Effect Of Hand Width On Upper Extremity Loading Symmetry During Plyometric Clap Push-ups

Data concerning the loads and intensity associated with upper extremity plyometrics is limited. Previous research has examined the overall intensity of plyometric clap push-ups (PCP). There appears to be a void examining whether hand width influences upper extremity loading during PCP. PURPOSE: To examine the effects of hand width on PCP performance and dominant (D)-nondominant (ND) upper extremity loading symmetry. METHODS: Twenty healthy active male subjects (18-35 years) with >6 months resistance training experience performed five continuous PCP repetitions using hand widths of 120% (W1), 150% (W2) and 170% (W3) biacromial distance in a counterbalanced order. Ground reaction forces (GRF) under each limb and kinematic data of the trunk were recorded. Prior to the data collection session (>72 hr), participants completed a familiarization session. Vertical trunk velocity at ground-contact (GC) and ground-off (GO) and peak flight height (PFH) were computed. Separately for each limb, the respective GRF (combined vector) were used to compute average force (AF), peak force (PF) and impulse (IMP). Standardized effect sizes (d) were computed (Hedges method) to interpret the meaningfulness of significant differences. RESULTS: PFH was significantly higher for W3 than W1 (P = .034, d = .28). GC/GO velocities were significantly greater for W3 compared to W1 (P < .001, d = .59) and W2 (P = .002, d = .21). AF limb symmetry significantly differed between widths with D > ND for W1 (P = .009, d = .79) and ND > D for W3 (P = .012, d = .67). IMP limb symmetry significantly differed between widths, with D > ND for W1 (P = .003, d = .58) and ND > D for W3 (P = .015, d = .28). There were no limb differences in AF (P = .422, d = .22) or IMP (P = .141, d = .27) for W2. While a significant PF limb by width interaction was identified (P = .025), post hoc comparisons between limbs for W1 (P = .090, d = .41), W2 (P = .808, d = .04) and W3 (P = .128, d = .19) were not statistically significant. CONCLUSION: Unexpectedly, there were no significant limb differences for PF, whereas AF and IMP limb asymmetry depended upon hand width. Loading shifts could have occurred between limbs during the PCP phases. Thus, further research is recommended to assist with the interpretation of these data as well as clarify the upper extremity demands imposed during the eccentric and concentric phases.