Effects of cycle strategy and fibre composition on muscle glycogen depletion pattern and subsequent running economy

Purpose In this study, the effects of variable and constant-intensity cycling on muscle glycogen depletion patterns and subsequent running economy was examined. 60 minutes of cycling at a constant power (CON) or variable intensity (VAR) followed by a treadmill run to determine running economy was completed by nine male triathletes (Vo 2 max = 67.7 (4.9 ml) kg − min −1 ). During CON, there was greater glycogen depletion in the type I fibres compared with type II (0.08 (0.04) vs 0.02 (0.01) optical density (OD) units; p −1 min −1 ). There was a strong correlation between total muscle glycogen depletion and the change in running Vo 2 (r = 0.73, p