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The Relationship Between Body Composition and Athletic Performance

 

Functional Definitions:

 

Body Mass “ is equivalent to the individual total body weight.

Fat Mass (FM) - is equivalent to the percent of an individual adipose tissue mass.

Lean Body Mass (LBM)“ is the weight of all other tissues excluding fat mass.

 

            Body composition, also known as fat mass (FM), has become a very important issue in individuals who desire a healthy lifestyle. A positive correlation has been demonstrated between obese individuals and subsequent health risks (Williams, M.H. 1983).  In addition to choosing to maintain a positive body composition for health, many athletes and coaches alike want to know if there is an optimal level of FM for their chosen sport. It is the goal of this article to examine correlations between FM and performance, as well as to provide recommendations concerning optimal levels of FM.

            Many types of tests have been developed to monitor FM and lean body mass (LBM) of athletes.  Some of the more common tests used by coaches include skin fold measurements, DEXA, bioelectrical impedance, and hydrostatic weighting.  The aforementioned tests are all estimates of FM and have an error range of 1-6% depending on the specific test (Webster et al. 1992).  Despite this margin of error, it has become common practice for coaches to monitor an athlete™s body composition using these tests.

            Coaches use body composition analysis for several reasons.  For instance, coaches derive two main sets of data from the body composition analysis. First is LBM, which tells the coach what percent of the individual’s body mass is fatless.  Second, the coach determines what percent of the individual body mass is fat.  By knowing an athlete's LBM and FM, can allow a coach to monitor changes in body weight and determine if those changes were provided through increases/decreases in FM or LBM.  To most coaches and athletes it is understood that an increase in lean body mass would enhance performance.  Thus, increases in body mass due to increases in LBM are more desirable.  One can also infer that decreases in body mass due to losses of LBM would be detrimental to performance.  Therefore, if a coach is monitoring an athlete body composition during the off-season and implementing a training program that is designed to change body mass, he/she can monitor if performance increase/decreases.

            There are many ways for coaches to keep track of the changes.  However, as previously mentioned, the correlation between FM and athletic performance still remains unanswered.  One study on female gymnasts found no significant correlation between the amount of FM and gymnastic performance (Webster et al. 1992).  Despite the clear negative correlation between FM and performance, many gymnasts still make tremendous efforts to fit the œideal gymnast mold. In addition to the issue of one actual performance, there is also something to be said about the aesthetic aspect of gymnastics.  It is believed by many that the ideal gymnast body is slender and toned. Due to this gymnast ideal, judges may hold a certain level of bias against those gymnasts who do not fit the mold.  Other sports such as, American football, also demonstrate negative correlations (Burke et al. 1980, mayhew et al. 1989, Miller et al. 1992).   In the sport of football the goal is to be as powerful as possible and Sir Isaac Newton tells us that:  Power = Force x Velocity.  Therefore, the more mass (force) an individual has the more powerful he will be as long as he can move with the same amount of speed (velocity).  In essence, one can deduce that a football athletes goal should be to get as big and as fast as possible, irrespective of ones FM.  There are also sports in which performance is measured relative to a persons body mass. This is done primarily for those athletes who wish to compete in a specific weight class.  For example, in the sport of wrestling it is common practice for athletes to cut weight before competitions.  Wrestlers have been known to drop tremendous amounts of weight going into a competition.  These types of drops in weight are usually attributed to losses in hydration.  These kinds of extreme decreases in hydration can severely hinder an individual™s performance.  A much safer way to cut weight for a sporting event would be to decrease FM over a longer period of diet and exercise.  In this type of situation an athlete could maintain a relative low FM during the season. As a result, the athlete would decrease his/her need to loose water weight, which could be detrimental to ones performance.

            Through extensive research, it has been demonstrated that no correlations exist between FM and performance thus far (Webster et al. 1992).  Despite this overwhelming evidence, many organizations and coaches have developed guidelines or recommendations for a range of FM that is suitable for a specific sport.  These types of guidelines are unfounded for many reasons.  One reason is that there is range of error that exists within the commonly used tests.  If an athlete is asked to decrease his/her FM from 15% to 10%, there is no way of knowing if that athlete is already at 10% because the tests have an error range of 1-6%. Some guidelines give mean team recommendations such as 10%.  In this type of situation, the coach will suggest that his athletes aim to keep his/her FM as close to 10% as possible.  This type of recommendation is not valid because it does not take into account the size of the range between each athlete.  For instance, the range may be 4 to 16 % with a mean score of 10%. In essence, it would be unwise to ask an athlete who is performing well at 4% to increase their FM. Conversely, it would not be smart to ask an athlete who is performing well at 16% FM to decrease his/her FM to10%.  As indicated by the previous data, there is no positive correlation between FM and performance. Therefore, any recommendations concerning these variables would be undesirable and possibly detrimental to one™s performance.

