SOME ENDURANCE MEASURES IN PERSONS WITH CHRONIC LOW-BACK-PAIN

Muscle fatigue and lack of endurance are complaints of persons with ch ronic low back pain, but there are no standard ways to assess enduranc e in this population. The purposes of this study were to examine three measures of endurance, to determine relationships of these measures t o each other, and to describe effects of gender, obesity, smoking, and self-reported fitness on the clinical measures. The measures of endur ance selected were not dependent on maximal voluntary muscular contrac tions. They were the Sorensen test, median frequency decline of select ed muscles, and a submaximal bicycle ergometer test. Thirty-five conse nting individuals who were referred for treatment answered questions a bout their daily exercise prior to being tested. Repeatability of the Sorensen test holding time and of the slope measure of decline in the median frequencies was acceptable for subjects who reported a higher a ctivity level. The decline of the median frequency in the biceps femor is muscles correlated with holding time of the Sorensen test. Smoking, gender, or obesity level did not affect test results on any of the en durance measures. Subjects who reportedly were more active achieved si gnificantly higher scores on the Sorensen test. The importance of cont rolling for self-perception of activity in physical testing is discuss ed.