AUTHOR=Harrison Amelia J. , Burdon Catriona A. , Groeller Herbert , Peoples Gregory E. 

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

JOURNAL=Frontiers in Physiology

VOLUME=Volume 11 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2020.00336

DOI=10.3389/fphys.2020.00336

ISSN=1664-042X

ABSTRACT=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 HIIT cycling trial to determine acute cardiopulmonary, thermal and psycho-physiological responses. Twelve males (age 28 y [SD 6], peak oxygen consumption 48 mL·kg-1·min-1 [SD 6]) completed two high intensity interval cycling trials (4x5 min, 60% peak power output (PPO)) separated by 7-10 days. The CONR trial required participants to cycle concentrically during each recovery period (5 min, 30% PPO). The ECCR trial modified the recovery to be eccentric cycling (5 min, 60% PPO). High intensity workload (CONR: 187 ± 17; ECCR: 187 ± 21W), oxygen consumption (CONR: 2.55 ± 0.17; ECCR: 2.68 ± 0.20 L·min-1), heart rate (CONR: 165 ± 7; ECCR: 171 ± 10 b·min-1) and RPE legs (CONR: 15 ± 3; ECCR: 15 ± 3) were equivalent between trials. Eccentric cycling recovery significantly increased external workload (CONR: 93 ± 18; ECCR: 196 ± 24W, P<0.01) yet lowered oxygen consumption (CONR: 1.51 ± 0.18; ECCR: 1.20 ± 0.20 L·min-1, P<0.05) while heart rate (CONR: 132 ± 13; ECCR: 137 ± 12 b·min-1) and RPE of the legs (CONR: 11 ± 7; ECCR: 12 ± 7) remained equivalent. There was no significant difference in the aural temperature between the trials (ECCR 37.3 ± 0.1°C; CONR 37.4 ± 0.1°C, P>0.05), yet during recovery periods mean skin temperature was significantly elevated in the ECCR (ECCR: 33.3 ± 0.2°C; CONR: 33.9 ± 0.2°C, P<0.05). Participants preferred ECCR (10/12) and rated the ECCR as more achievable (82.8 ± 11.4mm) than CONR (79.4 ± 15.9mm, 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.