The relationship between clinical outcomes and gait biomechanics in individuals with plantar fasciitis.

Introduction: Plantar fasciitis (PF) is a common musculoskeletal disorder characterized by heel pain that disrupts gait and daily function. This study examined relationships between clinical outcomes and gait biomechanics, determined whether these relationships differ between recent- and chronic-onset cases, and identified key clinical predictors of gait speed. Methods: A cross-sectional study was conducted with 42 individuals with PF. Clinical outcomes included worst pain, normalized gastrocnemius and soleus muscle length, normalized lower limb muscle strength, and normalized dynamic balance. Gait biomechanics during barefoot walking were captured using a motion analysis system and force plates, focusing on spatiotemporal parameters and ground reaction forces (GRFs). Correlation coefficients were used to assess relationships across the overall cohort, as well as in recent- and chronic-onset PF, while multiple linear regression identified clinical predictors of gait speed. Results: Clinical outcomes related differently to sptiotemporal parameters and GRFs depending on symptom duration, with the recent-onset PF showing widespread correlations and chronic-onset PF showing more selective links with ankle strength and dynamic balance. Regression analysis identified gastrocnemius muscle length and anterior reach distance on the Y-Balance Test (YBT) as significant predictors of gait speed, explaining 28.0% of the variance (p = 0.002). Conclusion: Symptom duration influences gait biomechanics in PF, with recent onset showing broad adaptations and chronic onset exhibiting more specific strength- and balance-related changes. Gastrocnemius muscle length and dynamic balance in the anterior direction were identified as significant contributors to gait performance. Targeting these factors, with consideration of symptom duration, may improve gait in individuals with PF.