-minute and 5-minute rest intervals. While all of the second sets produced fewer repetitions, after both the 3-minute and 5-minute rest intervals, subjects were able to perform between 8 – 12 repetitions. Subjects were only able to perform 4 – 6 repetitions on the second set after only a 1-minute rest.
The researchers point out that the population used for this study is recreational weight trainers. Other studies that have used highly trained weightlifters and bodybuilders have suggested that rest periods of one minute adequate for full recovery. More research is needed into the reasons the two different populations had different results.
As the authors point out, rest intervals will depend on training goals. If the goal is to maintain the same number of repetitions in each set, then the rest interval may need to be longer than five minutes. But if the goal is 8 – 12 repetitions, 3 – 5 minutes rest should be adequate.
Richmond SR, Godard MP. (2004). The effects of varied rest periods between sets to failure using the bench press in recreationally trained men. Journal of Strength and Conditioning Research, 18(4):846 – 849.
Bosco vs. Wingate Test for Anaerobic Power
Monday, February 14, 2005
Researchers from the United States Olympic Committee, Eastern Washington University, and Leeds Metropolitan University in the United Kingdom concluded that the Wingate and Bosco tests—though both anaerobic in nature—are measuring somewhat different aspects of anaerobic performance. The purpose of this study was to compare and contrast the Wingate and Bosco anaerobic tests. Twenty college athletes (women = 9, men = 11) participated in the study. Participants were encouraged to pedal at maximum speed for the 30s duration for the Wingate protocol. During the Bosco test, participants were instructed to perform continuous rapid jumps of maximum effort for the entire 60-second duration of the test. Researchers looked at variables such as average and peak power and peak lactate.
Although the Bosco test can be used to acquire roughly the same information acquired during the Wingate test, it may be more specific for sports such as gymnastics, track and field, basketball, and volleyball that invoke the use of the stretch shortening cycle used during jumping movements. However, the Bosco test may not be suitable for those inadequately trained in jumping.
Sands W, McNeal, J, Ochi M, Urbanek T, Jemni M, Stone M (2004). Comparison of the Wingate and Bosco Anaerobic Tests. Journal of Strength and Conditioning Research, 18 (4):810–815.
Can short-term interval training improve fitness in prepubertal children?
Wednesday, February 02, 2005
Researchers in France recently investigated the effects of short-term interval training on fitness in prepubertal children. The investigators were interested in the effects on the children's aerobic performance and explosive strength.
One hundred boys and girls aged 8 – 11 years comprised of 46 boys and 54 girls volunteered for the study, with the consent and approval of the parents. The same physician evaluated the sexual maturity of each child prior to the onset of training. There was a control group was comprised of 25 boys and 28 girls, and an experimental group involving 21 boys and 26 girls. Five field tests from the EUROFIT protocol were performed at the beginning of the study to establish a baseline of fitness for the children. The tests included the standing broad jump, the 10 x 5-m shuttle run, the sit-and-reach, the 30-second sit-up test, and the 20-m shuttle run test.
The experimental group followed an interval-training program for 7 weeks. This group performed high-intensity, intermittent-running exercises 2 sessions per week for a period of 30 minutes per session. These exercises ranged from 10 – 20 seconds at 100 – 130% of maximal aerobic speed. A recovery period of 10 – 20 seconds followed each run. All exercises were performed on a short track and the children were placed in lanes corresponding to their maximal aerobic speed.
Results reveled that there was no significant difference at baseline between the experimental and control groups. The experimental group did experience a significant improvement in their standing broad jump values and their maximal shuttle run velocity. These improvements were observed to be independent of gender and growth. No improvement was found in the control group.
These results suggest that high-intensity, short-term interval training can elicit an improvement in some aspects of fitness for prepubertal children. It must be noted that children will perform better in a physical education environment when they are having fun within a group setting and when the instructions remain simple. Including these sessions within a physical education curriculum may provide an alternative for educators.
Baquet G, Guinhouya C, Dupont G, Nourry C, Berthoin S. (2004). Effects of a short-term interval training program on physical fitness in prepubertal children. Journal of Strength and Conditioning Research, 18(4): 708 – 713.
Effects of Single vs. Multiple Set Resistance Training on Maximum Strength and Body Composition in Trained Postmenopausal Women
Thursday, January 20, 2005
Researchers from the University of Erlangen, Germany have concluded that in pre-trained subjects, multiple-set protocols are superior to single-set protocols in increasing maximum strength.
The purpose of this study was to examine the effect of a single- vs. a multiple-set resistance training protocol in well-trained early postmenopausal women. Seventy-one subjects were randomly assigned to begin either with 12 weeks of the single-set or 12 weeks multiple-set protocol. After another five weeks of training, the subgroup performing the single set training during the first 12 weeks crossed over to the multiple set protocol and vice versa. One repetition max values for leg press, bench press, rowing, and leg adduction were measured at baseline and after each period. Multiple set training resulted in significant increase (3.5% – 5.5%) for all four strength measurements, whereas single-set training resulted in significant decreases (-1.1% – 2.0%). Body mass and body composition did not change during the study.
Kemmler W, Lauber D, Engelke K, Weineck J. (2004). Effects of Single vs. Multiple Set Resistance Training on Maximum Strength and Body Composition in Trained Postmenopausal Women. Journal of Strength and Conditioning Research, 18 (4):689 – 694.
Reduce ACL Injuries in Women?
Tuesday, January 04, 2005
Researchers from Boise State University and the University of Louisville concluded that a low volume and intensity plyometric training program can improve landing mechanics in a manner conducive to injury prevention. This study examined peak vertical impact forces and rate of force development following a 9-week, low intensity (simple jump-landing-jump tasks) and volume plyometric based knee ligament injury prevention program. Fourteen women were assigned to perform the plyometric program while the control group received no intervention. Significant reduction in peak vertical impact forces and rate of force development in the treatment group were observed after the 9-weeks of training. These changes are considered conducive to a reduced risk of knee injury while landing.
Irmischer B, Harris C, Pfeiffer R, DeBeliso M, Adams K, Shea K. (2004). Effects of a Knee Ligament Injury Prevention Exercise Program on Impact Forces in Women. Journal of Strength and Conditioning Research, 18 (4): 703 – 707.
The Effect of High-Load vs. High-Repetition Training on Endurance Performance
Tuesday, December 21, 2004
What type of training is best for endurance athletes, high-load or high-repetition? Researchers from Marquette University recently studied the effects of high-load and high-repetition training on both varsity and novice female rowers.
Twenty-six females rowers participated in this study. The high-load training group consisted of 5 novice and 8 varsity rowers, and performed a traditional periodized program ranging from 3 sets of 12 repetitions to 3 sets of 5 repetitions. The high-repetition training group consisted of 7 novice and 6 varsity rowers and performed a reverse step loading periodization program ranging from 2 sets of 15 repetitions to 2 sets of 32 repetitions.
After 8-weeks of training, both the high-load and high-repetition training groups increased their 2,000-m time trial performance on a rowing ergometer. Both groups also increased their power output with no changes in total strokes or stroke rate.
The most interesting finding however is that the novices had a greater improvement with the high-repetition training, while the varsity rowers had a greater improvement with the high-load program. These results support previous recommendations of high-repetition training for endurance athletes, and the theory that pretraining status dictates the magnitude of potential adaptation.
Obviously more research is required in this area, both in regards to resistance training methodologies for endurance athletes, and adaptations for these athletes based on pretraining status.
Ebben WP, Kindler AG, Chirdaon KA, Jenkins NC, Polichnowski AJ, NG AV. (2004). The effect of high-load vs. high-repetition training on endurance performance. Journal of Strength and Conditioning Research, 18(3):513 – 517.
Strength Recovery Following Cold Immersion
Tuesday, December 07, 2004
A recent study from New York Institute of Technology and Stony Brook University examined how long muscular strength takes to recover from cold immersion. Previous research has demonstrated that cold immersion, or cryotherapy, can significantly reduce both the force and power generated by a muscle. But how long do these affects last?
Sixteen males submerged their forearm in 10 degree C water for 5,10, 15, or 20 minutes. Maximal isometric grip strength was measured before, immediately after, and 5, 10, and 15 minutes after immersion. Even after 5 minutes of immersion, there was a significant decrease in isometric strength. This decrease was still present after 15 minutes of recovery.
The authors hypothesize that the decrease in strength after cold immersion may be due to vasoconstriction, which causes a decrease in the amount of calcium released from the sacoplasmic reticulum, ultimately interfering with muscle cross bridge formation. The end result is a decrease in muscular strength.
