Physical performance: Differences in men and women with and without low back pain

Objective: To determine the extent to which there may be major differences in scores on a battery of physical performance tasks among men with nonspecific, mechanical low back pain (LBP), women with LBP, healthy men, and healthy women. Design: Case series survey. Setting: A referral- based orthopedic clinic. Patients: Thirty-three men and 46 women with LBP. Control Subjects: Twenty-one men and 25 women healthy controls. Intervention: Completion of six clinician-assessed physical performance tasks and self- report inventories. Main Outcome Measure: Performance scores on distance walked in 5 minutes, 50-foot walk at fastest speed, repeated sit-to-stand, repeated trunk flexion, loaded forward reach, and the Sorensen fatigue tasks. Results: Discriminant function analysis revealed that the four groups of subjects performed the physical tasks significantly different in two major ways: (1) healthy control subjects outperformed LBP patients, irrespective of gender, on tasks involving trunk control, coordination, and stability while withstanding heavy or quickly changing loads on the spine; (2) men outperformed women, irrespective of patient or nonpatient status, on tasks involving anthropometric features of limb length. The findings provide guidance on reasonable performance expectations for men and women patients with LBP. Future studies of treatment effectiveness also will be able to assess physical performance change in terms of the intersection between standards set by the men and women healthy control subjects and those of men and women patients. However, whether a return to nonpatient status is an appropriate treatment goal is left to future research.