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Reliability of Performance Velocity for Jump Squats under Feedback and Nonfeedback Conditions

Randell, Aaron D; Cronin, John B; Keogh, Justin WL; Gill, Nicholas D; Pedersen, Murray C

The Journal of Strength & Conditioning Research: December 2011 - Volume 25 - Issue 12 - p 3514-3518
doi: 10.1519/JSC.0b013e318216001f
Research Notes

Randell, AD, Cronin, JB, Keogh, JWL, Gill, ND, and Pedersen, MC. Reliability of performance velocity for jump squats under feedback and nonfeedback conditions. J Strength Cond Res 25(12): 3514–3518, 2011—Advancements in the monitoring of kinematic and kinetic variables during resistance training have resulted in the ability to continuously monitor performance and provide feedback during training. If equipment and software can provide reliable instantaneous feedback related to the variable of interest during training, it is thought that this may result in goal-oriented movement tasks that increase the likelihood of transference to on-field performance or at the very least improve the mechanical variable of interest. The purpose of this study was to determine the reliability of performance velocity for jump squats under feedback and nonfeedback conditions over 3 consecutive training sessions. Twenty subjects were randomly allocated to a feedback or nonfeedback group, and each group performed a total of 3 “jump squat” training sessions with the velocity of each repetition measured using a linear position transducer. There was less change in mean velocities between sessions 1–2 and sessions 2–3 (0.07 and 0.02 vs. 0.13 and −0.04 m·s−1), less random variation (TE = 0.06 and 0.06 vs. 0.10 and 0.07 m·s−1) and greater consistency (intraclass correlation coefficient = 0.83 and 0.87 vs. 0.53 and 0.74) between sessions for the feedback condition as compared to the nonfeedback condition. It was concluded that there is approximately a 50–50 probability that the provision of feedback was beneficial to the performance in the squat jump over multiple sessions. It is suggested that this has the potential for increasing transference to on-field performance or at the very least improving the mechanical variable of interest.

1Sport Performance Research Institute New Zealand, AUT University, Auckland, New Zealand; 2School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia; and 3Bay of Plenty Rugby Union, Mount Maunganui, New Zealand

Address correspondence to Aaron D. Randell,

Copyright © 2011 by the National Strength & Conditioning Association.