The Core of the Issue: Plank Performance and Pain in the Lower Back

Background and Objectives: Low back pain (LBP) is a leading cause of disability worldwide. Core stabilization exercises such as the plank are often prescribed in rehabilitation settlings to improve neuromuscular control and spinal support. However, it remains unclear whether plank performance -accurately reflects trunk function or disability in individuals with LBP. The purpose of this study was to evaluate the relationship between plank endurance and low back pain in adults. Methods: A cross-sectional study was conducted with 117 adults aged 20-61 years (mean 26.0 ± 9.3), including both individuals with and without LBP. Participants completed a plank endurance test and the Modified Oswestry Disability Index (MODI). A subset of fifty-four participants with LBP also completed single-leg bridge tests to assess posterior chain endurance. Statistical analyses included Mann-Whitney U tests to compare plank times by LBP status, logistic regression to evaluate predictors of LBP, and correlation analyses to examine associations between the bridge-to-plank ratio and MODI scores. Results: Contrary to the initial hypothesis, individuals with LBP demonstrated significantly longer plank hold times than those without (U = 1861.00, p = 0.036). Logistic regression indicated that the overall model was statistically significant (χ² = 12.39, p = 0.030), but plank duration was not an independent predictor of LBP (p = 0.070). Among participants with LBP, a higher bridge-to-plank ratio, reflecting relatively greater posterior chain endurance, was significantly associated with lower disability scores (Pearson r = -0.31, p = 0.023; Spearman ρ = -0.32, p = 0.018). Conclusions: These findings suggest that, while plank duration differs by LBP status, longer plank times may not indicate lower risk or severity of back pain. A greater balance of posterior chain to anterior core endurance may be more intricately linked to reduced disability, highlighting the importance of comprehensive core assessment and training strategies in rehabilitation.