Quadriceps muscle strength reference value as index for functional deterioration of locomotive organs: Data from 3617 men and women in Japan.

BACKGROUND: Quadriceps muscle strength reference value of normal individuals in Japan is necessary to quantitatively evaluate functional deterioration of locomotive organs. Therefore, we established a reference value by using the Locomo Scan, a new device that measures knee extension muscle strength.

METHODS: We measured knee extension muscle strength with the Locomo Scan in 3617 individuals (1692 men, 1925 women, 20-89 years; mean age. 50.7 years) by implementing our own 49 measurement events in 20 prefectures.

RESULTS: The means of maximum knee extension muscle strength for men (women) in each age group were as follows: 20s, 546 (475) N; 30s. 552 (475) N; 40s, 534 (450) N; 50s, 507 (442) N; 60s, 471 (405) N; 70s, 385 (340) N; and 80s, 359 (267) N. No significant differences were found from the 20s to 40s age groups, but older groups had significantly decreased knee extension muscle strength with age for both sexes.

CONCLUSIONS: We established reference values for quadriceps muscle strength with the Locomo Scan as an index for functional deterioration of locomotive organs based on a large-scale sample.