Why You Should Train Anterior Hip Muscles with mTrigger Biofeedback

The muscles of the anterior hip are often not trained directly in physical therapy. The posterior hip, including the glute muscles, is often the primary focus with exercises. However, in certain presentations such as hip microinstability, hip replacements, and hip pain, training the anterior hip muscles can prove to be immensely beneficial.(1)

The anterior hip muscle, often referred to as the iliopsoas, consists of the iliacus, psoas major, and psoas minor.(1) The psoas serves as a primary hip flexor, but also plays a part in hip external rotation, lateral trunk flexion, and lumbopelvic stability.(1) The iliopsoas tendon runs across the anterior hip acting as an important stabilizer.(1) It provides a posterior compressive force to the femoral head helping to keep it in place and protect the anterior hip, labrum, and joint capsule from shear forces and excessive femoral head movement.(1)This role is very similar to that of the rotator cuff muscles in the shoulder where they act to help keep the humeral head centralized in the glenoid. Excessive femoral head movement, also known as hip microinstability can be caused by insufficient acetabular coverage of the femoral head and/or capsular laxity.(1) This can lead to supraphysiological movement of the femoral head causing damage to the capsulolabral structures. The role of the iliopsoas as an anterior hip stabilizer becomes increasingly important in the presence of hip microinstability where bony stabilization is less.(1) In fact, studies have shown that individuals with hip dysplasia exhibit increased utilization of the iliopsoas muscles as an anterior hip joint stabilizer. (1)

Strengthening of the anterior hip is also critical in patients following THA, with femoral nerve injuries, L1-3 nerve root pathology, post-partum or pelvic floor dysfunction, and runners/sprinters.(1) Even in patience with hip pain / hip OA there is a reduction in gait speed that progressively gets worse until the loss of anterior hip strength is addressed.(1) In these pathologies and populations, the iliopsoas carries an increasing importance in providing stability and function.

Clincial Application
To help determine the best iliopsoas exercises, we can turn to EMG studies on iliopsoas activation levels during common hip exercises and use that to guide our interventions.(1) In general, we see an increase in iliacus, psoas, and iliopsoas muscle activation with increasing angles of hip flexion, lower extremity movement on the trunk (think leg lowers), trunk movement on the lower extremities while supported on the ground (think sit up) and with added resistance to these exercises.(1)

To break it down further, the iliacus demonstrates higher muscle activation during standing hip flexion exercises, hip abduction, and bilateral lower extremity movement on trunk.(1)

Here are some video examples using mTrigger biofeedback to enhance muscle engagement.

Hip Abduction

Leg Lowers

The psoas (major and minor) will have a high activation during ipsilateral trunk flexion against gravity.(1)

Here is an example.

Together, the iliopsoas has a high activation during supine hip flexion (both concentrically and eccentrically), hip abduction with slight external rotation, clamshell, and side lying hip abduction.(1)

Here are some video examples using mTrigger biofeedback.

Clamshell

Supine Hip Flexion

Biomechanical Principles(1)
Understanding the biomechanics at the hip joint can help with exercise selection when it comes to targeting the anterior hip.

Levers
A longer lever in open chain (straight leg lower) will increase activation of the iliacus compared to a short lever in open chain (bent knee lowers). The longer lever increases torque, meaning a higher muscle activation is required to overcome the demand of the movement. Note, if these exercises are performed before a patient is ready, they can cause anterior hip pain as a lack of strength will result in a shear across the capsulolabral structures.

Angles
Deeper angles of hip flexion, 30–60 degrees, will yield a higher activation level of the iliopsoas compared to 0-30 degrees. At 0-30 degrees, the sartorius and TFL are at a better mechanical advantage and will contribute more to the movement.

Bilateral vs. Unilateral
Bilateral exercises such as a bilateral leg lower, will require increased anterior hip muscle activation due to the added stability component.

Resistance
Unsurprisingly, adding resistance to any of these exercises will increase the demand and level of muscle activation.

Suggested Exercise Progression(1)
Given EMG data, a suggested progression of anterior hip exercises might look something like this.

Phase 1 exercises will be performed with shorter levers requiring lower muscle activation levels. Examples include: clamshells, hip abduction, seated lateral trunk flexion against gravity, and standing hip flexion to 30, 60, and 90 degrees.

Phase 2 exercises will be progressed to include moderate activation levels, increased hip flexion angles, and changing lever arms. Examples include: supine hip flexion isometrics at 30/60/90 degrees, SLR, and supine hip flexion (march).

Phase 3 exercises will be progressed to include open chain, bilateral movements, and eccentric work. Examples include: sit up with supported straight legs, sit up feet unsupported, sit up with supported bent legs, eccentric leg raise, and bilateral leg lift.

For a bonus phase, in the presence of an iliopsoas tendinopathy, which can occur following THA, hip surgery, or in high-speed sprinting athletes, the use of these exercises for eccentrics, heavy slow training, and isometrics is effective for reducing symptoms and improving strength.

Summary
Training the muscles of the anterior hip is not something that should be overlooked. Common rehab exercises already target the iliopsoas and can be progressively loaded to properly train the strength and stability of the anterior hip. Using mTrigger biofeedback for hip insatiability, THA, hip pain, and femoral nerve injury should be your go to.

Post Op Hip Protocol with mTrigger Biofeedback

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More ways to use mTrigger Biofeedback