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The purpose of the present study was to examine the influence of an acute bout of high-intensity resistance exercise on measures of cognitive function. Ten men (Mean ± SD: age = 24.4 ± 3.2 yrs; body mass = 85.7 ± 11.8 kg; height = 1.78 ± 0.08 m; 1 repetition maximum (1RM) = 139.0 ± 24.1 kg) gave informed consent and performed a high-intensity 6 sets of 10 repetitions of barbell back squat exercise at 80% 1RM with 2 minutes rest between sets. The Automated Neuropsychological Assessment Metrics (ANAM) was completed to assess various cognitive domains during the familiarization period, immediately before, and immediately after the high-intensity resistance exercise bout. The repeated measures ANOVAs for throughput scores (r·m-1) demonstrated significant mean differences for the Mathematical Processing task (MTH; p < 0.001, η2p = 0.625) where post hoc pairwise comparisons demonstrated that the post-fatigue throughput (32.0 ± 8.8 r·m-1) was significantly greater than the pre-fatigue (23.8 ± 7.4 r·m-1, p = 0.003, d = 1.01) and the familiarization throughput (26.4 ± 5.3 r·m-1, p = 0.024, d = 0.77). The Coded Substitution-Delay task also demonstrated significant mean differences (CDD; p = 0.027, η2p = 0.394) with post hoc pairwise comparisons demonstrating that the post-fatigue throughput (49.3 ± 14.4 r·m-1) was significantly less than the pre-fatigue throughput (63.2 ± 9.6 r·m-1, p = 0.011, d = 1.14). The repeated measures ANOVAs for reaction time (ms) demonstrated significant mean differences for MTH (p < 0.001, η2p = 0.624) where post hoc pairwise comparisons demonstrated that the post-fatigue reaction time (1885.2 ± 582.8 ms) was significantly less than the pre-fatigue (2518.2 ± 884.8 ms, p = 0.005, d = 0.85) and familiarization (2253.7 ± 567.6 ms, p = 0.009, d = 0.64) reaction times. The Go/No-Go task demonstrated significant mean differences (GNG; p = 0.031, η2p = 0.320) with post hoc pairwise comparisons demonstrating that the post-fatigue (285.9 ± 16.3 ms) was significantly less than the pre-fatigue (298.5 ± 12.1 ms, p = 0.006, d = 0.88) reaction times. High-intensity resistance exercise may elicit domain-specific influences on cognitive function, characterized by the facilitation of simple cognitive tasks and impairments of complex cognitive tasks.
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Cognição/fisiologia , Treinamento Resistido/métodos , Adulto , Atenção , Frequência Cardíaca , Humanos , Ácido Láctico/sangue , Masculino , Memória , Rememoração Mental , Fadiga Muscular/fisiologia , Força Muscular , Tempo de Reação , Adulto JovemRESUMO
Kraemer, WJ, Caldwell, LK, Post, EM, DuPont, WH, Martini, ER, Ratamess, NA, Szivak, TK, Shurley, JP, Beeler, MK, Volek, JS, Maresh, CM, Todd, JS, Walrod, BJ, Hyde, PN, Fairman, C, and Best, TM. Body composition in elite strongman competitors. J Strength Cond Res 34(12): 3326-3330, 2020-The purpose of this descriptive investigation was to characterize a group of elite strongman competitors to document the body composition of this unique population of strength athletes. Data were collected from eligible competitors as part of a health screening program conducted over 5 consecutive years. Imaging was acquired using dual-energy x-ray absorptiometry (DXA), providing total body measures of fat mass, lean mass, and bone mineral content (BMC). Year to year, testing groups showed a homogenous grouping of anthropometric, body composition, and bone density metrics. Composite averages were calculated to provide an anthropometric profile of the elite strongman competitor (N = 18; mean ± SD): age, 33.0 ± 5.2 years; body height, 187.4 ± 7.1 cm; body mass, 152.9 ± 19.3 kg; body mass index, 43.5 ± 4.8 kg·m; fat mass, 30.9 ± 11.1 kg; lean mass, 118.0 ± 11.7 kg, body fat, 18.7 ± 6.2%, total BMC, 5.23 ± 0.41 kg, and bone mineral density, 1.78 ± 0.14 g·cm. These data demonstrate that elite strongman competitors are among the largest human male athletes, and in some cases, they are at the extreme limits reported for body size and structure. Elite strongman competitors undergo a high degree of mechanical stress, providing further insight into the potent role of physical training in mediating structural remodeling even into adulthood. Such data provide a glimpse into a unique group of competitive athletes pushing the limits not only of human performance but also of human physiology.
