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The Performance Enhancing Phenomenon You Didn’t Know About

Post-Activation Potentiation (PAP) is a physiological phenomenon that increases the rate of force development (e.g. the ability to produce force quickly). Therefore, PAP is most commonly used to enhance power performance (e.g. an activity involving quick force executions such as a vertical jump). PAP is traditionally achieved by completing a heavy resistance exercise (i.e., the conditioning or preloading event) before a biomechanically similar explosive exercise (i.e., a short sprint or jump). A typical example includes completing a heavy barbell back squat before a vertical jump. Enhanced power performance during the vertical jump may be recognized through improved jump height, ground-reaction force, or take-off velocity.

This article will discuss how PAP can be achieved and the underlying physiology of PAP. Lastly, how PAP can be applied to improve athletic and/or training performance measures.

Evidence of PAP

Research on PAP has noted performance enhancements in the upper and lower body!

Before diving into the mechanisms of PAP, it is noteworthy to recognize some current research. PAP has been extensively studied in exercise science, producing many instances where PAP has been implemented to produce performance benefits. Research on PAP has noted performance enhancements in the upper and lower body. Additionally, it has progressed to better define PAP by detecting underlying physiology, determining approximate methodologies to induce it, and determining how long performance enhancements last. Further research is still needed on alternate methods to induce PAP beyond the traditional heavy load and how the PAP effect can be optimized based on individual differences.

Improved upper body performance was found by Baker (2003). Baker produced a 4.5% increase in power output during explosive bench press throws after completing 6-repetitions of a bench press at 65% of one’s 1-repetition maximum (RM) (2003). Additionally, in a study by Sas-Nowosielski & Kandzia, 5RM pull-ups caused a 6.8% improvement in the power performance of climbers (2020).

In terms of lower body performance improvements, Gourgoulis et. al. (2003) found a 2.39% improvement in vertical jump performance following five sets of half squats at increasing intensities. Moreover, Weber et. al. (2008) produced a 4% increase in vertical jump height following back squats with 85% 1RM.

Although the percent increases in power performance may seem small, they are significant performance improvements by research statistical analysis. Additionally, these improvements are immediate since they are achieved within minutes. Therefore, by utilizing the PAP phenomenon, one can improve performance levels beyond their potential maximum capabilities from consistent training adaptations. Athletes can reach new optimal performance levels when used before an athletic performance measure. Differences in PAP achievement and percentage of performance improvement can be attributed to differences in the methods in each study. There are many considerations when developing a protocol to induce PAP. These considerations will be discussed further in the following section.

Traditional Elicitation of PAP

Intensity, volume, and rest period determine the effectiveness of a preloading event in producing subsequent performance enhancement.

PAP onset and following performance gains depend on the intensity and volume of the conditioning activity and the rest period between the conditioning activity and the power performance. Research on PAP has considered multiple loads, sets, repetitions, and rest periods.

Studies suggest that the greatest PAP effects are achieved after completing a conditioning activity with a load of 80% or greater of one’s 1 RM (Baker, 2003; Tillin & Bishop, 2009; Villalon-Gasch et. al., 2020). Additionally, the conditioning activity should be completed for 1-3 sets with 1-5 repetitions (Villalon-Gasch et. al., 2020). A prolonged preloading event of greater intensity is believed to exploit PAP to a greater effect (Sale, 2002). However, in this case, as PAP increases, so does fatigue. Fatigue diminishes performance enhancements of PAP. Therefore, performance enhancement is greatest when there is a balance between PAP and fatigue.

To achieve the optimal balance between PAP and fatigue, there should be a rest period between the conditioning activity and the performance. Since fatigue dissipates faster than PAP, the rest period allows the PAP effect to overcome fatigue (Tillin & Bishop, 2009). A rest period between 2-10 minutes supports the greatest PAP performance enhancements (Tillin & Bishop, 2009). The rest period should be closer to 10 minutes with a more intense conditioning activity since more fatigue has developed, which masks the PAP effects. On the other hand, with a less intense conditioning activity, the rest period should be shorter since less fatigue occurs and the PAP effect may be less. With recovery, although fatigue diminishes faster, PAP also decreases. Consequently, the rest period mustn't be long enough to decay the entirety of the PAP mechanism, causing a loss of performance benefits.

Relationship between PAP and Fatigue. With low conditioning volume (i.e., 1-repetition of 90% 1RM back squat), PAP is greater than fatigue, and following performance enhancements can be executed almost immediately in window 1. With increasing conditioning volume (i.e., 6 repetitions at 80% 1RM), fatigue dominates the PAP effects. A rest period is needed for fatigue to diminish; the effect during the subsequent performance is evident in window 2. (Tillin & Bishop 2009).

Physiological Mechanism of PAP

PAP is proposed to be a result of phosphorylation of myosin regulatory light chains and increased recruitment of type II muscle fibers.