<b>Comparison of Lower Extremity Function and Hamstring Tightness in Individuals With or Without Plantar Fasciitis</b>

Background: Plantar fasciitis is a prevalent source of plantar heel pain that may reflect broader kinetic-chain dysfunction, including posterior muscle tightness and impaired lower-limb performance. Objective: To compare hamstring tightness and lower extremity function in young adults with and without plantar fasciitis and to determine the association between plantar fasciitis, hamstring tightness, and functional limitation. Methods: A cross-sectional observational study was conducted in multiple hospitals in Sialkot, Pakistan over six months. Using convenience sampling, 375 adults aged 19–35 years were enrolled and classified as plantar fasciitis positive (n=187) or negative (n=188) based on clinical assessment. Hamstring tightness was assessed using the Active Knee Extension (AKE) test with goniometric measurement, and lower extremity function was evaluated using the Lower Extremity Functional Scale (LEFS; 0–80). Group comparisons were performed using Mann–Whitney U and chi-square tests with effect sizes and 95% confidence intervals. Results: Participants with plantar fasciitis demonstrated significantly lower AKE range of motion than controls (right: 57.31±10.16° vs 71.85±8.74°; left: 58.01±9.98° vs 72.21±8.51°; both p<0.001) and a higher prevalence of hamstring tightness (72.7% vs 28.2%; OR 6.78, 95% CI 4.32–10.65). LEFS scores were significantly lower in plantar fasciitis (45.74±9.87) compared with controls (58.94±8.91), with a mean difference of 13.20 points (95% CI −15.1 to −11.2; p<0.001). Conclusion: In young adults, plantar fasciitis is strongly associated with increased hamstring tightness and clinically meaningful reductions in lower extremity function, supporting comprehensive posterior-chain assessment and targeted flexibility rehabilitation.