            In this article it has been clearly demonstrated that no positive correlations have been found between FM and athletic performance thus far.  However, body composition analysis may exhibit some benefit in monitoring changes in LBM and FM during a body mass modification training program.  Despite the fact that no correlations have been found between FM and wrestling performance, low FM may be desirable in place of extreme dehydration for those athletes who wish to drop weight for a match.

 

References

Burke, E.J., Winslow, E., & Strube, W.V. (1980). Measures of body composition and           
  performance in major college football players. Journal of Sports Medicine, 20,         173-180.

 

Mayhew, J.L., Piper, F.C., Schwegler, T.M., & Ball, T.E. (1989). Contributions of speed,       
agility, and body composition to anaerobic power measurement in college football          
players. Journal of Applied Sport Science Research, 3, 101-106.

 

Miller, T.A., White, E.D., Kinley, K.A., Congleton, J.J., & Clark, M.J. (2002). The   
effects of training history, player position, and body composition on exercise      
performance in collegiate football players. Journal of Strength and Conditioning  
Research, 16, 44-49.

 

Webster, B.L. & Barr, S.I. (1992). Body composition analysis of female adolescent     
athletes: comparing six regression equations. Medicine and Science in Sports and          
Exercise, 648-650.

 

Williams, M.H. (1983). Body composition and sports medicine: directions for future    
  research. Medicine and Science in Sports and Exercise, 15, 21-31.
 
 

Anaerobic Conditioning for Football


April 29, 2003


Traditionally, many sport conditioning programs have been structured by following regimens used by teams that have successful records.  This type of reasoning is illogical, since win-loss records alone do not scientifically validate the conditioning programs used by these teams.  Other factors, such as superiority of the teams athletes, may have contributed to the success of the team.  Without question the planning of an effective sport conditioning program for an athlete is critical, since failure to properly condition an athletic team may likely result in poor performance and often defeat.

            Misconceptions in the field of sport conditioning can be detrimental to the success of an athlete and are riddled throughout the conditioning programs of teams and athletes.  One concept vital to the success of a conditioning program often overlooked is specificity (6).  Specificity refers not only to the specific muscles involved in a particular movement, but also to the energy systems that provide the ATP required to complete the movement during competition.  For this reason, training programs need to allocate the appropriate type of conditioning to match the energy demand of the sport.  In some programs, it has become standard practice for strength and conditioning practitioners to implement aerobic training in all sports as a means to prepare an athlete for higher intensity conditioning in the later stages of training and to maximize anaerobic power (3).  Based on training specificity, the degree to which aerobic conditioning should be emphasized should be relative to the extent at which aerobic metabolism contributes to the success of the sport (3).  Even though the relationship between aerobic power and anaerobic sport performance is extremely weak, coaches insist on building an aerobic base for athletes involved in anaerobic sports (3,6). Aerobic conditioning is also utilized to transition to higher intensity anaerobic training.  However, concurrent strength and endurance training has been shown to adversely effect power development (1).

Football is a sport that is comprised of short bursts of maximal intensity, separated by brief recovery periods.  Observations of actual collegiate and professional games have been evaluated through video analysis.  Work to relief interval frequency per game along with, number of series, average yards gained per play, and number of plays per game, quarter, and series were identified.  Collegiate games averaged 5.49 seconds (1.87-12.88) per play, where as rest between plays of a series averaged 32.67 seconds.  Professional football games averaged 5.05 seconds (1.99-12.31) per play and rest between plays averaged 38.46 seconds (4).  The professional football game was composed of between 12.3-13.3 series per game, 3.1-3.3 series per quarter, 64.7-74.7 plays per game, 16.2-18.7 plays per quarter, and plays per series range of 3-20 (5).

