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Applied Bionics and Biomechanics
Volume 2017, Article ID 9084725, 8 pages
https://doi.org/10.1155/2017/9084725
Research Article

Kinematic and Electromyographic Activity Changes during Back Squat with Submaximal and Maximal Loading

1Department of Sports Medicine, Faculty of Medicine, Near East University, Nicosia, Northern Cyprus, Mersin 10, Turkey
2School of Physical Education and Sport, Near East University, Nicosia, Northern Cyprus, Mersin 10, Turkey

Correspondence should be addressed to Hasan U. Yavuz; moc.liamg@dmzuvaysalu

Received 14 October 2016; Revised 12 February 2017; Accepted 6 March 2017; Published 4 May 2017

Academic Editor: Le Ping Li

Copyright © 2017 Hasan U. Yavuz and Deniz Erdag. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The aim of this study was to investigate the possible kinematic and muscular activity changes with maximal loading during squat maneuver. Fourteen healthy male individuals, who were experienced at performing squats, participated in this study. Each subject performed squats with 80%, 90%, and 100% of the previously established 1 repetition maximum (1RM). Electromyographic (EMG) activities were measured for the vastus lateralis, vastus medialis, rectus femoris, semitendinosus, biceps femoris, gluteus maximus, and erector spinae by using an 8-channel dual-mode portable EMG and physiological signal data acquisition system (Myomonitor IV, Delsys Inc., Boston, MA, USA). Kinematical data were analyzed by using saSuite 2D kinematical analysis program. Data were analyzed with repeated measures analysis of variance (). Overall muscle activities increased with increasing loads, but significant increases were seen only for vastus medialis and gluteus maximus during 90% and 100% of 1RM compared to 80% while there was no significant difference between 90% and 100% for any muscle. The movement pattern in the hip joint changed with an increase in forward lean during maximal loading. Results may suggest that maximal loading during squat may not be necessary for focusing on knee extensor improvement and may increase the lumbar injury risk.