Log Roll Test: how to assess passive hip rotation

When you want to know how much rotation the hip joint actually has, without muscle tension or the subject's active control "masking" the result, the log roll test (or rolling test) is one of the simplest and most direct out there. It literally consists of "rolling" the leg like a log, hence its name.

What does this test measure?

The log roll assesses the internal and external rotation range of the hip joint in a completely passive way, meaning the subject doesn't activate any muscle.

This makes it particularly useful for:

• Differentiating whether a rotation limitation is joint/capsular in origin (it stays the same passively) or more muscular/motor control related (it improves a lot when the subject isn't actively participating)
• Detecting pain associated with passive rotation, which can point toward intra-articular involvement

Equipment needed

• A treatment table
• Optional: a goniometer, if you want to quantify the range in degrees in addition to a qualitative assessment

Step-by-step protocol

1. The subject lies supine, with the legs extended and relaxed, in as comfortable and "passive" a position as possible
2. The examiner places their hands on the thigh and/or leg (above and below the knee) of the side being assessed
3. Gently roll the whole leg inward (internal rotation) and outward (external rotation), as if rolling a log on the table, letting the foot move freely as an indicator of the motion
4. Observe the available range, the symmetry between both legs, and whether pain or abnormal resistance appears at any point
5. If using a goniometer, measure the internal and external rotation angle by placing the axis over the patella and the moving arm aligned with the tibial crest

Common mistakes

• Asking the subject to "help" or assist with the movement (this turns the test active, losing its differential value)
• Abrupt movements in people with suspected acute joint pathology
• Not comparing both sides, which is especially important since asymmetry is often more relevant than the absolute value

How to interpret the result

Rotation range (approximate)	Interpretation
Internal rotation ~30-40° / external ~40-60°	Ranges frequently cited as reference for a healthy hip, though with considerable individual variability
Markedly increased internal rotation (>45-50°) and reduced external rotation	Compatible with greater femoral anteversion (see Craig's test)
Markedly increased external rotation and very limited internal rotation	Compatible with greater femoral retroversion, or posterior capsular restriction
Pain during passive rotation, especially internal rotation in flexion	Suggests possible intra-articular involvement — consider assessment with other tests (FADIR, Scour)

Remember these ranges are approximate and vary quite a bit depending on the source and population. What's most useful in practice is comparing side to side and, above all, tracking the same person over time.

Relationship with other tests

The log roll combines well with:

• Craig's Test — the log roll lets you easily confirm the rotation range predicted by Craig's test based on femoral anatomy
• Scour Test — if the log roll causes pain on internal rotation, the Scour helps explore the joint further under compression

Track and monitor progress

Hip rotation is a measure worth keeping recorded and up to date, especially in sports that demand a lot of rotation (golf, tennis, martial arts, dance) or in people with knee/lower-back pain where limited hip rotation is often part of the problem. With Movalytics you can save the internal and external rotation degrees for each side at every assessment, and check whether your mobility work is producing real changes over time.

Frequently asked questions

Does the log roll replace a goniometer measurement? It can be used qualitatively (without measuring degrees) as a quick screen, but if you want comparable data over time, it's best to complement it with a goniometric range measurement. Why is it done passively instead of asking the subject to actively rotate the leg? Because that removes the influence of strength, motor control, or "fear of movement" from the subject, and assesses only the range available at the joint and the surrounding tissues. Is a rotation asymmetry between both hips always a problem? Not necessarily — small asymmetries are common and can be structural (different femoral anteversion/retroversion between sides). What matters is whether that asymmetry is associated with pain, limits performance, or changes over time.