What does the Active Straight-Leg Raise measure?

The ASLR measures how far you can raise a straight leg from the floor, which reflects hamstring length and posterior-chain flexibility. A raise of 80° or more is considered excellent, while under 45° is poor and points to significant tightness.

Why does side-to-side asymmetry matter?

A difference of more than 10° between legs may indicate prior injury, neural tension, or hip pathology. Correcting asymmetry lowers strain risk in sprinting and field sports, where the weaker side is more likely to be injured.

How can I improve my hamstring flexibility?

Combine regular static stretching of the tighter side with eccentric strengthening such as Nordic curls, plus hip hinge drills to groove the movement pattern. Improvements usually appear within 4–6 weeks of consistent work.

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Hamstring Flexibility Test

Use the Active Straight-Leg Raise (ASLR) to measure hamstring length in each leg, detect side-to-side asymmetry, and screen for hamstring strain and lower-back risk.

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What is the Active Straight-Leg Raise?

Anatomy & biomechanics

Corrective drills & programming

Limitations