Short-term effect of superficial heat treatment on paraspinal muscle activity, stature recovery, and psychological factors in patients with chronic low back pain

Abstract

Objective: To test the hypothesis that patients with chronic low back pain (CLBP) would have reduced paraspinal muscle activity when wearing a heat wrap and that this would be associated with increased stature recovery and short-term improvements in psychological factors.

Design: A within-subject repeated-measures design. Muscle activity and stature recovery were assessed before and after a 40-minute unloading period, both without a heat wrap and after 2 hours of wear. Questionnaires were completed after both sessions.

Setting: Hospital physiotherapy department.

Participants: Patients with CLBP (n=24; age, 48.0±9.0 y; height, 166.6±7.3 cm; body mass, 80.2±12.9 kg) and asymptomatic participants (n=11; age, 47.9±15.4 y; height, 168.7±11.6 cm; body mass, 69.3±13.1 kg) took part in the investigation. Patients on the waiting list for 2 physiotherapist-led rehabilitation programs, and those who had attended the programs during the previous 2 years, were invited to participate.

Intervention: Superficial heat wrap.

Main outcome measures: Paraspinal muscle activity, stature recovery over a 40-minute unloading period, pain, disability, and psychological factors.

Results: For the CLBP patients only, the heat wrap was associated with a reduction in nonnormalized muscle activity and a positive short-term effect on self-report of disability, pain-related anxiety, catastrophizing, and self-efficacy. Changes in muscle activity were correlated with changes in stature recovery, and both were also correlated to changes in psychological factors.

Conclusions: Use of the heat wrap was associated with a decrease in muscle activity and a short-term improvement in certain aspects of well-being for the CLBP patients. The results confirm the link between the biomechanical and psychological outcome measures.