Strength training reduces freely chosen pedal rate during submaximal cycling

The freely chosen pedal rate is relatively high and energetically inefficient during submaximal cycling, which is a paradox since the rate of energy expenditure is considered important for voluntary motor behavior in other cyclical activities as, e.g., running. For example, it has been suggested that subjects pedal fast to reduce the perception of force. In this study, we investigated the hypothesis that strength training would cause subjects to pedal at a slower rate during low to moderate submaximal cycling. Fourteen healthy subjects performed supervised heavy (2-12 RM) strength training 4 days/week for 12 weeks, including 2 days/week with leg-extensor and knee-flexor exercises. Seven healthy subjects formed the control group. The training group increased strength (one repetition maximum, 1 RM) in both squat [20%(3), mean (SEM)] and leg curl [12%(1)] exercises from the beginning to the end of the study period (p<0.01). At the same time, freely chosen pedal rate was reduced by 8 (2) and 10 (2) rpm, respectively, during cycling at 37 and 57% of maximal power output (Wmax) (p<0.01). In addition, rate of energy expenditure is 3% (2) lower at 37% of Wmax (p<0.05) and tended to be lower at 57% Wmax (p=0.07) at the end of the study. Values for strength, freely chosen pedal rate, and rate of energy expenditure, were unchanged for the control group from the beginning to the end of the study. In conclusion, strength training caused subjects to choose an approximately 9 rpm lower pedal rate during submaximal cycling. This was accompanied by a approximately 3% lower rate of energy expenditure.