Assessment of Task-Specific Gait and Balance Deficits in Chronic Low Back Pain Using Multi-Sensor Inertial Measurement Units

Chronic low back pain (cLBP) compromises daily function, but associated balance deficits remain difficult to quantify using traditional scales. We recruited 50 participants with CLBP (age: 65.68 ± 11.84) and 50 age-matched controls (age: 65.26 ± 10.73) wearing multiple inertial measurement units (IMUs) to evaluate kinematics: average absolute angular velocity (Jω) and linear acceleration (Jα) across static (single-leg stance), perturbed (balance board), locomotor (walking, tandem gait), and transitional (five times sit-to-stand) tasks. Group differences were assessed using multivariate analysis of variance and Bonferroni-adjusted univariate tests. During the balance board test, Jω was significantly higher at the chest (p = 0.027) and hip (p = 0.003) in the CLBP group. Conversely, during the sit-to-stand tests, the CLBP group showed significantly lower Jα and Jω (p < 0.0001) at the hip. The CLBP group exhibited globally lower Jω (p < 0.01) during normal walking, while the AmpPR (p = 0.001) was exclusively reduced during tandem gait. These results suggest that multi-sensor IMU-based assessments provide a sensitive tool for detecting subtle, task-specific balance deficits in CLBP, indicating that rehabilitation should target rotational mobility and reactive control rather than core stiffening alone. Larger-scale and longitudinal research is still required to determine their clinical utility.