More Evidence in Favor of Post-Activation Potentiation (PAP)

We have previous discussed post-activation potentiation (PAP) by which an explosive athletic performance is improved by doing heavy resistance exercise beforehand (see http://mens-fitness-and-healthdotcom.blogspot.com/2010/10/method-for-improving-explosive-physical.html).  A recent study provides further evidence of the effectiveness of this technique.

Matthews, Comfort and Crebin performed a study on ice hockey players from the English National League.

Experimental Procedure
On two different days, 11 players were timed for their maximal 25-meter sprint-speed on ice both before and 4 minutes after doing the following:

1. resting
2. sprinting while towing another skater

Results

• When the players rested between sprints, they showed no significant improvement in time between their first and second sprints.
• When the players skated against resistance following the first sprint, their second sprint took a significant 2.6% less time than their first one.

Bottom Line
This study supports others that have found improvement in explosive athletic performance when heavy resistance exercise is performed first. The resistance exercise should call upon the same muscles used in the athletic performance. Using resisted skating in this study was a good way to achieve this goal.

Plyometric Training for Improved Sports Performance

Plyometric training has been popular among strength and physical conditioning coaches for a number of years. Yet many people who exercise on their own are not familiar with this method. Simply put, plyometric exercise involved rapid stretch and shortening of a muscle. This occurs in such movements as hopping, jumping, and bouncing. For example, when you jump vertically, you naturally first do a countermovement in which you bend your knees quickly while stretching your quadriceps (front thigh) muscles, then rapidly contract those muscles to straighten the knees and propel the body upwards. Thus, repeated vertical jumps are one kind of plyometric exercise.

There are various gradations of plyometric exercise, and it is considered prudent to start with low-stress ones before progressing to more difficult ones. One of the most stressful plyometric exercises is depth-jumping, in which one jumps down from a box and, after contacting the ground, immediately jumps vertically. This is considered dangerous for anyone who does not already have a strong lower body and has not progressed from low-stress, through moderate-stress, to high-stress plyometric exercise. Various sources have recommended being able to squat with 1.5 times one’s bodyweight before taking on a serious plyometric exercise program. However, it is generally considered safe for people in good health without orthopedic problems to perform low-stress plyometric exercises like low bounces, hops, and jumps.

A recent study by Chelly et al. in the Journal of Strength and Conditioning Research (Vol 24, no. 10, pp. 2670-2676, 2010), showed how effective plyometric training can be.

Method
A group of experienced young male soccer players, average age 19 years, trained as follows:

• August - preseason training consisting of light resistance exercise and calisthenics
• September through March (the competitive season) - The players trained 5 days per week for 90 minutes by doing skill and tactical drills along with 30 minutes of continuous play. On one day per week they engaged in a competitive soccer game against another team.

The subjects were divided into 2 groups:

Group 1 only did the training program above.
Group 2 did the training program above plus from January-March they also did the following plyometric training twice per week:

• Week 1: 5 sets of jumping over ten 40-cm (24“) hurdles spaced 1 meter (39.4”) apart
• Week 2: 7 sets of jumping over ten 40-cm (24“) hurdles spaced 1 meter (39.4”) apart
• Week 3: 10 sets of jumping over ten 40-cm (24“) hurdles spaced 1 meter (39.4”) apart
• Week 4: 5 sets of jumping over ten 60-cm (36“) hurdles spaced 1 meter (39.4”) apart
• Week 5: 4 sets of depth-jumps from a 40-cm (24“) box
• Week 6: 4 sets of depth-jumps from a 40-cm (24“) box
• Week 7: 4 sets of depth-jumps from a 40-cm (24“) box
• Week 8: 4 sets of depth-jumps from a 40-cm (24“) box

Extensive testing on speed, power, and jump height was performed before and after the training.

Results

The group that did regular soccer training did not show significant improvement in any of the pre-post tests.

