Passive knee extension test to measure hamstring muscle tightness

Area of Science:

• Biomechanics
• Kinesiology
• Musculoskeletal assessment

Background:

• Assessing hamstring muscle tightness is crucial for understanding lower limb biomechanics and preventing injuries.
• Existing methods for measuring hamstring tightness vary in reliability and complexity.
• Understanding associated pelvic motion during testing is important for accurate interpretation of results.

Purpose of the Study:

• To evaluate the reliability of a passive knee extension test for quantifying hamstring tightness.
• To assess the degree of pelvic motion that occurs during this specific hamstring flexibility test.

Main Methods:

• A standardized passive force was used to extend the knee with the hip stabilized at 120 degrees of flexion.
• Hamstring tightness was measured using a goniometer to determine the knee angle at the point of maximal stretch.
• Pelvic motion was quantified using a MacReflex measurement system.
• Twenty-eight test-retest trials were conducted to assess reliability.

Main Results:

• The passive knee extension test demonstrated high reliability, with a correlation coefficient of 0.99.
• The coefficient of variation (CV) for the test was found to be 1%, indicating minimal measurement error.
• Associated pelvic motion during the test was minimal, with a median measurement of 4.1 degrees.

Conclusions:

• The passive knee extension test is a simple, reliable, and valid method for measuring hamstring tightness.
• The associated pelvic motion during this test is negligible, ensuring that measurements primarily reflect hamstring flexibility.
• This test offers a practical and accurate approach for clinical and research settings to assess hamstring flexibility.