Bicycle Shoe Insoles and Their Effect on Lateral Knee Movement, Leg Muscle Activation Patterns, and Performance in Experienced Cyclists

Orthotic insoles in cycling shoes are an intervention used to correct pedaling mechanics in riders, which has received little attention in the literature. This study was designed to test the hypothesis that the use of orthotic insoles in cycling shoes would alter the pedaling mechanics, muscle activity, and submaximal efficiency of healthy, experienced, male cyclists. Additionally, it was hypothesized that the insole that allowed the lowest level of lateral knee movement would produce the greatest improvement in these variables, and be related to the rider\u27s arch height. Nine cyclists were evaluated during four VO2max tests, using four different insole conditions (flat [no insole], low, medium, and high arch support) in a random order. High-definition video recordings were used to measure lateral knee movement, wireless electromyography to measure muscle activity, and telemetry-based gas analysis to determine cycling efficiency. VO2max tests were performed at least 48 hours apart to control for fatigue. The non-flat insole that resulted in the lowest level of lateral knee movement was identified for each leg; Spearman rank-order correlations showed no relationship between arch variables and this best fit insole. Because the best fit insole was not the same between feet for most participants, general linear mixed models were run 2 ways, with the best insole for the dominant leg and non-dominant leg identified as the overall best fit insoles. When the best fit for the dominant leg was identified as the overall best fit insole, it produced effects on dominant knee lateral movement (p=.001) and heart rate at anaerobic threshold (p=.014). The non-dominant best fit insole had a significant effect on heart rate at anaerobic threshold (p=.017). There was also an interaction effect in the dominant leg hamstrings ratio between insoles and pedal float type (p=.007). The implication of these findings is that orthotic insoles may be an effective intervention to alter pedaling mechanics and upper leg muscle activation ratios about the knee, but have little effect on cycling performance