Time course of muscle soreness following different types of exercise

This is a reanalysis of data from three previous clinical trials. The trials included 400 runners taking part in long-distance races and 82 untrained volunteers performing a bench-stepping test. Subjects completed a Likert scale of muscle soreness every morning and evening for the five days following their exercise.Interaction between trial and time is highly significant, suggesting a different time course of soreness following running and bench-stepping. 45% of subjects in the bench-stepping trial experienced peak soreness at the third or fourth follow-up (approximately 36 – 48 hours after exercise) compared to only 14% of those in the running trial. The difference between groups is robust to multivariate analysis incorporating possible confounding variables.Soreness in runners following long-distance running follows a different time course to that in untrained individuals undertaking bench-stepping. Research on exercise taking place in the laboratory context does not necessarily generalize to exercise undertaken by trained athletes when engaged in their chosen sport.Post-exercise muscle soreness – a dull, aching sensation following unaccustomed muscular exertion – is usually said to follow an inverted U-shaped curve over time. Typical statements found in the literature are that soreness: "develops" 24 to 48 hours after exercise [1] ; "is usually perceived approximately 24 hours after the exercise bout [and] may linger for an additional 24 to 48 hours" [2] and "peaks 24–48 hours after exercise" [3].These claims are well supported by data from studies which have measured soreness at various times following an exercise bout. For example. High et al. [4] assessed soreness at 24 and 48 hours after eccentric contractions of the elbow flexors. Soreness scores were higher at the 48 hour follow-up. Similarly, Byrnes et al. [5] reported that muscle soreness steadily increased when measured 6, 18 and 42 hours following 30 minutes of downhill treadmill running. Soreness has a