Performance on the single-leg squat task indicates hip abductor muscle function.

Area of Science:

• Orthopedics
• Sports Medicine
• Biomechanics

Background:

• Anterior knee pain management benefits from addressing hip muscle dysfunction.
• Effective treatment requires accurate identification of individuals with impaired hip function.
• A reliable clinical assessment tool for hip muscle function is needed.

Purpose of the Study:

• To establish the inter- and intrarater reliability of the single-leg squat assessment.
• To determine if good single-leg squat performance correlates with superior hip muscle function.
• To compare hip muscle activation and strength between good and poor single-leg squat performers.

Main Methods:

• A consensus panel developed criteria for rating single-leg squat performance (good, fair, poor).
• Thirty-four asymptomatic participants were assessed for interrater and intrarater reliability.
• Hip muscle strength and gluteus medius (GM) electromyography (EMG) onset timing were compared between good (n=9) and poor (n=12) performers.

Main Results:

• Excellent to substantial interrater (κ = 0.800-0.600) and intrarater (κ = 0.800-0.613) reliability was achieved.
• Good performers demonstrated significantly earlier anterior (AGM) and posterior gluteus medius (PGM) EMG onset.
• Good performers exhibited greater hip abduction torque and trunk side flexion strength compared to poor performers.

Conclusions:

• The single-leg squat task is a reliable clinical tool for assessing hip muscle function.
• This assessment can identify individuals with hip muscle dysfunction, potentially benefiting from targeted interventions.
• Accurate identification of hip dysfunction aids in tailoring treatments for anterior knee pain.