Isometric mid-thigh pull vs. plyometric post activation potentiation and their effects on maximum velocity in athletic males

Abstract

Postactivation potentiation (PAP), an acute enhancement of muscular performance observed after a preconditioning stimulus, has been reported to increase sprint acceleration performance after a variety of contraction types. Very few studies have analysed different contraction type effects on subsequent sprint performance, with no current studies solely investigating the maximal velocity phase of sprinting or kinematic data, therefore the present study examined the effects of both isometric mid-thigh pulls (IMTP) and plyometric pogo hops (PPH) on subsequent maximum velocity phase sprinting performance. In a randomized crossover study design, athletic men (n = 13) performed a standardised warm up with no further PAP stimulus (C) or the standardised warm up followed by 3 sets of 5s maximal isometric contraction (IMTP) or 3 sets of 20 plyometric hops (PPH). 8 minutes of passive rest was utilised and then subjects performed three 45m sprints each separated by 4 minutes rest (with the 30-40m split being analysed). 2D video analysis was used to calculate changes in step length and frequency between trials and force data was also collected during the IMTP. Repeated measures ANOVA indicated no significant differences between PPH and IMTP 30-40m times (p= 1.00) and IMTP vs. C 30-40m times (p= .064). A significant decrease in performance was observed between PPH and C 30-40m times (p= .05). No significant differences were observed in C vs. PPH average step length (p= .168), C vs. IMTP (p= 1.00) and PPH vs. IMTP (p= .281). No significant differences were observed between C vs. PPH (p= 1.00) and C vs. IMTP average step frequency (p= .216). Differences in PPH vs. IMTP average step frequency approached significance (p=0.53). There were also no significant differences in performance responses between the strongest and weakest subjects but large variations in individual responses were found between the subjects. The findings suggest that the present protocol in the present subject population will lead to decreases in maximal velocity sprint performance. However large individual responses were present and thus PAP should be considered on an individual basis. Factors including contraction type, volume, intensity and rest period should be carefully considered in PAP practical application, with future research aiming to utilise a similar protocol in elite populations.