Relationship between joint passive stiffness and hip lateral rotator concentric torque.

Area of Science:

• Biomechanics
• Musculoskeletal health
• Sports science

Background:

• Adequate hip joint passive stiffness is crucial for controlling lower limb movements in the transverse plane.
• Hip lateral rotator muscle strengthening is a potential method to enhance hip joint stiffness.
• The direct relationship between hip passive stiffness and muscle strength is not well-established.

Purpose of the Study:

• To examine the association between hip passive stiffness during medial rotation and hip lateral rotator concentric torque.
• To provide empirical data on the link between hip joint passive stiffness and muscle strength in young adults.

Main Methods:

• Twenty-six healthy young adults participated.
• Hip passive stiffness was quantified using an isokinetic dynamometer measuring passive resistance torque during medial rotation.
• Hip lateral rotator peak torque and work were assessed using the same dynamometer, with electromyography ensuring muscle inactivity during stiffness measurements.

Main Results:

• A moderate to good association was found between hip passive stiffness and hip lateral rotator concentric torque (r=0.70, R²=0.50, p<0.001).
• A similar association was observed between hip passive stiffness and lateral rotator work (r=0.77, R²=0.59, p<0.001).

Conclusions:

• Hip passive stiffness is moderately to strongly associated with hip lateral rotator concentric torque and work.
• These findings suggest that strength training targeting the hip lateral rotators could effectively increase hip joint passive stiffness.
• This relationship has implications for improving lower limb stability and movement control.