Cryotherapy is commonly used in treating athletic injuries and is also used prior to other treatments for both athletes and the general population. Practitioners that apply this modality need to be aware that it can have a negative affect on muscle strength up to 15 minutes after application.
Douris P, McKenna R, Madigan K, Cesarski B, Costiera R, Lu M. (2003). Recovery of maximal isometric grip strength following cold immersion. Journal of Strength and Conditioning Research, 17(3):509 – 513.
Strength and Conditioning Practices of National Hockey League Strength and Conditioning Coaches
Wednesday, November 24, 2004
Researchers at Marquette University in Milwaukee, WI conducted a survey among the 30 National Hockey League Strength and Conditioning (NHL S&C) Coaches. The purpose of this survey was to establish what the current practices of the NHL S&C coaches are in regards to training NHL players. There were 23 out of the 30 NHL S&C coaches that responded to the survey.
The survey indicates that 23 out of 23 of the reporting NHL S&C coaches do some type of testing and 22 do some type of flexibility and speed development. Twenty-one NHL S&C coaches use plyometric training but they vary on what time of year they use it. Most NHL S&C coaches used a periodization model in their program design and also indicated using Olympic-style lifts to train their players.
The survey results are good resource for young coaches to see what type of training is being used to train hockey athletes at the highest level.
Ebben WP, Carroll RM, and Simenz CJ. (2004). Strength and Conditioning Practices of National Hockey League Strength and Conditioning Coaches. Journal of Strength and Conditioning Research, 18(4):889 – 897
Can partial range of motion be as effective as full range of motion for developing maximal strength?
Thursday, November 11, 2004
Research conducted at University of Southern Mississippi and University of Alabama suggests that partial range of motion training can positively influence the development of maximal strength as well as full range of motion on the bench press.
The purpose of this investigation was to compare partial range of motion versus full range of motion training in the development of maximal strength. The bench press was used as the criterion measurement. The study was conducted over a 10-week period with training sessions occurring twice per week. Subjects were divided into three groups: full range of motion, partial range, or combination of both full and partial range. A full range of motion was used as a pre- and post-test. At the conclusion of the 10 weeks, no differences were found between groups. The researchers concluded that those involved in the strength and conditioning profession can confidently include this method as an adjunct to their normal training protocols when working with individuals similar to those found in this investigation.
Massey D, Vincent J, Maneval M, Moore M, Johnson JT. (2004). An Analysis of Full Range of Motion vs. Partial Range of Motion Training in the Development of Strength in Untrained Men. Journal of Strength and Conditioning Research, 18 (3): 518 – 521.
The Effect of In-Season, High Intensity Interval Training in Soccer Players
Tuesday, October 26, 2004
Researchers at the University of Lille 2, Lille, France wanted to examine the effect of in-season, high intensity interval training had in soccer players. Twenty-two subjects participated in two consecutive 10-week training periods. The first 10-week period was used as a control period to compare with the second 10-week training period.
The training program consisted of two high-intensity interval training exercises that were included in the subjects' usual in-season training sessions. For the repeated sprints, subjects were required to perform 12 – 15 40-meter sprints with 30 seconds of passive recovery during the training program. These tests were specifically picked since they are classified as primarily anaerobic exercise. The second exercise utilized in the program consisted of 12 – 15 intermittent runs lasting 15 seconds at 120% of maximal aerobic speed alternated with 15 seconds of rest.
The study has shown that aerobic and anaerobic performances were able to increase during the in-season due to the specific training program that was followed. The study also showed that the control group was able to maintain performance levels through their regular training program but did not show an increase in performance measures like the additional training group. This study helps to reaffirm that in season training can have a positive effect on a team's performance, not a negative effect, if a sound and specific program is incorporated.
Dupont G, Akakpo K, Berthoin S. (2004). The Effect of In-Season, High Intensity Interval Training in Soccer Players. Journal of Strength and Conditioning Research, 18(3): 584 – 589.
The Effect of Short-Term Swiss Ball Training on Core Stability and Running Economy
Tuesday, October 12, 2004
Researchers at Central Queensland University, Australia and Ball State University, USA investigated the use of Swiss ball training on core stability and running economy on eighteen young male athletes. The subject were tested before and after training for stature, body mass, core stability, electromyographic activity of the abdominal and back muscles, treadmill VO2 max, running economy, and running posture. The experimental group performed two Swiss ball training sessions per week for six weeks. Data analysis revealed a significant effect of Swiss ball training on core stability in the experimental group but no effect in any of the other measurements.
In light of the findings of this study, the use of Swiss ball training either alone or as an adjunct to other physical training to enhance core stability appears promising. However, whether gains in core stability achieve through such training are converted to enhanced physical performance remains to be demonstrated.
Stanton R, Reaburn P, Humphries B. (2004). The effect of short-term swiss ball training on core stability and running economy. Journal of Strength and Conditioning Research, 18(3): 522 – 528.
Can You Predict a 10RM Squat From a 45-Degree Leg Press?
Thursday, September 09, 2004
It is common when beginning a resistance training program for individuals to use a leg press machine for ease of use instead of performing squats. Once experience and strength are built, the individual may want to begin performing squats. However, determining the equivalent workload on the squat exercise has usually involved trial and error. To alleviate some of the guesswork, researchers from Arizona State University and Utah State University have developed an equation to predict a 10-repetition maximum (10RM) for the free weight squat using a 45-degree leg press.
Based on test results, the researchers developed the following equations to predict 10RM squat from 10RM leg press.
- Novice Group Squat Mass = Leg Press Mass (0.210) + 36.244 kg
- Advanced Group Squat Mass = Leg Press Mass (0.310) + 19.438 kg
- Subject Pool Squat Mass = Leg Press Mass (0.354) + 2.235 kg
The researchers stress that their study has its limitations, and that other studies have shown limb length and body mass to be predictors for squat mass lifted. Such limitations include not measuring cross-sectional area and variations in technique. However within the limitations of this study, these equations can be applied to males 18 – 31 on a plate-loaded Cybex 45 degree angled hip sled.
Does Vertical Jump Correlate to Weightlifting Ability?
Thursday, August 26, 2004
Researchers from the USA and Australia examined the usefulness of the vertical jump and estimated vertical jump power for assessing weightlifting capability.
Sixty-four USA National level weightlifters, both men and woman ranging from ages 15 – 30 years, were selected for this study. The athletes were tested in the vertical jump using two methods. First, with hands-on-hips, they were tested on the counter movement jump, then they were tested on the static jump, again with hands-on-hips. All athletes were measured 1 – 2 hours before lunch and after a low volume training day approximately 4 – 5 weeks prior to their next competition.
Test results yielded a direct correlation between vertical jump and weightlifting capability in both men and women and junior and senior lifters. The authors of this study conclude that peak power as measured by a vertical jump can be a very useful tool for the coach in assessing weightlifting performance. Furthermore, this type of assessment does not interfere with the normal training regimen of the athlete.
Participation in High School Sports Decreases Risk for Osteoporosis
Thursday, August 12, 2004
Researchers at Florida Atlantic University, Sam Houston State University, and University of Arkansas recently examined the effect of past and recent physical activity on bone mineral density in college-aged women. One hundred fifty seven women age 18-39 had their bone mineral density measured, and participated in a history of physical activity survey.
The results showed that women who did not participate in high school athletics were seven times more likely to have low bone mineral density than those who had high school athletic backgrounds. Present physical activity and lean tissue were also shown to be significant predictors of bone mineral density.
Osteoporosis affects over 25 million people in the US, 80% that are female. The best method to attack this disease appears to be building bone mineral density in the earlier years before females have reached peak bone mineral density. The results of this study add to the current body of research supporting physical activity to build bone mineral density during peak bone growth years. This study also demonstrates that high school sports participation is an excellent form of physical activity to build bone mineral density during that time.
Ford MA, Bass MA, Turner LW, Mauromoustakos A, Graves BS. (2004). Past and recent physical activity and bone mineral density in college-aged women. Journal of Strength and Conditioning Research, 18(3).
Do novices select the appropriate resistance?
Monday, July 12, 2004
Do individuals who select their own resistance exercise at the recommended intensity level? According to researchers at Grand Valley State University and Wayne State College, no they do not.
Thirteen men and seventeen women volunteered for the study. All subjects were previously untrained, and novices to resistance training. The subjects were asked to “choose a load that you feel will be sufficient to improve your muscular strength.” No instructions were provided on the number of repetitions to perform, or to lift to fatigue.
