Reliability of knee flexor peak torque measurements from a standardized test protocol on a Kin/Com dynamometer

Area of Science:

• Biomechanics
• Kinesiology
• Sports Medicine

Background:

• Assessing knee flexor muscle strength is crucial in clinical and sports settings.
• The Kin/Com dynamometer is a common tool for measuring muscle torque.
• Establishing reliable testing protocols is essential for accurate strength assessment.

Purpose of the Study:

• To evaluate the test-retest reliability of a specific protocol for measuring peak knee flexor torque.
• To assess reliability at two different angular velocities (30°/sec and 180°/sec).
• To determine reliability for both concentric (resisted-muscle shortening) and eccentric (resisted-muscle lengthening) contractions.

Main Methods:

• 11 healthy women performed tests measuring peak torque of knee flexors using a Kin/Com dynamometer.
• Measurements were taken in a sitting position at 30°/sec and 180°/sec, including resisted-muscle shortening (RMS) and resisted-muscle lengthening (RML) cycles.
• Subjects repeated the tests within a single session and again one week later.
• Intraclass correlation coefficients (ICCs) were calculated to assess reliability.

Main Results:

• High within-session reliability was observed, with ICCs ranging from 0.92 to 0.98 across velocities and contraction types.
• Between-session reliability was generally lower but still strong, with ICCs ranging from 0.75 to 0.90.
• Peak torque measurements for both RMS and RML demonstrated good to excellent reliability.

Conclusions:

• The evaluated test protocol provides a reliable method for measuring peak knee flexor torque.
• High reliability was confirmed for both concentric and eccentric contractions at 30°/sec and 180°/sec.
• This protocol can be confidently used in research and clinical practice for assessing knee flexor strength.