To further acquire answers on the relationship of the aerobic energy system on anaerobic performance researchers examined the extent to which aerobic power could account for performance during a thirty second Wingate test.  This research has demonstrated that the oxidative energy system contributes only 3% of the energy produced in a 10 second sprint test.  This study is in agreement with previous evidence for a decreasing role of aerobic power with decreasing duration of a target maximum effort performance (3).

Analysis of football play has shown that the activity periods last on average for 5.25 seconds, with recovery periods averaging 36 seconds.  This exercise to rest ratio appears to highly stress the anaerobic energy systems with the ATP-CP system being the predominate energy contributor, categorizing football as an anaerobic sport.  At first glance, one would suspect that with football™s relatively short activity periods, the ATP-CP system is the only energy source that is stressed.  Due to the amount of rest provided between plays, averaging 36 seconds, it appears that the glycolytic energy system will also contribute to energy production during competition.  The utilization of the glycolytic system occurs because the amount of recovery between plays does not appear to be sufficient to allow complete restoration of intramuscular phosphocreatine (2,4,6).  The repletion of ATP stores via anaerobic glycolysis may become more important as a game continues due to the fatigue status of an athlete and the extent to which phosphocreatine is depleted (4,6).

Blood lactate levels acquired during football practice and competition further support these athletes™ reliance on the glycolytic energy system. Physiologists often utilize a blood lactate concentration of 4.0 mL/L as a marker for lactate threshold.  If the level of blood lactate exceeds 4.0 mL/L one can presume that anaerobic glycolysis is occurring.  This research demonstrates that football produces a moderate lactate demand on players, which supports previous research that lactate production has been shown to play a greater role in repetitive short maximal bursts of activity followed by brief periods of recovery (4).

Short duration anaerobic activities involving maximum effort have been shown to utilize aerobic power to a small degree.  Research has demonstrated that the aerobic energy system contributes only 3% of the energy produced in a 10 second sprint test (3).  Knowing that the activity period of a football play is similar to that of the 10 second sprint test, it is conceivable that a football play has similar reliance on the aerobic energy system.   Since low correlations exist between aerobic power and anaerobic performance, it can be hypothesized that aerobic training can only contribute very little to performance (3).  A form of training that has been found to be more appropriate for enhancing anaerobic endurance is interval training.  Interval training involves the performance of repeated exercise bouts, separated by periods of brief recovery.  The length and intensity of the work is dependent on the goals of the athlete and his respective sport.  The utilization of short more intense intervals provides greater utilization of the anaerobic energy systems.  When compared to low intensity intervals, high intensity interval training is more effective in improving aerobic power and lactate threshold than which ultimately yield enhanced recovery (6).  The adaptations that occur as a result of high intensity interval training include increased storage of phosphocreatine and glycogen, and increased activity and concentration of glycolytic enzymes (6).

Since football predominantly relies on the ATP-CP system for the energy needed during competition, short, high intensity intervals similar to the activity periods during a game (5-10 seconds) are ideal for training.  Because of the short durations of this type of interval, small amounts of lactic acid are produced and recovery is rapid.  The rest interval may range between 25-60 seconds, depending on the fitness levels of the athletes and the specific goals of the program.  For example, the style of offensive play, whether it be run and shoot, no huddle, or traditional, should be considered when developing an interval training program because each type of offense requires different relief to work ratios. It was also concluded that conditioning and not position drills provide a sufficient metabolic stimulus for lactate production that is similar to a football game (4,7).  Taking this into account, coaches should implement some type of conditioning that stresses anaerobic glycolysis to a small extent, opposed to utilizing practice as a means to maintain anaerobic endurance. One final recommendation for the implementation of interval training into a football conditioning program is to exclude it from training during early stages of the off- season conditioning program.  Research has shown that simultaneous strength and endurance training, while eliciting gains in endurance and upper body strength, compromises gains in lower body strength and does not improve power or speed (1).  This training adaptation can prove to be detrimental since power and success in the sport of football has been shown to be highly correlated at all levels of competition (2,4).  Strength training alone has been demonstrated to improve strength and power while maintaining endurance (1).  The primary goal of the off-season training program should be to focus on maximizing power output.  When the competitive season is between 6-8 weeks away, the athlete should begin the interval training program in order to prepare him for the stresses of competition. Depending on whether an athlete will participate in spring football, will determine when and how often interval training will occur.

