Ely's Test (Quadriceps/Rectus Femoris Flexibility)

If an athlete has anterior knee discomfort, lower back tension at the end of a run, or simply can't bring their heel close to their glutes during a prone knee flexion, Ely's test is the most direct way to check whether the rectus femoris is tight. It's quick, requires no equipment, and can be done on any treatment table.

Unlike a "general" quad stretch, Ely's test specifically isolates the biarticular component of the rectus femoris (it crosses both the hip and the knee).

What does this test measure?

It assesses the flexibility of the rectus femoris, the only one of the four quadriceps muscles that crosses two joints (hip and knee). A tight rectus femoris limits knee flexion when the hip is extended (prone position) and, if very tight, causes the pelvis to lift off the table during passive knee flexion (positive Ely's sign).

This tightness is linked to anterior knee pain, lower back overload (through compensatory anterior pelvic tilt), and limitations in movements like the stride or the heel-to-glute kick while running.

Equipment needed

• Treatment table
• Optional: goniometer to measure the knee flexion angle reached

Step-by-step protocol

1. The person lies prone (face down) on the table, with legs extended and relaxed
2. Stabilize the pelvis by placing a hand over the sacrum/glutes to detect any lift-off
3. With the other hand, passively flex the knee of the leg being tested, bringing the heel toward the glutes
4. Watch for two things:

- Whether the pelvis lifts off the table (the hip flexes/tilts anteriorly) before the knee range is complete — this is a positive Ely's sign - The knee flexion angle reached before pelvic lift-off or clear resistance appears

1. Repeat on the other side and compare

Common mistakes

• Not stabilizing the pelvis properly, missing a subtle positive sign (pelvic lift can be small)
• Flexing the knee too quickly, triggering a muscular defense response that skews the result
• Not measuring the flexion angle reached, settling for just "positive/negative"
• Confusing tension from femoral nerve sensitization with pure muscle tightness (if radiating pain appears, consider a neural assessment)

How to interpret the results

Finding	Interpretation
Knee flexion ~135-145° without pelvic lift	Rectus femoris flexibility within normal range
Knee flexion < 120-130° without pelvic lift	Mild-to-moderate rectus femoris restriction
Pelvis lifts before completing the range (positive Ely's sign)	Significant rectus femoris tightness, compensated by anterior pelvic tilt
Marked asymmetry between legs	Possible unilateral overload, common in kicking sports or running with a dominant support leg

As a reference, heels that don't reach the glutes and stay more than 2-3 cm away, combined with pelvic lift-off, usually indicate a tightness that warrants targeted work.

How this test relates to others

A tight rectus femoris often coexists with restrictions in other anterior and posterior chain structures:

• Thomas Test — assesses overall hip flexor flexibility (including the rectus femoris) in a different position; together they give a more complete picture
• Hamstring Flexibility Test — an imbalance between a tight quadriceps and tight hamstrings is very common and worth assessing on both sides

Track it with Movalytics

Rectus femoris tightness is one of the findings that responds best to targeted stretching and hip mobility work in extension, and changes can be noticeable within a few weeks. With Movalytics you can record whether Ely's sign is positive or negative for each leg, along with the knee flexion angle reached, and see how it evolves after introducing targeted flexibility work.

FAQ

What does a positive Ely's sign mean? It means that, during passive knee flexion in prone, the pelvis lifts off the table before the movement is complete, indicating the rectus femoris is tight enough to "pull" the pelvis into anterior tilt. How does this test relate to knee pain? A tight rectus femoris increases tension on the patellar tendon and can contribute to anterior knee pain (such as patellofemoral pain syndrome), especially in jumping and running sports. How do you address a tight rectus femoris? With targeted stretches in hip extension and knee flexion (similar to the test position itself), hip mobility work, and in some cases, complementary myofascial release techniques.