Necessity of Leg Length Adjustment When Measuring the Knee Extensor Strength Using Hand-held Dynamometers

Abstract

[Purpose] To clarify the necessity of leg length adjustment when measuring the knee extensor strength using hand-held dynamometers. [Subjects and Methods] The following items were measured in 108 (male: 21 and female: 87) elderly and middle-aged community residents of the general public: the knee extensor strength, maximum walking speed, and StandUp Test and 2-step Test scores. The knee extensor strength was evaluated by calculating the muscle strength- (N/kg) and torque- (Nm/kg) body weight ratios and examining their reproducibility, correlations, and associations with performance based on the sex. [Results] Both the muscle strength- and torque-body weight ratios showed high reproducibility and strong correlations, and these measurement values were consistent with the results of each performance test, regardless of the sex. [Conclusion] The influence of lower-leg length on the knee extensor strength of the elderly and middle-aged residents measured using hand-held dynamometers was not marked. Therefore, it may be possible to evaluate such strength based on non-adjusted values while carefully considering the purpose of their use.