The relationship of disability (Oswestry) and pain drawings to functional testing.

UNLABELLED: There was much enthusiasm about the development of computerized dynamometry in providing large quantities of data to objectively assess muscle performance. However, a much more basic issue arose questioning what these machines actual measure, particularly in pain populations. The purpose of the present study was to determine whether patients' self-reported disability and pain expression, as evaluated with simple questionnaires, were related to isokinetic performance in low back pain patients. METHOD: Oswestry Disability Questionnaires and pain drawings were collected from 76 patients undergoing isokinetic testing upon entering a physical rehabilitation program. Isokinetic trunk testing was performed in the standing position and results recorded for flexion and extension at speeds of 50 degrees, 100 degrees, and 150 degrees per second. RESULTS: Patients indicating minimal disability on the Oswestry questionnaire performed better than those indicating greater levels of disability (P < 0.05; ANOVA with Tukey adjustment for multiple comparisons). Patients with greater pain drawing scores, indicating unusual pain patterns, performed more poorly during isokinetic testing than those with normal drawings (P < 0.05). Regression analysis revealed that the lifting question from the Oswestry questionnaire, pain drawings scores, and sex were all significantly related to isokinetic performance and could account for 37.6-48.1% of the variance in performance (varying with speed of test). CONCLUSIONS: The results of this study indicate that isokinetic test values are significantly influenced by a patient's self-reported disability and pain expression, which can be evaluated using simple tools such as pain drawings and the Oswestry questionnaire. This study supports the supposition that dynamometry testing is related to factors other than muscle performance.

Decreased isokinetic trunk muscle strength and performance in long-term survivors of childhood malignancies: correlation with hormonal defects.

OBJECTIVE: To evaluate trunk muscle strength and performance in long-term survivors of childhood malignancies relative to age and sex-matched controls, and to relate the muscle strength observations to the therapeutic agents used and possible hormonal disturbances. DESIGN: Age and sex-matched cohort study. SETTING: Referral center in the northern part of Finland. PATIENTS: Forty-six long-term survivors of childhood cancer. Mean age at examination 19.1 years and median off-therapy time 9.4 years. INTERVENTION: Isokinetic dynamometer testing. MAIN OUTCOME MEASURES: Measurements of trunk muscle peak torque (PT) and total work done (TWD) were performed at angle speeds of 50 degrees/sec and 200 degrees/sec. The results were normalized relative to body fat-free weight (FFW). RESULTS: PT in the trunk muscles was lower in the patients at both angle speeds (mean normalized PT = 5.7Nm/kgFFW vs 7.6Nm/kgFFW for controls at 50 degrees/sec), as also was TWD except for extension TWD at the higher angle speed (mean normalized TWD = 59.9J/kgFFW vs 84.6J/kgFFW for controls at 200 degrees/sec). The normalized PT at 50 degrees/sec and TWD at 200 degrees/sec were lower in the males with testicular damage; also, low age at diagnosis correlated positively with muscle strength and performance. There were no differences in normalized PTs or TWDs between cranial radiation and non-radiation cases, or between growth-hormone-deficient and non-deficient cases, and the patients without cranial radiation or with normal growth hormone secretion still had lower normalized PTs and TWDs than the controls. CONCLUSIONS: Survivors of childhood malignancies have decreased maximal trunk muscle strength and performance. The etiology of this effect remains unclear, but young age at diagnosis, as well as serum testosterone levels in male survivors, evidently influence muscle strength and performance.