Comparison of Ground Reaction Forces Between Four Plyometric Pushup Variations

Document Type

Article

Publication Date

6-3-2010

Publication Title

Medicine and Science in Sports and Exercise

DOI

10.1249/01.MSS.0000385135.75613.c2

ISSN

1530-0315

Abstract

Plyometric exercises utilize the stretch-shortening muscle cycle to produce large amounts of force in short durations. Unlike the lower extremity plyometrics, data concerning the loads and intensity associated with upper extremity plyometrics is limited.

PURPOSE: To compare ground reaction forces (GRF) between the clap pushup (CPU) and drop box pushups (DPU) from 3.8cm (1.5 in), 7.6cm (3 in), and 10.2cm (4.5 in) heights.

METHODS: Fifteen healthy active male subjects (18-35 years) performed four repetitions of each plyometric pushup variation in a counterbalanced order. Pushups were completed with each upper extremity positioned over a separate forceplate. Four dependent variables, peak force (PF), time to peak force (TPF), loading rate (LR) and propulsion rate (PR), were calculated for each extremity from the computed vertical GRF. Statistical analysis consisted of separate limb by variation repeated measures analysis of variance. In addition, repetition time (RT), defined as the length of time the dominant limb was in contact with the forceplate, was statistically compared between variations.

RESULTS: No significant differences were revealed for RT (P=.080, h2p=.193) or PF (P=.752, h2p=.030). The dominant limb demonstrated a significantly earlier TPF (P=.003, h2p=.502). Post hoc analysis of a significant limb by variation interaction (P=.003, h2p=.300) revealed the dominant CPU and 10.2cm DPU LR to be significantly greater than the nondominant. Further, for both limbs, the CPU LR was significantly greater than the DPU at the two lowest heights. The CPU PR was significantly greater than the three DPU (P<.001, h2p=.422).

CONCLUSION: These data provide documentation and add rationale for determining upper extremity plyometric progression. The PF associated with CPU and DPU are similar and altering DPU height did not affect PF. In contrast, the CPU demonstrated the highest LR and PR suggesting that it may be a more powerful exercise than DPU. The longer TPF and higher LR (CPU and 10.2cm DPU) for the dominant extremity illustrate bilateral disparity in rate of eccentric loading. Further research on these exercises is needed to better clarify the demands imposed on the upper extremity during the eccentric and concentric phases when performing plyometric exercise.

Comments

© 2010 American College of Sports Medicine

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