A football player™s success largely depends on speed, agility, and power. Still, it is not only sufficient to be able to run fast and change direction quickly for only a few plays. An athlete must be able to sustain high levels of speed, agility and power for an entire game.  The limiting factor of an athlete to provide an all out effort for each play during a competitive football game depends on how efficiently the body is able to replenish its phosphocreatine stores. Training an athlete to maintain high levels of performance throughout a game can be achieved by enhancing ones anaerobic endurance through interval training. 


References:

 

  1. Hennessy L. C., and A. W. S. Watson.  The interference effects of training for strength and endurance simultaneously.  J. Strength and Cond. Res. 8:12-19, 1994.
  2. Hoffman, J. R., C. M. Maresh, R. U. Newton, M. R. Rubin, D. N. French, J. S. Volek, J. Sutherland, M. Robertson, A. L. Gomez, N. A. Ratamess, J. Kang, W. J. Kraemer.  Performance, biochemical, and endocrine changes during a competitive football game.  Med. Sci Sports Exerc.  34(11):1845-1853, 2002.
  3. Koziris, L. P., W. J. Kraemer, J. F. Patton, N. T. Triplett, A. C. Fry, S. E. Gordon, and H. G. Knuttgen.  Relationship of aerobic power to anaerobic performance indices.  J. Strength and Cond. Res.  10:35-39, 1996.
  4. Kraemer, W. J., and L. A. Gotshalk.  Physiology of American football.  In: Exercise and Sport Science, W. E. Garrett and D. T. Kirkendall (Eds.). Philadelphia: Lippincott, Williams & Wilkins, 2000, pp. 795-813.
  5. Plisk, S. S., and V. Gambetta.  Tactical metabolic training, part I.  Strength Condit. 19:44-53, 1997.
  6. Plisk, S. S.  Anaerobic metabolic conditioning:  A brief review of theory, strategy and practical application.  J. Appl. Sport Sci. Res. 5:22-34, 1991. 
 

 

Anabolic Androgenic Steroids in Exercise and Sport
 

Functional definitions:

 

Anabolic – process of building (specifically muscle)

 

Anabolic Androgenic Steroids (AAS) - Derivatives of testosterone, consisting of both anabolic and androgenic properties.

 

Androgenic – Type of hormone responsible for secondary male sex characteristics.

 

androstenedione- Prohormone (pre-curser of testosterone) developed in the testes and ovaries, it is converted to testosterone.

 

 

            Testosterone was first isolated in 1930 and was synthesized shortly there after.  Synthetic anabolic-androgenic steroids (AAS) were developed first to assist with a positive nitrogen balance in starvation victims.  By the 1940™s the German military figured out that it could also improve strength and increase aggressiveness.  The earliest reports of sport use appeared in 1954 when Russian athletes used them to increase their weight training ability.  Rumors began to circulate about the effectiveness of these drugs, which eventually led to wide spread use in athletes.

            As the popularity of AAS spread, Olympic athletes soon began experimenting with these drugs. The first were athletes from the weightlifting and throwing events in the 1956 Olympic Games in Melbourne, Australia.  This attracted the attention of clinical investigators who in the 1960s and 1970™s attempted to determine the effects of AAS on sports performance.  During the 1960™s the International Olympic Committee (IOC) included AAS on its original list of banned substances.  It was not until 1976 that the IOC began testing urine for AAS, during the Montreal Olympics in Canada. 

            AAS received the most notoriety in 1988 when Ben Johnson effortlessly achieved victory over his competitors in Seoul, while simultaneously setting a new world record.  Following the race Ben tested positive for AAS, which was detected in his urine.  He was stripped of his metal and following a second positive test in 1993, Ben was banned from competition for life.

            As a result of the Ben Johnson incident, people worldwide learned about the use of AAS in sports.  In 1991, AAS were reclassified as a schedule III controlled substance.   Despite the recent media attention of AAS, the use of these drugs by elite athletes appeared to be on the decline at this time.  This is largely due in part to more rigorous testing of athletes (Smith and Perry 1992).  Conversely, use amongst recreational, college, and high school athletes was on the rise (See Figure 1).

