Aerobic fitness in patients at work despite recurrent low back pain: a cross-sectional study with healthy age- and gender-matched controls.

Objective: The aims of this study were to compare the aerobic fitness level of working patients who have recurrent low back pain with those of healthy age- and gender-matched controls, and to investigate the relationship of aerobic fitness level with pain intensity, general health, perceived disability, fear-avoidance beliefs and self-efficacy.

Subjects And Methods: A total of 57 patients with recurrent low back pain, with a mean of 10 years' pain duration and 57 healthy controls performed a sub-maximal Astrand cycle test. Predicted maximum oxygen consumption was calculated and compared. Correlations between the low back pain patients' predicted aerobic fitness level and the assessed variables were calculated.

Results: The women with low back pain had lower predicted aerobic fitness levels than the healthy women (p<0.05). For the men there was no such difference. Multiple regression analysis showed that age, gender, body mass index and self-efficacy were associated with the predicted aerobic fitness level.

Conclusion: This study suggests no overall difference in predicted aerobic fitness level for a sample of subjects with recurrent low back pain compared with healthy controls. This is perhaps because all the patients were still at work despite the pain. The results indicate, however, that the factors associated with aerobic fitness differ between men and women.