Dr Donal O’Gorman’s lab has previously conducted a study comparing the physiological responses during cycling at different pedalling rates. In that study, they observed that 30 rpm (65 versus 95rpm) of a difference resulted in no difference on maximal exercise but significantly greater oxygen consumption at the higher pedalling rate during sub-maximal exercise, even though the total amount of work performed was the same. This finding has prompted his research group to conduct more detailed experiments to investigate the possible mechanism behind this observed difference.
For this study participants will be asked to cycle on a stationary bicycle for a max of 60 minutes on 3 separate occasions at 55% of their peak power output (55%PP), determined during a standard test of aerobic fitness. The intensity (55%PP) is within the recommended range for physical activity according to Irish and international guidelines. As the attainment of peak power is also influenced by the pedalling rates we will perform the standard aerobic fitness test at 65 and 95 rpm pedalling frequencies also. In total there will be 5 visits to the lab. A muscle biopsy of the vastus lateralis will be performed before and after each of the submaximal exercise trials. The outcome of this study will allow us to determine
1. Whether the length of time or number of contractions has a greater impact on oxygen consumption
2. The influence of contraction rate on muscle metabolism.
