Post-Activation Potentiation: Theory and Application

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Tue, 04/06/10 | Bret Contreras

I’ve been enthralled by PAP ever since I heard about legendary Canadian Sprinter Ben Johnson squatting 600 lbs for 3 reps ten-minutes prior to his infamous 1988 Olympic 9.79-second world-record performance in the 100-meter sprint. Although Ben’s gold medal was later stripped due to a positive test result for performance enhancing substances (Stanozolol), and despite the fact that Johnson’s coach Charlie Francis stated that the incident was fictitious and never actually occurred, the story still peaked my interest. More stories involving PAP have surfaced from time to time in the Strength & Conditioning industry. For instance, researchers Gillich and Schmidtbliecher reported that a 1995 bobsledding team used MVC’s prior to competition to elicit PAP and subsequently won the world championship. As a final example, strength coach Tony Gentilcore recently utilized PAP to leap onto the stage at an Alicia Keys concert prior to his arrest.


The first time I recall learning about PAP was when Charles Poliquin first started writing about it on T-Nation. Poliquin states that he first heard about PAP’s application to weight training (The 1-6 Principle) at a 1991 NSCA convention in San Diego from U.S. Weightlifting coach Dragomir Cioroslan. However, Poliquin mentions that it was first discussed in strength training circles in the early 1980’s after German strength physiologist Dietmar Schmidtbleicher’s work was translated to English. Other sources state that Yuri Verhkoshansky first introduced PAP to around forty U.S. and Canadian strength coaches in the summer of 1986 at the Moscow Institute of Sport. Regardless of where the principle originated, PAP has some very intriguing applications to sport training.



In this article, I’m going to first shed some light on PAP and then offer some suggestions as to how it can be appropriately programmed into your training.


What is PAP? Is it Different from Complex or Contrast Training?


If you’ve been reading strength training literature for a substantial period of time, then chances are you’ve seen the acronyms PAP, PTF, PTP, and/or PAF. PAP stands for Post-Activation Potentiation. PTF stands for Post-Tetanic Facilitation. You might seldom see PTP, which stands for Post-Tetanic Potentiation, and PAF, which stands for Post-Activation Facilitation.


How is PAP different from PTF? PAP involves voluntary contractions, such as a maximum isometric contraction or a set of heavy squats, while PTP involves involuntary contractions, such as those elicited by electric muscle stimulation (EMS). Obviously as a strength coach I’m more interested in PAP, as I’m not yet interested in hooking my athletes up to electrodes and zapping them prior to their explosive exercises.


Sometimes individuals will use the terms “complex training” and “contrast training” in reference to PAP. Although strength coaches often have different opinions as to what complex and contrast training entails, PAP indeed forms the basis for both methods. Complex training involves combining biomechanically-similar traditional heavy strength training and plyometric/ballistic training methods in an attempt to transfer strength into power. Numerous studies and reviews including those by Ebben, Verkhoshansky and Tatyan, Adams et al., and Lyttle et al. indicate that complex training is equally or more effective than strength training alone or plyometric training alone in increasing explosiveness.


In Neuromuscular Basis of Kinesiology Roger Enoka states that, “The magnitude of the twitch force is variable and depends on the activation history of the muscle. A twitch elicited in a resting muscle does not represent the maximum twitch. Rather, twitch force is maximal following a brief tetanus; this effect is known as posttetanic potentiation of twitch force.” This means that an electrical stimulation of the muscles can lead to a subsequently more powerful contraction.


Here’s a simpler definition: PAP is a phenomena by which muscular performance characteristics are acutely enhanced as a result of their contractile history. The underlying principle surrounding PAP is that heavy loading prior to explosive activity induces a high degree of CNS stimulation which results in greater motor unit recruitment lasting anywhere from five to thirty minutes.


There are many different ways to utilize PAP. In the past, legendary strength coach Charles Poliquin has recommended using wave-loading to induce PAP, popular strength coach/author Christian Thibaudeau has recommended using maximal isometrics for PAP, and popular personal trainer/author Chad Waterbury has recommended using supramaximal holds as a method to elicit PAP.


