Continuous low-level heat wrap therapy for the prevention and early phase treatment of delayed-onset muscle soreness of the low back: A randomized controlled trial

Objective: To evaluate the effects of continuous low-level heat wrap therapy for the prevention and early phase treatment (ie, 0-48h postexercise) of delayed-onset muscle soreness (DOMS) of the low back. Design: Two prospective randomized controlled trials. Setting: Outpatient medical facility. Participants: Sixty-seven subjects asymptomatic of back pain and in good general health (mean age, 23.5 +/- 6.6y). Interventions: Participants performed vigorous eccentric exercise to experimentally induce low back DOMS. Participants were assigned to 1 of 2 substudies (prevention and treatment) and randomized to 1 of 2 treatment groups within each substudy: prevention study (heat wrap, n=17; control [nontarget muscle stretch], n=18) and treatment study (heat wrap, n=16; cold pack, n=16). Interventions were administered 4 hours before and 4 hours after exercise in the prevention study and between hours 18 to 42 postexercise in the treatment study. Main Outcome Measures: To coincide with the expected occurrence of peak symptoms related to exercise-induced low back DOMS, hour 24 postexercise was considered primary. Pain intensity (prevention) and pain relief (treatment) were primary measures, and self-reported physical function and disability were secondary measures. Results: In the prevention study, at hour 24 postexercise, pain intensity, disability, and deficits in self-reported physical function in subjects with the heat wrap were reduced by 47% (P<.001), 52.3% (P=.029), and 45% (P=.013), respectively, compared with the control group. At hour 24 in the treatment study, postexercise, pain relief with the heat wrap was 138% greater (P=.026) than with the cold pack; there were no differences between the groups in changes in self-reported physical function and disability. Conclusions: In this small study, continuous low-level heat wrap therapy was of significant benefit in the prevention and early phase treatment of low back DOMS.