Active Knee Extension Check
Also known as AKE test, hamstring length test.
Checks: The length and irritability of the hamstring muscles
What this checks
This checks how far you can straighten your knee with your hip held bent, which tells you how tight or sensitive the hamstrings are. A big difference between legs, or a pull in one specific spot, can point towards a hamstring that has not fully recovered.
Do not do this test if
you have had a recent sudden painful tear at the back of the thigh with heavy bruising, you cannot walk normally, there is a lump or a gap you can feel in the muscle, the leg is very painful at rest, or you feel unwell. See a doctor or physiotherapist first if any of those apply.
How to do it
Step 1
Lie on your back in a doorway
- Lie down with one leg flat through an open doorway.
- Bring the test leg up so the back of the thigh rests against the door frame, hip bent to about a right angle.
Step 2
Hold the thigh vertical
- Keep the thigh still against the frame so the hip angle does not change.
- Let the knee be bent and relaxed to start.
Step 3
Slowly straighten the knee
- Straighten the knee as far as it will comfortably go, keeping the thigh against the frame.
- Stop at the first firm pull at the back of the thigh.
Step 4
Note how far it goes and where you feel it, then compare
- Note roughly how far short of straight the knee stops, and exactly where the pull is.
- Repeat with the other leg and compare the range and the feeling.
What your result means
Likely normal
A negative result usually looks like this.
- Both knees straighten to a similar point.
- You feel a broad, even stretch across the back of the thigh.
- No sharp or pinpoint pain.
Possible problem
A positive result usually looks like this.
- The injured leg stops noticeably further from straight than the other.
- A sharp or pinpoint pull at one spot in the hamstring, often where it was injured.
- The stretch reproduces your familiar hamstring pain.
Tips for a clearer result
Small things that make the test easier to read.
- Keep the thigh still against the frame - letting the hip move changes the result.
- Move slowly and stop at the first firm pull.
- Compare the two legs on the same day, one straight after the other.
How to read this
A positive result may point towards a hamstring strain that has not fully recovered its length and comfort, but it cannot confirm it - back and nerve problems can limit this movement too, and only a hands-on assessment can tell you for sure.
This is a guide, not a diagnosis. It cannot rule a problem in or out - a physiotherapist can. If your symptoms are severe, spreading, or you feel unwell, see a doctor. Please do not start exercises based on these tests without guidance from a physiotherapist who has assessed you; doing so is at your own risk.
Points towards
If your result points to a problem, these condition guides are a good place to start reading.
Reproduced your pain?
A positive result is worth getting looked at. Book a £40 online assessment with an HCPC-registered physiotherapist, wherever you are in the UK.
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