While the science involving PAP is solid and makes perfect sense, prior research on PAP is equivocal. There have been plenty of studies showing that PAP works and plenty of studies showing that PAP doesn’t work. PAP research is most likely inconclusive due to the large number of variables involved in implementing PAP, which I’ll elaborate upon later in the article.


Arguments in Favor of Using PAP


Here is a list of arguments that strength coaches may have in favor of using PAP:


1. Short-term enhancement – May increased neuromuscular performance in actual competitive event through PAP
2. Chronic adaptation – May increase training effect using PAP in training which would result in increased Rate of Force Development (RFD)
3. Increased workout density – Combined training allows for more activity with less actual resting time which is critical if total workout time is limited
4. Increased dynamic transfer – By combining biomechanically similar activities athletes may groove more efficient neural patterns by learning to perform the lift in a manner more specific to the athletic activity
5. Increased work capacity – By increasing workout density athletes will increase their work capacity which is characterized by high levels of average power output over an interval (which I call power endurance)


Arguments Against Using PAP


Here is a list of arguments that strength coaches may have against using PAP:


1. There is not enough research supporting it’s use, we don’t have an adequate handle on all the variables involved in PAP
2. Recent research shows that combined training can lead to inferior results due to inhibition of physiological pathways, it may be wiser to train max strength and max speed/power in separate sessions
3. PAP is often impractical – depending on the protocol it may require a precise amount of time or “window of opportunity,” it may require equipment that is unavailable in a competitive or training situation
4. A simple dynamic warm-up could enhance contractility of muscles equally or better than max contractions involved in PAP
5. Positive studies using PAP could be the result of increased muscle temperature or other characteristic of general warm-up
6. Testing to see if PAP works on an individual athlete or to determine the optimal protocol for an individual can be tedious and if done incorrectly could lead to decrease in neuromuscular performance or decreased training effect
7. Using PAP may fail to maximize strength and power by combining the two and training them in fatigued state


How Does PAP Work from a Scientific Standpoint?


There are three proposed mechanisms as to how PAP works:


1. Phosphorylation of myosin regulatory light chains – max contraction alters structure of myosin head and leads to increased sensitivity of myosin head to calcium ions released by the sarcoplasmic reticulum
2. Increased recruitment of higher order motor units – max contraction activates adjacent motoneurons via afferent neural volley and H-Reflex enhancement which increases neurotransmission
3. Change in pennation angle – max contraction decreases pennation angle which increases force transmission to the tendon


How Does PAP Work from a Non-Scientific Standpoint?


Yuri Verhoshansky has explained PAP as follows:


When you perform a 3-5 RM followed by a light explosive set…to your nervous system it’s like ‘‘lifting a ½ can of water when you think its full.”


Why Doesn’t PAP Always Work?


First, a max contraction will always generate fatigue and PAP at the same time. Fatigue attenuates or diminishes force-generating capabilities of the muscles while PAP potentiates or enhances them. PAP and fatigue develop and dissipate at different rates. Fatigue subsides at a faster rate than PAP, so potentiation of performance can be realized at some point during recovery period. The max contraction could enhance power and training effect via PAP, or it could induce fatigue. The balance of PAP and fatigue determines the net effect on performance of the subsequent explosive activity. Fatigue can be either central or peripheral. Isometric contractions lead to more central fatigue, but more peripheral PAP, whereas dynamic contractions lead to more peripheral fatigue, but more central PAP.


Second, PAP may be more beneficial to single actions such as a max vertical or broad jump, a max throw or swing, or even a max isometric contraction rather than repetitive cyclical actions such as sprinting, cycling, or swimming.


Third, the parameters of the variables involved in PAP may require tinkering and optimization. Forth, PAP may not work for certain individuals.


I will expound upon the third and forth reasons later in this article.


What is the Ideal “Window” of PAP?


The optimal recovery or “window” of PAP depends on the decay-rate of PAP and the dissipation of fatigue. The coexistence of PAP and fatigue may result in a net-potentiated state, a net-attenuated state, or a constant state as compared to the prestimulus state.


