Rugby codes

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Sprinting is integral to American football and is thought to be influenced by the same gait parameters as track runners; however, the heavier mass of American football players may influence performance. The purpose of this study was to investigate the relationship between mass, contact time (TC), aerial time (TA), swing time (TS), and stance-averaged vertical ground reaction forces (vGRF) for both limbs. Subjects ran on an instrumented treadmill for 5 sec at 6.5 m/s. Tc, TA, TS and stance-averaged vGRF were compared between limbs and examined for association with mass. All parameters were symmetrical between limbs, p>.05. Mass (103.0+12.2 kg) was moderately associated with Tc (0.17+.02 sec) on the left, r=0.666, p=0.013, but not the right (r=0.551, p=.051). The high mass of American football players may affect variables associated with speed.