Resistive force selection during brief cycle ergometer exercise: implications for power assessment in international rugby union players

The purpose of this study was to examine power values generated during brief high intensity cycle ergometry exercise when the ergometer resistive forces were derived from total body mass (TBM) or fat free mass (FFM). International rugby union players (front row forwards; n = 8; and backs; n =8) volunteered as subjects. Body density was calculated from the sum of skin-folds using population specific regression procedures. Fat mass was determined from body density. Subjects were required to pedal maximally on a cycle ergometer (Monark 864) against randomly assigned resistive forces ranging from 70 g/kg - 95 g/kg for a 6 s period to determine optimal peak power outputs (PPO) for both the TBM and FFM protocols. PPO for backs and forwards using the TBM protocol were 1058 ± 84 Watts vs. 1293 ± 144 Watts, respectively (p < 0.01) Make sure all ± symbols are 12 font size. Using the FFM protocol the peak power output values increased (p < 0.01) Do not italicise this content for both groups (1163 ± 100 Watts for backs vs. 1481 ± 137 Watts for forwards). Differences (p < 0.01) were also observed between forwards and backs for cradle resistive forces and pedal revolutions (6.7 ± 0.6 kg TBM vs. 6.2 ± 0.5 kg FFM for backs; 8.4 ± 0.6 kg TBM vs. 7.3 ± 0.9 kg FFM for forwards; 143 ± 8.6 rev/min TBM vs. 147 ± 5.2 rev/min FFM for backs; 137 ± 8.2 rev/min TBM vs. 147 ± 5.2 rev/min FFM for forwards). The findings of this study indicate that rugby union forwards are more powerful than rugby union backs. Increased peak power output values observed during load optimisation procedures for FFM demonstrate that this protocol represents a method by which greater peak power can be consistently obtained during high intensity cycle ergometry.