Some studies show increased power immediately following a max isometric or dynamic contraction. A performance improvement is indeed possible if initial peak PAP overrides initial peak fatigue. PAP may initially rise above baseline, then dip down below baseline, and then rise above baseline again before returning to normal over a ten minute period. Windows are immediately after a low volume contraction or after a specific recovery period for high volume contractions.


An excellent journal article titled “Factors Modulating Post-Activation Potentiation and its Effect on Performance of Subsequent Explosive Activities” shows two theoretical “ideal windows of opportunity” for PAP. These windows illustrate periods where PAP exceeds fatigue and would therefore lead to a “potentiation” of performance. Following a low-volume maximal contraction, you want to perform the explosive activity immediately following the set. Following a high-volume maximal contraction, you want to wait several minutes before performing the explosive activity.


An example of a low-volume max contraction would be a heavy single for squats. An example of a high-volume max contraction would be eight sets of five second isoholds separated by 40 seconds of rest in between sets.


This graph does a good job of illustrating the two windows of opportunity for PAP:



What Factors Influence the PAP-Fatigue Relationship?


The PAP-fatigue relationship is affected by


1. The volume of contraction (sets. reps, rest interval)
2. The intensity of contraction (it seems that maximum contractions are optimal)
3. The type of contraction (dynamic or isometric)
4. Subject characteristics (strength, fiber-type distribution, training status, power-strength ration), and
5. The type of subsequent activity


The parameters for the training variables involved in PAP have yet to be determined.


Does PAP work for everyone?


Research indicates that PAP is very specific to the individual. Some evidence shows that PAP works better in stronger individuals than weaker individuals (Gourgoulis et al., Kilduff et al.). Some research shows that PAP works better for more fast-twitched individuals in comparison to more slow-twitched individuals (Hamada et al.). Evidence points towards PAP being more effective in highly trained individuals (Chiu et al.). Some evidence shows that PAP works better for strong individuals who aren’t very powerful; ie: they have trouble converting their strength to power (Schneiker et al.). Finally, research indicates that not all individuals display increased phosphorylation following a max contraction (Smith and Fry).


Furthermore, different muscles may have different rates of recovery in terms of fatigue and PAP. PAP appears to work better if the kinematics of the max contraction match the kinematics of the subsequent explosive activity. PAP appears to work best in activities involving type II fibers (Hamada, Sale, & MacDougall). Many PAP studies indicate a 2-10% improvement in performance, so this area indeed warrants further investigation.


Why Does the Author Believe in Utilizing PAP?


Most strength coaches around the country like to do explosive work before strength work, simply because they feel that power work should be done while the nervous system is “fresh.”


Regarding pure strength work, Poliquin utilized PAP for his 1,6 program. I’ve experimented with the 1,6 program and didn’t find that it worked well for me, but perhaps I fatigue easier than others, or perhaps there are other issues at play. Eric Cressey mentioned in an article that he didn’t buy into PAP in regards to schemes like the 1,6 program. I have a powerlifter-friend who swore by the 1,6 program. In this regard, PAP appears to work very well for some people and not-so-well for others (which jives with the research I listed above).


As stated above, research indicates that PAP works better for more experienced lifters, those with more fast twitch muscle fibers, and especially for those who sit on the “static” end of the static-spring continuum (static being very strong, spring being very elastic and explosive). Most gym-rats like me are very “static” from years of heavy lifting.


I stumbled upon some recent research which indicates that combined training involving speed work and heavy lifting interfere with each other due to negations in adaptations of respective physiological pathways. So for hypertrophy purposes, it may not be wise to incorporate explosive/speed activities along with heavy strength training or at least separate explosive/speed/plyo training from heavy strength training by several hours. For more information on this topic visit this link:


http://ajpregu.physiology.org/cgi/content/short/297/5/R1441


However, many individuals and athletes like to go to the gym one time per day and do not wish to perform multiple training sessions per day. Some are limited by time availability and are unable to perform multiple daily training sessions. In this case, I believe that PAP is one’s best bet for preserving or enhancing power while training heavy.