 

Figure 1

Population                                                                            n                                            Prevalence (%)

Bodybuilders                                                                      380

Male                                                                                                                                    59 / 108 (54.6)

Female                                                                                                                                  7 / 68 (10.3)

College students                                                              NA

Athletes:         1970

                     1976

                     1980

                     1984

Nonathletes:    1984

Male bodybuilders                                                            138                                        53 (38.4)

High school students                                                         NA

Male                                                                                                                                     (5)

Female                                                                                                                                   (1)

12th Grade male students                                                 3403                                       226 (6.6)

11thgrade male students                                                 853                                         95 (11.1)

High school students                                                         1010

Male                                                                                                                                      23/ 463 (5)

Female                                                                                                                                   6 / 439 (1.4)

High school Students                                                        3047

Male                                                                                                                                      67 /1028 (6.5)

Female                                                                                                                                   27 / 1085

NA = not available / n = number of subjects

adapted form Smith and Perry 1992.

 

            As AAS became more popular, scientists started to try to understand the physiological processes by which AAS improved performance.  Even though a great deal of research has been dedicated to this particular topic, questions as to the effects of AAS on athletic performance still remain unresolved. Since controlled studies generally evaluate doses much lower than those used by AAS abusing athletes, it is difficult to determine the true benefits of AAS (Yesalis 1993).  What is known for a fact is that natural testosterone is produced in the Leydig cells of the testes.  Testosterone is subsequently the hormone that is responsible for the male formation of secondary sex characteristics (e.g., growth, acne, deep voice, aggressiveness, etc).  The level of testosterone is largely responsible for the differences in male and female characteristics.  On average, men have about 25 times more circulating testosterone than women.  The majority of the effects previously mentioned are related to the androgenic properties of testosterone.  This specific hormone also has important anabolic responsibilities such as, muscle build up, increased formation of red blood cells, and regeneration.  Many of the effects afore mentioned are positively associated with sport performance, which led to the use of the synthesized compound of testosterone.

            For those individuals who choose to use AAS, they find that the anabolic characteristics of these drugs are much more valued than the androgenic characteristics.  Thus, science has set out to produce a purely anabolic steroid in order to eliminate the negative side effects of the androgens. Although science did come close to developing these types of steroids, it is unfortunate for AAS users because there is no purely anabolic steroid that has been discovered or created to date.  As a steroid becomes more anabolic in nature one would assume that the muscle growth potential would increase, but this is not the case.  It appears that the androgenic component plays a vital role in the growth of muscle.

            Having developed a wide range of steroids that contain high anabolic and or androgenic properties gives the steroid user a wide spectrum of steroids to choose from.  The wide variety of AAS available to users is the main reason that there is such a broad array of bodily responses, depending largely upon the specific drug used. AAS research is limited because most of the research is done on moderate doses of more anabolic steroids, it would be unethical to formulate a study based on the levels that today’s athletes are using.  There is a fair amount of clinical and empirical evidence supporting this particular subject. 

            The most relevant issues of the effects of AAS are those acting on skeletal muscle, metabolic effects, and cardiovascular effects. The physiological effects of synthetic testosterone are mediated through a steroid receptor complex.  General physiological principles dictate that drugs must first bind to a receptor in order to produce a physiological response, and any unbound testosterone is metabolized.  In a creative and revealing study investigators administered 6000 mg of testosterone enanthate over a ten week period.  Testosterone enanthate is a highly anabolic androgenic steroid.  For comparison, based on the recommended dose range for this agent for the treatment of male hypogonadism, a total dose of 125 to 2000 mg would be administered in ten week period.  This study showed that the combination of resistance exercise and supraphysiological doses of testosterone produced greater increases in muscle size than were achieved by either intervention alone( Hickson 1986).  

            On the other hand, the metabolic effects of anabolic steroids do not appear to be very significant.  Male bodybuilders who start taking anabolic steroids do not demonstrate acute metabolic changes during exercise that differ from those experienced by bodybuilders who do not take steroids.  One metabolic change that has been demonstrated in bodybuilders is an increase in creatine kinase.  However, this adaptation still requires further research (McKillop et al. 1989). 

            AAS have also demonstrated many effects on the cardiovascular system.  For instance, AAS increase diastolic blood pressure (Kuipers et al. 1991), but do not significantly affect resting or exercise heart rate.  AAS has also demonstrated increases in red blood cell density (Yesalis 1993).  This exerts a possible increase in VO2 max, but research remains somewhat limited on this topic (Johnson et al. 1975). 

