Hooper, D. R., Szivak, T. K., Comstock, B. A., Dunn-Lewis, C., Apicella, J. M., Kelly, N. A., Creighton, B. C., DiStefano, L. J., Volek, J., Maresh, C. M., & Kraemer, W. J. (2012). Changes in movement patterns following a fatiguing resistance training protocol. Presentation 2190 at the 59th Annual Meeting of the American College of Sports Medicine, San Francisco, California; May 29-June 2, 2012.

The purpose of this study was to establish the effects that fatigue from resistance exercise has on joint biomechanics and therefore, assess the potential consequences these changes might have in men (N = 14). Ss underwent a 3-dimensional analysis of five bodyweight squats before and after a highly fatiguing resistance training workout. The workout included barbell squat, barbell bench press, and barbell deadlift performed at 75% 1RM with a descending pyramid of repetitions beginning at 10 and ending at 1 for all lifts. Peak angle, total angular displacement and displacement rate were assessed for knee flexion, trunk flexion, hip flexion, hip rotation, and hip adduction.

Following a fatiguing resistance training workout, there was a significant decrease in peak angle for knee flexion, hip flexion, and hip adduction. There was a significant reduction in angular displacement for knee flexion, hip flexion, hip adduction, and hip rotation. There was also a significant reduction in displacement rate for knee flexion, hip flexion, hip adduction, and hip rotation.

Implication. Resistance training combining high loads and short rests produce fatigue that results in significant changes in movement technique. Changes in movement technique have been associated with injury, therefore it is important for strength coaches to consider the effects that fatigue has on joint biomechanics to prevent possible injury.

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