Inclusion of eccentric actions on net caloric cost resulting from isoinertial resistance exercise.
Net O(2) uptake was measured from maximal-effort 3-set, 8-repetition seated leg press protocols on an isoinertial ergometer. Subjects (25 women, 9 men) did 2 workouts each exerting concentric-eccentric (CE) and concentric-only (CO) knee extensor forces to measure work and net caloric cost. Significant (p < 0.05) relationships between work and net caloric cost resulted from CE and CO workouts for the male, female, and total subject sample. Two-way repeated-measures analyses of variance showed CE workouts resulted in significantly higher work but not net caloric cost and values. CE workouts likely relied on the knee extensors series elastic element to perform an additional approximately 3,600 J of eccentric work at no additional net caloric cost. Unlike other exercise modes, maximal-effort eccentric actions on the isoinertial ergometer, as done in the current study, provide no additional net caloric cost and is thus safe to administer to populations in whom metabolic cost is a concern.