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Atletas , Composição Corporal , Absorciometria de Fóton , Adulto , Índice de Massa Corporal , Densidade Óssea , Humanos , MasculinoRESUMO
The purpose of this double-blind, placebo-controlled investigation was to examine the effects of a Korean Ginseng (GINST15) on measures of perception and physical performance following an acute bout of resistance exercise. Ten women (age: 38.7 ± 7.8 years; height: 1.64 ± 0.05 m; body mass: 76.0 ± 11.6 kg) and nine men (age: 41.2. ± 9.7 years; height: 1.77 ± 0.05 m; body mass: 88.5 ± 5.0 kg) completed the investigation. Participants were randomized to a three-cycle testing scheme consisting of high dose ginseng (HIGH: 960 mg/day), low dose ginseng (LOW: 160 mg/day) and placebo (PBO: 0 mg/day). After 14 days of supplementation participants returned to the laboratory for an acute resistance exercise trial (5 sets of 12 repetitions of the leg press at 70% of one-repetition-maximum [1RM]). Ratings of perceived exertion (RPE) were assessed after each set. Muscle pain/soreness was assessed before exercise and 24 hours post exercise. Psychomotor performance and peak power were measured before exercise, immediately post exercise and 24 hours after exercise. Each treatment cycle was separated by a minimum one-week washout period. HIGH significantly reduced perceived exertion during exercise. HIGH and LOW significantly reduced change in muscle soreness at 24 hours post exercise. Analysis of peak power demonstrated the presence of responders (n = 13) and non-responders (n = 6). Responders showed a significant effect of HIGH GINST15 on maintenance of neuromuscular function. The appearance of responders and non-responders, could explain the mixed literature base on the ergogenic properties of ginseng.
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Compression and cold therapy used separately have shown to reduce negative effects of tissue damage. The combining compression and cold therapy (cryocompression) as a single recovery modality has yet to be fully examined. To examine the effects of cryocompression on recovery following a bout of heavy resistance exercise, recreationally resistance trained men (n =16) were recruited, matched, and randomly assigned to either a cryocompression group (CRC) or control group (CON). Testing was performed before and then immediately after exercise, 60 minutes, 24 hours, and 48 hours after a heavy resistance exercise workout (barbell back squats for 4 sets of 6 reps at 80% 1RM, 90 sec rest between sets, stiff legged deadlifts for 4 sets of 8 reps at 1.0 X body mass with 60 sec rest between sets, 4 sets of 10 eccentric Nordic hamstring curls, 45 sec rest between sets). The CRC group used the CRC system for 20-mins of cryocompression treatment immediately after exercise, 24 hours, and 48 hours after exercise. CON sat quietly for 20-mins at the same time points. Muscle damage [creatine kinase], soreness (visual analog scale, 0-100), pain (McGill Pain Q, 0-5), fatigue, sleep quality, and jump power were significantly (p < 0.05) improved for CRC compared to CON at 24 and 48 hours after exercise. Pain was also significantly lower for CRC compared to CON at 60-mins post exercise. These findings show that cryocompression can enhance recovery and performance following a heavy resistance exercise workout.
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OBJECTIVE: Nitrate-rich (NR) supplements can enhance exercise performance by improving neuromuscular function and the aerobic cost of exercise. However, little is known about the effects of nitrate on dynamic, multijoint resistance exercise. METHODS: Fourteen resistance-trained men (age, 21.1 ± 0.9 years; height, 173.2 ± 2.9 cm: body mass, 77.6 ± 4.3 kg; squat one-repetition maximum [1RM], 127.5 ± 18.8 kg) participated in a randomized, double-blind, crossover experiment. Subjects consumed an NR or nitrate-poor (NP) supplement for 3 days, performed a bout of heavy resistance exercise, completed a washout, and then repeated the procedures with the remaining supplement. Before, during, and after exercise, individual and gross motor unit efficiency was assessed during isometric and dynamic muscle contractions. In addition, we compared physical performance, heart rate, lactate, and oxygen consumption (VO2). RESULTS: Nitrate-rich supplementation resulted in lower initial muscle firing rates at rest and lower mean and maximum firing rates over the course of fatiguing exercise. Nitrate-poor supplementation was accompanied by increased mean and maximum firing rates by the end of exercise and lower initial firing rates. In addition, NR supplementation resulted in higher mean peak electromyography (EMG) amplitudes. Heart rate, lactate, and physical performance did not differ by treatment, but oxygen consumption increased more frequently when the NP supplement was consumed. CONCLUSION: Supplementation with an NR beetroot extract-based supplement provided neuromuscular advantages during metabolically taxing resistance exercise.
