The Effects of Instrument-Assisted Soft Tissue Mobilization in Sedentary Individuals With Hamstring Tightness

Hamstring tightness will be assessed using the PostureScreen Mobile application, a validated tool for photographic posture and joint angle analysis. Participants will lie supine on a treatment table with the non-test leg stabilized using a strap. The test leg will be positioned with both the hip and knee at 90° flexion, adjusted with a stool and pillow as needed. The anatomical landmarks-the greater trochanter, lateral femoral condyle, and lateral malleolus-will be marked on the test leg. While the participant wears minimal clothing, a lateral photograph will be taken from 1.5 metres using a tripod-mounted smartphone. Participants will be instructed to extend their knee as much as possible with their ankle dorsiflexed. The application will calculate the knee extension angle from the marked points, and the range of motion will be recorded in degrees. The test will be repeated if compensatory movements are observed.

The site will be marked at the midpoint of the posterior thigh, halfway between the ischial tuberosity and the popliteal region. The skinfold will be grasped 1 cm from the marked point using the thumb and index finger, maintaining consistent pressure throughout the measurement. Skinfold thickness will be measured with a skinfold calliper (Holtain Ltd, Crymych, UK). The reading will be taken 3-4 seconds after applying the calliper and then recorded. At least two measurements will be taken with a one-minute interval between them. Results will be recorded in millimetres (mm).

A pressure algometer will be used to assess the sensitivity of the area where pain is felt and to obtain a quantitative measure of pressure perception. In the assessment, a digital algometer (Algometer Commander, Jtech Medical, 801-478, USA) will be used. For the measurement, the participant will be positioned in the prone position. The motor point on the participant's hamstring muscle will be marked with a pen. The calibrated algometer, with a probe tip of 1 cm² diameter, will be placed perpendicularly on the marked point of the hamstring muscle. The physiotherapist will gradually apply pressure, and pressure will be increased until the participant perceives pain. Upon the participant's signal indicating pain, the pressure will be stopped and the probe will be removed. This test will be repeated three times, and the average value will be recorded.

The "Five Times Sit-to-Stand Test" will be used to assess functional muscle strength. This test will evaluate the functional strength of the lower extremity, transitional movements, balance, and risk of falling. Participants will be asked to sit on a chair with a straight back and a seat height of 43-45 cm from the ground. They will be instructed to cross their arms over their chest, placing their hands on the opposite shoulders, and to stand up and sit down five times as quickly as possible without pausing. The test will begin with the participant standing, feet shoulder-width apart, and the trunk upright. Each complete sit-to-stand movement will be counted as one repetition. The time taken to complete five repetitions will be measured with a stopwatch and recorded in seconds. The stopwatch will be stopped when the participant stands up for the fifth time, and the result will be documented.