Cycling impairs neuromuscular control during running in triathletes: Implications for performance, injury and intervention

Abstract

Triathletes report incoordination when running after cycling. Fatigue is likely to contribute but impaired coordination of running may also relate to interference with neuromuscular control independent of fatigue. We investigated (a) the influence of the bike-run transition on neuromuscular coordination of running (i.e. does cycling have a direct effect on running?), (b) the effect of altered neuromuscular coordination on run-economy (RE, steady-state V02), (c) the association between exercise-related-leg-pain (ERLP) and neuromuscular coordination of running, (d) the role of fatigue in coordination changes, and (e) the effectiveness of taping as an intervention for impaired neuromuscular coordination. 34 highly trained triathletes participated. Three-dimensional kinematics, muscle recruitment and RE were compared between a control-run (no prior exercise) and a 30-min transition-run (preceded by 20 min of moderate-intensity cycling; i.e. run vs. cycle-run). Fatigue was evaluated using an established isometric protocol. Neuromuscular coordination was compared between transition-runs with and without augmented-low-Dye anti-pronation-taping applied. Short periods of cycling had no direct effect on running kinematics or muscle activity in most (−70%) highly trained triathletes. However, running muscle activity was influenced by cycling in a proportion (−30%) of highly trained triathletes (70.1 ± 13.7% change in mean EMG amplitude). This influence was not related to altered kinematics or fatigue, but instead was a direct effect of cycling on motor commands for running. This altered muscle recruitment was associated with reduced RE (3.7 ± 0.9% increase in V02) and 2.5-times greater likelihood of a history of ERLP, but was improved by an established taping intervention (70.5 ± 18.6% reversal of altered muscle recruitment).