Data reproducibility of an inertial resistance exercise device suggested for use during space travel

• Published in: Isokinetics and exercise science 2006-01, Vol.14 (4), p.371-382
• Main Authors: CARUSO, J. F, WILLIAMS, J. A, HARI, P, MCCOY, J. D, CODAY, M. A, RAMSEY, C. A, CAPPS, L. B
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports
• ISSN: 0959-3020; 1878-5913
• DOI: 10.3233/ies-2006-0251

An exercise ergometer that employs two flywheels for inertial resistance was created to abate ankle extensor mass and strength losses incurred with space flight. Unlike other flywheel- and inertia-based devices, the ergometer imparts muscle-lengthening resistance so that the ankle extensors may perform concentric and eccentric muscle actions within a single exercise repetition. Due to the unique manner the ergometer operates and the need to quantify workout data for the development of in-flight exercise protocols, instrumentation of the device is an important concern. After calculation of the flywheels' moment of inertia, a motor with a small rotary shaft and rubber wheel at its terminal end was mounted on the ergometer so that it stayed in contact with, and rotated concurrently with, a single flywheel. Voltage samples produced from changes in flywheel velocity were recorded on-line at 100 MHz. Exercise performance was assessed in healthy college-age subjects (n=34) across two workouts spaced one week apart. Workouts entailed two sets of ten seated calf press repetitions as subjects were instructed to exert maximal voluntary effort. Multiple test-retest measures revealed the inertial resistance ergometer, instrumented as described herein, elicits reproducible intra- and inter-workout performance data.