What are the standards for isokinetic strength testing (H/Q ratio and LSI) in evaluating return to sport after ACL or lower limb surgery?

Doctor’s answer

Isokinetic strength testing is the gold standard for quantifying neuromuscular function recovery. General requirements include: ① Limb Symmetry Index (LSI): The peak torque of the quadriceps and hamstrings on the affected side should reach at least 90% of the healthy side; ② Hamstring/Quadriceps strength ratio (H/Q ratio): At an angular velocity of 60°/s, the same-side ratio should typically be ≥60%~70% (higher for females/pivoting athletes) to ensure the hamstrings provide sufficient dynamic posterior pull to protect the ACL reconstruction graft.

This content is for education. Diagnosis, treatment, and rehabilitation require an individual assessment by a sports medicine specialist.