The Acute Physiological Responses of Eccentric Cycling During the Recovery Periods of a High Intensity Concentric Cycling Interval Session

Eccentric and concentric exercise is associated with disparate acute and chronic responses. We uniquely interspersed workload equivalent eccentric cycling during each recovery period of a high intensity interval training (HIIT) cycling trial to determine acute cardiopulmonary, thermal and psycho-physiological responses. Twelve males [age 28 years (SD 6), peak oxygen consumption 48 mL ⋅ kg(–1) ⋅ min(–1) (SD 6)] completed two high intensity interval cycling trials [4 × 5 min, 60% peak power output (PPO)] separated by 7–10 days. The CON(R) trial required participants to cycle concentrically during each recovery period (5 min, 30% PPO). The ECC(R) trial modified the recovery to be eccentric cycling (5 min, 60% PPO). High intensity workload (CON(R): 187 ± 17; ECC(R): 187 ± 21 W), oxygen consumption (CON(R): 2.55 ± 0.17; ECC(R): 2.68 ± 0.20 L ⋅ min(–1)), heart rate (CON(R): 165 ± 7; ECC(R): 171 ± 10 beats ⋅ min(–1)) and RPE legs (CON(R): 15 ± 3; ECC(R): 15 ± 3) were equivalent between trials. Eccentric cycling recovery significantly increased external workload (CON(R): 93 ± 18; ECC(R): 196 ± 24 W, P < 0.01) yet lowered oxygen consumption (CON(R): 1.51 ± 0.18; ECC(R): 1.20 ± 0.20 L ⋅ min(–1), P < 0.05) while heart rate (CON(R): 132 ± 13; ECC(R): 137 ± 12 beats ⋅ min(–1)) and RPE of the legs (CON(R): 11 ± 7; ECC(R): 12 ± 7) remained equivalent. There was no significant difference in the aural temperature between the trials (ECC(R): 37.3 ± 0.1°C; CON(R): 37.4 ± 0.1°C, P > 0.05), yet during recovery periods mean skin temperature was significantly elevated in the ECC(R) (ECC(R): 33.9 ± 0.2°C; CON(R): 33.3 ± 0.2°C, P < 0.05). Participants preferred ECC(R) (10/12) and rated the ECC(R) as more achievable (82.8 ± 11.4 mm) than CON(R) (79.4 ± 15.9 mm, P < 0.01). In conclusion, eccentric cycling during the recovery period of a HIIT training session, offers a novel approach to concurrent training methodology. The unique cardiopulmonary and skeletal muscle responses facilitate the achievement of both training stimuli within a single exercise bout.