Association between body mass index, postural deviations, and self-reported musculoskeletal disorders in physically active adults

Abstract

Excess body weight contributes to biomechanical imbalance and musculoskeletal dysfunction, yet evidence on its association with postural deviations in physically active adults remains limited. This study examined the relationship between body mass index (BMI), self-reported musculoskeletal problems, and postural deviations by anatomical region in adults engaged in regular exercise. A cross-sectional study was conducted with 309 adults (207 females, 102 males) aged 20–59 years, training two to three times per week. Anthropometric data, BMI, musculoskeletal complaints, and postural characteristics were assessed. Posture was evaluated using the Portland State University (PSU) method via digital biophotogrammetry, generating a Postural Correction Index (PCI), with ≥80% indicating normal alignment. Statistical analyses were performed using JAVOMI software, with p ≤ 0.05 considered significant. Males presented higher BMI (26.7 ± 3.5 kg/m²; p < 0.005), classified as overweight. The most frequent musculoskeletal complaints were spine (32.6%) and knees (20.5%). PCI values were below reference in both sexes (females: 79.5%; males: 76.5%; p < 0.005). Common deviations included forward head posture (89.8%), thoracic scoliosis (100%), shoulder protrusion (68.8%), pelvic tilt (91.7%), and knee hyperextension (94.7%). Males also showed abdominal protrusion (43.1%) and lateral hip rotation (91.2%). Physically active males demonstrated higher BMI and postural deviations suggestive of increased mechanical load and risk for chronic musculoskeletal conditions. Both sexes exhibited clinically relevant postural imbalances, reinforcing the need to integrate BMI and posture evaluation into exercise prescription to optimize musculoskeletal health.