Human Testosterone and Lactate Values from Flywheel Ergometry: Effect of Contractile Mode and Work Volume

In-flight resistive exercise workouts are performed on novel flywheel-based hardware. Designs of such workouts may be better served by measuring changes to lactate and testosterone values. To make workouts pertinent to μ they should utilize unique features of flywheel-based hardware, such as the option to exert eccentric torque. Our study compares changes to blood lactate and testosterone concentrations ([BLa ], [T]) from leg press workouts that differ by contractile mode and work volume, on a flywheel ergometer. Subjects performed three workouts; two entailed two sets of concentric-eccentric (CE2) or concentric-only (CO2) actions. A third involved four sets of concentric-only actions (CO4). Workouts entailed eight-repetition sets with 90-second rest periods. Total work (TW) was quantified per workout. [T] were assessed, both pre- and post-exercise. [BLa ] were measured pre- and at 0-, 5-, 10-, 15-, and 20-minutes post-exercise. TW was assessed with a one-way analysis of variance (ANOVA). [BLa ] and [T] were evaluated with two- and three-factor ANOVAs, respectively. Scheffe’s test was our post-hoc. TW data had an inter-workout (CE2, CO4 > CO2) difference. [BLa ] included a two-way interaction as CO4 workouts evoked higher post-exercise values. Results for [T] produced gender (men > women) and time (post > pre) main effects. Our results imply flywheel-based workouts with a large volume of concentric actions evoke no greater increase in [T] than workouts with only half the muscle shortening activity, despite attainment of higher TW and post-workout [BLa ].