Range of Motion: Hip Modified Thomas Test

The Hip Modified Thomas Test assesses hip extension position and anterior hip or thigh length response while the client lies at the edge of a table. It can provide useful information about hip flexor and rectus femoris length, but pelvic position must be controlled carefully. The result should be recorded with hip angle, knee angle, side, pain, symptoms and compensation.

Introduction

A client may report tightness at the front of the hip during lunges, running, bridging or split squats. Another client may appear to arch the lower back when trying to extend the hip. The Hip Modified Thomas Test helps assess anterior hip and thigh length while monitoring whether the pelvis stays controlled.

This test is commonly used to assess hip flexor length, but it should not be treated as a single-structure test. Hip position, knee angle, pelvic tilt, table setup, symptoms and client relaxation can all affect the result.

Quick Summary

Test name: Hip Modified Thomas Test
Purpose: Assess hip extension position and anterior hip/thigh length response
Movement/position: One hip flexed toward the chest while the tested thigh relaxes over the table edge
Joint/body region: Hip, anterior thigh and pelvis
ROM type: Passive position-based ROM/flexibility assessment
Score: Hip angle, knee angle, thigh position, pain score and compensation notes
Equipment: Treatment table, goniometer or inclinometer, pain scale and Measurz
Best used with: Hip extension ROM, Ely Test, knee flexion ROM, lunge, running, gait and glute strength assessment
Key limitation: Pelvic tilt can change the result and must be controlled or recorded

What Is the Hip Modified Thomas Test?

The Hip Modified Thomas Test is performed with the client lying near the edge of a treatment table. One knee is held toward the chest to help control pelvic position while the tested leg relaxes off the table.

The professional observes or measures the position of the tested thigh and knee. A thigh that stays elevated may suggest reduced hip extension position under the test setup. A more extended knee may suggest reduced anterior thigh or rectus femoris length response, depending on the full position and symptoms.

Why It Is Used

The test is used to assess anterior hip and thigh movement capacity, compare sides and track change over time.

It may help inform:

Hip flexor mobility programming
Lunge and split squat assessment
Running stride interpretation
Gait and hip extension assessment
Anterior hip symptom monitoring
Side-to-side comparison
Progress tracking across sessions

What It Measures

The test may provide information about:

Hip extension position
Anterior hip tissue length response
Rectus femoris length response
Tensor fasciae latae or lateral thigh contribution
Pelvic control
Pain or symptom response
Side-to-side difference

It does not isolate one muscle perfectly and does not diagnose a condition.

Active vs Passive Range of Motion

The Modified Thomas Test is mostly a passive position-based assessment. The client relaxes while the professional observes the resting position of the tested limb.

If active hip extension is also assessed, it should be recorded separately as a different result.

Who It Is Useful For

This test may be useful for runners, field sport athletes, dancers, gym clients, clients working on lunges or hip extension, and anyone where anterior hip or thigh mobility may influence movement.

Equipment Required

Treatment table
Goniometer or inclinometer
Pain scale
Measurz for recording ROM and symptoms
Optional towel or pillow
Optional comparison side notes

Step-by-Step Protocol or How to Apply This in Practice

Starting position

Ask the client to sit at the edge of a treatment table, then roll back while holding one knee toward the chest.

Client position

The tested leg relaxes over the edge of the table. The opposite hip stays flexed toward the chest to help reduce lumbar extension and anterior pelvic tilt.

Professional position

Stand beside the tested leg with a clear view of the pelvis, thigh and knee.

Body/joint setup

Make sure the client is close enough to the table edge for the tested thigh to hang freely.

Stabilisation

Monitor the pelvis. Avoid allowing lumbar extension or anterior pelvic tilt to create the appearance of more hip extension.

Movement instruction

Ask the client to relax the tested leg and avoid actively holding the thigh up.

Measurement landmarks

Measure the thigh angle relative to the horizontal or trunk, depending on your method. If measuring knee flexion, use standard knee landmarks.

Inclinometer or device placement

Place the inclinometer consistently on the thigh for hip angle and on the tibia if measuring knee angle.

What to ask

Ask about anterior hip stretch, anterior thigh stretch, pinching, discomfort, symptom location and whether symptoms are familiar.

Stopping rules

Stop if the client cannot tolerate the position, back discomfort increases, symptoms increase sharply or pelvic control cannot be maintained.