The group that did plyometric training in addition to their regular soccer training showed the following statistically significant improvements:

• Thigh muscle volume: +2.5%
• Cycle ergometer absolute power: +4.5%
• Cycle ergometer power relative to body mass: +5.9%
• Jump height without a countermovement: +8.3%
• Jump height with a countermovement: +2.5%
• 40-meter sprint first step velocity: +18.2%
• 40-meter sprint velocity over first 5 meters: +10.0%
• 40-meter sprint velocity between 35 and 40 meters: +9.8%

Bottom Line
Although not all studies of plyometric training have produced improvements of this magnitude, it appears that the evidence supports inclusion of plyometric exercise in physical training programs for sports involving sprinting and/or jumping.

NOTE: This description of experimental results is for informational purposes only and does not constitute a recommendation. Anyone engaging in an exercise program should obtain proper medical authorization before doing so.

Grouping Exercises Saves Times While Providing Equal Benefits

The benefits of the multiple mini-circuit method of performing resistance exercise have been described previously in this blog. It involves doing a set of each of 2-5 exercises in a grouping, then repeating the cycle 3 or more times before going on to the next exercise grouping. The advantages include:

• A lot of exercise can be done in a given time period.
• Each muscle group has adequate recovery time.
• Heart rate remains high, affording some aerobic conditioning.
• The body becomes accustomed to intermittent high-intensity exertions, relevant to many sports.

A recent article by Robbins at al. in the Journal of Strength and Conditioning Research (vol. 24, no. 7, pp. 1782-1789, 2010) provides research support for this exercise method.

Study Method
18 physically trained men performed the following two exercises:

• Bench Pull - lie face down on a bench and perform a rowing movement to raise a barbell lying under the bench
• Bench Throw - Perform an explosive bench press movement throwing the bar upwards, using a specially designed machine that catches the barbell so it does not fall back down on the lifter

On one day they first did 3 sets of bench pulls followed by 3 sets of bench throws for a total of about 20 minutes of exercise. On another day, they alternated sets of bench pull and bench press, accomplishing 3 sets of each, for a total of about 10 minutes of exercise.

Results
Even though the alternating sets took half as much time as performing 3 sets of one exercise followed by 3 sets of the other exercise, the subjects were able to handle as much weight for as many repetitions of each exercise in both types of routines. In addition, measures such as bench press throw height, peak power, peak velocity, and muscle electrical activity were the same for both routines.

Bottom Line
While saving a lot of time, performing exercises in groupings worked the muscles as well as doing all sets of each exercise before going on to the next exercise. Thus, the grouping method enables a full workout to be performed in much less time or allows more work to be done in a given amount of time.

NOTE: Our descriptions of exercise programs are for educational purposes and do not constitute recommendations. Anyone embarking on a physical exercise program must be in good enough health to safely do so. Fitness to exercise can best be determined by a physician's clearance.

Complex, Specific Training Improves Sports Performance

Introduction
It is much more difficult to improve the physical performance of highly trained athletes than of previously untrained subjects. Thus, it is noteworthy that the study described below by Alves et al. (Journal of Strength and Conditioning Research, vol 24, no 4, pages 936-941, 2010) produced significant performance improvement among elite young Portugese soccer players using brief exercise sessions once or twice per week.

Experimental Method
23 young elite soccer players underwent the following tests before and after an 8-week period:

• vertical jump from a static, bent-knee position
• vertical jump using a dynamic countermovement (natural quick knee bend)
• 5 meter sprint
• 15 meter sprint
• soccer agility test

All subject initially did 2 weeks of general weight training before being divided into 3 experimental groups that did the following for 6 weeks in addition to their normal soccer training:

Group 1 - Once a week, before their regular soccer training session, they went through the following 3 exercise stations:

1. 6 reps of squats with 85% of max weight, 5 meters of high-knee skipping, 5 meter sprint
2. 6 reps of calf raises with 90% of max weight, 8 vertical jumps, 3 soccer-ball high-head hits
3. 6 reps of knee extension with 80% of max weight, 6 jumps from seated position, 3 60-cm drop jumps

Group 2 - The same routine as Group 1, but done twice a week instead of once a week.

