Comparing the effects of static and variable loading in potentiation of the lower extremities through vertical jump

Post-activation potentiation (PAP) can elicit increased force in a muscular contraction following a specific preparatory activity, though little research exists regarding how various loading methods in said activity impact the potentiation effect. This study seeks to determine if banded PAP activities are more effective than static loading in improving power production.

Participants in this randomized cross-over design study were 7 female collegiate volleyball players with a 6-month minimum training age and no significant injuries. The study took place across 3 sessions, each 48 hours apart. At the 1^st session, baseline vertical jump height (cm), power (W), and 1RM back squat were taken, and subjects were randomly placed into one of two different PAP activity groups at the 2^nd and 3^rd sessions. PAP activity was standardized to 2 sets of 2 back squats at 90% 1RM with a 3-second eccentric, with the variance in groups being the inclusion or exclusion of 20% of the load from elastic resistance bands. Following the PAP activity, and an 8-minute rest, subjects performed 3 vertical jumps.

The PAP band-resisted activity group showed significant improvements in vertical jump height (P=0.006) and power (P=0.006) when analyzed with an ANOVA repeated measures test. No significant difference was found in the same analysis with the non-banded group for height (P=0.512) or power (P=0.517), and there were no significant differences found between group peak performance or averages when comparing between groups. A priori power analysis showed sufficient statistical significance despite the small sample size (1 - β=0.95).

This study was conducted utilizing barbell back squats as the potentiation activity with the dynamic variable being 20% of the load being from elastic band resistance, and a standardized rest period of 8 minutes before testing the potential impact this PAP activity had on vertical jump performance. Utilizing PAP activities that are specific to the demands of a given sport may improve vertical jump and power capabilities within athletes.