Know your flexibility with the Thomas test

Healthy hip flexor muscles are essential for all athletes. While the hamstrings and glutes are responsible for most of the force in the momentum of running or jumping, the hip flexors decide how far behind the body the leg can go. A reduced range of motion in the hips means you slow down. Therefore, the Thomas test can get us out of doubt.

Tight hip flexors are going to limit the amount of force and propulsive motion we can use to move forward. These flexors also connect to the lower back, so if they are tight they will compromise the position of the spine, affecting posture. Poor posture decreases efficiency and also increases the risk of injury.

Fortunately, there is a simple movement test to determine whether or not we suffer from tight hip flexors. This is the Thomas test.

What is?

The Thomas test is a physical examination test, first described in 1875 by the Welsh orthopedic surgeon Hugh Owen Thomas. The test was used to diagnose hip flexion contracture and determine the duration of the disease process.

The modified Thomas test is most commonly used to assess and assess the flexibility of the hip flexors, including the iliopsoas, quadriceps, pectineus, gracilis, tensor fasciae latae, and sartorius muscle groups. It is easy to reproduce between doctors and patients and provides good information that can indirectly affect not only athletic performance, but can also help us know what happens if we have pain in different areas.

This test measures:

  • Iliopsoas length (hip flexion angle)
  • Quadriceps Passive Length (Knee Flexion Angle)
  • Tensor fasciae latae/iliotibial band flexibility (hip abduction angle relative to femur and pelvic angle)

mujer haciendo el test de thomas

muscles involved

The Thomas Test examines the iliopsoas, the group of muscles that connects the spine to the legs, through the pelvis; the rectus femoris, the quad muscles that extend from the hip to the knee; and the tensor fasciae latae, the lateral muscle of the thigh that lies below the IT band. Together, they form the hip flexor muscles.

iliopsoas muscle

The iliopsoas muscle, made up of the iliacus and psoas major muscles, is the most powerful hip flexor, while also functioning as a weak hip adductor and external rotator.

The iliopsoas attaches to the capsule of the hip joint, giving it some support. As the muscle spans the axial and appendicular components of the skeleton, it also functions as a flexor of the trunk and provides an important element for vertical stability of the lumbar spine, especially when the hip is in full extension and passive tension is greatest on the muscle.

A sufficiently strong and isolated bilateral contraction of any hip flexor muscle will rotate the femur toward the pelvis, the pelvis (and possibly the trunk) toward the femur, or both actions simultaneously.

rectus femoris muscle

This is one of four quadriceps muscles, and is a two-jointed muscle arising from two tendons: one, the anterior or rectus, from the anterior inferior iliac spine; the other, the posterior or reflected, from a groove above the rim of the acetabulum.

The rectus femoris combines movements of hip flexion and knee extension. It functions most effectively as a hip flexor when the knee is flexed, such as when a person kicks a ball.

pectineus and gracilis muscle

The pectineus is an adductor, flexor, and internal rotator of the hip. Like the iliopsoas, the pectineus attaches to and supports the hip joint capsule.

The gracilis, the longest of the hip adductors, is also the most superficial and medial of the hip adductor muscles. This works to adduct and flex the thigh and flex and internally rotate the leg.

tensor fascial nerve muscle

This muscle wraps around the thigh muscles. It is responsible for counteracting the backward pull of the gluteus maximus on the IT band. It also flexes, abducts, and externally rotates the hip.

The trochanteric bursa lies deep to this muscle, as it passes over the greater trochanter. The attachment of the tensor nerve muscle through the iliotibial band to the anterolateral tibia provides a bending moment in knee flexion and an extension moment in knee extension.

sartorius muscle

The sartorius muscle is the longest muscle in the body. The sartorius is responsible for flexion, abduction, and external rotation of the hip and some degree of flexion of the knee.

How is it done?

The easiest way to perform the Thomas test is to lie on your back on the edge of the bed or on a sturdy table, so that your legs hang down. We will bring both knees to the chest so that the back is flat against the bed. While holding one knee close to the chest, slowly stretch out the other leg and let it hang off the edge.

  1. We will sit at the end of a table with the middle of the thigh aligned with the edge. We will sit upright, raising our heads to the ceiling. We’ll tighten the abdominal muscles to strengthen the spine, then lower and retract the scapulae (pull the shoulders down and back) without arching the lower back.
  2. Keeping your abs tight, lean back slightly, bringing your left knee off the table toward your chest and crossing your hands under your left thigh without moving your torso. We will continue leaning back, keeping the head in line with the spine and the abdominals contracted. We will raise the right knee towards the ceiling, lifting the right thigh off the table.
  3. We will begin to round the back, lowering it to the table noting one vertebra at a time. Keeping the left thigh, we will allow the right knee to remain pointed towards the ceiling. As we bring our heads down and into a supine (face up) position, we will support our left leg and lower our right thigh toward the table maintaining a bent knee position to allow the lower leg to hang off the table and a stretch through the right hip flexor.
  4. We will hold the stretch position for 15 to 30 seconds at a time for a total of 2 to 4 repetitions.

The test will pass if the lowered back and lower thigh are flat against the bed and the hanging knee is bent at a 90 degree angle to the surface. However, there are a few things to keep in mind when it comes to failing the test:

  • If the lowered leg is extended straight instead of bending at the knee, the rectus femoris is tight. In the event that the lower knee is bent, but the back of the thigh is raised off the bed, it is the iliopsoas.
  • If the lower leg is bent at the knee and the thigh rests on the bed, but the leg hangs slightly to the side, then the tensor fasciae latae is tight.

Distance runners most likely experience a tight iliopsoas.

How to correct a negative result?

One of the nice things about this is that the Thomas test can become the same treatment. Keep in mind that muscles take a while to remodel with stretching. It’s generally recommended to do these stretches five to seven days a week for a total of three minutes a day. With just static stretching, we may need 8-10 weeks, so it is recommended to add lacrosse ball work to speed up the process.

thomas stretch

To do this stretch:

  1. We’ll be pulling one knee to the chest while lying on your back on an elevated surface, which we’ve already been doing while doing the test.
  2. We’ll just make sure to keep your back and thighs flat and keep your knee bent at a 90-degree angle.
  3. We’ll hold that stretch for 30 seconds to a minute.

lunge stretch

  1. We will get into a lunge position on our knees, with one foot forward.
  2. We will lean forward while squeezing the buttocks, contracting the abdomen and straightening the spine. We will hold the stretch for 30 seconds to a minute.

Since the hip flexors are so deeply embedded under the layers of muscle, using a lacrosse ball to stretch the area will work wonders. If a lacrosse ball is too intense, we can start with a tennis ball.