EFFECT OF CAFFEINE ON RECOVERY FROM AN ENDURANCE CYCLING EVENT Aaron R. Caldwell1, Matthew A. Tucker1, Cory L Butts1, Brendon P. McDermott1, Jakob L. Vingren FACSM2, Laura J. Kunces3, Elaine C. Lee4, Colleen X. Munoz4, Keith Williamson5, Lawrence E. Armstrong FACSM4, Matthew S. Ganio1 1University of Arkansas, Fayetteville, Arkansas; 2University of North Texas, Denton, Texas; 3EXOS, Phoenix, Arizona; 4University of Connecticut, Storrs, Connecticut; 5Midwestern State University, Wichita Falls, Texas Muscle soreness is commonly experienced following prolonged endurance exercise. Caffeine can reduce muscle pain during exercise. However, the effects of caffeine on recovery from a demanding exercise bout have not been elucidated. PURPOSE: The purpose of this study was to investigate the effects of caffeine intake on ratings of perceived muscle soreness (RPMS) and perceived lower extremity functionality (LEF) following the completion of a 100-mile endurance cycling event. METHODS: Males (n=26; age 53±10 years) and females (n=6; age 46±11 years) who participated in the Hotter’N Hell Hundred bicycle ride volunteered. Immediately following the ride 20 subjects, in a double-blinded randomized fashion, were provided 3 mg/kg body mass of caffeine (CAF) while 12 subjects ingested identical looking placebo (PLA) pills. Before cycling or pill ingestion, RPMS (1-to-6; 6=severe soreness) and LEF (0-to-80; 80=full functionality) was assessed via questionnaires. Participants repeated ingestion of their assigned pills and completed the questionnaires for the next 3 mornings and 4 afternoons. Only those with significant changes in RPMS or LEF immediately post-ride were included in the final analysis. Differences between treatment groups over time were assessed with a two-way repeated measures ANOVA. RESULTS: Sixteen participants were included in the analysis of LEF (PLA=9, CAF=7) and RPMS (PLA=12, CAF=4). There were no effects of condition or time on LEF when measured in the morning (p> 0.05). However, changes over time in LEF in the afternoon were dependent on treatment group (p=0.02) with the CAF group having significantly higher LEF at 1 day post ride [63.5± 6.3 vs 72.3± 6.7; arbitrary units (AU) for PLA and CAF, respectively; p=0.02]. There was an overall trend for the CAF group to have reduced RPMS in the morning compared to PLA (1.21 ± 0.13 vs. 0.70 ± 0.23; p=0.07). RPMS in the afternoon was significantly lower in the CAF group (1.33 ± 0.16 vs 0.52 ± 0.29; p=0.03). Specifically, on the afternoons of days 1 & 2 post race, RPMS was lower in the CAF vs. PLA (p<0.05). CONCLUSION: These data suggest that caffeine can reduce perceived leg soreness following an endurance cycling event. Therefore, there is potential for caffeine to aid in the recovery from an endurance cycling event. Twenty-six males (n=26; 53±10 y; 89.2±14.65 kg) and six females (n=6; 46±11 y; 70.2±12.35 kg) who were participating in the Hotter’n Hell Hundred bicycle ride (Wichita Falls, TX) completed this study. Subjects were not naïve to caffeine but restricted all forms of caffeine following the race outside of the pills provided to them. Participants were matched on gender and mass to consume either caffeine (252±39 mg per dose; 3.02 ± 0.15 mg/kg body mass) or identical placebo pills. Participants took their first dose immediately after the ride and ingested identical doses for the next 4 mornings (i.e., ~800 hrs) and 3 afternoons (i.e., ~1200 hrs). Paper and electronic questionnaires were completed prior to the ingestion of caffeine or placebo at each time-point to assess the following: LEF was assessed using the Lower Extremity Functionality Scale (Binkley, 1999). RPMS in the legs were rated on a 1-to-6 scale where 1 was the absence of soreness and 6 was severe pain that limited movement. Only those with significant decreases in LEF (PLA=9, CAF=7), and those with increases in RPMS (PLA=12, CAF=4) were included in the corresponding analysis. Data were separated and analyzed such that the effect of caffeine (or placebo) on recovery could be assessed when blood caffeine levels were low (i.e., morning measures) and high (i.e., afternoon measures). Differences between treatment groups over time were assessed with a two-way repeated measures ANOVA. Statistical significance was set at p<0.05 while a trend was identified when p<0.10. A Bonferroni correction was utilized for pairwise comparisons. INTRODUCTION METHODS ABSTRACT RESULTS CONCLUSIONS Caffeine has been shown to improve endurance performance in part because it may reduce muscle pain during exercise (Motl, 2005). Following prolonged endurance exercise Delayed Onset Muscle Soreness (DOMS) is commonly experienced, especially following an unaccustomed stimulus. Increases in soreness are usually accompanied by a decrease in perceived functionality (McBrier, 2010). Caffeine intake may reduce perceived soreness. However, caffeine’s half-life is only 3-10 hours (Magkos, 2010), and the perceptual effects caffeine may fade quickly. No known studies exist investigating the effects of caffeine on recovery from arduous exercise. Therefore the purpose of this study was to investigate the effects of caffeine supplementation on ratings of perceived muscle soreness (RPMS) and lower extremity functionality (LEF) following a 100-mile bicycle ride. Increased perceived functionality and lower leg soreness suggest that caffeine may reduce DOMS following an endurance cycling event (Figure 1). The greatest differences between groups were in the afternoon. Therefore, the effect of caffeine may be transient, and may modulate perceived soreness only when caffeine levels are high in circulation (Figure 1, Panel B and D). However, most cyclists, immediately following the 100-mile cycling ride, only reported moderate levels of Leg RPMS (1.53 ± 0.2 out of a max 6 AU). A more damaging bout of exercise may be needed to induce a greater DOMS and thus a potential for greater benefit with caffeine ingestion. There were no effects of condition or time on LEF when measured in the morning (p> 0.05; Figure 1A). Changes over time in LEF in the afternoon were dependent on treatment group (p=0.02; Figure 1B). CAF group had a significantly higher LEF at 1 day post, p=0.02. There was an overall trend for the CAF group to have reduced Leg RPMS in the morning compared to PLA (1.21 ± 0.13 vs. 0.70 ± 0.23 AU; p=0.07; Figure 1C). Changes over time in Leg RPMS in the afternoon were dependent on treatment group (p=0.03; Figure 1D). Afternoons of days 1 & 2 post race, Leg RPMS was lower in the CAF vs. PLA (p<0.05). Figure 1. Mean (+SD) LEF when assessed in the (A) morning and (B) afternoon, and RPMS when assessed in the (C) morning and (D) afternoon. * Significant difference between conditions (p<0.05); ^ Trend towards significant main effect of condition (p<0.10); AU = arbitrary units.