BODY MOTION PATTERNS DURING A NOVEL REPETITIVE WHEEL-ROTATION TASK - A COMPARATIVE-STUDY OF HEALTHY-SUBJECTS AND PATIENTS WITH LOW-BACK-PAIN

Study Design. This study evaluated performance differences between patients with chronic low back pain and a control group during their performance of a novel functional capacity task. Objective. To 1) evaluate strength and endurance differences between patients and control subjects, 2) test for movement pattern differences between these groups, and 3) evaluate how these patterns changed with repetitive performance of the wheel-turning task. Summary of Background Data. Despite increased emphasis quantifying functional capacities, few well-controlled studies comparing the performances of patients with low back pain with those of control subjects have appeared in the literature, particularly for movement patterns. Methods. Forty patients with low back pain and 40 control subjects performed a sustained isodynamic wheel turning task. This task was selected because it simultaneously combined several common pain-related movements. A set of kinematic measures to characterize the basic movement patterns during this task were developed. Results. Control subjects produced significantly higher levels of static torque and completed significantly more wheel-turning repetitions. Patients with low back pain exhibited significantly less upper torso and pelvic motion, upper torso rotations, and lateral trunk flexion than those in the control group. Conclusion. The dissimilar movement strategies found between the patients and control groups suggests that factors beyond more global physical explanations (e.g., deconditioning) may be important in accounting for the large discrepancy between these groups regarding the amount of work performed. These finding, along with the basic kinematic patterns developed in this study, may have important implications for determining the efficacy of instruction in body mechanics and treatment outcome for patients with chronic low back pain.