            Other categories of AAS have recently surfaced such as, the drug androstenedione.  This drug is classified as a prohormone and has been most recently popularized by Mark McGuire, who broke the homerun record in 1998. Androstenedione, commonly referred to as Andro, is produced by both the adrenal gland and the ovaries. Subsequently, it is either converted into testosterone or estrogen respectively.  Surprisingly, this drug can be purchased over the counter at any local nutrition store.  Despite the availability of Andro, both the NFL and IOC have banned the substance. Research appears to have mixed results on the effects of this particular drug. 

            Thus far we have mentioned the performance enhancing effects of AAS, but athletes must also understand the dangers of using this particular substance.  Most of the side effects associated with AAS are related to the androgenic properties of steroids, which are responsible for the secondary male sex characteristics (See Figure 2). 

 

Figure 2                                                                                                                    .

Cosmetic-related effects                                          Cardiovascular risk factors and Facial body acne                                                   diseases

Female-like breast enlargement in                                        Atherosclerotic serum lipid profile

males                                                                                       Decreased HDL-cholesterol

Premature baldness                                                                       Increased LDL-cholesterol

Masculinization in females                                                        High blood pressure

Facial and body hair growth in                                          Impaired glucose tolerance

females                                                                                    Stroke

Premature closure of growth centers                                            Heart disease

in adolescents, leading to stunted                                                      Liver function

growth                                                                                       Jaundice

Deepening of voice in females                                          Peliosis hepatic (blood-filling cysts)

Psychologic effects                                                                              Liver tumors

Increased aggressiveness and                                                           Athletic injuries

possible violent behavior                                                              Tendon rupture

Reproductive effects                                                                                  AIDS

Reduction of testicular size                                                  Use of contaminated needles

Reduction in sperm production

Decreased libido

Impotence in males

Enlargement of the prostate gland

Enlargement of the clitoris                                                                                                   .

adapted from Williams,M.H.1998.

 

           

            This artical has addressed both the positive effects as well as the negative effects of testosterone.  It is clear that we may never fully understand the potential effects of AAS.  Regardless of our lack of understanding athletes will continue to strive for any advantage in their sport, even if it cost them their lives Therefore each athlete will have to come to grips with his own moral decision when considering the use of AAS.

 

 

 

References

Hickson, R.C., and Kurowski, T,G., 1986. Anabolic steroids and training, Clin Sports Med 5:461-469.

 

Johnson L.C.,Roudy, E.S., Allsen, P.E., Fisher, A.G., and Slivester, L.F. 1975 Effect of anabolic steroid treatment on endurance. Med Sci Sports 7:287-289.

 

Kuipers, H., Wijnen, J.A.G., and Williams, S.M.M. 1991. Influence of anabolic steroids on body composition, blood pressure, lipid profile, and liver function in bodybuilders. Int j Sports Med12:413-418.

 

McKillop, G. Ballantyne, F.C., and Ballantyne, D.1989. Acute metabolic effects of exercise in bodybuilders using anabolic steroids. Br J Sports Med 23:186-187.

 

Smith, D.A., and Perry, P.J. 1992. The efficacy of ergogenic aids in  athletic competitions. Part I: Androgenic anabolic steroids. Ann Pharmacother 26:520-528.

 

Yesalis, C.E., Kennedy, N.J., Kopstein, A.N., and Bahrke, M.S.1993. Anabolic-androgenic steroid use in the United States. JAMA 270:1217-1221.

 
 

The Effects of Preperformance High-Intensity Lifting on Velocity and Mechanical Power

 

Introduction

The success of most athletic events depends to a large extent on an athlete’s ability to generate force rapidly.  This ability to generate force rapidly or quickly accelerate a load is known as the rate of force development (RFD). Activities that require explosive type movements include sprinting, jumping, throwing a shot put or javelin, kicking, and boxing. Since sport is by nature highly competitive, athletes are constantly striving to enhance their current levels of performance through various methods of training and nutritional supplementation.  High-intensity lifting for this paper will be defined as resistance training that yields the greatest neuromuscular response.  It is a method of training that athletes generally incorporate into their training regimen as a means to increase their RFD and ultimately achieve a higher level of performance.  The positive training adaptations acquired from high-intensity lifting are usually thought of as a long-term effect.  Most athletes are unaware of the resistance training methods that may induce acute responses that may possibly be exploited to enhance competitive performance.  One method that may enhance performance is postactivation potentiation (PAP).  