The protocol consisted of two sets with two-minute rest intervals. All exercises were performed on machines in the following order: seated bench press, leg extension, seated row, shoulder press, and bicep curl. The value of the weight was also covered with tape so that subjects were blind to the actual weight they were lifting. Subjects returned forty-eight to seventy-two hours later to perform a second trial. No feedback on repetitions or intensity of the previous trial was provided. Within 48 hours of the second trial, subjects were tested for 1RM.
Results showed that both males and females selected intensities that were below 60% 1RM for all lifts. As the authors point out, research has shown that intensities of at least 60-75% of 1RM are required for strength and hypertrophy gains. The individuals in this study selected intensities within the 40-60% 1RM range, which is not adequate to elicit any changes.
The authors suggest that in the health and fitness industry, trainers work with clients to perform strength testing, and proper instruction on the intensities required to elicit muscular changes. If individuals are left to self-select weights, their intensities will be too low. As a result, they will be more likely to drop out because they see no changes and become discouraged.
Today's D-1 Football Players are Bigger, Stronger, Faster, and More Powerful
Thursday, July 01, 2004
In a recently published study conducted at the University of Nebraska it has been determined that Division I football players today are bigger, stronger, faster, and more powerful than they were in 1987. The purpose of this study was to compare normative data from present Division I National Collegiate Athletic Association football teams to those from 1987. Players were divided into 8 positions for comparisons: quarterbacks, running backs, receivers, tight ends, offensive linemen, defensive linemen, linebackers, and defensive backs. Comparisons included height, body mass, bench press and squat strength, vertical jump, vertical jump power, 40-yd-dash speed, and body composition. Data on upper- and lower-body strength, explosive power, speed endurance, muscular endurance, flexibility, and body compositions were compared with positions and playing status. Significant differences were found in 50 of 88 comparisons.
Improvements in performance variables by Division I football players over the last 10 or so years suggest that strength and conditioning programs have had a positive impact on physical characteristics, strength, speed, and power. However, without investigating the impact of high school strength training or looking at the improvements gained during an athlete's eligibility period, the magnitude of impact cannot be speculated. Future studies in these areas are warranted.
The Effects of Static Stretching on Muscle Strength
Tuesday, June 15, 2004
Will static stretching negatively affect muscular force production? According to researchers at the University of Nebraska-Lincoln, the answer is yes.
Subjects in this study warmed up, and then had their concentric, isokinetic knee extension peak torque measured in both legs at 60 and 240 degrees per second. Subjects then underwent 4 static stretches (1 active and 3 passive) for the knee extensors on their dominant leg only. Each stretch was performed 4 times and held for 30 seconds. After static stretching, peak torque was again measured in both the dominant and non-dominant leg.
Following static stretching, peak torque decreased in both limbs and at both measured velocities. Other studies have also shown static stretching to decrease force production, and have suggested that decreases in peak torque are velocity specific. In this study, peak torque decreased at both 60 and 240 degrees per second, suggesting that the decrease in force production may not be velocity specific.
The cause of this decrease in peak torque is not known. However the current study suggests that the cause may be related to changes in the mechanical properties of the muscle, such as an altered length-tension relationship, or a central nervous system inhibitory mechanism (supported by the decrease in strength on the non-stretched leg).
Strength and conditioning professionals may want to reconsider static stretching before competition. As more and more studies continue to suggest that static stretching may decrease maximal force production, the effects that this decrease will have on performance must now be considered.
Cramer JT, Housh TJ, Johnson GO, Miller JM, Coburn JW, Beck TW. (2004). Acute effects of static stretching on peak torque in women. Journal of Strength and Conditioning Research, 18(2):236 – 241.
Physical Fitness and Job Performance of Firefighters
Tuesday, June 01, 2004
Researchers at Arizona State University in association with the Phoenix Fire Department have determined that it is most beneficial for firefighters to address all components of fitness while training for job performance. The purpose of this study was to examine the correlations of a wide range of fitness tests, including numerous tests for muscular strength and endurance, body composition, cardiovascular endurance, and anaerobic endurance.
Twenty professional firefighters performed numerous fitness and job-related performance tests. Results indicated significant correlations between job performance and total fitness, bench press strength, handgrip strength, bent-over row endurance, bicep endurance, squat endurance and 400-meter sprint time. Exercise programs for firefighters have traditionally focused on cardiovascular endurance and muscular strength. This current data suggests that traditional programming be replaced with training for all aspects of fitness.
Rhea M, Alvar B, Gray R. (2004). Physical Fitness and Job Performance of Firefighters. Journal of Strength and Conditioning Research, 18 (2): 348 – 352.
Does a single bout of resistance training affect the immune system?
Friday, May 14, 2004
Exercise immunology has traditionally looked at the effect of aerobic exercise on immune function. To provide a new angle, researchers from University of Northern Colorado, Western New Mexico University, and California State University-Fresno examined the effect of a resistance training session on white blood cell count.
Sixteen males volunteered for the study. Blood samples were taken before, immediately after, 15 minutes after, and 30 minutes after the resistance training workout. The workout consisted of 3 sets of 8-10 repetitions at 75% of 1RM. Exercises were performed on selectorized machines, and included: abdominal crunch, chest press, latissimus dorsi pull down, leg curl, leg extension, leg press, seated row, and shoulder press.
The results of this study showed resistance training to cause leukocytosis (elevated number of white blood cells). Similar results are seen with aerobic exercise. The authors suggest that resistance training-induced leukocytosis is not caused by one single event, but may be caused by a combination of increases in epinephrine, blood pressure, heart rate, blood velocity, plasma volume, and lymph return to the vascular space.
The authors conclude that the changes seen in immune cell numbers are small, and that an acute bout of resistance training will not result in immunoenhancement or immunosuppression. These results suggest that a resistance training session will not compromise the immune system leading to an increased risk of infectious episodes.
Simonson S and Jackson C. (2004). Leukocytosis occurs in response to resistance training exercise in men. Journal of Strength and Conditioning Research, 18(2):266 – 271.
Which is better to strengthen the rotator cuff, isolated or complex exercises?
Friday, April 09, 2004
The rotator cuff traditionally has been strengthened by using isolated movements. But can complex multi-joint movements strength the rotator cuff just as well? Researchers at Democritus University of Thrace in Komotini, Greece recently compared the effects of isolated and complex exercises on rotator cuff strength.
Thirty-nine males participated in this 6-week study. After initial isokinetic testing of internal and external rotation strength, the subjects were divided into 3 groups. The experimental isolated group performed internal and external dumbbell rotation exercises, the experimental complex group performed pull-ups, overhead presses, reverse pull-ups, and push-ups, while the control group performed no exercises. Both experimental groups performed 3 – 7 sets of 8 – 15 repetitions with 2 – 4 minutes rest between sets.
Both experimental groups increased rotator cuff strength, with the complex training group having a significantly greater improvement in both arms. The isolated group only had a significant improvement in the non-dominant arm, and this improvement was less than the complex group achieved in the same arm.
The authors of the study do not recommend replacing isolated movements with complex movements to strengthen the rotator cuff. Instead, they recommend a combination of both methods. The authors suggest that a program begin with isolated movements to better stimulate weak muscles, but after strength has been improved, switching to complex exercises that will provide greater improvements in strength.
Key Determining Factors for the NCAA Division I Head Strength and Conditioning Coach
Thursday, March 25, 2004
What do a Master's Degree, CSCS certification, practical experience with different sports, and presentations have in common? They are all desirable qualifications that NCAA institutions look for when hiring a head strength and conditioning coach.
A recently published study out of Pepperdine University determined the appropriate educational, competitive, and work experiences that an aspiring strength and conditioning coach should attain in pursuit of a head position at the intercollegiate level. Data were collected on demographic characteristics, educational background, competitive experiences, coaching experiences, duties, and opinions of the head strength and conditioning coaches in the NCAA. A total of 212 of 313 coaches returned the questionnaire.
In addition to the aforementioned qualifications, it was also found the knowledge in computers and technology is desirable and gaining experience as an assistant (part-time, full-time, graduate, or volunteer) is highly desirable. While comparing data from previous studies it was determined that trends show that the position has improved in the areas of salary (supported by findings with Division I-A and I-AA results), job attenuation, and the facilities available to the coach.
