Does postactivation potentiation (PAP) increase voluntary performance?

Abstract

The transient increase in torque of an electrically evoked twitch following a voluntary contraction is called postactivation potentiation (PAP). Phosphorylation of myosin regulatory light chains is the most accepted mechanism explaining the enhanced electrically evoked twitch torque. While many authors attribute voluntary postactivation performance enhancement (PAPE) to the positive effects of PAP, few actually confirmed that contraction was indeed potentiated using electrical stimulation (twitch response) at the time that PAPE was measured. Thus, this review aims to investigate if increases in voluntary performance after a conditioning contraction (CC) are related to the PAP phenomenon. For this, studies that confirmed the presence of PAP through an evoked response after a voluntary CC and concurrently evaluated PAPE were reviewed. Some studies reported increases in PAPE when PAP reaches extremely high values. However, PAPE has also been reported when PAP was not present, and unchanged/diminished performance has been identified when PAP was present. This range of observations demonstrates that mechanisms of PAPE are different from mechanisms of PAP. These mechanisms of PAPE still need to be understood and those studying PAPE should not assume that regulatory light chain phosphorylation is the mechanism for such enhanced voluntary performance. Novelty The occurrence of PAP does not necessarily mean that the voluntary performance will be improved. Improvement in voluntary performance is sometimes observed when the PAP level reaches extremely high values. Other mechanisms may be more relevant than that for PAP in the manifestation of acute increases in performance following a conditioning contraction.

Proposal of a Conditioning Activity Model on Sprint Swimming Performance

“…Currently, the scientific community has deepened several reflections on this mechanism, and it is believed that it is linked to post-activation potentiation (PAP) which explains the increase in torque caused by an electrical stimulus after a maximum voluntary contraction (Blazevich and Babault, 2019;Prieske et al, 2020;Zimmermann et al, 2020). Other factors (i.e., temperature, muscle activation, muscle and cellular water content) seem to determine whether the stimulus of the CA will sustain an improvement in performance or an improvement in voluntary strength (Blazevich and Babault, 2019).…”

Time to Differentiate Postactivation “Potentiation” from “Performance Enhancement” in the Strength and Conditioning Community

“…These relatively poor and inconsistent associations between changes in twitch contractile properties and the corresponding strength, power, or speed performance indicate that individuals with greater twitch PAP effects in single muscle groups are not necessarily those showing the greatest single-/multi-joint performance improvements following acute exercise. In fact, other studies observed PAP effects following high-intensity contractions (e.g., MVC, submaximal leg press) but no acute performance changes [ 24 , 44 – 46 ]. In female young elite soccer players, submaximal exercises on a leg press resulted in large-sized enhancements in twitch rate of torque development (ES = 1.98) 7 min following conditioning contractions compared with a passive control condition [ 24 ].…”

Post-activation performance enhancement strategies in sport: a brief review for practitioners

“…Meanwhile, PAP would refer to force increases during twitch verification tests. In this regard, it is common to simultaneously identify PAP and PAPE after the same CAs [2,6]. Therefore, as we will present only studies with athletes in sport settings, PAPE is the correct term ( Figure 1).…”

“…In fact, most studies in sport have not been conducted with twitch verification tests, but with muscle power tests (e.g. vertical jumps), promoting some misconception around potentiation responses [2]. For this reason, Cuenca-Fernández et al [3] have introduced the term 'post-activation performance enhancement' (PAPE) [3][4][5] to clearly differentiate between PAP and PAPE.…”