Electromyography (EMG) analysis of core bracing mechanism after verbal cueing during a bodyweight squat

Context: Verbal instruction on core bracing is used by healthcare providers and strength and conditioning professionals with the aim of increasing intrabdominal pressure via co-contraction to prevent potential prevent low back pain (LBP) and injury. Objective: To determine if verbal instruction immediately increases bilateral external oblique (EO) and lumbar erector spinae (LES) muscle activation during a bodyweight squat. Design: An experimental within subjects repeated-measures study. Setting: University of Utah Sports Medicine Research Lab. Participants: 28 healthy adults. Interventions: Participants were verbally instructed on how to brace their core musculature. They performed 3 bodyweight squats without instruction and 3 bodyweight squats immediately after instruction while surface electromyography (EMG) activity was recorded from the EO and LES muscles. Main Outcome Measure: The mean percent of 3 maximal isometric voluntary contraction values during squat trials were calculated and compared using a paired samples t test. Results: All muscles tested, with the exception of the right LES, had significantly more activation after verbal instruction on abdominal bracing compared to bodyweight squats without verbal instruction. Conclusions: Verbal instruction for abdominal bracing increases core muscle activation during a bodyweight squat but not to a level that is clinically significant.