title: Caffeine Attenuates Decreases in Leg Power Without Increased Muscle Damage.
abstract: Ribeiro, BG, Morales, AP, Sampaio-Jorge, F, Barth, T, de Oliveira, MBC, Coelho, GMdO, and Leite, TC. Caffeine attenuates decreases in leg power without increased muscle damage. J Strength Cond Res 30(8): 2354-2360, 2016-Caffeine ingestion has been shown to be an effective ergogenic aid in several sports. Caffeine administration may increase exercise capacity, which could lead to a greater degree of muscle damage after exercise. This was a randomized, double-blind, placebo-controlled crossover study. Six male handball athletes ingested placebo (PLA) or caffeine (CAF) (6 mg·kg body mass) capsules on 2 different occasions. Sixty minutes after ingestion of the capsules, serum CAF levels were evaluated. Thereafter, all participants performed a protocol of vertical jumps (VJs). The protocol consisted of 4 sets of 30 seconds of continuous VJs with 60 seconds of recovery between sets. Blood lactate (LAC) and creatine kinase (CK) levels were determined before and after the protocol. We found significant differences in serum CAF levels between PLA (0.09 ± 0.18 µg·ml) vs. CAF (6.59 ± 4.44 µg·ml) (p < 0.001). Caffeine elicited a 5.23% (p ≤ 0.05) improvement in the leg power compared with PLA. The CAF trial displayed higher LAC (p ≤ 0.05) compared with PLA (6.26 ± 2.01 vs. 4.39 ± 2.42 mmol·L, respectively) after protocol of VJs, whereas no difference in CK was observed between trials (p > 0.05). These results indicate that immediate ingestion of CAF (6 mg·kg body weight) can reduce the level of muscle fatigue and preserve leg power during the test, possibly resulting in increase in LAC. There was no increase in muscle damage, which indicates that immediate administration of (6 mg·kg body weight) CAF is safe. Thus, nutritional interventions with CAF could help athletes withstand a greater physiological overload during high-intensity training sessions. The results of this study would be applicable to sports and activities that require repetitive leg power.
authors.affiliation: 1Laboratory Research and Innovation in Sports Sciences, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil; 2Macaé Sports Foundation, City Government of Macaé (PMM), Rio de Janeiro, Brazil; 3Laboratory of Chemistry and Biomolecules, Higher Institutes of Education of CENSA (ISECENSA), Rio de Janeiro, Brazil; 4Laboratory of Natural Products, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil; and 5Rio de Janeiro State University, Rio de Janeiro, Brazil.
authors.forename: Beatriz G
authors.initials: BG
authors.lastname: Ribeiro
authors.forename: Anderson P
authors.initials: AP
authors.lastname: Morales
authors.forename: Felipe
authors.initials: F
authors.lastname: Sampaio-Jorge
authors.forename: Thiago
authors.initials: T
authors.lastname: Barth
authors.forename: Marcio B C
authors.initials: MB
authors.lastname: de Oliveira
authors.forename: Gabriela M D O
authors.initials: GM
authors.lastname: Coelho
authors.forename: Tiago C
authors.initials: TC
authors.lastname: Leite
mesh_terms: D000328:Adult; D056352:Athletes; D002110:Caffeine / Q000008:administration & dosage* / Q000097:blood; D000697:Central Nervous System Stimulants / Q000008:administration & dosage*; D003402:Creatine Kinase / Q000097:blood; D018592:Cross-Over Studies; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D007866:Leg / Q000502:physiology; D008297:Male; D018763:Muscle Fatigue / Q000187:drug effects* / Q000502:physiology; D053580:Muscle Strength / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D055815:Young Adult
chemical_list: D000697:Central Nervous System Stimulants; D019344:Lactic Acid; D002110:Caffeine; D003402:Creatine Kinase