title: Power absorption and production during slow, large-amplitude stretch-shorten cycle motions.
abstract: The purpose of this study was to determine the important predictors of power absorption and power production during slow, large-amplitude stretch-shorten cycle (SSC) motions. The relationship between power absorption (mean eccentric power output) and production (mean concentric power output) across different inertial loads was also investigated. Fifty-four subjects with a sporting background performed concentric (CBP) and rebound bench-presses (RBP) at 40% and 80% of their one-repetition maximum (1RM). The relationship between kinematic and kinetic variables and mean eccentric power and RBP mean power output was determined using correlation and multiple regression analysis. Maximal strength was found to be the best single predictor of power absorption, explaining between 44.2% and 69.1% of the variability that was associated with mean eccentric power output for 40% and 80% 1RM loads. Stretch velocity in combination with maximal strength was found to be the best two-predictor model of power absorption ( R(2)=83.7-97.3%). The best single predictor of SSC power production was found to be concentric mean power output ( R(2)=49.2-88.0%). The utilisation of the power absorbed during the power production phase differed across loads. It was suggested that as maximal strength is more trainable than speed, training to improve power absorption might emphasise maximal strength development. It was also suggested that SSC power output might benefit from training methods that focus on concentric force development. Further research is needed to evaluate these hypotheses and whether the findings of this study are similar for fast SSC motion.
authors.affiliation: Sport Performance Research Centre, Auckland University of Technology, Private Bag 92006, Auckland 1020, New Zealand. john.cronin@aut.ac.nz
authors.forename: John B
authors.initials: JB
authors.lastname: Cronin
authors.forename: Peter J
authors.initials: PJ
authors.lastname: McNair
authors.forename: Robert N
authors.initials: RN
authors.lastname: Marshall
mesh_terms: D000328:Adult; D004548:Elasticity; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D014891:Weight Lifting / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology