| [PMID]: | 29209154 |
| [Au] Autor: | Tinsley GM; Hamm MA; Hurtado AK; Cross AG; Pineda JG; Martin AY; Uribe VA; Palmer TB |
| [Ad] Endereço: | Energy Balance & Body Composition Laboratory, Musculoskeletal Assessment Laboratory, Department of Kinesiology & Sport Management, Texas Tech University, Box 43011, Lubbock, TX 79409 USA. |
| [Ti] Título: | Effects of two pre-workout supplements on concentric and eccentric force production during lower body resistance exercise in males and females: a counterbalanced, double-blind, placebo-controlled trial. |
| [So] Source: | J Int Soc Sports Nutr;14:46, 2017. |
| [Is] ISSN: | 1550-2783 |
| [Cp] País de publicação: | United States |
| [La] Idioma: | eng |
| [Ab] Resumo: | Background: Pre-workout supplements purportedly enhance feelings of energy, reduce fatigue and improve exercise performance. The purpose of this study was to examine the performance effects of caffeinated and non-caffeinated multi-ingredient pre-workout supplements. Methods: In a counterbalanced, double-blind, placebo-controlled design, eccentric and concentric force production during lower body resistance exercise on a mechanized squat device were assessed after supplement ingestion. Repetitions-in-reserve/RPE and subjective feelings of energy, focus and fatigue were also examined. Twenty-one resistance-trained adults (12 F, 9 M) completed three conditions in random order: caffeinated supplement, non-caffeinated supplement and placebo. Subjects were not informed of the presence of a placebo condition. Thirty minutes after supplement ingestion, a 3-repetition maximum test and 5 sets of 6 repetitions were completed using the squat device. Each repetition involved 4-s eccentric and concentric phases, and the force signal throughout each repetition was sampled from a load cell contained within the squat device. The scaled and filtered force signals were analyzed using customized software. Repeated measures analysis of variance and appropriate follow-up analyses were utilized to compare dependent variables, and relevant effect sizes (d) were calculated. Results: Supplement or placebo ingestion led to similar subjective responses ( > 0.05). Energy (+8 to 44%; d = 0.3 to 0.8) and focus (+8 to 25%; d = 0.3 to 0.5) were acutely increased by supplement or placebo ingestion and decreased as the exercise session progressed. Fatigue was acutely decreased by supplement or placebo ingestion (-7 to 38%; d = -0.1 to -0.6) and increased as the exercise session progressed. Eccentric and concentric forces were unimproved by supplementation during the exercise sets for both sexes. In the non-caffeinated supplement condition only, maximal eccentric force production was lower during sets 3 to 5, as compared to set 1 ( < 0.05). Effect size data indicated that both the caffeinated and non-caffeinated supplements may contribute to small increases in concentric force production in males (+5 to 20%, d = 0.2 to 0.4 relative to placebo), but not females. Conclusions: As compared to placebo, caffeinated and non-caffeinated multi-ingredient pre-workout supplements failed to improve concentric and eccentric force production. In males, effect size data indicate a possible small benefit of supplementation on concentric force production, although this was not statistically significant. When resistance-trained subjects were unaware of the presence of a placebo, resistance exercise performance was similar regardless of whether a placebo or multi-ingredient supplement was ingested. |
| [Mh] Termos MeSH primário: |
Cafeína/farmacologia
Suplementos Nutricionais
Músculo Esquelético/efeitos dos fármacos
Músculo Esquelético/fisiologia
Treinamento de Resistência
|
| [Mh] Termos MeSH secundário: |
Análise de Variância
Método Duplo-Cego
Fadiga
Feminino
Alimentos Formulados
Seres Humanos
Masculino
Resistência Física/efeitos dos fármacos
Resistência Física/fisiologia
Fatores Sexuais
Fenômenos Fisiológicos da Nutrição Esportiva
Adulto Jovem
|
| [Pt] Tipo de publicação: | JOURNAL ARTICLE; RANDOMIZED CONTROLLED TRIAL |
[Nm] Nome de substância:
| 3G6A5W338E (Caffeine) |
| [Em] Mês de entrada: | 1803 |
| [Cu] Atualização por classe: | 180308 |
[Lr] Data última revisão:
| 180308 |
| [Sb] Subgrupo de revista: | IM |
| [Da] Data de entrada para processamento: | 171207 |
| [St] Status: | MEDLINE |
| [do] DOI: | 10.1186/s12970-017-0203-x |
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