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Suplementos Nutricionais/análise , Exercício Físico/fisiologia , Nitratos/farmacologia , Recrutamento Neurofisiológico/efeitos dos fármacos , Beta vulgaris/química , Método Duplo-Cego , Humanos , Masculino , Nitratos/administração & dosagem , Nitratos/química , Raízes de Plantas/química , Adulto JovemRESUMO
Nucleotide supplementation can reduce postexercise immunosuppression and hypothalamic-pituitary axis (HPA) axis activation in endurance exercise models. Nucleotide supplementation may aid recovery from other exercise modalities, such as heavy resistance exercise. Thus, the purpose of this investigation was to investigate the effects of nucleotide supplementation on the acute cortisol and immune responses to heavy resistance exercise and its effects on recovery. A double-blinded, crossover, mixed methods design with 10 men and 10 women was used. Each performed an acute heavy resistance exercise protocol (AHREP) after a loading period with a nucleotide or placebo supplement. Before and after the AHREP, and at 24, 48, and 72 hours post, blood samples were analyzed for cortisol, myeloperoxidase (MPO), and absolute neutrophil, lymphocyte, and monocyte counts. Creatine kinase (CK) was analyzed before and 24, 48, and 72 hours after the AHREP. Performance measures, including peak back squat isometric force and peak countermovement jump power were also analyzed. Nucleotide supplementation resulted in significant (p ≤ 0.05) decreases in cortisol and MPO immediately after the AHREP, and significantly lower CK values 24 hours later. The AHREP significantly affected leukocyte counts; however, no treatment effects were observed. Greater isometric force was observed immediately after AHREP and at 24 hours and 48 hours with nucleotide supplementation. Nucleotide supplementation seems to attenuate muscle damage, HPA axis and immune system activation, and performance decrements after heavy resistance exercise.
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Desempenho Atlético/fisiologia , Suplementos Nutricionais , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Nucleotídeos/farmacologia , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Treinamento Resistido , Estresse Fisiológico/efeitos dos fármacos , Adulto , Biomarcadores/sangue , Creatina Quinase/sangue , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Hidrocortisona/sangue , Sistema Hipotálamo-Hipofisário/fisiologia , Masculino , Força Muscular/efeitos dos fármacos , Força Muscular/fisiologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/fisiologia , Nucleotídeos/administração & dosagem , Sistema Hipófise-Suprarrenal/fisiologia , Estresse Fisiológico/fisiologia , Adulto JovemRESUMO
This investigation examined peak motor unit activity during sets that differed in resistance (50, 70, or 90% 1 repetition maximum [1RM]). Ten resistance-trained men (age, 23 ± 3 years; height, 187 ± 7 cm; body mass, 91.5 ± 6.9 kg; squat 1RM, 141 ± 28 kg) were assessed by electromyography (EMG) on the vastus lateralis and vastus medialis muscles in a randomized within-subject experiment consisting of 2 test visits: a drop-set day and a single-set day using only the 50% of 1RM intensity performed to failure. At the start of each day, subjects performed 2 submaximal repetition sets (50% 1RM × 10 repetitions and 70% 1RM × 7 repetitions). On the drop-set day, subjects performed 3 consecutive maximal repetition sets at 90%, 70%, and 50% 1RM to failure with no rest periods in between. On the single-set day, subjects performed a maximal repetition set at 50% 1RM to failure. Overall, the maximal repetition sets to failure at 50% and 70% 1RM resulted in higher peak EMG amplitude than during submaximal repetition sets with the same resistance. However, peak EMG amplitude was significantly (p ≤ 0.05) greater in the maximal 90% 1RM set than all other sets performed. When sets were performed to failure, ratings of perceived exertion (CR-10) did not differ over the intensity range of loads and suggests that perception is not capable of accurately detecting the actual amount of motor unit activation. The results of this investigation indicate that using higher external resistance is a more effective means of increasing motor unit activity than increasing the number of repetitions performed with lighter weights even when the end point is muscular failure. Accordingly, previous recommendations for the use of heavier loads during resistance training programs to stimulate the maximal development of strength and hypertrophy are further supported.
