Preventing and Testing Knee Pain: The Modified Thomas Test

There’s a saying in the sports performance industry “If you’re not assessing, your guessing”. At Higher Power Training (HPT), when we first start with an athlete, we spend 75 to 90 minutes performing our “Comprehensive Athletic Performance Assessment (CAPA)”. Within the CAPA we perform muscle balance screens to identify any underlying imbalances that are either currently contributing to knee pain or may cause an injury in the future. Although we take the time to do a thorough screening process at the beginning of training, it’s also important to monitor the athlete on a more frequent basis, possibly daily with quick multifaceted screens.

Conversely spending too much time assessing can also derail progress. There is another saying in our world called “paralysis analysis”.  Strength coaches that suffer from “paralysis analysis” spend so much time screening their athletes that they lose valuable training time. As stated earlier, screening is important, but should be done efficiently. At HPT we are always looking for the “perfect screen” which can actually be performed as an exercise, thus not wasting training time.

The Perfect Screen:

  1. Is fast to perform
  2. Is simple to perform
  3. Is multifaceted (reveals multiple imbalances)
  4. Requires minimal and inexpensive equipment
  5. Doubles as a corrective exercise

Additionally, since knee and low back pain are very common sources of injury in athletes, it’s very important to have a screening tool to help prevent this.  Our favorite screen at HPT to assess possible muscular imbalance related to the knee and low back is the “Modified Thomas Test (MTT).” The MTT tests for the range of motion of the knee and hip, specifically hip extension and knee flexion.  This test mainly looks at the length of the Rectus Femoris, and the IllioPsoas.  It also looks for flexibility of the Tensor Fascia Latae (TFL) and the Sartorius.  When any of these muscles are tight the athlete may develop low back, hip, and knee pain.

The Modified Thomas Test fits the “perfect screen” perfectly:

  1. Is fast to perform: If you eyeball it, you can do it in 30 seconds or less.  If you measure it, you are looking at 1-2 minutes.
  2. Is simple to perform: This test is very easy to measure and perform.
  3. Is multifaceted (reveals multiple imbalances): This test looks at tightness of the Rectus Femoris, the Iliopsoas, the Tensor Fasciae Latae, and the Sartorius.
  4. Requires minimal and inexpensive equipment: All you need is a table, a good set of eyes if you want to eyeball it and add a goniometer if you want to measure it.
  5. Doubles as a corrective exercise: Anytime you do the screen, you can take a couple minutes and actually stretch the athlete with PNF in the exact position they are in.  This is the Modified Thomas Stretch.

How to perform the Modified Thomas Test


  1. Treatment Table or Stable Elevated Surface
  2. Goniometer (optional)

Technique and Testing Position

  1. Have the athlete sit at the end of the table so their buttocks are barely on the edge.
  2. Instruct the athlete to cradle one leg knee to chest and slowly roll back. The leg cradled is the non-testing leg. This test is contraindicated for athletes with severe back pain (and possibly moderate).  Use your discretion with this test. Some athletes may need assistance, if so, stand to the side and support their torso as they roll back.
  3. Once supine, instruct the athlete to gently pull their non-testing leg towards their stomach, just enough to flatten the low back. Instruct them to lock this position. Note it’s very important that the low back be slightly held flat during this test.
  4. For the testing leg, many athletes will naturally bend this. Instruct them to relax their hamstring and just let the leg hang.
  5. Further instruct them to freeze and not move while you make your measurements.
  6. Once all measurements are made, have them switch legs

Muscle Assessment


knee pain - testing Psoas
  • Goni Alignment:
    • Axis: center of the hip
    • Stationary Arm: parallel with torso or level with table
    • Movement Arm: parallel with femur and lined with lateral epicondyle
  • Normal Length:
    • Thigh should hang -10 degrees below table, otherwise there is restricted hip flexion. This could also be a Rectus Femoris restriction.  To rule out the Rectus, retest this with a straight leg to put the Rectus in slack, if the leg still doesn’t drop -10, than the Illiopsoas is tight.

Rectus Femoris:

  • Tight rectus femoris with restricted hip flexors
    Goni Alignment:
    • Axis: center of the knee
    • Stationary Arm: parallel femur and at hip midpoint
    • Movement arm: parallel with tibia and lined up with lateral malleolus of ankle
  • Normal Length:
    • Knee flexion greater than 80 degrees, otherwise this muscle is tight.
  • See Picture 2 for a “tight Rectus Femoris with Restricted Hip Flexors”.
  • See Picture 3 for a “tight Rectus Femoris with normal hip flexion”.

Here is a picture of an elite figure skater with a very tight Rectus Femoris.  One of the difficulties this skater had was performing a layback spin.  The restriction in her Rectus was only allowing a score of 2 out of 4 on this move.  One month later after increasing the flexibility of the Rectus and the TFL, this athlete was scoring a perfect score of 4 on this move.

knee pain - testing Rectus Femoris


  • Goni Alignment for Hip Abduction
    • Axis: center of the hip
    • Stationary Arm: Centered with the hip and parallel with the axis of the spine
    • Movement Arm: Parallel with line of the femur and centered with midpoint of the patella
  • Normal Length:
    • Hip Abduction of 0 degrees. If the muscle is in a position of hip abduction this muscle is tight.
  • Note: Another thing to look for is if the tibia is internally rotated, if so, this is also a tight TFL.

Tight Sartorius:

knee pain - testing tight Sartorius
  • For a tight Sartorius, look for a combination of any of these 3:
    1. Hip Abducts
    2. Hip Flexes
    3. Hip External Rotation
    4. Knee Flexion

The screen is also used as a stretch. This is our number one go to at HPT for anterior knee pain. If an athlete is having pain, we will usually perform this stretch and “superset” the stretch with some prone leg curls. This will either improve or eliminate anterior knee pain most of the time.

How To Stretch Each Position

Jason Ivesdal Picture 6. Modified Thomas PNF Stretch

First instruct the client on:

  • Breathing:
    1. Breathe in and out a few times with the iso hold.
    2. Try to breathe out after the isometric pushes. Ideally, just breathe rhythmically.
  • Intensity or how hard to push:
    1. Start at 50% intensity, can progress as high as 80% if necessary
  • Frequency or how many reps you will be doing:
    1. Two or more
    2. If you get better, keep going

What Conditions Does the Modified Thomas Stretch Help?

  • Low back:
    1. Contractures leading to low back pain
    2. Low back pain due to tight hip flexors
  • Knee: There are at least 6 conditions that can cause anterior knee pain:
    1. Contracture of the Rectus Femoris
    2. Chondromalacia Patellae
    3. Illiotibial Band syndrome
    4. Osgood-Schlatter’s disease
    5. Patellofemoral Syndrome
    6. Pateller Tendonitis

Taking the time to do a Comprehensive Assessment is a great step with every athlete. But having a screen that you can do every day and can actually be incorporated as a daily assessment, and as an exercise, that’s even better.  This is what’s so awesome about the Modified Thomas Test (MTT).  Performing this stretch frequently allows you to track muscle imbalances while you stretch the athlete!

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