Group 3 - Control group - did no exercises supplementary to their regular soccer practice.

Results:
5-meter sprint time improved 9% for Group 1 and 6% for Group 2
15-meter sprint time improved 7% for Group 1 and 3% for Group 2
vertical jump from static bent-knee position improved 13% for Group 1 and 10% for Group 2
none of the groups improved significantly in the countermovement jumps or agility test
the control group did not improve in any of the tests

Conclusions
A relatively short exercise program of weight-lifting, jumping, and sport-specific movements performed once or twice per week can significantly improve the physical performance of elite athletes. Even though the results of the once per week and twice per week exercise groups did not differ significantly, it appears that the subjects responded better to doing the program once per week rather than twice per week when regular sport training was persued concurrently.

Static Stretching Reduces Jumping Power

Introduction
In static stretching, a muscle is stretched to the point of mild discomfort and the position is held for 15 sec or more. In contrast, dynamic stretching involves rapidly moving in and out of the stretched position. The former recommendation in favor of static stretching was based on the finding that it was effective for lasting improvements in flexibility. Thus, for many years, pre-competition static stretching was widely recommended for a broad range of athletes. However, recent studies, such as the one described below, have shown that static stretching before athletic efforts requiring explosive power (e.g. sprinting and jumping) actually hurts performance.

Study Methods
In a study by La Torre et al. (Journal of Strength and Conditioning Research, vol 24, no 3, pages 687-694, 2010), 17 young men performed vertical squat jumps from a force-detecting platform using various starting knee angles. On one day, they did the jumps after performing static stretches of their quadriceps and calf muscles for 10 minutes. Each muscle was stretched on both legs using 4 sets of 30-second holds with 30-second rests between sets. On another day they did the jumps without stretching beforehand.

Results
At all starting knee angles, stretching before the jump test reduced jump height, peak force, and maximal acceleration, but only the differences for jumps beginning with the knees least bent were statistically significant. When starting the jump with the knees flexed 50 degrees (about a half-squat position) jump height, peak force, and maximum acceleration were respectively 21%, 9%, and 15% lower when stretching was performed first than when no stretching was performed.

Bottom Line 
This study reinforces other ones showing that static stretching prior to an athletic event reduces explosive muscular power. The fact that the negative effect is most pronounced when the knees are only bent to a moderate degree is highly relevant to sports activities because most sports do not involve deeply bending the knee. Dynamic stretching does not have the same detrimental effect. Thus, it appears that before athletic events that require power but not great flexibility it is best to warm up thoroughly and perform dynamic stretches before the event. The detrimental effect of static stretching on muscular power has not been shown to carry over to the following day. Therefore, static stretching may be performed after an athletic event to promote general flexibility without harming physical performance.

Brock Lesnar's Workout - Perfect Example of Functional Training

See the video of one of Brock Lesnar's workouts. Lesnar is the current top heavyweight of the Ultimate Fighting Championship (UFC), the most popular mixed martial arts organization in the U.S. He won the NCAA heavyweight wrestling championship in 2000 and later became a professional (choreographed) wrestler. When he joined the UFC, he became a dominant force. Watch this highlight video to see his speed and power.

Lesnar's workout is a prime example of functional training. No doubt weight-lifting and running are essential for a base level of fitness. However, to really excel in a sport or other physically demanding activity, one has to train in ways that simulate the activity to be improved. Lesnar's routine is based on 5-minute rounds as are UFC fights. His exercises are mostly whole-body, multi-directional, asymmetrical, and highly taxing to the lactic-acid energy system. No doubt Lesnar does a lot of conventional weight-liting. However, his lesson to us is that, in order to excel in a sport or other physical activity, training must be supplemented by routines that simulate the target activity as to which muscles and energy systems are used and the way they are used.