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Tolerância ao Exercício/fisiologia , Esforço Físico , Músculo Quadríceps/fisiologia , Treinamento Resistido/métodos , Adulto , Eletromiografia , Humanos , Contração Isométrica , Masculino , Percepção , Distribuição Aleatória , Adulto JovemRESUMO
OBJECTIVE: This study evaluated whether a combination of whey protein (WP), calcium beta-hydroxy-beta-methylbutyrate (HMB), and carbohydrate exert additive effects on recovery from highly demanding resistance exercise. METHODS: Thirteen resistance-trained men (age: 22.6 ± 3.9 years; height: 175.3 ± 12.2 cm; weight: 86.2 ± 9.8 kg) completed a double-blinded, counterbalanced, within-group study. Subjects ingested EAS Recovery Protein (RP; EAS Sports Nutrition/Abbott Laboratories, Columbus, OH) or WP twice daily for 2 weeks prior to, during, and for 2 days following 3 consecutive days of intense resistance exercise. The workout sequence included heavy resistance exercise (day 1) and metabolic resistance exercise (days 2 and 3). The subjects performed no physical activity during day 4 (+24 hours) and day 5 (+48 hours), where recovery testing was performed. Before, during, and following the 3 workouts, treatment outcomes were evaluated using blood-based muscle damage markers and hormones, perceptual measures of muscle soreness, and countermovement jump performance. RESULTS: Creatine kinase was lower for the RP treatment on day 2 (RP: 166.9 ± 56.4 vs WP: 307.1 ± 125.2 IU · L(-1), p ≤ 0.05), day 4 (RP: 232.5 ± 67.4 vs WP: 432.6 ± 223.3 IU · L(-1), p ≤ 0.05), and day 5 (RP: 176.1 ± 38.7 vs 264.5 ± 120.9 IU · L(-1), p ≤ 0.05). Interleukin-6 was lower for the RP treatment on day 4 (RP: 1.2 ± 0.2 vs WP: 1.6 ± 0.6 pg · ml(-1), p ≤ 0.05) and day 5 (RP: 1.1 ± 0.2 vs WP: 1.6 ± 0.4 pg · ml(-1), p ≤ 0.05). Muscle soreness was lower for RP treatment on day 4 (RP: 2.0 ± 0.7 vs WP: 2.8 ± 1.1 cm, p ≤ 0.05). Vertical jump power was higher for the RP treatment on day 4 (RP: 5983.2 ± 624 vs WP 5303.9 ± 641.7 W, p ≤ 0.05) and day 5 (RP: 5792.5 ± 595.4 vs WP: 5200.4 ± 501 W, p ≤ 0.05). CONCLUSIONS: Our findings suggest that during times of intense conditioning, the recovery benefits of WP are enhanced with the addition of HMB and a slow-release carbohydrate. We observed reductions in markers of muscle damage and improved athletic performance.
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Isomaltose/análogos & derivados , Recuperação de Função Fisiológica/efeitos dos fármacos , Treinamento Resistido/métodos , Valeratos/uso terapêutico , Proteínas do Soro do Leite/uso terapêutico , Adulto , Desempenho Atlético/fisiologia , Creatina Quinase/sangue , Método Duplo-Cego , Humanos , Interleucina-6/sangue , Isomaltose/uso terapêutico , Masculino , Movimento/fisiologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/fisiologia , Mialgia/fisiopatologia , Percepção da Dor/efeitos dos fármacos , Percepção da Dor/fisiologia , Condicionamento Físico Humano/métodos , Recuperação de Função Fisiológica/fisiologia , Fatores de Tempo , Adulto JovemRESUMO
The ability of a fabric to transfer moisture is referred to as "wicking," and an increase in this property may have benefits in terms of comfort and thermoregulation. However, this phenomenon has not been studied in the context of sporting-type activities. Therefore, the purpose of this study is to assess whether comfort, thermal physiological parameters, and physical performance can be affected by the garment that is used. Ten men (age: 27.5 ± 4.4 years; height: 169.3 ± 14.2 cm; weight: 80.05 ± 10.87 kg) and 10 women (age: 26.8 ± 3.7 years; height: 166.6 ± 4.46 cm; weight: 64.63 ± 4.49 kg) volunteered to participate in the study. A within-group crossover counterbalanced design was used that included the Illinois Agility Run (IAR) and the Multistage Fitness Test (MSFT). The IAR was also performed while wearing protective padding. The protocol was completed on 2 occasions, once while wearing a cotton garment (C) and again while wearing a polyester (P) garment. Questionnaires referring to sensations of various components of comfort were completed after each test. The P garment provided significantly (p ≤ 0.05) greater comfort in men and women after both the IAR and the MSFT. The P garment led to significantly (p ≤ 0.05) improved performance during the IAR in women. The P garment also provided significantly (p ≤ 0.05) greater body mass loss during the protocol in women. This study demonstrated dramatic increases in the comfort of P garments, including while using protective equipment. This study also discovered the influence of P garments on anaerobic tasks and also revealed dramatic sex differences, where women seem to be much more sensitive to the benefits of P garments. Strength and conditioning coaches should be aware of the dramatic impact of garment choice, in aerobic and anaerobic tasks, particularly in women.