Postactivation Potentiation (PAP)

PAP is the performance of high-intensity lifting to increase motor unit excitability and enhance acute force production (2,10).  The performance of high-intensity lifting or maximal voluntary contractions (MVC) has demonstrated the ability to affect the neural output in humans (2,9).  Recent literature has been contradictory reporting both enhanced (2,8,9) and unaffected (5,10) athletic performance consequent to PAP.  Most of the research conducted on this phenomenon has dealt with its biomechanical and physiological mechanisms (1,3,4,6,7).  The testing protocols used to measure PAP and their effects on specific athletic performance vary considerably.  Numerous forms of preperformance conditioning stimulus were implemented.  Literature includes variations between types of contraction, sets, reps, rest intervals, the conditioned stimulus, muscles involved, subjects used, and dependent performance variables.  The vast differences between testing protocols give no definitive design to exploit PAP, however there seems to be some underlying principles to its proper utilization. 

If PAP is able to increase RFD, then athletes may have the capability to perform at greater speeds and generate more power during competition.  This is contingent on the extent to which PAP is activated.  The magnitude of PAP depends upon two simultaneously occurring opposing effects caused by the conditioning stimulus.  The negative effect fatigue, and the positive effect is potentiation.  In order to gain an understanding of how potentiation and fatigue affect performance, it is important to recognize the mechanisms of both these phenomena.

Physiological and Biomechanical Mechanisms of PAP

              The underlying mechanism responsible for PAP is considered to be phosphorylation of regulatory myosin light chains during the MVC.  This process causes the contractile proteins, actomyosin –ATP, to become more sensitive to calcium in a subsequent contraction.  Thus, the enhanced sub-maximal force caused by the MVC is a result of an increased rate of attachment between the actomyosin –ATP (cross-bridges) (1,3,4,6,7).  At the conclusion of the MVC stimulus, potentiation begins to decline at a slow rate. It has been reported that the duration of potentiation can last between 5 and 20 minutes (2,3,4,6,7,8).  Opposing this potentiation effect is fatigue. Fatigue refers to a decrease response to stimulation, resulting in a decrease in high frequency force capability. The fatigue effect occurs at the onset of the MVC stimulus and increases until the stimulation ceases, where fatigue is at its highest levels.  Compared to its counterpart, fatigue generally returns to normal levels at a much faster rate.  The simultaneous existence of potentiation and fatigue affect each other and ultimately determines the performance outcome.  The rate at which fatigue diminishes and the length potentiation lasts will determine performance effects.  Recovery from fatigue and the extent to which potentiation is activated may depend on the individuals training state, fiber type composition, and the magnitude of the induced stimulus (2,3,4,5).  It has been demonstrated that an optimal recovery interval occurs somewhere in the range of 2.5-5 minutes following the conditioned stimulus (2,3,8,10).

The characteristic of muscle fiber type and duration of twitch contraction time have a significant effect on the level of PAP that can be produced. Muscles with the fastest twitch contraction time and the highest percentage of fast twitch fibers appear to show the highest levels of PAP (4,6).  These characteristics have also been known to result increased RFD (1,2,4,6). This increase occurs along the force velocity relationship between the unchangeable qualities of maximum velocity and maximum force (1,2).  This alteration of the force-velocity relationship by PAP may be the reason why athletes demonstrate increased levels of explosive performance.

 

Recommendation for Applying PAP

            There are a few important factors that must be considered in order to gain a positive effect from PAP.  The first factor is choosing a preperformance exercise stimulus that closely resembles the activity to be enhanced.  Research shows that single-joint and multi-joint conditioned stimuli may differ in the recruitment patterns of motor units.  The inability of the single-joint MVC to recruit similar fibers of the performance activity may yield lower PAP (11).

Appropriate attention should be given to the time interval between the induced MVC and the beginning of competition or performance.  The importance of this parameter suggests that there may be a cumulative effect between the rate of potentiation decrease and the rate of fatigue recovery (1).  Research has ruled out that rest intervals between MVC and subsequent performance must be longer than 60 seconds (1,2).  A more effective time frame of recovery from the conditioned stimulus was found to be in the range of 2.5-5 minutes (2,3,8,10).

