Document Detail

Knee Joint Kinetics in Relation to Commonly Prescribed Squat Loads and Depths.
MedLine Citation:
PMID:  23085977     Owner:  NLM     Status:  Publisher    
ABSTRACT: Controversy exists regarding the safety and performance benefits of performing the squat exercise to depths beyond 90° of knee flexion. Our aim was to compare the net peak external knee flexion moments (pEKFM) experienced over typical ranges of squat loads and depths. Sixteen recreationally trained males (n = 16; 22.7 ± 1.1 yrs; 85.4 ± 2.1 kg; 177.6 ± 0.96 cm; mean ±SEM) with no previous lower limb surgeries or other orthopedic issues and at least one year of consistent resistance training experience while utilizing the squat exercise performed single repetition squat trials in a random order at squat depths of above parallel, parallel, and below parallel. Less than one week before testing, one repetition maximum (1RM) values were found for each squat depth. Subsequent testing required subjects to perform squats at the three depths with three different loads: unloaded, 50% 1RM, and 85% 1RM (nine total trials). Force platform and kinematic data were collected to calculate pEKFM. To assess differences among loads and depths, a two-factor (load and depth) repeated-measures ANOVA with significance set at the P < 0.05 level was used. Squat 1RM significantly decreased 13.6% from the above parallel to parallel squat and another 3.6% from the parallel to the below parallel squat (P < 0.05). Net peak external knee flexion moments significantly increased as both squat depth and load were increased (P ≤ 0.02). Slopes of pEKFM were greater from unloaded to 50% 1RM than when progressing from 50% to 85% 1RM (P < 0.001). The results suggest that that typical decreases in squat loads used with increasing depths are not enough to offset increases in pEKFM.
Joshua A Cotter; Ajit M Chaudhari; Steve T Jamison; Steven T Devor
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-10-18
Journal Detail:
Title:  Journal of strength and conditioning research / National Strength & Conditioning Association     Volume:  -     ISSN:  1533-4287     ISO Abbreviation:  J Strength Cond Res     Publication Date:  2012 Oct 
Date Detail:
Created Date:  2012-10-22     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9415084     Medline TA:  J Strength Cond Res     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
1Department of Orthopaedics, University of California, Irvine 2Department of Orthopaedics, The Ohio State University 3Department of Mechanical & Aerospace Engineering, The Ohio State University 4Sports Health & Performance Institute, The Ohio State University 5Department of Health and Exercise Science, The Ohio State University 6Department of Physiology and Cell Biology, The Ohio State University 7Department of Human Nutrition, The Ohio State University.
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