PHYSIOLOGICAL-EFFECTS OF VARIATIONS IN SPONTANEOUSLY CHOSEN CRANK RATE DURING INCREMENTAL UPPER-BODY EXERCISE

The aims of the present study were: first, to assess the interindividu al variations of a spontaneously chosen crank rate (SCCR) in relation to the power developed during an incremental upper body exercise on an arm ergometer set at a constant power regime, and second, to compare heart rate (HR) responses, expired minute ventilation ((V) over dot (E )) and oxygen consumption ((V) over dot O-2) when the pedal rates were chosen spontaneously (T-SCCR) or set at +/-10% of the freely chosen r ates (T+10% and T-10%, respectively), The mean pedal rate values were linearly related (P < 0.01) with the pourer developed during arm crank ing (r = 0.96), although large variations of pedalling rate strategies were observed between subjects. Maximal power (MP) and time to exhaus tion values were significantly higher (P < 0.05) during T-SCCR than du ring T+10% and T-10%. Peak (V) over dot O-2 values were significantly higher (P < 0.05) in T+10% than in T-SCCR and T-10%. The increase in H R, V-E, and (V) over dot O-2 mean values, in relation to the increase in the power developed, was significantly higher(P < 0.05) when the pe dal rate was set at plus 10% of the SCCR (T+10%) than in the two other conditions. The findings of the present study suggest that the use of an electromagnetically braked ergometer, which automatically adjusts the resistance component to maintain a constant work Fate, should be u sed in order to achieve the highest MP values during an incremental up per body exercise. A 10% increase of the SCCR should be used in order to provide the highest peak (V) over dot O-2 value.