90/90 Hip Mobility Test

If you've ever seen someone doing hip stretches sitting on the floor, with both legs bent forming "L-shapes" pointing in opposite directions, that was probably the 90/90 test. It's one of the most commonly used tests for assessing hip rotation because, in addition to measuring range, it requires a degree of motor control to hold the position without using the hands for support.

It's especially useful with runners, cyclists, and any athlete who spends a lot of time in flexed-hip positions.

What does this test measure?

It measures the range of internal and external hip rotation with the hip and knee flexed at 90°, while sitting on the floor. Unlike a passive table-based assessment, here the subject must keep the torso upright without using their hands for support, which adds a motor control component on top of pure range of motion.

Important: don't confuse this with the FABER test. The 90/90 assesses active internal/external hip rotation ranges in a seated position, while the FABER test assesses combined passive flexibility (adductors, external rotators, sacroiliac joint) lying down. They're complementary tests, not interchangeable.

Equipment needed

• Floor or mat
• Optional: goniometer or angle-measuring app to quantify range in degrees

Execution protocol

1. The subject sits on the floor with both hips and knees flexed at 90°: one leg in front (internal rotation of that hip) and the other to the side (external rotation of the opposite hip), forming a kind of "Z" shape with the legs
2. The torso must remain upright and vertical, without leaning forward or placing the hands on the floor for support
3. Observe whether both knees and hips can stay in contact with the floor (or close to it) without compensations
4. Measure the height of the knee from the floor, or the hip angle, on each side
5. Ask the subject to rotate both legs to the opposite side, swapping roles (the leg that was in internal rotation moves into external rotation and vice versa), always without using the hands
6. Repeat the assessment on both sides and compare

Common mistakes

• Allowing hand support to maintain balance (this invalidates the motor control assessment)
• Letting the torso lean forward to "gain" apparent range
• Not systematically comparing both sides
• Confusing this test with FABER due to the superficial similarity of "bent legs"

How to interpret the result

Finding	Interpretation
Knees and hips close to the floor, no hand support, smooth transition between sides	Good hip rotation mobility and control
Knee raised off the floor (>10-15 cm) in internal or external rotation	Range restriction in that rotation direction
Needing hand support to keep the torso upright	Motor control/hip-trunk stability deficit, beyond pure range of motion
Marked asymmetry between sides	Possible compensation or unilateral overload, particularly relevant in runners

As a reference, hip internal and external rotation of roughly 30-45° each is generally considered an adequate functional range for most sports activities.

Related tests

The 90/90 pairs well with other hip tests:

• FABER hip mobility test — assesses passive flexibility lying down, different from but complementary to the 90/90
• Thomas test — if you detect a rotation restriction, it's also worth assessing hip flexor flexibility

Track it over time

Rotational hip mobility is key in sports involving changes of direction, running, and cycling, and it usually responds well to targeted mobility work (hip CARs, dynamic stretching, motor control work). In Movalytics you can log the 90/90 result for each side (with or without hand support, and the angle if you measure it) and compare progress across assessments to check whether asymmetries are decreasing.

Frequently asked questions

Is the 90/90 test the same as the FABER test? No. The 90/90 is performed seated, assesses active internal/external rotation with motor control, and is done in both directions while alternating legs. FABER is performed lying down and is a passive measurement of adductor/external rotator flexibility and sacroiliac joint mobility. They're different tests that provide complementary information. Why does motor control matter as much as range of motion? Because having range of motion without the ability to actively control it (without compensating with the trunk or relying on the hands) has little functional value for real sports movements. Which sports benefit most from good 90/90 mobility? Especially sports involving changes of direction (soccer, basketball, martial arts), but also disciplines like yoga, dance, and martial arts where rotated hip positions are common.