Effect of volitional preemptive abdominal contraction on superficial multifidus response in healthy subjects during unipodal lower extremity reach task

• Published in: Journal of bodywork and movement therapies Vol. 42; pp. 885 - 893
• Main Authors: Garcia, Luciano, Drusch, Alex, Hooper, Troy, Yang, Hyung Suk, Kublawi, Marwan, Brismée, Jean-Michel, Sizer, Phil
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.06.2025
• Subjects: Abdominal muscles; Abdominal Muscles - physiology; Adult; Bracing; Electromyography; Female; Healthy Volunteers; Humans; Lower Extremity - physiology; Male; Muscle Contraction - physiology; Paraspinal Muscles - physiology; Physical Medicine and Rehabilitation; Rehabilitation; Spine; Surface electromyography; Young Adult; Bracing; Surface electromyography; Rehabilitation; Spine; Abdominal muscles
• ISSN: 1360-8592; 1532-9283; 1532-9283
• DOI: 10.1016/j.jbmt.2025.02.010

To determine the effect of volitional preemptive abdominal contraction (VPAC) on abdominal and superficial multifidus (sMf) activation in healthy subjects during a lower extremity (LE) unipodal functional task. Within-subjects, repeated measure cohort design. Clinical laboratory setting. 30 healthy adults (18 female/12 male), age 20−41 years (26.4 ± 5.1 years), height (170.0 ± 8.5 cm), weight (71.0 ± 14.5 kg) and body mass index (25.0 ± 4.3 kg/m2). The Y-balance test (YBT) on the dominant LE in anterior (ANT), posteromedial (PM), and posterolateral (PL) directions during No-VPAC, abdominal bracing maneuver (ABM), and abdominal drawing-in maneuver (ADIM) conditions. Superficial Mf (sMf), internal oblique (IO), and external oblique (EO) activity measured by surface electromyography. One-way Analysis of Variance (ANOVA) based on 2 (EO/IO) × 3 (VPAC Strategy) design revealed a significant VPAC strategy main effect for IO and EO amplitudes in all directions (p < .05). Post-hoc tests indicated that ABM and ADIM produced significantly greater abdominal contraction relative to No-VPAC. Findings yielded by repeated measures 2 (sMf side) × 3 (VPAC) ANOVAs indicate a significant interaction in PM (p = .002) and PL (p = .003) directions, with greater activation on stance-side sMf established via post-hoc comparisons (p < .001). Pearson correlation analyses failed to uncover any relationships between sMf activation and reach distances. Performing VPAC produces abdominal and stance-side sMf co-activation during PM and PL directed YBT performance. These outcomes give credence to the supportive role of abdominal-multifidus co-activation during unipodal functional reaching activities. •Abdominal co-contraction was able to be produced during the Y-Balance Test.•Lumbar multifidus activation increased with a mild or strong abdominal contraction.•Stance side multifidus activation increased in posterior directions only.•Abdominal contraction did not increase reach distances during the Y-Balance Test.