RESUMO
Leucine is a critical amino acid stimulating myofibrillar protein synthesis (MyoPS). The consumption of higher leucine-containing drinks stimulates MyoPS, but we know less about higher leucine solid foods. Here, we examined the effect of short-term resistance exercise training (STRT) combined with supplementation of a protein and leucine-enriched bar, compared with STRT alone, on integrated (%/day) rates of MyoPS and anabolic protein signaling. In a nonblinded, randomized crossover trial, eight young adults performed four sessions of STRT without or while consuming the study bar (STRT+Leu, 16 g of protein containing â¼3 g of leucine) for two 4-day phases, separated by 2 days nonexercise (Rest) washout. In combination with serial muscle biopsies, deuterated water permitted the measurement of MyoPS and protein signaling phosphorylation. MyoPS during STRT (1.43 ± 0.06%/day) and STRT+Leu (1.53 ± 0.06%/day) were greater than Rest (1.31 ± 0.05%/day), and MyoPS during STRT+Leu (1.53 ± 0.06%/day) was greater than STRT alone (1.43 ± 0.06%/day). STRT+Leu increased the ratio of phosphorylated to total mechanistic target of rapamycin and 4EBP1 compared to Rest. Engaging in STRT increased integrated MyoPS and protein signaling in young adults and was enhanced with increased protein intake derived from a leucine-enriched protein bar. This study was registered at clinicaltrials.gov as NCT03796897.
Assuntos
Treinamento Resistido , Masculino , Adulto Jovem , Humanos , Feminino , Leucina/farmacologia , Aminoácidos/metabolismo , Proteínas Musculares/metabolismo , Exercício Físico , Músculo Esquelético/metabolismoRESUMO
We investigated the effects of ingesting a leucine-enriched essential amino acid (EAA) gel alone or combined with resistance exercise (RE) versus RE alone (control) on plasma aminoacidemia and intramyocellular anabolic signaling in healthy younger (28 ± 4 years) and older (71 ± 3 years) adults. Blood samples were obtained throughout the three trials, while muscle biopsies were collected in the postabsorptive state and 2 h following RE, following the consumption of two 50 mL EAA gels (40% leucine, 15 g total EAA), and following RE with EAA (combination (COM)). Protein content and the phosphorylation status of key anabolic signaling proteins were determined via immunoblotting. Irrespective of age, during EAA and COM peak leucinemia (younger: 454 ± 32 µM and 537 ± 111 µM; older: 417 ± 99 µM and 553 ± 136 µM) occurred ~60-120 min post-ingestion (younger: 66 ± 6 min and 120 ± 60 min; older: 90 ± 13 min and 78 ± 12 min). In the pooled sample, the area under the curve for plasma leucine and the sum of branched-chain amino acids was significantly greater in EAA and COM compared with RE. For intramyocellular signaling, significant main effects were found for condition (mTOR (Ser2481), rpS6 (Ser235/236)) and age (S6K1 (Thr421/Ser424), 4E-BP1 (Thr37/46)) in age group analyses. The phosphorylation of rpS6 was of similar magnitude (~8-fold) in pooled and age group data 2 h following COM. Our findings suggest that a gel-based, leucine-enriched EAA supplement is associated with aminoacidemia and a muscle anabolic signaling response, thus representing an effective means of stimulating muscle protein anabolism in younger and older adults following EAA and COM.
Assuntos
Envelhecimento/metabolismo , Aminoácidos Essenciais/administração & dosagem , Aminoácidos Essenciais/sangue , Suplementos Nutricionais , Exercício Físico/fisiologia , Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Treinamento Resistido , Adulto , Idoso , Aminoácidos Essenciais/metabolismo , Feminino , Humanos , Leucina/administração & dosagem , Leucina/sangue , Leucina/metabolismo , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Sarcopenia/metabolismo , Adulto JovemRESUMO
We examined the aminoacidemic, glycemic, and insulinemic responses following ingestion of 25 g of native whey protein, micellar casein, and a 1:1 blend of whey and casein in randomized order in young adult men. Blood samples were drawn at baseline and at regular intervals for 6 h following ingestion. Area under curve and peak plasma essential amino acid concentrations after the ingestion of the protein blend were similar to whey and greater compared with casein.
Assuntos
Aminoácidos/sangue , Caseínas/sangue , Proteínas do Soro do Leite/sangue , Adulto , Fatores Etários , Biomarcadores/sangue , Glicemia/metabolismo , Caseínas/administração & dosagem , Humanos , Insulina/sangue , Masculino , Micelas , Ontário , Período Pós-Prandial , Fatores Sexuais , Fatores de Tempo , Proteínas do Soro do Leite/administração & dosagem , Adulto JovemRESUMO
Twenty-one men (mean ± SD; age = 23.5 ± 2.6 years, BMI = 26.0 ± 2.4 kg-1·m-2) completed this randomized, double-blinded, placebo-controlled, crossover study to examine acute responses to a thermogenic nutritional supplement. Each testing session included: (a) 30 minutes resting, followed by placebo or thermogenic nutritional supplementation, (b) 50 minutes postsupplementation resting, (c) 60 minutes walking, and (d) 50 minutes postexercise recovery. Gas exchange variables and heart rate (HR) were recorded during each phase. Blood pressure was recorded during all phases except exercise. Ratings of perceived exertion (RPE) were recorded only during exercise. There were no significant differences for any of the measures between the supplement and placebo during the initial resting or postsupplementation phases. During exercise, energy expenditure (EE) (placebo = 18.98-19.06 kJ·min-1 and supplement = 19.44-19.82 kJ·min-1) and VO2 (placebo = 11.27-11.35 ml·kg-1·min-1; supplement = 11.64-11.82 ml·kg-1·min-1) were greater for the supplement than placebo. There were no differences in respiratory exchange ratio (RER), HR, or RPE between the supplement and placebo during exercise. Postexercise, only VO2 (placebo = 3.53-3.63 ml·kg-1·min-1; supplement = 3.71-3.84 ml·kg-1·min-1) was greater for the supplement than placebo, but there were no differences in EE, RER, HR, or blood pressure. These findings suggested that the specific blend of ingredients in the thermogenic nutritional supplement, when combined with exercise, increased the metabolic rate with minimal changes in cardiovascular function and no effect on RPE.
