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Date Permissions Signed


Date of Award

Fall 2018

Document Type

Masters Thesis

Degree Name

Master of Science (MS)


Health and Human Development

First Advisor

Suprak, David N. (David Nathan)

Second Advisor

Brilla, Lorraine R., 1955-

Third Advisor

Chalmers, Gordon R.


This study compared the effects of two conditioning exercise types on subsequent countermovement jump performance. Fifteen male collegiate rugby players (age 21.1 ± 2.3) completed two experimental protocols in a randomized order. The first protocol consisted of 3 sets of a 5 second maximal isometric half squat (ISO), with 1 minute rest intervals between sets. The second protocol consisted of 2 sets of 5 depth jumps (DJ) at a platform height which was determined by the athletes’ reactive strength index (RSI). These methods were each adapted from prior literature where post-activation potentiation (PAP) was achieved, in order to determine the relative timing and amplitude of the effect using a repeated measures design. Results of a two-way ANOVA for CMJ height reveal a significant main effect of time ((F[5,60] = 8.291, p < 0.001, η² = 0.409), and pairwise comparisons reveal a significant increase in CMJ height at 4-minutes compared to baseline (3.4 ± 0.9%, p = 0.044), as well as a significant decline in CMJ performance from 4-minutes to both 8-minutes (-7.7 ± 3.3%, p = 0.001), and 10-minutes (-4.7 ± 0.7%, p = 0.005). No significant interactions or main effects were found for CMJ height or other performance indices. Potentiating via the DJ or ISO protocols lent no significant difference in CMJ variables, therefore practitioners may use either protocol to enhance jumping performance in their athletes.




Countermovement vertical jump, maximal voluntary isometric contraction, ballistic exercise, complex training



Western Washington University

OCLC Number


Subject – LCSH

Exercise--Physiological aspects; Interval training--Physiological aspects; Rest--Physiological aspects; Biomechanics; Human mechanics




masters theses




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