Martinez D. (2004). Study of the Key Determining Factors for the NCAA Division I Head Strength and Conditioning Coach. Journal of Strength and Conditioning Research, 18 (1): 5 – 18.
Quantitative Analysis of Single- vs. Multiple-Set Programs in Resistance Training
Tuesday, March 16, 2004
Researchers at the University of Pennsylvania, Bloomsburg and Le Moyne College, Syracuse examined the existing research on single-set vs. multiple-set resistance training programs. They identified 16 studies that met the following criteria: 1) a minimum of 6 subjects per group; 2) programs that consisted of single set vs. multiple set training regimes; 3) looked at pretest and posttest measures; 4) lasted 6 weeks or more in duration; 5) used "healthy" subjects for study; and 6) published in an English-language journal. During analysis the authors noted that there were there some interesting effects based on the age of the subject, training status, and research design. Significant interactions were observed for training status and program duration (6 – 16 weeks vs. 17– 40 weeks) and the number of sets performed (single vs. multiple).
The study found that trained individuals using multiple-set protocols generated significantly greater increases in strength than individuals using single-set protocols, especially over longer training periods. However, the authors also noted that untrained individuals, over a short time period, showed similar strength gains with either a single-set or multiple-set protocol. The increases in strength over a short time period in untrained individuals were attributed to neural adaptations.
The authors conclude that the data overall does support the use of multiple-set programs as more effective than single-set especially as longer training progressions occur and higher gains are desired.
Wolfe BL, LeMura LM, Cole PJ. 2004. Quantitative Analysis of Single- vs. Multiple-Set Programs in Resistance Training. Journal of Strength and Conditioning Research, 18(1):35 – 47.
Combine Plyometrics and Weight Training to Improve Driving Distance
Monday, March 01, 2004
Traditionally, improvements in golf performance have focused on modifying technique. However, as top golf professionals have begun conditioning programs to improve their performance and increase the longevity of their career, amateur golfers have begun taking an interest in conditioning. But will a conditioning program increase an amateur golfer's performance?
Researchers at the University of Luton, in Luton, Bedfordshire, United Kingdom examined the effects 8-weeks of combined plyometric and weight training had on club head speed and driving distance for amateur golfers. Eleven golfers, with a mean handicap of 5.5 (very good club standard golfer) participated in the study. Subjects were randomly assigned to either a control group or an experimental group. The control group continued with their current training program, while the experimental group performed combined weight and plyometric training twice a week.
The combined weight and plyometric training group showed significant changes in club head speed and driving distance between pre- and post-tests. Mean driving distance increased 4.3% for the combined training group, with mean club head speed increasing 1.5%.
A common fear for golfers is that weight training will decrease their flexibility and affect their swing. Although this study did not measure flexibility, subjects reported no negative effects on their swing mechanics or driving accuracy.
Although the authors stress that the long term training effect still needs to be examined, those looking to improve their distance off the tee may benefit from a program combining weight training and plyometrics.
Fletcher IM, Hartwell M. (2004). Effect of an 8-week combined weights and plyometrics training program on golf drive performance. Journal of Strength and Conditioning Research, 18(1):59 – 62.
Field Testing for Basketball
Tuesday, February 10, 2004
Research done at Ribstein Center for Research and Sports Medicine Sciences in Israel suggests that a line drill and jump tests may be acceptable field measures of anaerobic power specific for basketball players.
The purpose of the study was to compare 2 sport-specific field tests common in the training programs of basketball players to a laboratory measure of anaerobic power. Nine members of the Israel National Youth Basketball Team participated in the investigation. The field tests included a countermovement jump, a 15-second anaerobic jump test, and a sprint test/ line drill, which was completed three times, to assess anaerobic power. The laboratory test was the Wingate anaerobic power test to determine peak power, mean power, and fatigue index. No significant correlations were observed between peak power and the line drill. However significant positive correlations were noted between the vertical jump and the peak power and mean power. These results suggest that the line drill and jump tests may be acceptable field measures of anaerobic power specific for basketball players.
Hoffman J, Epstein S, Einbinder M, Weinstein Y. (1999). A comparison between the Wingate anaerobic power test to both vertical jump and line drill tests in basketball players. Journal of Strength and Conditioning Research, 14(3): 261 – 264.
Effects of Short-Term Training Using Powercranks on Cardiovascular Fitness and Cycling Efficiency
Wednesday, January 28, 2004
Powercranks use a specially designed clutch to promote independent pedal work by each leg during cycling in the downward and upward phases. This study examined the effects of 6 weeks of training using Powercranks or normal cranks on maximal oxygen consumption (VO2 max) and anaerobic threshold (AT) during a graded exercise test, and heart rate, oxygen consumption, respiratory exchange ratio, and gross efficiency during a submaximal 1-hour ride. The subjects trained for an hour a day, 3 days a week for 6 weeks. No differences were observed between or within groups for VO2 max or AT. However the Powercranks group had significantly higher gross efficiency, lower heart rate and VO2 at various times during the 1 hour ride post-training.
Powercranks training appears to result in a decrease in energy expenditure and enhance physiological adaptations at a given workload, which may ultimately enable cyclists to increase speed more readily during competition and thereby improve performance.
Luttrell, M, Potteiger, J. (2003). Effects of Short-Term Training Using Powercranks on Cardiovascular Fitness and Cycling Efficiency. Journal of Strength and Conditioning Research, 17 (4), 785 – 791.
Effects of Delayed Onset Muscle Soreness on Endurance Training
Thursday, January 15, 2004
Delayed Onset Muscle Soreness (DOMS) is the skeletal muscle pain that occurs following unaccustomed activity. Many athletes continue to exercise while experiencing DOMS, however the effect DOMS has on endurance activities is unknown. For this reason, researchers at California State University, Long Beach recently examined the effect DOMS has on physiological responses to submaximal running.
Eleven subjects participated in this study. Subjects first performed a submaximal treadmill test, followed by a resistance training program designed to induce DOMS. Subjects were then retested on the treadmill 24 – 30 hours later. Oxygen uptake, heart rate, respiratory exchange ratio, rating of perceived exertion (RPE), and blood lactate were all measured during both treadmill trials.
The results of this study showed DOMS to have no effect on submaximal oxygen uptake. While blood lactate concentrations and respiratory exchange ratio were not significantly different between the two trials, RPE was higher after the induction of DOMS. This suggests that while DOMS may not affect submaximal oxygen uptake, it does affect an individual's perception of effort.
The researchers suggest that the lack of any effect on oxygen uptake may be due to: 1) insufficient muscle damage to produce changes that could alter oxygen uptake, 2) undamaged muscles being recruited to compensate for the damaged muscles, and 3) the resistance exercises used to induce DOMS not being specific enough to cause any affect on running.
The authors stress that although this study suggests that endurance athletes can train in a DOMS state, the risk of injury and overtraining in this condition should not be overlooked. The authors suggest that when an individual experiences DOMS and perceives the effort to be higher than usual, a low intensity workout is more appropriate.
Scott KE, Rozenek R, Russo A, Crussemeyer JA, Lacourse MG. (2003). Effects of delayed onset muscle soreness on selected physiological responses to submaximal running. Journal of Strength and Conditioning Research, 17(4):652 – 658.
Effects of Resisted Sled Towing on Spring Kinematics in Field-Sport Athletes
Wednesday, December 31, 2003
Weighted sled towing is a common resisted sprint training technique even though relatively little is known about the effects that such practice has on sprint kinematics. The purpose of this study was to explore the effects of sled towing on acceleration sprint kinematics in field sport athletes.
Twenty men completed a series of sprints without resistance and with loads equating to 12.6 and 32.2% of their body mass. Stride length was significantly reduced by approximately 10 and 24% for each load, respectively. Stride frequency also decreased, but not to the extent of stride length. Other notable changes in kinematics were increased ground contact time, trunk lean and hip flexion, and increased shoulder range of motion with the greater resistance. Generally, the greater the load the greater the disruption from normal acceleration mechanics.
Some of the conclusions that authors made were:
- A resisted sled towing protocol maybe very effective in order to overload an athlete’s sprint technique and develop the specific recruitment of fast twitch muscle fibers.
- If a coach wants minimal disruption in kinematics then a lighter load would be more appropriate.
- Extended periods of heavy loaded sprint training may lead to lower speed, high type muscular adaptation, which would be detrimental to sprint performance. Therefore it is suggested that sled training be appropriately periodized in an athlete’s training program.
