Caffeine Attenuates Delayed Onset Muscle Pain Following Eccentric Exercise

Abstract

PURPOSE: This double-blind, placebo-controlled, repeated measures experiment examined the effects of a 5 mg.kg−1 body weight dose of caffeine on delayed onset muscle pain intensity and force loss in response to 64 eccentric actions of the dominant quadriceps induced by electrical stimulation METHODS: Low caffeine consuming college-aged females (N=9) ingested caffeine or placebo 24 and 48 hours following electrically stimulated eccentric exercise of the quadriceps. One hour after ingestion, maximal voluntary isometric contractions (MVIC) and submaximal voluntary eccentric actions (SVEA) were used to determine whether caffeine attenuates muscle pain intensity or force loss during activation of damaged quadriceps. Pain intensity was measured using a 0 to 100 visual analog scale (VAS). RESULTS: Caffeine produced a large (12.7 raw VAS units; −48%; d=−0.88) statistically significant hypoalgesia during the MVIC (t=−2.52; df=8; p=0.030. The reduction in pain scores during SVEA was smaller (7.8 raw VAS units; −26%; d=−0.34) as was the increase in MVIC force (4.4%; d=0.13). CONCLUSIONS: Caffeine can produce large reductions in pain resulting from eccentric exercise induced delayed onset muscle injury.