Net energy expenditure of gravity-independent high-speed resistive exercise done by women.

INTRODUCTION: Elevated metabolism is common to spaceflight while exercise in microgravity exacerbates energy costs. Thus in-flight exercise countermeasures must be devised that minimize energy costs as they are performed on hardware operable in microgravity. METHODS: Female subjects (N = 28), subdivided into athletic and sedentary groups, each performed two workouts on a resistive exercise device (Impulse Training Systems; Newnan, GA). Comprised exclusively of either tonic or phasic repetitions, each exercise bout entailed two 1 -min sets interspersed by a 90-s rest from which the work volume was determined. Oxygen consumption was measured before, during, and after workouts until gas uptake returned to pre-exercise levels. Net oxygen consumption was converted to net energy expenditures via indirect calorimetry. Mean net energy expenditure and work volume values were each compared with 2 (athletes, sedentaries) x 2 (tonic, phasic) ANOVAs, with repeated measures for workout. In addition, multivariate regression employed three predictor (body mass, body fat percentage, work volume) variables to account for the net energy expenditure variance. RESULTS: Workouts yielded a metabolic cost of approximately 14 kcal, yet the data produced no significant intergroup or workout differences. However, work volume analysis yielded a significant (tonic > phasic) effect. The multivariate analysis explained small yet significant amounts of net energy expenditure variance. DISCUSSION: Current results: 1) are partly attributable to higher series elastic element activity seen with Impulse repetitions; and 2) offer new information with respect to in-flight exercise protocols for female astronauts.

Anthropometry as a predictor of bench press performance done at different loads.

The purpose of our study was to examine the ability of anthropometric variables (body mass, total arm length, biacromial width) to predict bench press performance at both maximal and submaximal loads. Our methods required 36 men to visit our laboratory and submit to anthropometric measurements, followed by lifting as much weight as possible in good form one time (1 repetition maximum, 1RM) in the exercise. They made 3 more visits in which they performed 4 sets of bench presses to volitional failure at 1 of 3 (40, 55, or 75% 1RM) submaximal loads. An accelerometer (Myotest Inc., Royal Oak MI) measured peak force, velocity, and power after each submaximal load set. With stepwise multivariate regression, our 3 anthropometric variables attempted to explain significant amounts of variance for 13 bench press performance indices. For criterion measures that reached significance, separate Pearson product moment correlation coefficients further assessed if the strength of association each anthropometric variable had with the criterion was also significant. Our analyses showed that anthropometry explained significant amounts (p < 0.05) of variance for 8 criterion measures. It was concluded that body mass had strong univariate correlations with 1RM and force-related measures, total arm length was moderately associated with 1RM and criterion variables at the lightest load, whereas biacromial width had an inverse relationship with the peak number of repetitions performed per set at the 2 lighter loads. Practical applications suggest results may help coaches and practitioners identify anthropometric features that may best predict various measures of bench press prowess in athletes.