An athlete should also account for the intensity and duration of the MVC stimulus, which affects the amounts of potentiation and fatigue that are created (2). Previous research has demonstrated that a MVC that lasted 10 seconds in duration was optimal to induce PAP (4,6).  The load of the conditioning stimulus that resulted in the highest performance results was observed at or between a 1-5 repetition maximum (2,8,10). 

As an athlete becomes more highly trained the benefits of PAP become greater. Within the literature reviewed, studies utilizing untrained or active subjects found that there was not a significant influence of MVC on the subsequent performance variable to be measured (5,11).  Conversely, studies utilizing better-trained individuals have demonstrated a significant gain between the MVC and the subsequent testing performance (2,3,8,10). 

Limitations of PAP Studies

            A number of limitations are apparent in the literature regarding PAP.  Some of the studies reviewed used untrained or active subjects (3,5,11) for data collection while others used moderately strength trained subjects (3,8,10) or competitive athletes (2).  As research has demonstrated, there is a difference in magnitude of PAP response to a stimulus for competitive athletes, resistance trained individuals, active individuals, and untrained individuals (2,3).  Future experiments should take into account that a difference in PAP occurs in various subject populations and results of the different training groups should not be generalized.

            With the exception of five studies (2,5,8,10,11), the mode of exercise to induce PAP utilized single joint exercise protocols (1,3,4,6,7,9).  Although this model of training may be sufficient to study the mechanisms of PAP, it is not specific to the training and movement patterns of athletes. Most athletes tend to resistance train using multi-joint free weight exercises. Therefore, effects of PAP on multi-joint free weight resistance training need to be researched in order to apply the results to the circumstances of an athlete.

Also methodologies of the training protocols in several of the studies (1,2) failed to account for the possibility that the exercises themselves could have caused PAP and fatigue.  In both cases there was a potential increase in PAP by the performance of a series of repetitions during the testing measure.  Future studies should better control for this occurrence.

In order to evaluate which parameters are effective and how to optimally employ the phenomenon of PAP in training and competition, variables with in each study should be tested systematically.

Conclusion

            Current research dealing with the effects of PAP on athletic performance and its underlying mechanisms seem to have some promising evidence on the potential for improving power and velocity of athletic movement.  However, since many questions on how to specifically interpolate PAP in an athletic training program are indefinite, further research is needed.

References

  1. Gossen ER and DG Sale.  Effect of postactivation potentiation on dynamic knee extension performance.  EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 83:524-530, 2000.
  2. Gullich A and D Schmidtbleicher.  MVC-induced short-term potentiation of explosive force.  NEW STUDIES IN ATHLETICS, 11(4): 67-81, 1996.
  3. Hamada T, DG Sale, and JD MacDougall.  Postactivation potentiation in endurance-trained male athletes.  MEDICINE SCIENCE IN SPORTS AND EXERCISE, 32(3): 403-411, 2000.
  4. Hamada T, DG Sale, JD MacDougall, and MA Tarnopolsky.  Posttetanic potentiation, fiber type, and twitch contraction time in human knee extensor muscles.  JOURNAL OF APPLIED PHYSIOLOGY, 88:2131-2137, 2000.
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  7. O’Leary DD, K Hope, and DG Sale.  Influence of gender on post-tetanic potentiation in human dorsiflexors.  CANADIAN JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY, 76:772-779, 1998.
  8. Smith JC, AC Fry, LW Weiss, Y Li, and SJ Kinzey.  The effects of high-intensity exercise on a 10-second sprint cycle test.  JOURNAL OF STRENGTH AND CONDITIONING RESEARCH, 15(3): 344-348, 2001.
  9. Trimble MH and SS Harp.  Postexercise potentiation of the H-reflex in humans.  MEDICINE SCIENCE IN SPORTS AND EXERCISE, 30(6): 933-941, 1998.

10.    Young WB, A Jenner, and K Griffiths.  Acute enhancement of power performance from heavy load squats. JOURNAL OF STRENGTH AND CONDITIONING RESEARCH, 12(2): 82-84, 1998.

11.    Young WB and S Elliot.  Acute effects of static stretching, proprioceptive neuromuscular facilitation stretching and maximum voluntary contraction on explosive force production and jumping performance.  RESEARCH QUARTERLY FOR EXERCISE AND SPORT, 72(3): 273-279, 2001.