Superior effects of high-intensity interval eccentric cycling training on neuromuscular adaptations with similar aerobic adaptations to concentric cycling

Abstract

Purpose: We compared the effects of high-intensity interval eccentric (EC) versus concentric cycling (CC) training on aerobic capacity, muscle function and morphology.

Methods: Healthy men (19-56 y) performed EC (n = 9) or CC (n = 8) training twice a week for 8 weeks. The training progressed from 5 × 2-min intervals with 1-min rest to 7 × 2-min intervals with 30-s rest. EC and CC were matched for perceived effort, and progressed from 30 to 36% of concentric peak power output (PPO_10s) for CC and from 45 to 70% PPO_10s for EC. Changes in peak oxygen consumption (VO_2peak), incremental concentric PPO (PPO_inc), 6-min walking distance (6 MW), 10 s concentric PPO (PPO_10s), maximal voluntary isometric contraction knee extensor strength (MVC), countermovement (CMJ) and squat jump height (SJ), quadriceps cross-sectional area (CSA), and fascicle length (FL) and pennation angle (PA) of vastus lateralis were compared between EC and CC.

Results: Greater (P < 0.05) changes in PPO_10s (EC: 26.9 ± 10.5% vs. CC: 8.9 ± 8.0%, Hedges'g = 2.03), CMJ (3.9 ± 1.8 vs. - 3.3 ± 7.4%, g = 1.46), SJ (7.4 ± 4.7% vs. - 2.3 ± 4.4%, g = 2.26), and CSA (6.1 ± 4.7 vs. 0.1 ± 3.8%, g = 1.48) were observed after EC than CC. No significant differences between EC and CC were found for changes in VO_2peak (3.7 ± 3.9 vs. 6.6 ± 6.9%, g = -0.55), PPO_inc (6.0 ± 4.2 vs. 6.4 ± 4.6%, g = - 0.11), 6 MW (6.0 ± 4.2 vs. 6.4 ± 4.6%, g = -1.03) and MVC (12.5 ± 13.3 vs. 6.2 ± 8.3%, g = 0.59). FL and PA did not show significant changes after EC and CC.

Conclusion: EC was more effective than CC for improving several markers of muscle function. High-intensity interval eccentric cycling appears to be suitable for simultaneously improving strength and endurance.

Keywords: Eccentric training; HIIT; Lengthening contraction; Muscle cross sectional area; Peak power output; VO2peak.