Vibration Training Can Increase Jump Height

Introduction

Because of evidence supporting their effectiveness for improving strength, flexibility and power, whole body vibration platforms have become increasingly available in fitness centers and athletic training facilities. These platforms generally provide repeated vertical fluctuations at a user-selected rate and amplitude (distance). One study reported that frequencies of 20-30 Hz (cycles per second) produced the greatest gains in flexibility and strength. Amplitude adjustment generally ranges from 1-15 mm (0.04-0.60").

While it is easy to train previously untrained people to increase strength and power, it is more difficult to produce improvement in those already trained. Thus, the study described below provided a challenge to whole-body vibration training.

Experimental Method

In a study by Wyon, Guinan, and Hawkey published in the Journal of Strength and Conditioning Research (vol 24, no 3, pp. 866-870, 2010) 18 female undergraduate dance majors, who were currently engaged in 12-16 hours of dance training per week, were divided into the following two groups that were tested before and after a 6-week experimental period:

Experimental Group: In addition to their normal dance training, these subjects did whole-body vibration training two times a week separated by 2 rest days. The training consisted of twice holding each of the following positions for 30 sec while on a vibration platform set at a frequency of 35 Hz and amplitude of 4 mm (0.16").

     Half-squat with knees pointing outwards
     Right leg leading lunge
     Left leg leading lunge
     Maximal height calf raise
     Forward torso bend (at least 90 degrees) with knees straight

Control Group: In addition to their normal dance training, this group held each of the same positions as the experimental group, but on a stable floor rather than on a vibration platform.

Results

The experimental groups improved 2.3 cm (0.9" or 6%) in their maximal vertical jump, while the control group actually declined by 1.5 cm (0.6" or 4%). This difference was statistically significant.

Bottom Line

Whole-body vibration training appears to hold promise for training athletes and dancers. The experimental training required only 5 minutes twice a week. Because the physical demands on in-season dancers and athletes are great, strength and power training is usually limited to avoid overtraining. However, whole-body vibration training seems to be able to improve performance without excessively stressing the athlete. An added advantage is the previous evidence that such training can improve bone mineral density. Low bone density has been a problem with female dancers and athletes who maintain low bodyfat, such as gymnasts and distance runners.

An Effective Method for Improving Sprint Speed

Introduction
Resisted sprinting has become a standard training method for sprinters and other athletes who rely on their sprint speed (e.g. football players). There are various way to provide resistance to sprinting, such as small parachutes pulled by sprinters, push and pull sleds and carts, and long elastic cords. Evidence for the effectiveness of resisted sprinting, especially in combination with strength training, was provided in a recent article by Ross et al. in the Journal of Strength and Conditioning Research (vol 23, no 2, 2009).

Experimental Method
25 college-age male athletes (American football, soccer, track and field), were divided among the following 3 training groups, all of which trained for 7 weeks:

1. Resisted Sprint Training: Did 8-12 sets of 40-60-meter sprints on a treadmill with 2-3 minutes rest in between. A proprietary device pulled back on the sprinters with up to 25% of their bodyweight. 25-40% of the sprints in each training session were resisted and the rest were unresisted.
2. Strength Training: Did a split routine of 10 weight-resisted exercises two days per week and 9 other exercises two days per week plus a core circuit each workout. Each exercise was done for 3-4 sets of 6-10 repetitions. There were 26-30 total sets per workout in addition to the core circuit.
3. Combined-Training: Did both the Resisted Sprint Training and Strength Training programs described above, on different days.

Experimental Results

• Only the Combined-Training group improved significantly in 30-meter sprint time.
• The Resisted-Sprint Training group improved somewhat in 30-m sprint time, but the change did not quite reach statistical significance.
• Only the Combined-Training group improved significantly in treadmill sprint peak power.
• All 3 training groups significantly improved their maximum barbell squat (6.6-8.4 kg) without any statistically significant difference among the improvements of the groups.

Bottom Line:
Resisted Sprint Training, especially in combination with Strength Training, is effective in improving sprint time, even among athletes who are already practiced in their sports.

