Isokinetic measurement of trunk muscle strength in women with chronic low-back pain

Objectives: To investigate the relationships among chronic low-back pain an d obesity, total spinal range of motion, and trunk muscle strength. The sho rt-term impact of trunk muscle strengthening exercises on this condition wa s also examined. Design: A controlled, prospective study of trunk muscle strengths of patien ts with chronic low-back pain and the short-term impact of exercise on stre ngth. The study group consisted of 25 female patients who had been experien cing low-back pain for at least 3 mo, and the control group included 20 age -matched women without known low-back trouble. The Davenport Index was used to calculate the body mass indexes of all subjects. The Oswestry Disabilit y Questionnaire was used to assess pain in the study group. Full flexion an d extension ranges of motion were measured, then isokinetic measurements of trunk muscles were performed at 60-, 120-, and 180-degrees/sec velocities. Isometric measurements were also recorded for both flexors and extensors a t a 60-degree angle. Results: Increased body mass index and decreased trunk muscle strength were found to be directly associated with chronic low-back pain (P < 0.05). Aft er a 15-day standard trunk strengthening exercise program in the patient gr oup, trunk muscle strength was found to be increased (P < 0.05). Conclusions: Obesity and decrease in trunk muscle strength are important fa ctors in chronic low-back pain, and a trunk muscle strengthening program wi ll be helpful in reducing the pain.