Hamstring Tightness and Lumbar Lordosis Angel Across Functional Sitting Posture.

The goal of this observational study is to learn about the relationship between hamstring tightness and the lumbar lordosis angle in sedentary adults across different sitting postures. The main question it aims to answer is: Is hamstring tightness related to the lumbar lordosis angle across three functional sitting postures (upright, slumped, and forward-leaning)? It also asks whether hamstring tightness differs between men and women, whether it differs between the dominant and non-dominant leg, and whether the lumbar lordosis angle differs between men and women across the three postures. Participants will have their hamstring tightness measured with the Active Knee Extension test and their lumbar lordosis angle measured with a bubble inclinometer while sitting in each of the three postures.

Inclusion Criteria: * Healthy adults aged 18-45 years. * Sedentary occupation requiring \> 6 hours of sitting per day. * Active Knee Extension (AKE) angle \>15°. * Bilateral hamstring tightness. * Sedentary individual as determined by IPAQ (MET≤ 600 min/week). * Asymptomatic for low back pain at the time of testing. Exclusion Criteria: * History of significant low back pain requiring medical treatment in the past 12 months. * Previous spinal surgery or structural spinal deformities. * Lower extremity injury or surgery within the past 6 months. * Neurological disorders affecting sensation or movement. * Pregnant female or get birth in the last year. * Body mass index (BMI) ≥ 30 kg/m². * postural deviations resulting from shortening of the iliopsoas and erector spinae or insufficiency of the core stabilizers and hip extensors