The magnitude of CSEMs is sufficiently small to detect change in patients with initial scores in the central portion of the scale (4-20 RMQ points); however, the magnitude is too large to detect improvement in patients with scores of less than 4 and deterioration in patients who have scores greater than 20.

Based on the latter finding, we believe the RM questionnaire may be the preferred instrument for assessing change over time in patients with low back pain.

ow back pain presents a large health care problem, and efforts to iden-I tify effective methods of prevention and treatment have proven difficult. Abdominal and trunk extensor muscle strength measurements are potentially important for identifying risk factors and prognostic indicators, planning treatment goals, and measuring patient progress.The identification of risk factors allows one to target preventative strategies. Studies have identified that trunk muscle performance is important in preventing an occurrence or recurrence of a back injury. Cady et a1 (5) measured fitness in a group of firefighters and showed that muscle strength was a risk factor for low back pain. There were differences in age between those who developed low back pain and those who did not, and, hence, age may have been a confounder in this study. In a group of nursing students, Videman et al (17) found that the number of sit-ups performed in 30 seconds was a significant predictor of back injury at 1 year. BieringSorensen (4) reported that those with recurrent back pain had weaker muscles compared with healthy subjects in a prospective p o p ulation study. He also found that good isometric endurance of back extensor muscles in men appeared to protect them from low back pain

There is poor interrater agreement on determination of the segmental level of a marked spinous process. There is poor interrater reliability of P-A accessory mobility testing in the absence of corroborating clinical data. Caution should be exercised when physical therapists make clinical decisions related to the evaluation of motion at a specific spinal level using P-A accessory motion testing.

No abstract