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Desempenho Atlético/fisiologia , Regulação da Temperatura Corporal/fisiologia , Vestuário , Fibra de Algodão , Poliésteres , Adulto , Estudos Cross-Over , Feminino , Humanos , Masculino , Fatores SexuaisRESUMO
To better understand how developmental differences impact performance on a broad selection of common physical fitness measures, we examined changes in boys and girls from fourth to fifth grade. Subjects included 273 boys (age, 9.5 ± 0.6 years; height, 139.86 ± 7.52 cm; mass, 38.00 ± 9.55 kg) and 295 girls (age, 9.6 ± 0.5 years; height, 139.30 ± 7.19 cm; weight, 37.44 ± 9.35 kg). We compared anthropometrics, cardiorespiratory and local muscular endurance, flexibility, power, and strength. A mixed-method analysis of variance was used to compare boys and girls at the 2 time points. Pearson correlation coefficients were used to examine relationships between anthropometric and fitness measurements. Significance was set at p ≤ 0.05. Weight increased significantly (>10%) in both sexes, and girls became significantly taller than boys after growing 4.9% by fifth grade (vs. 3.5%). Both groups improved cardiorespiratory endurance and power, although boys performed better than girls at both time points. Boys were stronger in fourth grade, but girls improved more, leading to similar fifth-grade values. Girls were more flexible in fourth grade, but their significant decreases (â¼32.4%) coupled with large improvements in boys (â¼105%) resulted in similar fifth-grade scores. Body mass index (BMI) was positively correlated with run time regardless of grade or sex. Power was negatively correlated with BMI and run time in fourth grade. In conclusion, sex-specific differences in physical fitness are apparent before pubescence. Furthermore, this selection of measures reveals sexually dimorphic changes, which likely reflect the onset of puberty in girls. Coaches and teachers should account these developmental differences and their effects on anthropometrics and fitness in boys and girls.
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Resistência Física/fisiologia , Aptidão Física/fisiologia , Caracteres Sexuais , Desenvolvimento Sexual/fisiologia , Composição Corporal , Índice de Massa Corporal , Peso Corporal , Criança , Feminino , Humanos , Estudos Longitudinais , MasculinoRESUMO
Compression garments (CGs) have been previously shown to enhance proprioception; however, this benefit has not been previously shown to transfer to improved performance in sports skills. The purpose of this study was to assess whether enhanced proprioception and comfort can be manifested in improved sports performance of high-level athletes. Eleven Division I collegiate pitchers (age: 21.0 ± 2.9 years; height: 181.0 ± 4.6 cm; weight: 89.0 ± 13.0 kg; body fat: 12.0 ± 4.1%) and 10 Division I collegiate golfers (age: 20.0 ± 1.3 years; height: 178.1 ± 3.9 cm; weight: 76.4 ± 8.3 kg; body fat: 11.8 ± 2.6%) participated in the study. A counterbalanced within-group design was used. Subjects performed the respective baseball or golf protocol wearing either typical noncompressive (NC) or the experimental CG. Golfers participated in an assessment of driving distance and accuracy, as well as approach shot, chipping, and putting accuracy. Pitchers were assessed for fastball accuracy and velocity. In pitchers, there was a significant (p ≤ 0.05) improvement in fastball accuracy (NC: 0.30 ± 0.04 vs. CG: 0.21 ± 0.07 cm). There were no differences in pitching velocity. In golfers, there were significant (p ≤ 0.05) improvements in driving accuracy (NC: 86.7 ± 30.6 vs. CG: 68.9 ± 18.5 feet), as well as approach shot accuracy (NC: 26.6 ± 11.9 vs. CG: 22.1 ± 8.2 feet) and chipping accuracy (NC: 2.9 ± 0.6 vs. CG: 2.3 ± 0.6 inch). There was also a significant (p ≤ 0.05) increase in comfort for the golfers (NC: 3.7 ± 0.8 vs. CG: 4.5 ± 1.0). These results demonstrate that comfort and performance can be improved with the use of CGs in high-level athletes being most likely mediated by improved proprioceptive cues during upper-body movements.
