Physiological and biomechanical factors of cycling performance

Abstract

The two primary predictors of cycling performance are maximal oxygen consumption and lactate threshold. However, several physiological and biomechanical factors influence these variables. The purpose of study one was to investigate relative joint contribution, muscle activation, and muscle oxygenation differences between high (HLT) and low (LLT) lactate threshold cyclists with similar maximal oxygen consumption capabilities (VO [subscript 2max]). While there were no differences in muscle oxygenation, the HLT group had greater relative hip contribution at 90% of VO [subscript 2max] compared to the LLT group, as well as decreased vastus medialis EMG activation during exercise at 60 and 70% of VO [ subscript 2max] (p<0.05). These findings suggesting the HLT cyclists place a greater emphasis on the hip compared to the knee joint to generate power while cycling. The purpose of study two was to investigate the effects of short-term maximal power training on cycling peak oxygen consumption (VO [subscript 2peak-cycling]) in non-cyclists. Over the course of 5 days, the training group performed 10 maximal sprints a day each lasting ~4 seconds with two-minutes rest between each sprint. This protocol was designed to maximize recruitment of muscles involved in cycling while minimizing cardiovascular stress during training. Following training, absolute and relative VO [subscript 2peak-cycling] was 5.9 ± 1.6% and 5.6 ± 1.9% greater compared to pre-training (p<0.05), while in the control group VO [subscript 2peak-cycling] did not change (p>0.05). The improvement in VO [subscript 2peak-cycling] was accompanied by a 6.3 ± 2.5% increase (Pre: 228 ± 18 W vs. Post: 242 ± 19 W) in peak work rate achieved during post-testing in the training group (p<0.05). This suggests that VO [subscript 2peak-cycling] can be increased through maximal power training in non-cyclists likely as a result of increased ability to recruit additional muscle mass during intense cycling exercise. Taken together, these studies indicate that biomechanical muscle recruitment 'strategies' can influence both submaximal (i.e. LT [subscript VO2]) and peak oxygen consumption (i.e. VO [subscript 2peak-cycling]) during cycling.