Strength Training Helps Seniors in Daily Living Activities

A study by Hanson et al., published in the Journal of Strength and Conditioning Research (vol 23, no 9, 2009) tested the effectiveness of strength training in improving the ability of elderly people to perform activities of daily living. 35 men and 65 women, all initially sedentary, were trained 3 times per week for 22 weeks on Keiser pneumatically-resisted machines. The first 10 weeks involved only knee extension training, but the routine for the final 12 weeks included knee-extension, chest press, seated row, seated leg curl, abdominal crunch, and alternating leg press. The subjects improved significantly in knee-extension strength and power, leg-press strength, and fat free mass. They also became significantly faster in functional activity tests such as a 20-foot walk, repetitive (5x) standing up from and sitting down on a chair, and getting up from a chair and walking 16 feet. Improvements in strength, power, and fat-free mass correlated positively with improvement in the functional activities. This study shows that resistance training can improve strength and power at any age and such changes lead to improvement in performance of daily life activities.

The Magic of Interval Training

The evidence continues to mount that interval training is very effective in a number of ways. For those not familiar with interval training, it involves short bouts of intense exercise (usually running, cycling or rowing) interspersed with longer periods of light exercise. An example involving running would be to warm up thoroughly first, then run a quarter-mile (~400m) at 85-90% of max speed, then walk or jog an eighth-mile (~200 m), repeating the run/walk cycle for 8-10 repetitions followed by a warm-down. There are many variations of interval training, and some involve even shorter bursts of intense exercise (e.g. 200m runs).

A recent article in the Journal of Strength and Conditioning Research (Tanisho and Hirakawa, vol 23, no. 8, 2009, pages 2405-2410) reinforces the efficacy of interval training. The subjects were 18 Japanese male lacrosse players who trained 3 days/wk for 15 weeks on an exercise cycle. The continuous-training (CT) group pedaled continuously for 20-25 minutes, while the intermittent-training group (IT) alternated 10-second max-speed pedaling with 20-second easy pedaling, for a total of 10 intervals (total time = 5 minutes). There was also a control group that did no training. Interestingly, the IT group improved almost as much (10%) in the maximal oxygen uptake test (gold standard of aerobic fitness) as the CT group (12%). However, only the IT group improved in maximal power output. The IT group was also the only one to improve in fatigability, measured as the ability to maintain cycling power output over 10 intervals of 10-second max-speed pedaling interspersed with 40-second recovery periods.

One would have to conclude that the interval training produced amazing results. The 5-minute interval training sessions produced almost as much increase in aerobic capability as 20-25 minutes of endurance training. Yet the interval training also produced significant gains in maximum power and in resistance to fatigue from repeated intense exertions bouts. IT was a truly remarkable and time-efficient form of training.

This type of training is clearly advantageous for most team sports, which generally involve short bursts of intense activity interspersed with mild-to-moderate activity. The effectiveness of the interval training supports the concept of Specificity of Training, by which training is most effective when it reflects important aspects of the sport in which improvement is sought. Distance running is not effective for most team-sport athletes because it has been shown to actually reduce max power output, needed for jumping and sprinting. Thus long runs are only recommended for athletes in endurance sports.

A word of caution is in order. No-one should engage in an exercise program without first determining whether a doctor's clearance is needed first. See our Exercise Risk Questionnaire. Even if you are cleared for general exercise, you may not be ready yet for interval training, which should only be undertaken by people who are already well-conditioned. It is an intense form of exercise that puts considerable strain on the heart, lungs, muscles, and bones. Running intervals can easily cause muscle pulls or other musculoskeletal injuries, so very thorough pre-interval warmups are necessary. Cycling and rowing intervals involve less impact and peak force on the musculoskeletal system than running and are thus less likely to produce injury. However, any interval training must be approached with caution. The key points are to start with a well-conditioned individual, warm up very thoroughly, and start at a moderate level of difficulty, increasing the intensity of intervals over a period of several weeks.