Effect of Rest Interval Length on Repeated 1 Repetition Maximum Back Squats
Monday, December 22, 2003
Researchers at the University of Memphis and Lambuth University found that there was no significant difference in repeat performance of a one repetition maximum (1RM) squat with 1-, 3-, or 5-minute rest intervals.
Seventeen weight trained college males volunteered for this study. During testing sessions, subjects performed two 1RM squats with the rest intervals between each attempt being 1, 3, or 5 minutes in length. A Cochran Q test was used to determine whether or not the second 1RM attempt was equally likely to succeed following each of the three different rest intervals. Analysis showed that there was no significant difference in the ability to perform a repetitive 1RM using the 1-, 3-, or 5-minute rest periods.
The findings suggest that a 1-minute rest period is a sufficient recovery period between 1RM squat attempts. This is consistent with other studies reported in the literature. The authors caution that these results should not be extrapolated to an actual resistance training program. An actual training program utilizes much larger volumes of work. This larger volume combined with a short rest period (e.g., one minute) could lead to considerable metabolic and neurological fatigue, which could lead to significant decreases in strength for athletes.
What Is the Optimal Recovery Time Between Aerobic and Strength Training Sessions?
Friday, December 05, 2003
Researchers at the University of Victoria in British Columbia recently investigated concurrent strength and aerobic training. Some questions they looked at were: 1) does aerobic training diminish strength training performance, 2) does aerobic training intensity affect subsequent strength training performance, and 3) are any performance diminishments specific to the muscle groups used for the endurance activity?
Sixteen subjects were randomly assigned to either a high-intensity interval training group, or a submaximal aerobic continuous training group. Both groups performed aerobic training sessions followed by strength training sessions (leg press and bench press), with varying amounts of rest between the training sessions. The subjects also performed a control condition where no aerobic training was performed before strength training.
Both groups were significantly affected by the recovery time between aerobic and strength training sessions. Four and eight hour recovery times produced significantly fewer strength training repetitions when compared to the control condition (25% and 9% decrease in volume respectively). However no difference was seen in the number of repetitions performed at 24 hours of recovery and the control condition.
No significant differences were found between the high-intensity interval group and submaximal continuous group. Also, the aerobic exercise produced no effect on the number of repetitions performed on the bench press.
From the results of this study, the researchers suggest that: 1) 24 hours of recovery occur between aerobic and strength training sessions if optimal performance is desired in the strength training session, 2) both maximal and submaximal aerobic training have similar negative effects on subsequent strength training volume, and 3) decreases in strength performance are specific to the muscle groups used during the prior aerobic training.
Physioball Training More Effective Than the Same Movements on the Floor
Tuesday, November 18, 2003
Researchers at Springfield College, Massachusetts concluded that early adaptations in a short-term core exercise program using the physioball resulted in greater gains in torso balance and EMG neuronal activity in previously untrained women when compared to performing exercises on the floor.
The purpose of this study was to compare the effects of five weeks of physioball core stability and balance exercises with conventional floor exercises in untrained women. The experimental group of 15 performed curl-ups and back extensions on the physioball while the control group of 15 performed the same exercises on the floor. Baseline and post-training tests included electromyography (EMG) recording of the rectus abdominus and erector spinae muscles; abdominal, back, and knee strength measurements with the Cybex Norm System; and 2 balance tests. The physioball group was found to have significantly greater mean change in EMG flexion and extension activity and greater balance scores than the floor exercise group. No significant changes were observed for heart rate or Cybex strength measurements.
This study has shown that significant gains in trunk stability and balance can occur in untrained women even when a well-designed core stability and balance training program is conducted on a short-term basis.
Cosio-Lima L, Reynolds K, Winter C, Paolone V, Jones M. (2003). Effects of Physioball and Conventional Floor Exercises on Early Phase Adaptations in Back and Abdominal Core Stability and Balance in Women. Journal of Strength and Conditioning Research, 17(4): 721 – 725.
The Effect of Resistance Training on Intraocular Pressure
Monday, November 03, 2003
Intraocular pressure (IOP) is the internal pressure within the eye. A high IOP is related to an increased risk of developing glaucoma, the second leading cause of legal blindness. Aerobic exercise has been shown to decrease IOP immediately after a training session, and decrease IOP long-term after an aerobic training program. However the effects of strength training on IOP are still unclear.
Thirty healthy subjects (15 male and 15 female) participated in a study at Mississippi State University and The University of Mississippi School of Medicine to study the effects of resistance training on IOP. Subjects performed 3 sets of 10 repetitions at 70% one repetition maximum, with 2-minute rest periods on either a chest press or leg press. IOP was measured before exercise, after each set, and 5 minutes after exercise.
The results of this study show that IOP decreases after one or more sets of chest press or leg press exercise. The cause of this decrease is not known, however research suggests it may be related to increases in blood osmolality and lactate, and decreases in blood pH and blood CO2. The researchers suggest that changes in blood flow to the eye may also affect IOP post exercise.
The authors of this study stress caution about generalizing these results to those with glaucoma or elevated IOP. Although this study suggests that resistance training can reduce IOP, more research is needed in this area, especially concerning those in the previously mentioned populations.
Chromiak JA, Abadie BR, Braswell RA, Koh YS, Chilek DR. (2003). Resistance training exercises acutely reduce intraocular pressure in physically active men and women. Journal of Strength and Conditioning Research, 17(4): 715 – 720.
Are Portable Abdominal Exercisers More Efficient Than Traditional Crunches?
Monday, October 13, 2003
Researchers at Occidental College in California, USA have determined that there is no significant difference in abdominal activity between portable abdominal devices and traditional crunches in nearly all of the positions tested. Thirty-three adults participated in the study and were tested on four training devices (Ab Roller Plus, Torso Track 2, AB-Doer Pro, and the Perfect Abs) and a traditional crunch. Surface electromyography was recorded from the upper and lower portions of the rectus abdominis, external oblique, and the rectus femoris during each repetition of the study.
Of the four devices tested, only the Perfect Abs when used in the supine position with the medium and high-resistance bands elicited more abdominal activity than a traditional crunch. The results suggest that portable abdominal devices are most effective if they not only mimic the mechanics of a traditional crunch, but also provide external resistance to increase the involvement of the abdominal musculature.
Sternlicht E, Rugg S. (2003). Electromyographical Analysis of Abdominal Muscle Activity Using Portable Abdominal Exercise Devices and a Traditional Crunch. Journal of Strength and Conditioning Research. 17(3), 463 – 468.
Light resistance training can reduce body fat and increase strength in women
Monday, September 29, 2003
Researchers at the Centre for Exercise and Nutrition Studies and Department of Physical Education and Sports Science, University College, Chester, United Kingdom, investigated the effects of a light resistance program on body composition and muscular strength. Thirty-nine already aerobically active women (avg. age 38) participated in the study. Two randomly formed groups were organized. The control group continued to participate in aerobic-only exercises, and the experimental group performed resistance training (Bodymax) three times a week with a high repetition and low weights protocol.
The subjects were pre- and post-tested during the 12-week study. The testing included six muscular strength tests: leg extension, leg curl, lateral pulldown, chest press, shoulder press, and pec dec. The workouts consisted of a group session for one hour three times a week. The resistance training group performed the following exercises during workouts: squats, side lateral raises, lunges, rows, dead lifts, upright rows, side squats, kick backs, crunches, calf raises, and bicep curls. Body composition was determined by skin-fold measurements at four sites (triceps, abdomen, superilliac, and mid thigh). These numbers were then converted to raw values and not specific composition percentages, to avoid using the standard percent fat prediction formula and its associated errors.
The study clearly shows that a resistance training program incorporating light weights and high repetitions (Bodymax) can increase strength gains and decrease body fat in already active women. Women with similar or lower activity levels who would like to reduce body fat and increase strength should consider incorporating such training into their regular fitness programs.
O'Conner TE, Lamb KL. (2003). The Effects of Bodymax High-Repetition Resistance Training on Measures of Body Composition and Muscular Strength in Active Adult Women. Journal of Strength and Conditioning Research, 17(3): 614 – 619.
Effect of 15 Days of Training Cessation on Performance
Wednesday, September 17, 2003
Fifteen middle-distance, competitive, female runners were divided into a cessation training group, or a maintenance training group. For the duration of the 15-week study, the cessation training group completely ceased their training, while the maintenance group maintained their current training program.
No changes were noted in VO2 max after 5 days of cessation of training. However, at the completion of the 15 day study, the cessation training group was 4% slower on the 2,400 meter time trial, and had a 7.8% decrease in VO2 max when compared to the maintenance training group.
