Reliability Variations of Strength in Test-Retest Situations

The reliability of right wrist flexor strength was studied in test-retest situations using 20 male subjects. Five trials were secured three days in succession. Measurement procedures were repeated three weeks later, and again three months later. Acceptable, though varying, levels of reliability were obtained under each of the test conditions separately (R's of .91, .99 and .97). Significant differences ranging from 8 to 15 percent for means of tensiometer strength between test condition 1 and both retest conditions affected test-retest reliability. The apparent factors affecting reliability were tentatively identified as being due to either a physiological response to initial measurement procedures, a lasting motor learning effect, or a combination of such factors. Consideration of the significance of such factors in strength research was noted.