I believe that performing more than one explosive exercise first in the workout diminishes the capacity to perform maximum strength work. Conversely, I believe that performing more than one heavy strength exercise first in the workout diminishes the capacity to perform maximum explosive strength work. For example, if one were to perform a few hard sets of squats, deadlifts, and barbell glute bridges prior to vertical jumps and sprints, his jumping and sprinting power would suffer and the athlete would feel like his feet were heavy and he was slower than normal. However, if one were to perform jump squats, power cleans, and sled pushes prior to heavy squatting, deadlifting, and hip thrusting, his strength would suffer and the lifter would feel that he did not maximize the strength component to his workout. Alternating the two types of activities in the form of complex training may therefore provide the perfect scenario.


Personally, I love hypertrophy, I love strength, and I love power…I want it all. I am not willing to gain a ton of muscle at the expense of becoming slow. If all one does is medium-high rep hypertrophy training year in, year out, science indicates that that individual will become slower. This means slow punches, slow sprint times, and a pathetic vertical jump. By incorporating PAP at strategic times throughout the year, one can maintain or build power and prevent power/speed losses over the years. The best thing about incorporating PAP is that it doesn’t affect the training routine too much; it’s not very difficult to add in a vertical jump right after a set of squats or a plyo push up right after a set of bench press.


Even if research were to one day show that PAP offers no for performance enhancing effects beyond that of a dynamic warm-up I’d still be interested in incorporating PAP into workouts due to increased training density. Strength coaches Mike Boyle and Nick Tumminello have written extensively about utilizing active recovery in the form of mobility, flexibility, and activation drills in order to increase training density. Perhaps combining a strength movement, a biomechanically similar power movement, and a non-interfering flexibility, mobility, or activation movement serves as the ultimate method to maximize workout efficiency while minimizing total training time.


If you want to utilize PAP for short-term performance boosting purposes it would be very wise to actually test the individual to see if it works. Don’t assume that PAP works for everyone or assume that the same PAP protocol is best for each individual!


What Would My Ideal Complex-Training Scenario Look Like?


Here are some exercise pairs that I feel are worthy of experimentation:


Heavy Bench Press — Med Ball Throws, Shot-Put, Plyo Push Ups
Heavy Squats — Vertical Jumps, Jumping Lunges, RFESS Jumps, Power Skips
Heavy Deadlifts, Good Mornings, Hip Thrusts, Barbell Glute Bridges, Reverse Hypers, Back Extensions — Sprints, Woodway Speedboard Sprints, Broad Jumps
Heavy Landmines, Woodchops, Pallof Press — Bat, Racquet, or Golf Swings, Discus Throw
Eccentric Ab Wheel Rollouts from Feet — Javelin Throw


Combining squats and jumps is a no-brainer. I really like the idea of combining hip thrusts and sprints off the Woodway speedboard as well. It’s not too often that you see any “core” movements utilized in PAP such as using ab wheel rollouts or woodchops to load up the anterior chain prior to throwing or swinging activities but I would love to experiment to see if it could lead to an enhancement of performance.



Some exercises are well-suited for 1RM’s or heavy singles. These exercises include squats, deadllifts, bench press, and eccentric ab wheel rollouts. I believe that hip thrusts, glute bridges, good mornings, back extensions, reverse hypers, landmines, woodchops, and Pallof presses are better suited for reps of five.


I’d try to keep the reps for heavy strength work under or equal to five and I wouldn’t be afraid to prescribe heavy singles. For subsequent explosive work, I’d stick to five reps or less as well and also wouldn’t be afraid to prescribe single efforts. For example, a heavy squat single immediately followed by a max vertical jump might work very well.


I’m more interested in experimenting with low-volume contractions with little to no rest time as opposed to high-volume contractions with longer rest times.