The authors of this study point out that the results suggest that female middle-distance runners can undertake short periods of no training without negative effects on their performance. This may be useful for rehabilitation, travel, and bouts of minor illness. However by 10 days without training, physiological adaptations begin to occur, and performance may suffer.
Doherty RA, Neary JP, Bhambhani YN, Wenger HA. (2003). Fifteen-Day Cessation of Training on Selected Physiological and Performance Variables in Women Runners. Journal of Strength and Conditioning Research , 17(3):599 – 607.
Increase Power Output by Alternating Heavy and Light Resistances
Friday, September 05, 2003
Researchers at Edith Cowan University in Western Australia have determined that alternating light and heavy resistances while training the upper body can significantly increase power output. Sixteen rugby league players, who were experienced in power training and who performed complex training on a regular basis, served as subjects. The subjects were divided into two groups and were pre- and post- tested on an explosive bench press test using a Smith machine. Pre-testing of the two groups showed no difference in power output. The experimental group used an explosive six repetitions at a 65% of a 1-repetition max while also using heavier resistances. The control group only used the heavier resistances. At post-testing there was a 4.5% increase in power output for the experimental group, which was significantly different from the control group.
Using medicine balls or other various forms of explosive push-ups concurrently with bench pressing could elicit a similar response if increasing upper body power is a desirable.
Baker D. (2003). Acute Effect of Alternating Heavy and Light Resistances on Power Output During Upper-Body Complex Power Training. Journal of Strength and Conditioning Research, 17(3):493 – 497.
Health Club Members Use Weight Belts Inappropriately
Tuesday, August 26, 2003
Researchers at the Dan Abraham Healthy Living Center in Rochester, Minnesota, looked at weight lifting belt patterns of use in a population of health club members. Over a 1-month period 352 voluntary club members were asked to fill out a brief survey to identify if they presently use a weight belt or had used one in the past. The survey was also used to identify the rationale for using weight belts. Of the 352 members who filled out the survey, 189 were men and 156 were women with ages running from 20 to 72 years.
Results showed that 27% of the participants were weight belt users, and 34% of the non-users were former users. Current and former weight belt users identified the weight belt as being most important for use during the following exercises: squat, dead lift, shoulder press, bench press, and bent over row. The two primary reasons cited for this were to prevent injuries and improve performance.
The most important finding was that most people used the belts for inappropriate situations such as during light loads, and exercises where trunk musculature was predominately uninvolved. The existing literature only supports weight belt use in specific circumstances—such as maximal or near-maximal lifts.
The authors suggest that health club members need to be educated about the proper use of weight belts. The researchers also suggest that strength trainers should be doing a better job teaching the proper use of intrinsic trunk musculature for stability instead of an external device such as a weight belt. The NSCA recommends that exercisers work with a Certified Strength and Conditioning Specialist (CSCS) to learn the proper usage of weight belts and how to perform exercises for improving core stability.
Finnie SB, Wheeldon TJ, Hensrud DD, Dahm DL, Smith J. (2003). Weight Lifting Belt Use Patterns Among a Population of Health Club Members. Journal of Strength and Conditioning Research, 17(3):498 – 502.
Do different exercises affect upper and lower abdominal muscles differently?
Wednesday, August 13, 2003
Although the rectus abdominis muscle is just one muscle, there is a current debate over whether different abdominal exercises affect the upper and lower portion of the rectus abdominis differently. Researchers at Dalhousie University in Halifax, Nova Scotia recently examined this question.
Eight subjects performed 6 different abdominal exercises while researchers used electromyography (EMG) to record action potentials of the upper and lower portions of the rectus abdominis. The exercises studied were: the crunch, crunch on a stability ball, crunch with an Ab Trainer, supine leg lowering, stability ball roll out, and reverse curl up.
Results showed no significant difference between the upper and lower portion of the rectus abdominis during the concentric phases of all 6 exercises. While all exercises produced a response in both the upper and lower portions of the muscle, the crunch, crunch with an Ab Trainer, and crunch on stability ball produced higher EMG activity on the average than the supine leg lowering, stability ball roll out, and reverse curl up. Also, the crunch on stability ball had a significantly higher EMG activity than all other exercises due to the balance component of the exercise.
The authors mention that from a mechanical viewpoint, the rectus abdominis may not have the ability to contract with significantly more force on one end than the other. The results of this study support this statement.
Clark KM, Holt LE, Sinyard J. (2003). Electromyographic comparison of the upper and lower rectus abdominis during abdominal exercises. Journal of Strength and Conditioning Research, 17(3): 475 – 483.
Does Body Fat Affect Performance in Football Players?
Monday, July 21, 2003
Is body fat percentage a good predictor for success in common performance tests for football players? According to researchers at Gettysburg College and University of Massachusetts, the answer is no.
Seventy-seven NCAA division III football players participated in this study. Players were grouped according to position and playing status. Height, body mass, body mass index, and body composition (measured through hydrostatic weighing) were calculated, along with the administration of the vertical jump, sit and reach, 1RM bench press, 10 and 40 yard sprints, and pro shuttle tests.
Analysis revealed significant differences for all positions on all body composition measurements, and all performance tests except the sit and reach. Starters also outperformed nonstarters in all tests except the 10-yard sprint and sit and reach. However no correlation was found between body composition and performance on any of the tests.
As the authors point out, “Intuition tells us that excessive body fat should negatively affect performance; however, this assumption was not supported by the data.” This area may warrant more research and discussion.
Stuempfle KJ, Katch FI, Petrie DF. (2003). Body Composition Relates Poorly to Performance Tests in NCAA Division III Football Players. Journal of Strength and Conditioning Research, 17(2):238 – 244.
Effects of Concurrent Endurance and Strength Training
Friday, July 11, 2003
Researchers at The University of Athens and St. Savas Hospital in Athens, Greece recently compared the effects of concurrent strength and endurance training to strength training and endurance training alone. The results of this study showed concurrent strength and endurance training to improve anaerobic power better than strength training alone, and improve VO2 max better than endurance training alone.
Twenty-six male basketball players were divided into four groups: endurance group, strength group, strength and endurance group, and control group. All groups, except the control group, trained four times a week for seven weeks. The strength and endurance group performed both the endurance group’s, and the strength group’s programs on the same day, with a seven-hour recovery period between sessions.
Improvements in vertical jump, anaerobic power (via Wingate test), and aerobic capacity (via one mile walk) were higher for the strength and endurance training group than for the endurance group or strength group on all measures. The strength training alone group increased anaerobic power; however this group also decreased aerobic capacity. The endurance training only group increased capacity, but decreased anaerobic power.
The results of this study contradict others that have shown concurrent strength and endurance training to produce smaller gains in strength than strength training alone. However other studies have used different training modes, intensities, and frequencies to produce different results.
Balabinis CP, Psarakis CH, Moukas M, Vassiliou MP, Behrakis PK. (2003). Early phase changes by concurrent endurance and strength training. Journal of Strength and Conditioning Research , 71(2):393 – 401.
Pre-exhaustive Training May Have Negative Effect on Performance
Monday, June 30, 2003
The purpose of this study was to investigate the effect of pre-exhaustive exercise (leg extension) in lower-extremity muscle activation during the leg press exercise. Pre-exhaustive exercises are typically a single joint movement performed prior to performing a related multi-joint movement. The theory is to more effectively enhance muscle activity compared with traditional methods: multi-joint to single joint.
Seventeen healthy subjects performed one set of leg presses with and without leg extensions. EMG was recorded from the vastus lateralis, rectus femoris, and gluteus maximus. The activation of the vastus lateralis and the rectus femoris were significantly less when pre-exhausted and the subjects performed significantly fewer repetitions. These findings do not support the popular belief that performing pre-exhaustion exercise more effectively enhances muscle activity compared with regular weight training. Furthermore, pre-exhaustive exercise may have a negative effect on performance.
Augustsson J, Thomee R, Hornstedt P, Lindblom J, Karlsson J, Grimby G. (2003). Effect of pre-exhaustion exercise on lower-extremity muslce activation during a leg press exercise. Journal of Strength and Conditioning Research, 17(2):411 – 416.
