Benefits of a four-week functional restoration program in chronic low back pain patients and three-month follow-up: focus on paraspinal muscle aerobic metabolism responses to exercise

Abstract

c hronic low back pain (CLBP) is a major health concern in industrial country, which leads to physical and psychological limitations, resulting notably of high level of paraspinal muscle fatigability in patients. 1, 2 clBpinduced muscle fatigability could be associated with an alteration in aerobic metabolism during paraspinal muscle contractions, in an attempt to satisfy muscular energy re-quirements for spine mobilization and stabilization. 3 an imbalance between muscle O 2 needs and utilization could limit aerobic metabolism and induce high level of paraspinal muscle fatigability.functional restoration programs for clBp patients, described by Mayer and Gatchell, 4 have been recognized as being more effective than the traditional medical inter-BACKGROUND: Chronic low back pain (CLBP) is a major health concern characterized by paraspinal muscle fatigability. This can be im-proved following a functional restoration program. Muscle fatigability can be related to impairment in aerobic metabolism responses. In this study, we investigated paraspinal muscles aerobic metabolism in CLBP patients before and after a functional restoration program, in order to determine if the enhancement in patients' condition following the program is associated to changes in metabolism responses. METHODS: Twenty-two CLBP patients (11 women, 11 men; 41.6±1.8 years; 73.7±3.1 kg; 1.74±0.02 m) were evaluated before and after a 4-week functional restoration program, with exercise therapy as the main component. Three months later, 12 patients were seen for a follow-up visit. During each testing session, patients performed a five-minute isokinetic trunk extension exercise in measuring pulmonary gas exchanges and paraspinal muscle oxygenation. Mechanical efficiency and onset V ̇ O2 kinetics were also calculated, in addition to usual questionnaires and exercises designed to evaluate psychosocial and physical factors. RESULTS: At the end of the program, paraspinal muscle oxygenation, mechanical efficiency, and the V ̇ O2 onset kinetics were improved (P<0.05). All measures remained stable during the three-month follow-up except for paraspinal muscle oxygenation, which deteriorated (P<0.05). Returnto-work was associated with the level of workday physical activities and to a decrease in fear-avoidance beliefs. CONCLUSIONS: At the end of the program, aerobic metabolism responses were improved in paraspinal muscles in patients. These improve-ments were not associated with return-to-work, which was primarily influenced by socio-psychological factors.