title: Methodological concerns for determining power output in the jump squat.
abstract: The purpose of this study was to investigate the validity of power measurement techniques during the jump squat (JS) utilizing various combinations of a force plate and linear position transducer (LPT) devices. Nine men with at least 6 months of prior resistance training experience participated in this acute investigation. One repetition maximums (1RM) in the squat were determined, followed by JS testing under 2 loading conditions (30% of 1RM [JS30] and 90% of 1RM [JS90]). Three different techniques were used simultaneously in data collection: (a) 1 linear position transducer (1-LPT); (b) 1 linear position transducer and a force plate (1-LPT + FP); and (c) 2 linear position transducers and a force place (2-LPT + FP). Vertical velocity-, force-, and power-time curves were calculated for each lift using these methodologies and were compared. Peak force and peak power were overestimated by 1-LPT in both JS30 and JS90 compared with 2-LPT + FP and 1-LPT + FP (p <or= 0.05). Peak power determined by 2-LPT + FP was significantly higher than that determined by 1-LPT + FP under the JS90 loading condition. Peak vertical velocity determined by 2-LPT + FP was significantly lower than that determined by either 1-LPT and 1-LPT + FP in JS90. This investigation indicates that peak power and the timing of power output in the jump squat varies according to the measurement technique utilized. The 1-LPT methodology is not a valid means of determining power output in the jump squat. Furthermore, the 1-LPT + FP method may not accurately represent power output in free weight movements that involve a significant amount of horizontal motion.
authors.affiliation: School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Perth, Western Australia.
authors.forename: Prue
authors.initials: P
authors.lastname: Cormie
authors.forename: Russell
authors.initials: R
authors.lastname: Deane
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: McBride
mesh_terms: D000328:Adult; D003625:Data Collection / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007866:Leg / Q000502:physiology*; D016014:Linear Models; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010806:Physical Education and Training; D014159:Transducers