Comparison of isokinetic internal and external hip rotation torques using different testing positions

Area of Science:

• Orthopedics
• Sports Medicine
• Physical Therapy

Background:

• Limited data exists on the relative strength of hip internal and external rotator muscles.
• Understanding hip musculature strength is crucial for injury prevention and rehabilitation in athletes and the general population.

Purpose of the Study:

• To investigate and quantify the relative strength of hip internal and external rotator muscles.
• To determine the influence of different testing positions on hip rotation torque measurements.

Main Methods:

• Sixty healthy subjects were tested using a Cybex(R) 340 isokinetic dynamometer.
• Maximum voluntary isometric hip internal and external rotation torques were measured in three distinct positions: seated, supine with knee flexed, and supine with knee extended.
• Statistical analysis was performed to assess the significance of position and movement type on torque output.

Main Results:

• Hip rotation torque was significantly influenced by the testing position (p < 0.05).
• The seated position yielded the highest torque values, followed by supine with knee flexed, then supine with knee extended.
• Internal rotation torques were consistently greater than external rotation torques across all positions, contradicting prior research.

Conclusions:

• The study provides essential normative data on hip rotator muscle strength proportions.
• Findings suggest that internal rotators are stronger than external rotators, a critical consideration for physical therapy and sports performance.
• Testing position significantly impacts hip rotation strength measurements, highlighting the importance of standardized protocols.