Physiological Effects of Variations in Spontaneously Chosen Crank Rate During Sub-Maximal and Supra-Maximal Upper Body Exercises

The aim of the present study was to compare the physiological responses when the crank rate was chosen spontaneously (T_s) or set at ±10 % (T_{-10 %}, T_{+10 %}) of the freely chosen rate, during two upper body exercises: i) a sub-maxirmal test (T_SUB) in which intensities ranged from 50 to 80 % (118.4±10.2 to 189.5±16.3 watts) of maximal power (MP) and ii) a supra-maximal test (T_SUPRA) in which power output was set at 110 and 120 % (260.5±22.4 and 284.2±24.4 watts) of MP. Eight nationally and internationally ranked kayakers, aged 20±2 years, performed these tests in which power outputs were normalised in relation to the maximal power output determined during T_MP. In T_{SUB+10 %}, oxygen uptake and ventilation were significantly (P < 0.05) higher than during T_SUB,S. In T_{SUB+10 %} and T_{SUB-10 %}. energy expenditure was significantly (P < 0.05) higher and gross and net efficiencies lower than during T_SUB,S. During T_{SUPRA-10 %} when the power output was set at 110 % of MP, time to exhaustion was significantly higher (P < 0.05) than during T_SUPRA,S. The findings of the present study suggest that upper body exercise performed on an ergocycle should be conducted using the freely and spontaneously chosen crank rate.

Key words

Crank rate - arm ergometer - power output - kayakers