Graduate Program

Kinesiology and Sports Studies

Degree Name

Master of Science (MS)

Semester of Degree Completion


Thesis Director

Jeffrey M. Willardson

Thesis Committee Member

John D. (Jake) Emmett

Thesis Committee Member

Brian L. Pritschet


The purpose of this study was to examine whether a combination of a low volume, moderately-heavy (80% 1RM) back squat combined with whole body vibration would optimize the post activation potentiation (PAP) response compared to a set of low volume, moderately-heavy back squat without vibration in Division I collegiate female volleyball players. The study design consisted of two groups (n = 5, n = 5) of current Eastern Illinois University female volleyball players matched by 1RM back squat strength. Prior to the experimental intervention, subjects in each group attended two sessions during which standing reach height and demographic information ( age, height, weight, body mass) were obtained and familiarity with the procedures and equipment were achieved. Subjects in each group began the experimental session by completing a five minute dynamic lower body warm-up followed by two baseline maximal effort countermovement jumps (CMJ) measured using a Vertec device. Following an active rest period subjects in both sessions were instructed to complete two ascending sets of back squats and then a single set of moderately-heavy back squat either with or without standing on a Vibeplate platform. Following the back squats, subjects completed two final maximal effort CMJ. Baseline and final CMJ heights were compared following each session to determine the possible presence of a PAP effect. Statistical analysis using an independent t-test showed no mean significance between group CMJ heights. Individual variations of CMJ height existed in both groups and further research with EMG recording devices is needed to determine the presence of PAP. The findings of the current study found no superiority of a combination protocol over a back squat only protocol at improving vertical jump height. Without additional measures, interpretation of whether the observed individual variations in CMJ height in this study were the result of a PAP effect or simply by chance is equivocal.