I wouldn’t quite “max out” or go to failure as I believe that grinding out a rep, exhibiting energy leaks, or pushing a set too far might lead to too much fatigue and prevent PAP from occurring. I’ve studied the muscle activation involved in form decrements such as squats with a serious forward bend or round-back deadlifts and the result is always decreased muscular involvement in the prime movers which is something you want to steer clear of in this instance. Furthermore, in studying muscle activation the second repetition of a set usually always results in increased muscle activation over the first rep, which is most likely due to the CNS “figuring out” the motor program. This plays a case for heavy doubles or triples for the max contraction used in PAP. In many instances one can maximize muscle activation by using 95% of 1RM and using picture-perfect form. This is what you want for PAP purposes – maximum muscle activation in the intended musculature.


I’d use mostly bilateral lifts for the max contraction as unilateral lifts would take too much time to do both legs and interfere with the PAP window of opportunity. I’d use mostly bodyweight explosive movements for the subsequent explosive movements or movements with actual sporting implements as opposed to speed-strength or strength-speed exercises such as jump squats or power cleans. I’d try to mimic directional load vectors and joint angles to maximize dynamic transfer. Two tools that I’d love to experiment with in eliciting PAP are weight releasers and whole body vibration platforms. I’ve heard Rob Panariello mention the former methodology and Charlie Weingroff mention the latter methodology.


Prior Research


I love reading review articles in the journals. While original research is great, review articles analyze previous research so one doesn’t have to go sifting through everything to try to get a grasp on a particular topic. In other words, researchers who write review articles do the work for you!


By far my favorite review article on PAP is titled Factors Modulating Post-Activation Potentiation and its Effect on Performance of Subsequent Explosive Activities by Australian researchers Neale Anthony Tillin and David Bishop. If you are interested in learning more about PAP, then this article is a must-read. Seriously, the article is amazing! Do yourself a favor and read it.


Two other excellent review articles are Postactivation Potentiation and its Practical Applicability: A Brief Review by Canadian researcher Daniel Robbins and The Application of Postactivation Potentiation to Elite Sports by D Docherty and MJ Hodgson.


Here is a free review article that you can access by clicking on the following link:


Roxanne Horwath and Len Kravitz, PhD


http://www.unm.edu/~lkravitz/Article%20folder/postactivationUNM.html


Prior Articles


Below you will find links to articles regarding PAP from various strength experts. Just click on the name and you will be taken to their article. From a practical standpoint, Nick Tumminello’s article will give you the most training-related ideas.


Charles Poliquin


http://www.tmuscle.com/free_online_article/sports_body_training_performance/the_16_principle


http://www.tmuscle.com/free_online_article/sports_body_training_performance/arm_yourself


Christian Thibaudeau


http://www.tmuscle.com/free_online_article/sports_body_training_performance/the_best_reps


http://www.tmuscle.com/article/most_recent/beast_building_part_1


http://www.tmuscle.com/free_online_article/sports_body_training_performance/the_thib_system_training_frequency_and_rest_periods&cr


Eric Cressey


http://www.tmuscle.com/free_online_article/sports_body_training_performance_repair/it_looked_good_on_paper


http://findarticles.com/p/articles/mi_m1608/is_3_22/ai_n16101385/


Chad Waterbury


http://www.tmuscle.com/free_online_article/sports_body_training_performance/primed_for_muscle


http://www.tmuscle.com/free_online_article/sports_body_training_performance/nervous_muscle


http://www.tmuscle.com/free_online_article/sports_body_training_performance/pimp_your_workouts_with_these_4_simple_tricks


http://www.dragondoor.com/articler/mode3/425/


Nick Tumminello


http://www.tmuscle.com/free_online_article/sports_body_training_performance/contrast_training_for_strength_size_and_power


TC Luoma


http://www.tmuscle.com/free_online_article/sports_body_training_performance/tsunami_training


John Paul Catanzaro


http://www.tmuscle.com/free_online_article/sports_body_training_performance/get_ready_for_the_workout_of_your_life


http://www.tmuscle.com/free_online_article/sports_body_training_performance/triple_threat_training


Patrick Ward


http://optimumsportsperformance.com/blog/?p=880

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