Affiliations: [a] Exercise and Sport Science Program, The University of
Tulsa, Tulsa, OK 74104, USA | [b] Exercise Physiology Laboratory, The University of
Nevada-Reno, Reno, NV 89557, USA
Note: [] Address for correspondence: John F. Caruso, Ph.D., 312 Chapman
Hall, 600 S. College Avenue, The University of Tulsa, Tulsa, OK 74104, USA.
Tel.: +1 918 631 2924; Fax: +1 918 631 2068; E-mail: [email protected]
Abstract: An inertia-based ergometer is among the latest devices suggested to
abate space flight-induced muscle deconditioning. The current study uses
separate sets of subjects to assess net caloric cost (n=14) and
electromyography (EMG) (n=46) responses to leg presses
done on the ergometer. All subjects performed the eight-repetition protocol
three times over a two-week period. Net caloric cost measurements entailed
indirect calorimetry from O_2 uptakes resulting from
exercise on the ergometer. EMG subjects provided first and eighth repetition
work, root mean square (RMS) and mean power frequency (MPF) data. Work output
was more correlated to net caloric cost (r=0.83,
p<0.05) than were anthropometric variables. EMG subject
data showed work had gender-by-muscle-action and repetition-by-muscle-action
effects, with male concentric and first repetition concentric data responsible
the respective interactions. From the first to the eighth repetition, eccentric
work incurred insignificant changes. RMS had a repetition-by-muscle-action
effect, with eighth eccentric repetition data the source of the interaction.
MPF showed an effect for repetition (eighth < first). In
lieu of significant eighth-repetition RMS and MPF changes, high-threshold
lengthening motor unit recruitment and/or greater series elastic element
activity may explain the lack of eccentric work losses.
Keywords: Metabolism, concentric, eccentric, strength training
