The Efficacy of Sustained Heat Treatment on Delayed-Onset Muscle Soreness

Objective: To assess the impact of heat applied for 8 hours immediately after or 24 hours after exercise on delayed-onset muscle soreness (DOMS) in large skeletal muscle groups measured by subjective and objective means. Design: Cross-sectional repeated measure design study. Setting: Research laboratory. Subjects: Three groups of 20 subjects, age range 20 to 40 years. Intervention: Squats were conducted in three 5-minute bouts to initiate DOMS; 3 minutes of rest separated the bouts. One group had heat applied immediately after exercise, and a second group had heat applied 24 hours after exercise. A third group was the control group where no heat was applied. Main Outcome Measures: Visual analog pain scales, muscle strength of quads, range of motion of quads, stiffness of quads (Continuous Passive Motion machine), algometer to measure quadriceps soreness, and blood myoglobin. Results: The most significant outcome was a reduction in soreness in the group that had low-temperature heat wraps applied immediately after exercise (P < 0.01). There was benefit to applying heat 24 hours after exercise, but to a smaller extent. This was corroborated by myoglobin, algometer, and stiffness data. Conclusions: Low-level continuous heat wraps left for 8 hours just after heavy exercise reduced DOMS in the population tested as assessed by subjective and objective measures.