Assuntos
Suplementos Nutricionais , Descanso/fisiologia , Caminhada/fisiologia , Adulto , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Estudos Cross-Over , Método Duplo-Cego , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/fisiologia , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Humanos , Masculino , Consumo de Oxigênio/efeitos dos fármacos , Consumo de Oxigênio/fisiologia , Esforço Físico/efeitos dos fármacos , Esforço Físico/fisiologia , Troca Gasosa Pulmonar/efeitos dos fármacos , Troca Gasosa Pulmonar/fisiologia , Termogênese , Adulto JovemRESUMO
The purpose of this study was to examine the effects of anatabine supplementation in conjunction with unilateral, maximal eccentric isokinetic muscle actions on serum markers of muscle damage and pro-inflammatory cytokines in humans. Seventeen men (mean ± S.D. age = 22.4 ± 3.2 yrs) participated in this double-blinded, placebo-controlled, crossover study. Participants were randomly assigned to two 10-day conditions (anatabine and placebo) separated by a 2-4 week washout period. After seven days of supplementation, blood was sampled immediately prior to PRE, immediately following POST, and 24, 48, and 72 h after 6 sets of 10 repetitions of unilateral, maximal eccentric isokinetic forearm flexion exercise. Concentrations of serum creatine kinase, lactate dehydrogenase, myoglobin, high sensitivity c-reactive protein, and TNF-α were measured. Creatine kinase, myoglobin, and lactate dehydrogenase increased (P<0.05), while high sensitivity c-reactive protein and TNF-α did not change (P>0.05) after the eccentric exercise during both conditions. Lactate dehydrogenase was higher (P<0.05) during the anatabine condition. The primary findings of this study were two-fold: (a) anatabine had no beneficial effects on traditional markers of muscle damage (creatine kinase, lactate dehydrogenase, and myoglobin) compared to placebo after the eccentric exercise protocol, and (b) the eccentric exercise protocol did not elicit increase in the pro-inflammatory cytokines (c-reactive protein and TNF-α). Future studies are needed to examine the effects of anatabine on naturally-occurring inflammation that is common with aging or obesity. Furthermore, additional research is needed to examine the relationship between muscle damage and inflammation after eccentric exercises of different modes, durations, and intensities.
Assuntos
Alcaloides/farmacologia , Anti-Inflamatórios não Esteroides/farmacologia , Biomarcadores/sangue , Exercício Físico , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/lesões , Piridinas/farmacologia , Adulto , Alcaloides/administração & dosagem , Anti-Inflamatórios não Esteroides/administração & dosagem , Estudos Cross-Over , Citocinas/sangue , Suplementos Nutricionais , Método Duplo-Cego , Exercício Físico/fisiologia , Humanos , Masculino , Contração Muscular/efeitos dos fármacos , Contração Muscular/imunologia , Músculo Esquelético/enzimologia , Músculo Esquelético/imunologia , Piridinas/administração & dosagem , Fatores de Tempo , Resultado do Tratamento , Adulto JovemRESUMO
The purpose of this study was to examine the effects of 28 days of polyethylene glycosylated creatine (PEG-creatine) supplementation (1.25 and 2.50 g·d) on anaerobic performance measures (vertical and broad jumps, 40-yard dash, 20-yard shuttle run, and 3-cone drill), upper- and lower-body muscular strength and endurance (bench press and leg extension), and body composition. This study used a randomized, double-blind, placebo-controlled parallel design. Seventy-seven adult men (mean age ± SD, 22.1 ± 2.5 years; body mass, 81.7 ± 10.8 kg) volunteered to participate and were randomly assigned to a placebo (n = 23), 1.25 g·d of PEG-creatine (n = 27), or 2.50 g·d of PEG-creatine (n = 27) group. The subjects performed anaerobic performance measures, muscular strength (one-repetition maximum [1RM]), and endurance (80% 1RM) tests for bench press and leg extension, and underwater weighing for the determination of body composition at day 0 (baseline), day 14, and day 28. The results indicated that there were improvements (p < 0.0167) in vertical jump, 20-yard shuttle run, 3-cone drill, muscular endurance for bench press, and body mass for at least one of the PEG-creatine groups without changes for the placebo group. Thus, the present results demonstrated that PEG-creatine supplementation at 1.25 or 2.50 g·d had an ergogenic effect on lower-body vertical power, agility, change-of-direction ability, upper-body muscular endurance, and body mass.