March 8, 2013

Elias K Tomaras* and Brian R MacIntosh
Human Performance Lab, University of Calgary

Elias K Tomaras, MSc, CSEP-CEP, is currently working for the Calgary Fire Department’s Wellness Clinic and the University of Calgary’s Human Performance Lab. This work was first presented at CSEP 2012 in Regina, Saskatchewan, and was awarded the 2012 CSEP Health and Fitness Program Certified Member Award.

What is postactivation potentiation (PAP)? PAP is the enhancement of a muscle’s contractile response resulting from prior contractile activity (i.e., warm-up). The topic of PAP has recently had high interest in the scientific, fitness, and competitive sport communities. Conditioning contractions are currently being used by competitive athletes during warm-up in an attempt to obtain PAP and enhance athletic performance. Yet, there is little scientific support that PAP contributes to warm-up in this way.

Why is PAP becoming so popular? To put it simply, research has shown that prior high intensity contractions can enhance a muscle’s force production in subsequent efforts, and this appears to translate to improved performance, 5 to 20 min after the warm-up; a time when PAP should be diminished. The major problem with much of the previous research examining PAP is that very few studies use a warm-up or stimulus that is sport-specific, and very few actually quantify PAP. Most studies used either an isometric knee extension or a vertical jump and assume any subsequent enhancement of performance is due to PAP.

Our lab wanted to examine how a high-intensity effort that is specific to cycling would impact muscle force producing capabilities (i.e., PAP). Specifically, how much twitch force enhancement would we obtain from a muscle group if we had elite cyclists and speed skaters perform warm-up that included high intensity (80-100% max) brief durations (5-10 sec) of cycling.

The results of our study were quite surprising. We found that twitch force production was enhanced, as in PAP, but there was a delayed enhancement as well. Force initially increased, but rapidly declined to resting levels a few minutes after the brief ‘warm-up’ sprint. This pattern is typical of PAP. However, this enhancement and decline was followed by a subsequent gradual increase in force production that peaked 10 minutes after warm-up. The increase in force averaged approximately 10% among the speed skaters and 17% among the cyclists. This force enhancement remained elevated for several minutes, and was still 6% above resting values even 30 minutes after their warm-up!

This study has demonstrated that significant force enhancement can be achieved by using a dynamic, sport-specific warm-up. Does this force enhancement actually improve performance? The 2nd phase of our study will explore this question. After all, performance enhancement is what everyone is trying to achieve through warm-up.

This Knowledge Translation article has been reviewed by the CSEP Knowledge Transfer Committee.