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Desempenho Atlético/fisiologia , Vestuário , Extremidade Superior/fisiologia , Beisebol/fisiologia , Golfe/fisiologia , Humanos , Masculino , Movimento/fisiologia , Propriocepção/fisiologia , Adulto JovemRESUMO
The recovery process from a college football game has been studied, yet the stability of such findings year to year in the same players remains unclear. The purpose of this study was to examine the same players' biochemical recovery process in 2 consecutive seasons to a National Collegiate Athletic Association (NCAA) Division I football game. Ten starting players volunteered to participate in the study in each of the 2 seasons. Players performed a periodized heavy resistance training program over the entire year for each season. Fasted resting blood samples were obtained at similar times the Friday before the game (T1), 18-20 hours after the game (T2), and 42-44 hours after the game (T3). In both seasons, serum creatine kinase (CK) concentrations increased significantly from T1 to T2, and returned to T1 values at T3. When we compared seasons, CK values did not differ at any time point. Myoglobin demonstrated similar patterns and results. Testosterone and cortisol values were similar at all time points and did not differ by season as no significant differences were observed for the resting hormonal concentrations. The results of this study indicate that yearly programs should maintain a periodized progressive program, which seeks to increase physical potential of players while providing a protective effect on skeletal muscle and stabilization of hormonal status in response to both game and season stressors.
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Futebol Americano/fisiologia , Hormônios/sangue , Músculo Esquelético/patologia , Treinamento Resistido , Universidades , Creatina Quinase/sangue , Jejum/sangue , Humanos , Hidrocortisona/sangue , Masculino , Mioglobina/sangue , Testosterona/sangue , Fatores de Tempo , Adulto JovemRESUMO
The relationship between muscle action and fatigue is not well understood, especially in terms of potential sex-specific differences. The purpose of this investigation was to determine whether a different number of repetitions could be performed on the individual muscle actions of the bench press and squat in men and women. Ten resistance-trained men (n = 10; age, 25.2 ± 1.2 years; height, 178.6 ± 8.8 cm; weight, 91.4 ± 18.1 kg; body fat, 12.7 ± 3.6%) and women (n = 10; age, 25.4 ± 2.4 years; height, 164 ± 4.0 cm; weight, 58.45 ± 3.3 kg; body fat, 20.8 ± 1.5%) participated in this balanced and randomized within-group study. Using 85% of a 1 repetition maximum, over the course of 3 visits, subjects performed 1 eccentric (ECC), concentric (CON), or combined (COMB) set to failure on the squat and bench press. Differences in muscle action and sex-specific number of repetitions to failure were compared on the squat and bench press, where significance was p ≤ 0.05. Across both exercises and sex, we observed significant differences between each of the 3 muscle actions, where the number of repetitions decreased from ECC to COMB to CON. While no sex-specific differences were observed in the squat, women performed significantly more repetitions on the ECC and CON muscle actions of the bench press. Men performed more combined repetitions, however, indicating a greater reliance on the stretch-shortening cycle. Different muscle actions contribute uniquely to the successful performance of a lift and fatigue. These contributions appear to differ in men and women.
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Tolerância ao Exercício/fisiologia , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiologia , Levantamento de Peso/fisiologia , Adulto , Teste de Esforço , Feminino , Humanos , Masculino , Distribuição Aleatória , Fatores Sexuais , Adulto JovemRESUMO
New technology offers potential advantages in physically demanding environments where convenience and comfort are important and accurate and reliable data collection is challenging. Nevertheless, it is important to validate the accuracy and reliability of such biological monitoring systems (BMS) before they are adopted. The purpose of this investigation was to assess the concurrent validity of a new heart rate monitor across a range of exercise intensities and with a large and diverse group of male subjects in a large cohort with diverse physical fitness characteristics. Seventy-five men (age, 23 ± 4 years; height, 181 ± 8 cm; body mass, 83 ± 12 kg; estimated V[Combining Dot Above]O2peak, 3.16 ± 0.63 [L·min]) volunteered and completed a graded cycle ergometer exercise protocol while heart rate was continuously monitored before, during, and after exercise with the new device (Armour39) and the gold standard (electrocardiogram). The 2-minute stages included sitting, standing, and cycling with 35 W increments until volitional fatigue. The coefficient of determination between mean heart rate values at each stage was R = 0.99, whereas Pearson correlations (r) at each stage were ≥ 0.99. Heart rates during exercise were typically within 1 beat of each other. The Armour39 BMS, therefore, is an acceptable means for the valid and reliable determination of heart rate under various bodily positions and levels of exertion, including maximal exercise intensity.