The Effect of B-Hydroxy B-Methylbutyrate(HMB) on Muscular Strength and Body Composition in Collegiate Football Players
Monday, June 16, 2003
Researchers at Oklahoma State University found that the use of HMB supplementation did not have a positive increase in muscular strength or body composition. Thirty-five Division I football players were utilized for this study. A randomized double blind crossover, placebo design method was utilized for this experiment. The study used a battery of four tests to evaluate athletic performance and body composition. The tests include the bench, squat, power clean, for strength evaluation and the Jackson & Pollock Equation for body composition. Of the 35 subjects, 16 were given 3g of HMB/day for 4 weeks, supplementation was then suspended for a "washout period" for 1 week. The same group was then supplemented with HMB for another 4 weeks. The remaining group of 19 were given a placebo for the experiment and followed the same methodology procedures as the group receiving the HMB. The subjects were then retested to see if any changes had taken place. The test showed no significant changes in any of the three strength tests. There was also no change in the body composition evident.
Using HMB supplementation does not increase strength or improve body composition for athletic performance based on this experiment. Once again, ergogenic aids that are not scientifically evaluated and proven usually do not work. The most reliable way to increase athletic performance is through a proven strength and conditioning program with proper nutritional and dietary habits.
Ransone J., Neighbors K., LeFavi R., Chromiak J. The Effect of B-Hydroxy B-Methylbutyrate on Muscular Strength and Body Composition in Collegiate Football Players. The Journal of Strength and Conditioning Research, 17(1): 34 – 39.
Effect of Magnetic Therapy on Physical Performance
Monday, May 19, 2003
Researchers at the University of Central Arkansas found that the use of magnetic therapy does not increase athletic performance. Fourteen Division II soccer players were put through a battery of four tests to evaluate athletic performance to include the vertical jump, 40-yard sprint, bench squat, and a soccer specific fitness test. Magnetic insoles were applied during both practice and competition sessions for a total of seven weeks. The results showed that there was no significant improvement between the control group and the treatment group on pre- and post-testing scores, indicating no increase in performance. Forty-yard sprint scores and vertical jump scores both actually declined. There was only a minor increase in bench squat and soccer fitness tests.
The results of this study do not support using magnets for increasing performance in the athletic arena. In attempts to find the competitive edge, athletes will resort to using ergogenic aids that are supported with only anecdotal evidence and that have no scientific backing to them. However, according to the National Strength and Conditioning Association, the best way to increase athletic performance and decrease injuries is through a proven strength and conditioning program under the supervision of a Certified Strength and Condition Specialist.
Schall DM, Ishee JH, Titlow LW. (2003). Effects of Magnetic Therapy on Selected Physical Performances. Journal of Strength and Conditioning Research. 17(2): 299 – 302.
Upper-body and lower-body response to single set versus multi set training
Friday, May 02, 2003
Researchers at the Norwegian University of Sport and Physical Education in Oslo, Norway set out to study the effects of single set versus multiple set programs on early adaptation to resistance training. Eighteen untrained subjects were divided into either a three sets in leg exercises and one set in upper-body exercise group (3L-1U), or a one set in leg and three sets in upper-body exercise group (1L-3U).
Exercises performed consisted of squat, knee extension, leg curl, bench press, shoulder press, rowing, and latissimus dorsi pull-down. Subjects performed their workouts three times per week, for the duration of the six-week study. Both groups performed seven repetitions in all sets, and were encouraged to increase their 7RM (the maximum amount of weight that can be lifted for seven repetitions) throughout the study.
The subjects were tested for 1RM in six of the exercises performed during the study (squat, knee extension, leg curl, bench press, shoulder press, latissimus dorsi). While both groups increased their 1RM in all six tests, the 3L-1U group had a greater increase in lower body 1RM (squat, knee extension, leg curl) than the 1L-3U group. Upper-body strength increases were similar for both groups.
The results of this study suggest that multiple set programs are more effective than single set programs when it comes to increases in lower body strength during early adaptation. However the results do not show a superior increase in upper-body strength. The authors suggest that it may be possible that upper-body muscles have a lower stimulus threshold than lower-body muscles in the early phases of adaptation. This may be the reason why there was no difference seen between the two groups in upper-body strength.
Paulsen G, Myklestad D, Raastad T. (2003). The influence of volume of exercise on early adaptations to strength training. Journal of Strength and Conditioning Research, 17(1): 115 – 120.
Steroids from Mexico
Wednesday, April 16, 2003
An article in the Journal Of Strength and Conditioning Research looks at the kinds of Mexican steroids being brought into the US and the prevalence of self-administration among adult male and female private gym users living in the US border city of El Paso, Texas. The goal of this article is to educate strength and conditioning professionals and athlete-related health-care personnel about the Mexican steroids most likely to be used by athletes in the US.
The article focuses on the results of a survey administered to gym members in El Paso. Survey results showed that steroid use was present in approximately 11% of the population surveyed. The most popular drug used was Deca Durabolin (nandrolone decanoate). Testosterone esters were also prevalent among users, including the following drugs: Sostanon 250, Primoteston, and Sten. The most popular oral preparations were Primobolan tablets and Stennox. In addition to the pharmaceutical androgen preparations, similar veterinary compounds were also popular among steroid users, including the drugs Laurabolin and Equipoise. Subjects reported using multiple drug combinations.
Most of the androgen users had only recently started using these drugs with a small minority having used androgens for several years. The length of the androgen user's drug cycle did not exceed 16 weeks with the majority of individuals completing 4 – 8 week cycles.
The most common side effects reported by subjects were hypersexuality, edema, abnormally aggressive behavior, and acne. Other studies have noted similar untoward effects, as well as some uncommon effects (e.g., knee joint sepsis and radial nerve palsy) and under-recognized effects (e.g., body dysmorphic disorder).
Strength and conditioning professionals, more so than any other group (i.e., physicians, nurses, physical therapists, scientists, and others), are likely to have regular contact with individuals who self-administer steroids. It is speculated that a large numbers are using Mexican steroids. It is also apparent that strength and conditioning professionals and members of the medical community who treat athletes must be educated about the preparations that are commonly used. To date, there are no peer-reviewed, athletically relevant sources of information detailing the use of these drugs. This lack of information could present a problem for physicians with patients who use androgens. Most professionals in the field must rely on underground reference guides containing often dangerous, scientifically incorrect information written by individuals with no academic training. Undoubtedly, most strength coaches will, at some time in their career, be presented with questions about these substances. It is in our athletes’ best interest to have current and accurate information about these compounds.
Street, C, Antonio, J. (2000). Steroids From Mexico: Educating the Strength and Conditioning Community. The Journal of Strength and Conditioning Research: 14(3):289 – 294.
Do anti-inflammatory drugs affect delayed-onset muscle soreness (DOMS) and/or subsequent performance?
Tuesday, April 01, 2003
It has been theorized that delayed-onset muscle soreness (DOMS) is caused by acute inflammation. Researchers at Democritus University of Thrace in Komotini, Greece decided to test this hypothesis by studying the effects of ibuprofen on delayed-muscle soreness and muscle performance after eccentric exercise.
Nineteen subjects participated in this double blind study. To induce DOMS, the subjects performed eccentric leg curls (6 sets of 10 repetitions at 100% 1 repetition max). Nine subjects took 400 mg of ibuprofen for 8 hours for the first 48 hours. The control group took a placebo during the same time frame.
Muscle soreness, assessed through questionnaire, increased at 24 and 48 hours in both groups. However the ibuprofen group rated the soreness as significantly less at both time periods. Maximal strength, range of motion, and vertical jump performance decreased in both groups at all measured times (4 – 6, 24, and 46 hours after exercise).
White blood cell count (a sign of inflammation) and creatine kinase (a sign of muscle damage) were measured at 4 – 6, 24, and 48 hours. White blood cell count significantly increased in both groups 4 – 6 hours after exercise. Creatine kinase levels were increased in both groups after 24 and 48 hours, but were significantly lower in the ibuprofen group after 48 hours.
The authors of this study suggest that ibuprofen may decrease perception of soreness induced by eccentric actions, but will not assist in restoring muscle function.
Tokmakidis S, Kokkinidis E, Smilios I, Douda H. (2003). The Effects of Ibuprofen on Delayed Muscle Soreness and Muscular Performance After Eccentric Exercise. Journal of Strength and Conditioning Research, 17(1):53 – 59.
Is Maximal Strength Testing Safe for Young Children?
Monday, March 03, 2003
Researchers at the University of Massachusetts in Boston investigated the practicality and safety of performing maximal strength testing in young children. There is a general sense in the strength and conditioning community that maximal strength testing in unsafe for adolescent and pre-adolescent children, as reflected in an NSCA survey in which 2043 of 2311 responders (88%) believed that 1RM (the maximal amount of weight that can be lifted one time) strength testing is inappropriate for children.
