The ratio of medial and lateral hamstring muscle thickness does not correlate with the lateral tibial rotation angle in the standing position in healthy young adults.

Only 30 male university students were studied, and they had no reported lower-limb orthopedic, surgical, drug, or neurological problems, so the results may not apply to women, older adults, or people with lower-limb problems. Measurements were made only in a static standing position, not during knee flexion, walking, or other movement, so they may not reflect dynamic knee control. The study looked for correlation, not whether changing hamstring thickness changes tibial rotation. The paper notes many structures may influence tibial torsion angle, including bone shape, ligaments, meniscus, ankle or pelvic alignment, and muscles that cross two joints, so hamstring thickness alone may be too narrow.

Do not conclude that hamstring thickness ratios explain standing tibial rotation or that changing them will change rotation. This was a small static correlation study in healthy young men, and the paper's written result is no correlation.