Objective
The purpose of this study was to determine the knee extension force of healthy Korean adults by using a hand-held dynamometer and evaulate the relationship of knee extension force between each decade.

Method
One hundred and twenty healthy subjects (60 males, 60 females) between the ages of 20 and 79 years were tested for knee extension force by using Nicholas Manual Muscle Tester (MMT). Data were analyzed for means, standard deviations, test-retest reliability and correlation with variables by using the SPSS^Ⱂ software package.

Results
The mean value of the knee extension force was 25.9⁑5.8 kg in the males and 16.5⁑4.1 kg in the females. Significant difference between each decade was found in the males but not in the females. The knee extension force of the males was stastically correlated with all of variables, i.e., age, weight and height, but the knee extension force of the females, was correlated only with weight. Intratester correlation coefficients were high for the Nicholas MMT to measure the knee extension force for healthy adults. Also the difference between the dominant and nondominant side for the knee extensor force was not significant, stastically.

Conclusion
This MMT may be useful to quickly and objectively evaluate force in the clinical setting.