90-90 Hamstring Test: How to Check for Hamstring Tightness

The 90-90 Hamstring Test (also known as the Active Knee Extension or AKE test) is a standard test used by physiotherapists to objectively measure the flexibility and tightness of the hamstring muscle group.

1. Purpose

The primary purpose is to **test for** the flexibility or tightness (contracture) of the hamstring muscles. By fixing the hip at 90 degrees, it isolates the hamstrings and assesses their ability to lengthen as the knee is extended.

2. How to Perform

1. The patient is positioned in supine (lying on their back).
2. The examiner (or patient) flexes one hip to 90 degrees, with the knee also bent to 90 degrees. The patient can hold behind their thigh to maintain the 90-degree hip position.
3. The other leg remains flat (extended) on the table.
4. The examiner instructs the patient to "Slowly straighten your leg" by actively extending the knee as far as possible, while keeping the hip at 90 degrees.
5. The examiner observes the final angle of knee extension.

3. Positive & Negative Sign

This test is measured in degrees of knee flexion, not a simple "yes" or "no".

Positive Sign (Test is POSITIVE):
A positive test (indicating tightness) is:

• The patient is unable to extend the knee beyond 20 degrees of flexion. (i.e., there is a >20 degree lack of full extension). This indicates significant hamstring tightness.

Negative Sign (Test is NEGATIVE):
A negative test (indicating normal flexibility) is:

• The patient can actively extend the knee to within 0-20 degrees of full extension.