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Exercício Físico/fisiologia , Frequência Cardíaca , Monitorização Ambulatorial/instrumentação , Esforço Físico/fisiologia , Adulto , Eletrocardiografia , Teste de Esforço , Tolerância ao Exercício/fisiologia , Humanos , Masculino , Consumo de Oxigênio , Aptidão Física/fisiologia , Postura , Adulto JovemRESUMO
Isolated ginsenoside metabolites such as Compound K (CK) are of increasing interest to consumer and clinical populations as safe and non-pharmacological means to enhance psychomotor performance constitutively and in response to physical or cognitive stress. Nevertheless, the influence of CK on behavioral performance and EEG measures of cortical activity in humans is undetermined. In this double-blinded, placebo-controlled, counterbalanced within-group study, dose-dependent responses to CK (placebo, 160 and 960 mg) were assessed after 2 weeks of supplementation in nineteen healthy men and women (age: 39.9 ± 7.9 year, height 170.2 ± 8.6 cm, weight 79.7 ± 11.9 kg). Performance on upper- and lower-body choice reaction tests (CRTs) was tested before and after intense lower-body anaerobic exercise. Treatment- and stress-related changes in brain activity were measured with high-density EEG based on event-related potentials, oscillations, and source activity. Upper- (-12.3 ± 3.5 ms, p = 0.002) and lower-body (-12.3 ± 4.9 ms, p = 0.021) response times improved after exercise, with no difference between treatments (upper: p = 0.354; lower: p = 0.926). Analysis of cortical activity in sensor and source space revealed global increases in cortical arousal after exercise. CK increased activity in cortical regions responsible for sustained attention and mitigated exercise-induced increases in arousal. Responses to exercise varied depending on task, but CK appeared to reduce sensory interference from lower-body exercise during an upper-body CRT and improve the general maintenance of task-relevant sensory processes.
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PURPOSE: Prior research has illustrated that high volumes of aerobic exercise result in a reduction in basal concentrations of testosterone in men. Those studies were mostly conducted on recreational runners and identified reduced testosterone, but not concentrations low enough to be considered pathological. Therefore, the purpose of this study was to assess the basal concentrations of testosterone and cortisol in elite triathletes, as well as the impact of a World Championship race, on the acute responses of these hormones. METHODS: A total of 22 men (age 40.6 [11.5] y, height 179 [6] cm, weight 77.0 [7.0] kg) who participated in the 2011 Ironman World Championships served as subjects. Resting blood samples were taken 2-4 d prior to provide a baseline (BL), as well as immediately, 1 d, and 2 d after the event and were later analyzed for total testosterone and cortisol concentrations. RESULTS: At BL, 9 men had a normal testosterone concentration, whereas 9 men fell within a "gray zone" and 4 other men demonstrated concentrations suggestive of deficiency. Testosterone was significantly lower than BL at 1 d (95% confidence interval [CI] 0.10-0.34, P < .001, ES = 0.53) and 2 d (95% CI 0.01-0.21, P = .034, ES = 0.35) after the event. Cortisol was significantly different from BL at immediate post (95% CI 1.07-0.83, P < .001, ES = 8.0). There were significant correlations between time and age (R = .68, P = .001), as well as BL testosterone and cortisol (R = .51, P = .015). CONCLUSION: Elite ultraendurance athletes may demonstrate not only reduced testosterone but also sometimes clinically low concentrations that could be indicative of androgen deficiency.
Assuntos
Exercício Físico/fisiologia , Hidrocortisona/sangue , Testosterona/sangue , Adulto , Atletas , Ciclismo , Metabolismo Energético , Humanos , Masculino , Pessoa de Meia-Idade , Resistência Física/fisiologia , Corrida , NataçãoRESUMO
PURPOSE: To evaluate the changes in the state of hydration in elite National Collegiate Athletic Association (NCAA) Division I college wrestlers during and after a season. METHODS: Ohio State University wrestling team members (N = 6; mean [SD] age = 19.6 [1.1] y; height = 171.6 [2.9] cm; body mass = 69.5 [8.1] kg) gave informed consent to participate in the investigation with measurements (ie, body mass, urine-specific gravity [USG; 2 methods], Visual Analog Scale thirst scale, plasma osmolality) obtained during and after the season. RESULTS: Measurements for USG, regardless of methods, were not significantly different between visits, but plasma osmolality was significantly (P = .001) higher at the beginning of the season-295.5 (4.9) mOsm·kg-1 compared with 279.6 (6.1) mOsm·kg-1 after the season. No changes in thirst ratings were observed, and the 2 measures of USG were highly correlated (r > .9, P = .000) at each time point, but USG and plasma osmolality were not related. CONCLUSIONS: A paradox in the clinical interpretation of euhydration in the beginning of the season was observed with the USG, indicating that the wrestlers were properly hydrated, while the plasma osmolality showed they were not. Thus, the tracking of hydration status during the season is a concern when using only NCAA policies and procedures. The wrestlers did return to normal euhydration levels after the season on both biomarkers, which is remarkable, as previous studies have indicated that this may not happen because of the reregulation of the osmol-regulatory center in the brain.
