Body mass and exercise variable relationships to lactate derived from gravity-independent devices.

Introduction: Historically, exercise performance outcomes may be predicted with anthropometric variables such as body mass. To assess body mass and resistance exercise (REX) performance variable correlations to blood lactate values, subjects performed five different workouts on two devices that do not employ gravitational resistance. One device uses flywheels to impose a low-speed high-resistance exercise stimulus while the other, dubbed a Dual Performance Device (DPD), has a sled mounted on a very low friction track to enable high-speed low-resistance repetitions.

Methods: Subjects (n = 18) performed 3 leg press workouts on the flywheel ergometer (FE), which entailed: 1) a 3-set 10-repetition protocol with concentric and eccentric actions; or 2) the same set-repetition paradigm with concentric-only actions; or 3) a 6-set 10-repetition protocol of concentric-only actions. DPD workouts, done by a separate (n = 22) group, involved 2 workouts each composed exclusively of tonic or phasic seated knee and hip extensor repetitions. Multivariate regression was employed, with post-exercise and delta (post/ pre) blood lactate values as criterion measures.

Results: While body mass and performance values from FE workouts were weakly correlated to the criterion measures, body mass and average power (AP) variables from DPD tonic workouts explained 99% of the post-exercise and delta[BLa-] variance and yielded two prediction equations: post-REX blood lactate' = 0.06 + 11.21(AP) + -11.53(body mass), delta blood lactate' = 0.03 + 11.83(AP) + -12.00(body mass).

Conclusions: Results were most likely due to differences in central command requirements for each exercise device.