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 ⋅ min (SD 6)] completed two high intensity interval cycling trials [4 × 5 min, 60% peak power output (PPO)] separated by 7-10 days. The trial required participants to cycle concentrically during each recovery period (5 min, 30% PPO). The trial modified the recovery to be eccentric cycling (5 min, 60% PPO). High intensity workload ( : 187 ± 17; : 187 ± 21 W), oxygen consumption ( : 2.55 ± 0.17; : 2.68 ± 0.20 L ⋅ min), heart rate ( : 165 ± 7; : 171 ± 10 beats ⋅ min) and RPE legs ( : 15 ± 3; : 15 ± 3) were equivalent between trials. Eccentric cycling recovery significantly increased external workload ( : 93 ± 18; : 196 ± 24 W, < 0.01) yet lowered oxygen consumption ( : 1.51 ± 0.18; : 1.20 ± 0.20 L ⋅ min, < 0.05) while heart rate ( : 132 ± 13; : 137 ± 12 beats ⋅ min) and RPE of the legs ( : 11 ± 7; : 12 ± 7) remained equivalent. There was no significant difference in the aural temperature between the trials ( : 37.3 ± 0.1°C; : 37.4 ± 0.1°C, > 0.05), yet during recovery periods mean skin temperature was significantly elevated in the ( : 33.9 ± 0.2°C; : 33.3 ± 0.2°C, < 0.05). Participants preferred (10/12) and rated the as more achievable (82.8 ± 11.4 mm) than (79.4 ± 15.9 mm, < 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.