Thomas Test: Hip to Be Square Part I

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Not surprisingly, when it comes to assessment, there are many school’s of thought.  During our staff in-service the other day, Eric made a great point in saying that most assessments are very general to start and then move into more specific things as you dig a little deeper.  For instance, in his book Movement, Gray Cook notes that the Functional Movement Screen hits on seven key movement patterns:

Deep Squat Movement Pattern
Hurdle Step Movement Pattern
Inline Lunge Movement Pattern
Shoulder Mobility Movement Pattern
Active Straight-Leg Raise Movement Pattern
Trunk Stability Push-Up Movement Pattern, and
Rotatry Stability Movement Pattern

All the above are very general and do a supberb job at assessing movement quality, addressing assymetries, and just covering our bases.

Conversely, Cook also has what he calls the Selective Functional Movement Assessment (SFMA), which, unlike the FMS, has many “breakout” (more specific) assessments depending on what you find.

As an example, Lower Body Extension can be broken down to:  standing hip extension, prone active hip extension, prone passive hip extension, FABER test, and the Thomas Test.

Not always, but because of the population we deal with at Cressey Peformance (baseball players), we start with more specific tests (testing GIRD, lead leg ROM, ect) and then go into more general things.

One test that seems universal, however, is the Thomas Test.  Named after Dr. Hugh Owen Thomas (thank you Wikipedia), this test is a great assessment tool to better ascertain hip flexor length (or lack thereof).

Here’s the deal, though.   As simple as this test is, many fitness professionals have no clue how to perform it correctly, let alone interpret the results.  Here, I’m going to try my best to break it down and hopefully clear up some of the confusion, and maybe drop some knowledge bombs along the way.

Starting Position:  Seated at the end of the table, with the thighs half off the table.

**This is an important point, because the body position shifts as the subject lies down and brings his or her knee toward their chest.  The end position for the start of the testing is with the other knee just at the edge of the table so that the knee is free to flex and the thigh is full length of the table.

From there, simply hold your thigh, pulling your knee towards the chest, only enough to flatten the low back and sacrum on the table.

In an ideal world, I like to hold down the pelvis – on the testing side – to allow a little more posterior tilt.  Many people will go into excessive lumbar extension, which will give the illusion of having ample hip flexor length.  By holding the pelvis down, they can’t cheat.

Conversely, in Muscles: Testing and Function With Posture and Pain, Kendall recommends NOT to bring both knees to the chest because it does allow excessive posterior tilt which can skew the results towards apparent (not actual) hip flexor shortness.

In the end, use your own discretion.  For those of you reading who are coaches or personal trainers, I prefer the “bring one leg towards the chest, pin the pelvis down approach.”  If performing this alone, I prefer the “two knees to the chest, lower one leg approach.”


So, what now?  As noted above, the Thomas Test is a great test to assess hip flexor length – namely the rectus femoris, psoas, and TFL.

Testing:  With the low back and sacrum flat on the table, a “passing test” will show that the posterior thigh touches the table, and the knee passively flexes – to approximately 80 degrees.

Almost always, you’ll rarely (if ever) come across a perfect Thomas Test.  We’re a very sedentary society, and it’s no surprise that pretty much everyone has poor hip flexor length.

One thing to consider, however (especially if you’re dealing with a well-trained individual), is the size of one’s hamstrings.  Dudes (and girls, too) who have well developed hamstrings will seemingly “fail” this test because the posterior thigh does not touch the table.  So, it’s not so much they have short hip flexors (which still could be the case), but rather, they have hamstrings the size of Kansas that prevents the thigh from coming down flush to the table.

Ruling this out, if the thigh does come off the table, we can rule out the rectus femoris by simply extending the lower leg.  Since the RF crosses both the hip and knee joint, if we extend the leg and the thigh then touches the table – viola – you found your culprit.

On the flipside, if you extend the lower leg, and the thigh still stays off the table, you can assume it’s the psoas that’s short and/or stiff.

In terms of the TFL, we don’t need to get too detailed here.  Some trainers like to get all geeky and bust out their protractors and Bunsen Burners and measure every degree.  I have my limits and just prefer to keep the assessment flowing.  If there’s an issue with the TFL, I’ll note any lateral deviation of the thigh from the midline of the body and move on with my life.

And that, ladies and gentlemen is the Thomas Test – in a nutshell……..more or less.  Tomorrow, in part II, I’ll discuss a handful of correcive strategies you can implement to help fix some of the issues you may have come across.  Till then, stay sexy.


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