RESUMO
The effect of GINST15, an enzyme fermented ginseng supplement, on hormonal and inflammatory responses to physical stress in humans is unknown. The purpose of this investigation was to examine the constitutive and stress-induced effects of GINST15 supplement on hypo-pituitary-adrenal (HPA) and antioxidant activity in addition to muscle damage. Ten women (age: 38.7 ± 7.8 years; height: 163.81 ± 4.4 cm; body mass 76.0 ± 11.6 kg) and nine men (age: 41.2. ± 9.7 years; height: 177.4 ± 5.3 cm; body mass: 88.5 ± 5.0 kg) participated in a double-blinded, placebo-controlled, counterbalanced within-group study. Participants completed three 14-day treatment cycles with different doses (high: 960 mg; low: 160 mg; placebo: 0 mg) separated by a 1-week washout period. At the end of treatment, physical stress was imposed with intense resistance exercise work stress. Participants provided blood at rest and various time points after exercise (immediately [IP], 30 min [30], 60 min [60], 24 h [+24HR]). Cortisol (CORT), superoxide dismutase (SOD), total glutathione, nonspecific antioxidant activity, total antioxidant power (TAP), and creatine kinase were measured. GINST15 supplementation produced stress-inducible dose-dependent reductions in circulating cortisol and increased enzymatic and nonspecific antioxidant activity. Twenty-four hours after intense exercise, a high dose GINST15, a bioactive ginsenoside metabolite, significantly reduces muscle damage and HPA responses to physical stress in humans; these effects may result from increased antioxidant expression.
Assuntos
Suplementos Nutricionais/análise , Exercício Físico , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Panax/química , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Extratos Vegetais/administração & dosagem , Adulto , Feminino , Glutationa/metabolismo , Humanos , Hidrocortisona/sangue , Sistema Hipotálamo-Hipofisário/metabolismo , Malondialdeído/metabolismo , Pessoa de Meia-Idade , Sistema Hipófise-Suprarrenal/metabolismo , República da Coreia , Treinamento ResistidoRESUMO
Chronic increases in testosterone levels can significantly increase hypertrophy and strength, as has been demonstrated by pharmacological intervention. However, decreases in basal testosterone levels can have the opposite result, as has been seen in hypogonadal populations. Because of these profound effects on hypertrophy and strength, testosterone has often been studied in conjunction with resistance exercise to examine whether the endocrine system plays a role in adaptations to the stimulus. Whereas some studies have demonstrated a chronic increase in basal testosterone, others have failed to find an adaptation to regular resistance exercise. However, improvements in strength and hypertrophy appear to be possible regardless of the presence of this adaptation. Testosterone has also been shown to acutely rise immediately following an acute resistance exercise bout. While this substantial mobilization of testosterone is brief, its effects are seen for several hours through the upregulation of the androgen receptor. The role of this acute response at present is unknown, but further study of the non-genomic action and possible intracrinological processes is warranted. This response does not seem to be necessary for resistance training adaptations to occur either, but whether this response optimizes such adaptations has not yet been determined.
Assuntos
Adaptação Fisiológica , Força Muscular/fisiologia , Músculo Esquelético/metabolismo , Treinamento Resistido , Testosterona/metabolismo , Exercício Físico , Humanos , Músculo Esquelético/crescimento & desenvolvimento , Treinamento Resistido/métodos , Testosterona/sangueRESUMO
Due to the important interactions of proenkephalin fragments (e.g., proenkephalin [107-140] Peptide F) to enhance activation of immune cells and potentially combat pain associated with exercise-induced muscle tissue damage, we examined the differential plasma responses of Peptide F to different exercise training programs. Participants were tested pre-training (T1), and after 8 weeks (T2) of training. Fifty-nine healthy women were matched and then randomly assigned to one of four groups: heavy resistance strength training (STR, n=18), high intensity endurance training (END, n=14), combined strength and endurance training (CMB, n=17), or control (CON, n=10). Blood was collected using a cannula inserted into a superficial vein in the antecubital fossa with samples collected at rest and immediately after an acute bout of 6 X 10 RM in a squat resistance exercise before training and after training. Prior to any training, no significant differences were observed for any of the groups before or after acute exercise. With training, significant (P≤0.95) elevations were observed with acute exercise in each of the exercise training groups and this effect was significantly greater in the CMB group. These data indicate that in untrained women exercise training will not change resting of plasma Peptide F concentrations unless both forms of exercise are performed but will result in significant increases in the immediate post-exercise responses. Such findings appear to indicate adrenal medullary adaptations opioid production significantly altered with exercise training.