The purposes of this study were to compare the forces produced by knee extensors during two kinds of muscle strength tests (knee at 90 degrees of flexion) and to determine the reliability of each test procedure with two retestings. A hand-held dynamometer was used to perform the tests on 30 elder women. It was founds that the forces produced by knee extensors during break-test were significantly larger than the forces produced in make-test (p < 0.001). The test and the first retesting of both procedures was reliable, but the second retesting showed decreased values in spite of the test and first retesting values, indicating fatigue. The make-test seems to be more indicated for elder people. In this same sample, non reliable data was obtained in the third measurement while doing three sequential measurements.

Key words: muscle strength; evaluation; method; physical therapy