Effect of concurrent power training and high-intensity interval cycling on muscle morphology and performance

The aim of the study was to examine the effect of performing high-intensity interval cycling on muscle morphology and performance immediately after power training (PT). Twenty healthy female physical education students were assigned into 2 training groups. One group performed PT, and the other group performed the same PT followed by high-intensity interval aerobic training on a cycle ergometer (PTC). Training was performed 3 days per week for 6 weeks. Countermovement jump (CMJ) height and CMJ power, half-squat maximal strength (1 repetition maximum), maximum aerobic power, vastus lateralis muscle fiber composition, and cross-sectional area (CSA) were evaluated before and after the intervention. Countermovement jump height increased after PT (10.1 6 6.6%, p 5 0.002) but not after PTC (25.1 6 10.5%, p 5 0.099), with significant difference between groups (p 5 0.001). Countermovement jump power increased after PT (4.5 6 4.9%, p 5 0.021) but not after PTC (22.4 6 6.4, p 5 0.278), with significant difference between groups (p 5 0.017). One repetition maximum increased similarly in both groups. Muscle fiber composition was not altered after either PT or PTC. Vastus lateralis muscle fiber CSA increased significantly and similarly after both PT (I: 16.9 6 16.2%, p 5 0.035, ΙΙΑ: 12.7 6 10.9%, p 5 0.008,ΙΙΧ: 15.5 6 17.1%, p 5 0.021) and PTC (Ι: 18.0 6 23.7%, p 5 0.033,ΙΙΑ: 18.2 6 11.4%, p 5 0.001,ΙΙΧ: 25.5 6 19.6%, p 5 0.003). These results suggest that the addition of high-intensity interval cycling to PT inhibits the anticipated increase in jumping performance induced by PT per se. This inhibition is not explained by changes in muscle fiber type composition or vastus lateralis muscle fiber CSA adaptations.