The subjects in the present experiment were 96 children (32 girls and 64 boys) ranging between 6.2 and 12.3 years of age. None had any previous strength training experience and all were required to undergo an initial medical screening before testing.
Subjects were required to per form one upper body exercise (standing chest press or seated chest press) and one lower body exercise (leg press or leg extension). All exercises were performed using weight machines designed for children. There was a 1:1 tester to athlete ratio and the weight that was lifted was gradually increased to find each subject's 1RM for each exercise. A post exercise survey and examination was performed to check for any injury or excessive soreness.
The results showed that 1RM tests can be performed safely and effectively if proper technique is used and the lifting is supervised by a trained strength and conditioning coach. No injuries were reported during or after the lifts. Additionally, the strength of the boys and girls was similar.
The authors suggest that maximal strength testing can be performed with young athletes as long as all sessions are supervised and proper technique is used. This may be used to evaluate the effectiveness of a strength training program and provide motivation. However, this type of testing is not appropriate for all strength programs and should definitely not be used if the training sessions cannot be adequately supervised.
Faigenbaum AD, Milliken LA, Westcott WL. (2003). Maximal strength testing in healthy children. Journal of Strength and Conditioning Research. 17(1):162 – 66.
Super Slow Training Does Not Metabolize More Calories than Traditional Resistance Training
Friday, February 21, 2003
One of the claims of “Super Slow” training is that it requires more energy than traditional weight training. Researchers at the University of Alabama at Birmingham recently decided to test this claim.
Seven male subjects with at least one year of previous resistance training experience participated in this study. The subjects' resting energy expenditure and one repetition maximum were determined after two days of abstinence from exercise. Five to six days after the pretest, randomly assigned subjects performed either a “Super Slow” program, or a traditional program. After three days of rest, the subjects switched, and performed the other program.
The exercise performed for both the “Super Slow” program and the traditional resistance training program included: leg extension, bench press, biceps curl, leg curl, behind the head triceps extension, bent over row, reverse curl, shoulder press, upright row, and squat. The “Super Slow” program consisted of eight repetitions with a 10 second concentric phase, and a 5 second eccentric phase at 25% of one repetition maximum. The traditional program consisted of two sets at 65% of one repetition maximum. No time constraints were set on concentric or eccentric action. Both programs took 29 minutes to perform.
Results showed the traditional resistance training program had a higher energy cost than “Super Slow” training program. The “Super Slow” program was significantly lower in total work and relative exercise intensity when compared to the traditional resistance training program. Intensity was 2.6 times greater, and over four times more work was performed with the traditional resistance training program.
This study does not support the claims of proponents that “Super Slow” is a superior method for energy expenditure. Individuals looking to lose weight through resistance training may do better to find a program that utilizes more energy than a “Super Slow” program.
Hunter GR, Seelhorst D, Snyder S. Comparison of metabolic and heart rate responses to super slow vs. traditional resistance training. Journal of Strength and Conditioning Research. 17(1):76 – 81. 2003.
The National Football League Combine: A Reliable Predictor of Draft Status?
Friday, February 07, 2003
Researchers at Arizona State University looked at the relationship between the measurements taken at the NFL combine and the round in which the collegiate student-athletes were drafted.
At the NFL draft combine the following measurements are typically taken.
- Height
- Weight
- 10-yard, 20-yard and 40-yard dash times
- Vertical jump
- Broad jump
- Shuttle run (20-yard and 60-yard)
- 3-cone drill
- 225 lb bench press
These variables were used to predict the draft status of wide receivers (WR), quarterbacks (QB), offensive linemen (OL), defensive linemen (DL), linebackers (LB), running backs (RB), and defensive backs (DB).
The results of the study showed that the information that is collected can be used to accurately predict the draft status (the round of the draft the athlete was chosen in) of WRs, RBs and DBs. The data could not accurately predict the draft order for QBs, OLs, DLs, and LBs.
This information has several implications.
- Strength trainers can train running backs, wide receivers, and defensive backs to optimize their performance of the skills currently assessed at the NFL combine and hopefully improve an athlete's draft status.
- The NFL may want to reconsider the skills assessed for the QB, OL, LB, and DL to more accurately identify the skills needed at those positions.
The results of this study were used only to predict draft order, and were not used to relate NFL combine performance with success or failure in the NFL.
McGee, KJ, Burkett, LN. (2003). The national football league combine: A reliable predictor of draft status? Journal of Strength and Conditioning Research, 17(1):6 – 11.
The National Football League Combine: A Reliable Predictor of Draft Status?
Friday, February 07, 2003
Researchers at Arizona State University looked at the relationship between the measurements taken at the NFL combine and the round in which the collegiate student-athletes were drafted.
At the NFL draft combine the following measurements are typically taken.
- Height
- Weight
- 10-yard, 20-yard and 40-yard dash times
- Vertical jump
- Broad jump
- Shuttle run (20-yard and 60-yard)
- 3-cone drill
- 225 lb bench press
These variables were used to predict the draft status of wide receivers (WR), quarterbacks (QB), offensive linemen (OL), defensive linemen (DL), linebackers (LB), running backs (RB), and defensive backs (DB).
The results of the study showed that the information that is collected can be used to accurately predict the draft status (the round of the draft the athlete was chosen in) of WRs, RBs and DBs. The data could not accurately predict the draft order for QBs, OLs, DLs, and LBs.
This information has several implications.
- Strength and conditioning coaches can train running backs, wide receivers, and defensive backs to optimize their performance of the skills currently assessed at the NFL combine and hopefully improve an athlete's draft status.
- The NFL may want to reconsider the skills assessed for the QB, OL, LB, and DL to more accurately identify the skills needed at those positions.
The results of this study were used only to predict draft order, and were not used to relate NFL combine performance with success or failure in the NFL.
McGee, KJ, Burkett, LN. (2003). The national football league combine: A reliable predictor of draft status? Journal of Strength and Conditioning Research, 17(1):6 – 11.
Vertical Jump Best Indicator of Football Playing Ability
Monday, January 27, 2003
Researchers at California State Hayward have determined that the vertical jump may be the best indicator to determine football playing ability in Division IA football players. The purpose of this study was to investigate the relationship between football playing ability and selected performance measures. Another purpose was to determine whether the relationship between football playing ability and selected performance measurers are differentially affected by player position.
Forty football players participated in this study. The selected performance measures were vertical jump, 10- and 20-yard dash, pro-shuttle run, bench press, squat, power clean, and snatch. The players were grouped together based upon position. After statistical analysis the vertical jump was the only variable that was significantly correlated with football-playing ability in all groups.
The researchers hypothesized that the basic elements in the vertical jump—rapid and powerful plantar flexion of the ankle and knee and hip extension—may be strongly shared characteristics of football playing ability as defined in this study. In addition, the researchers also indicated that the temporal aspects of vertical jump are organized in the central nervous system in a similar way to that of football playing ability.
Sawyer D, Ostarello J, Suess E, Dempsey M. (2002). Relationship Between Football Playing Ability and Selected Performance Measures. The Journal of Strength and Conditioning Research: 16(4): 611 – 616.
Does the BOD POD Accurately Measure Percent Body Fat in Females?
Tuesday, January 07, 2003
Percent body fat is a “marker” used by many coaches and athletes to assess fitness and body composition has a high correlation with performance in many sports. Relatively recently, the BOD POD—a body measurement device that combines body volume and weight to determine body composition—has been introduced to the world of sports performance. The accuracy of this device has been disputed in the literature and in one study has been shown to underestimate percent body fat in lean females.
In this study, researchers at George Washington University compared body fat measurements obtained using the BOD POD to hydrostatic weighing and skinfold measurements. The subjects in the study were college women (n=80, mean age 21.2). The data from a subset of lean women (n=39, <18% body fat determined by hydrostatic weighing) was also analyzed.
The results showed that the % body fat measured using the BOD POD was significantly higher than either the hydrostatic weighing or skinfold measurements. Percent body fat was overestimated by an average of 8% in the entire female population and by 16% in the lean athlete group.
The researchers conclude that hydrostatic weighing or skin fold measures are more accurate for determining body composition in women, and especially in lean women.
Vesconi JD, Hillderbrandt L, Miller W, Hammer R, Spiller A. (2002). Evaluation of the BOD POD for estimating percent body fat in female college athletes. Journal of Strength and Conditioning Research, 16(4):599 – 605