Kinetic Analysis of Isometric Back Squats and Isometric Belt SquatsLayer, Jacob S.1; Grenz, Christylynne1; Hinshaw, Taylour J.1; Smith, Derek T.1; Barrett, Steven F.2; Dai, Boyi1The Journal of Strength & Conditioning Research: December 2018 - Volume 32 - Issue 12 - p 3301–3309 doi: 10.1519/JSC.0000000000002854 Original Research Abstract Author InformationAuthors Article MetricsMetrics Layer, JS, Grenz, C, Hinshaw, TJ, Smith, DT, Barrett, SF, and Dai, B. Kinetic analysis of isometric back squats and isometric belt squats. J Strength Cond Res 32(12): 3301–3309, 2018—Belt squats seem to provide an alternative to back squats. However, it is not clear how musculoskeletal loading differs between the two. This study compared lower extremity and low-back kinetics during isometric back squats and isometric belt squats. Sixteen men (age: 22.6 ± 3.4 years; height: 1.74 ± 0.11 m; mass: 82.0 ± 5.6 kg) and 10 women (age: 21.5 ± 2.5 years; height: 1.64 ± 0.10 m; mass: 68.9 ± 7.1 kg) performed isometric back squats and belt squats at 4 squat depths. Joint resultant moments were calculated from kinematic and ground reaction force data. Linear interpolation was used to estimate peak vertical forces and joint moments at a 45° thigh segment angle. Subjects increased peak forces, ankle moments, and knee moments but decreased low-back moments from back to belt squats (p ≤ 0.023). Hip moments did not significantly change between 2 squats. Subjects demonstrating smaller ankle and knee moments during back squats showed greater increases in these moments from back to belt squats (p ≤ 0.012, R 2 ≤ 0.24). Subjects whose back squats were characterized by greater low-back moments displayed greater decreases in low-back moments from back to belt squats (p < 0.001, R 2 = 0.98). Compared with isometric back squats, isometric belt squats may provide a similar or greater external loading for the musculoskeletal system of the lower extremities while reducing external spinal loading. Belt squats may be considered by individuals with upper-body or spinal injuries and those displaying excessive external back moments. 1Division of Kinesiology and Health, University of Wyoming, Laramie, Wyoming; and 2Department of Electrical and Computer Engineering, University of Wyoming, Laramie, Wyoming Address correspondence to Boyi Dai, firstname.lastname@example.org. Copyright © 2018 by the National Strength & Conditioning Association.