Resumen de Body mass bias in a competition of muscle strength and aerobic power

Paul M. Vanderburgh, Lloyd L. Laubach

• Recently, a fitness competition called the Pump and Run (PR) has been popularized. Composed of 2 events, a 5-km road race time (RT) in seconds and a maximal-repetition bench press (BPR) with resistance based on a percentage of body mass (M), the final score (RTadj) equals RT ¿ 30(BPR). From published findings, the authors hypothesized that the PR would impose a bias against heavier competitors. Furthermore, the potential for age bias in this event has not been evaluated. Therefore, the purpose of this study was to investigate M and age bias in the PR for men and women. For 74 female and 343 male competitors in a large PR event, RT, BPR, M, and age were collected from official competition results. Two subsamples were randomly created from the original sample: the validation (VAL) (54 women and 258 men) and the cross-validation (CVAL) (20 women and 85 men). For the VAL sample, the RTadj showed significant bias against heavier runners (women r2 = 0.35; men r2 = 0.28; P < 0.01 for both) but no age bias (women r2 = 0.04; men r2 = 0.005; P > 0.05 for both). Using allometric modeling, the authors developed a set of M-based correction factors to be multiplied by each RTadj to yield new adjusted run times (NRTadj) that would be free of M bias. As applied to the CVAL sample, the NRTadj values virtually eliminated the M bias (women r2 = 0.04; men r2 = 0.002; P > 0.05 for both) of the current PR scoring system and retained the absence of age bias (women r2 = 0.02; men r2 = 0.0002; P > 0.05 for both). The authors recommend the use of the NRTadj scores for future PR competitions.