Kinetic Analysis of Isometric Back Squats and Isometric Belt Squats

• Published in: Journal of strength and conditioning research Vol. 32; no. 12; p. 3301
• Main Authors: Layer, Jacob S, Grenz, Christylynne, Hinshaw, Taylour J, Smith, Derek T, Barrett, Steven F, Dai, Boyi
• Format: Journal Article
• Language: English
• Published: United States 01.12.2018
• Subjects: Adult; Ankle Joint; Back - physiology; Biomechanical Phenomena; Female; Humans; Kinetics; Knee Joint; Lower Extremity - physiology; Male; Posture; Young Adult
• ISSN: 1064-8011; 1533-4287
• DOI: 10.1519/JSC.0000000000002854

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 ≤ 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 = 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.