What to record

Record side, hip angle, knee angle, pain score, symptom location, pelvic position, thigh position, knee position and compensation.

Number of trials

One to three trials may be used. Use the same scoring method across sessions.

Retest consistency

Use the same table height, client position, measurement landmarks, device placement and endpoint definition each session.

Scoring and Interpretation

The Modified Thomas Test can be recorded in several ways:

Hip angle of the tested thigh
Knee flexion angle of the tested leg
Whether the thigh rests below, level with or above the table
Pain or symptom response
Pelvic compensation
Side-to-side comparison

A thigh that remains elevated may indicate less hip extension position under the tested setup. A knee that extends more than expected may suggest increased anterior thigh tension contribution, but interpretation should be cautious and based on the whole position.

Interpret the result with hip extension ROM, knee flexion ROM, Ely Test, lunge assessment, running or gait findings and symptoms.

Normative Data, Benchmarks or Reference Values

Evidence level: Level 3 — practical benchmarks exist, but exact norms vary by protocol.

The most useful benchmarks are:

Compare both sides
Track baseline to retest
Record hip angle and knee angle
Record pelvic control
Record pain and stretch location
Use the same table and measurement method

Avoid using a single universal cut-off unless it comes from the same protocol and population.

Reliability and Validity

Recent work has continued to examine Modified Thomas Test reliability. A 2024 study specifically evaluated intra-rater and inter-rater reliability of goniometric techniques for measuring hip flexor length using the Modified Thomas Test and highlighted the importance of controlling pelvic tilt during testing.  

Earlier reliability work also found that measurement method can affect repeatability, with trigonometric methods showing stronger reliability than standard goniometry in one study.  

Common Errors and Testing Limitations

Common errors include allowing anterior pelvic tilt, placing the client too far from the table edge, not recording knee angle, forcing the tested leg down, ignoring symptoms, not comparing sides and treating the test as a single-muscle assessment.

Limitations include pelvic control difficulty, table height variation, body shape, symptoms, client guarding and measurement method differences.

Practical Applications

Use the Modified Thomas Test to monitor anterior hip and thigh mobility, guide hip extension or lunge programming and add context to running, gait, bridging or split squat movement findings.

How to Record This in Measurz

In Measurz, record the test side, hip angle, knee angle, pain score, symptom location, stretch location, pelvic compensation, table position, device used and comparison side.

Track progress across sessions and compare with hip extension ROM, knee flexion ROM, lunge findings, running notes and strength results.

Related Tests or Internal Linking Suggestions

Hip Extension Test
Knee Prone Heel-to-Butt Test
Ely Test
Knee Flexion Test
Hip Flexion Test
Lunge Assessment
Running Assessment
Glute Strength Testing

FAQs

What does the Modified Thomas Test measure?

It assesses hip extension position and anterior hip or thigh length response in a table-edge position.

Is the Modified Thomas Test active or passive?

It is mostly a passive position-based assessment because the tested leg relaxes over the table edge.

What should be recorded?

Record hip angle, knee angle, side, pain, symptoms, pelvic position and compensation.

Why does pelvic position matter?

Anterior pelvic tilt and lumbar extension can make hip extension appear greater than it is.

Can this test identify one tight muscle?

Not on its own. It may suggest patterns, but interpretation should include related hip and knee findings.

Key Takeaways

The Modified Thomas Test assesses anterior hip and thigh length response.
Pelvic control is essential.
Hip angle and knee angle should both be recorded when possible.
Avoid interpreting the test as a single-muscle finding.
Measurz should capture angles, symptoms, side and compensation.

References

Clarkson, H. M. (2020). Musculoskeletal assessment: Joint range of motion, muscle testing, and function (4th ed.). Wolters Kluwer.

Eimiller, K., Stoddard, E., et al. (2024). Reliability of goniometric techniques for measuring hip flexor length using the Modified Thomas Test. International Journal of Sports Physical Therapy. Needs verification.

Peeler, J., & Anderson, J. E. (2008). Reliability of the Thomas Test for assessing range of motion about the hip. Older contextual source.

Vigotsky, A. D., et al. (2015). Reliability of goniometric and trigonometric techniques for measuring hip-extension range of motion using the Modified Thomas Test. Journal of Athletic Training, 50(5), 460–466.