Abdominal Hoop Stress: A Field-Deployable Instrument for Quantifying Bracing During the Squat and Deadlift in Powerlifters.

Harris, SM, Wang, W, Morrow, RM, Hutton, M, and Gleeson, P. Abdominal hoop stress: A field-deployable instrument for quantifying bracing during the squat and deadlift in powerlifters. J Strength Cond Res XX(X): 000-000, 2026-Abdominal bracing is widely taught for spinal protection during heavy lifts, yet no field-deployable measure quantifies it directly during the squat and deadlift. We piloted a strain-gauge weightlifting belt that records peak abdominal hoop stress (AHS) in collegiate powerlifters and examined its consistency and associations with low back pain (LBP) history and maximal performance. Twenty-five powerlifters (17 men, 8 women; ages 18-25 years) completed squat and deadlift sets at 25, 50, 75, and 100% of a 75%-1RM target. Within-session repeatability used duplicate measures in 10 subjects. Independent t-tests, Pearson correlations, and general linear mixed models related peak AHS to LBP history, sex, body mass index (BMI), exercise type, and weight lifted. Abdominal hoop stress showed high reliability (intraclass correlation coefficient (2, 1) ≥ 0.996) and correlated strongly with maximal squat (r = 0.752) and deadlift (r = 0.654; both p < 0.001). Lifters with prior LBP showed substantially lower AHS (Cohen's d = 1.38; p = 0.002). After adjustment for exercise, sex, BMI, and prior LBP, weight lifted remained independently associated with AHS (β = 0.05, p < 0.001). These pilot data support AHS as a feasible field measure of abdominal bracing warranting further evaluation as a candidate screening signal and training target.