Effect of Magnesium Carbonate Use on Repeated Open-Handed and Pinch Grip Weight-Assisted Pull-Ups.

The purpose was to determine if pull-up performance was affected by the use of chalk (100% magnesium carbonate) during open-handed and pinch grip weight-assisted pull-ups (WAPU) in recreationally-trained rock climbers. Furthermore, the reliability of open-handed and pinch grip WAPU was also investigated. Recreationally-active volunteers (n = 9) completed six counterbalanced trials. Participants used chalk during four trials to determine the reliability (test-retest) of the open-handed and pinch grips. While two of the six trials were used to determine if open-handed and pinch grip WAPU performance was affected without using chalk. Three of the six trials included one set of open-handed WAPU, while the remaining trails included one set of pinch grip WAPU. Sets were performed until failure and consisted of either the open-handed or pinch grip pull-ups assisted by a 50% reduction of body weight. Heart rate, ratings of perceived exertion, perceived recovery scale and session-RPE were not significantly different (p > 0.05) among trials. Intraclass correlations (ICC's) for test-retest of the open-handed (R = 0.99) and pinch grip (R = 0.96) WAPU evidenced reliable values. When compared to the non-chalked trials, chalk improved both openhanded (mean = 22.8 ± 4.53 vs. mean no chalk = 19.7 ± 4.39 reps; p = 0.006,) and pinch grip (mean = 14.4 ± 4.47 vs. mean no chalk = 9.1 ± 4.83 reps; p = 0.007) WAPU. ICC's indicated a reliable measurement, while chalk improved performance for both open-handed and pinch grip WAPU when compared to no chalk trials.