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1.
Int J Exerc Sci ; 17(1): 438-444, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38665163

RESUMO

Stroboscopic vision training has shown to improve visual-motor control and dynamic visual acuity in sport performance; however, no studies have considered using this training to enhance kinesthetic awareness during walking, applicable to high fall-risk populations. Purpose: The purpose of this study was to assess the effect of stroboscopic vision training on blind-folded straight-line walking. Methods: Thirty-seven college-aged healthy participants (age: 20.14 ± 1.23 years; females: N = 32, males: N = 5) completed this study. In this pre-posttest quasi-experimental investigation, participants with no epileptic or balance disorder history completed a four-week progressive stroboscopic vision training protocol. To assess sensorimotor feedback participants were instructed to walk a 27.5 m straight line while blindfolded. PRE and POST blind-folded straight line walk tests were completed and deviations from endpoint were measured. A paired-samples t-test was used to analyze the calculated deviation angles. Results: Significant difference was noted from PRE (14.48 ± 5.95) to POST (11.60 ± 6.78) deviation angles (t(36) = 2.71, p = 0.01). Conclusions: This is the first study to examine the effects of stroboscopic training on a vision restricted walking task, which demands feedback re-weighting. These findings may be valuable for clinical settings or performance where reliance on non-visual systems may be beneficial.

2.
J Sports Med Phys Fitness ; 64(5): 439-445, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38385637

RESUMO

BACKGROUND: Traditional resistance training schemes often utilize higher loads for strength gains and lower loads for muscular endurance or hypertrophy. This study aimed to investigate muscular strength adaptations after nine weeks of high- or low-load resistance training. METHODS: Seventeen recreationally-trained male lifters were recruited for this study (age 20.4±2.7 years) and split into high-load (85% 1-RM; N.=8) or low-load (30% 1-RM; N.=9), completing three whole-body training sessions per week for nine weeks. Each session included three working sets of repetitions to failure. At baseline and every three weeks after, knee extension/flexion were tested using an isokinetic dynamometer. Participants completed three 5-s MVIC and isokinetic muscle actions at 60°/s and 120°/s, with the highest torque value used in analysis. Predicted 1-RM testing was at baseline and end of training program. ANCOVAs were conducted to analyze changes in strength, with significance set at P<0.05. RESULTS: This study demonstrated similar MVIC and peak torque values for both isokinetic speeds, although there were nonsignificant decreases largely driven by the 30% group. The high-load group showed greater increases in 1-RM following the training program. CONCLUSIONS: This study suggests training with lighter loads may be detrimental for long term isokinetic strength, whereas heavier loads could result in maintenance and greater increases in 1-RM despite performing repetitions to failure.


Assuntos
Força Muscular , Treinamento Resistido , Humanos , Masculino , Treinamento Resistido/métodos , Força Muscular/fisiologia , Adulto Jovem , Adaptação Fisiológica/fisiologia , Torque , Músculo Esquelético/fisiologia , Levantamento de Peso/fisiologia , Adulto
3.
Res Q Exerc Sport ; 94(4): 1011-1019, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36006695

RESUMO

Purpose: Physical inactivity is linked with several chronic diseases and poor academic outcomes. This study aimed to examine the effect an under-the-desk band would have on middle school students' physical activity level, and academic engagement. Methods: Two local middle school classrooms (n = 42, M = 20, F = 22) participated in the study, which was conducted over 14 weeks. Physical activity was measured with accelerometry, and academic engagement was assessed using momentary time sampling. Enrolled participants were provided an accelerometer to wear upon entering the classroom. The baseline period lasted for 36 days. During the intervention period, which lasted for the next 30 days, an under-the-desk band was provided to students to freely fidget at their desks. After the study, 13 participants (M = 5, F = 8) in Class A were included in final physical activity analysis, and the 6 participants (M = 3, F = 3) in Class B were included in the academic engagement analysis. Results: Class A had significant increases in percentage of sedentary time (MD = -12.91%, ES = .88) in addition to significant decreases in the percentage of light (MD = 8.82%, ES = .67), moderate (MD = 3.08%, ES = .84), and vigorous (MD = -.04%, ES = .63) physical activity time during the intervention period compared to the baseline period. No significant or meaningful changes occurred in academic engagement with the use of the under-the-desk band. Conclusions: This study high- lights the importance of finding appropriate methods to increase physical activity for adolescents.


Assuntos
Exercício Físico , Instituições Acadêmicas , Adolescente , Humanos , Estudantes , Comportamento Sedentário , Acelerometria
4.
Int J Exerc Sci ; 15(4): 414-422, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35518364

RESUMO

Traditional graded exercise testing to assess maximal oxygen uptake (VO2max) may not well represent resistance-trained athletes due to their unfamiliarity with continuous exercise. For this reason, it is possible discontinuous exercise protocols may better represent the maximum capacity for aerobic metabolism in resistance-trained athletes, in order to provide a more valid assessment of VO2max and risk of developing cardiovascular disease. Purpose: The purpose of this experiment was to compare VO2peak during a continuous and discontinuous modified Bruce protocol in both highly resistance-trained and endurance-trained males. Methods: 19 college-aged males (age: 20.6 ± 1.9 yr, height: 176.5 ± 7.6 cm, weight: 85.0 ± 25.6 kg) of intermediate resistance- or endurance-trained status were recruited for this study. Participants completed a continuous and discontinuous modified Bruce protocol on two visits separated by seven days. Results: A 2×2 one-way ANOVA revealed a significant group main effect for VO2peak (p = 0.004) in which endurance athletes achieved significantly higher VO2peak values compared to resistance-trained athletes. A significant group main effect for RPE was found (p = 0.045) in which endurance-trained reported significantly higher RPE values than the resistance-trained. A significant main effect for protocol for heart rate (p = 0.033) was found in which individuals achieved higher heart rates during the continuous protocol compared to the discontinuous. Conclusion: Although a discontinuous protocol with rest periods between stages is comparable to the exercise mode familiar to resistance-trained athletes, it did not provide any additional benefit to VO2peak values.

5.
Adv Physiol Educ ; 46(3): 362-364, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35482993

RESUMO

Captain America can bring more than entertainment value to the public. The pop icon can also be used effectively in the science classroom, encouraging students to more effectively learn the content. How Captain America uses nutrients and how often he eats are novel ways to communicate real science. The point is to make a connection using science to explain how the superhero can run faster, jump higher, or lift more than is humanly possible. In this way fun, teachable moments are available for the educator.


Assuntos
Aprendizagem , Estudantes , Humanos , Masculino
6.
Nutrients ; 13(6)2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-34073387

RESUMO

Adequate fluid replacement during exercise is an important consideration for athletes, however sweat rate (SR) can vary day-to-day. The purpose of this study was to investigate day-to-day variations in SR while performing self-selected exercise sessions to evaluate error in SR estimations in similar temperature conditions. Thirteen endurance-trained athletes completed training sessions in a case-series design 1x/week for a minimum 30 min of running/biking over 24 weeks. Body mass was recorded pre/post-training and corrected for fluid consumption. Data were split into three Wet-Bulb Globe Thermometer (WBGT) conditions: LOW (<10 °C), MOD (10-19.9 °C), HIGH (>20 °C). No significant differences existed in exercise duration, distance, pace, or WBGT for any group (p > 0.07). Significant differences in SR variability occurred for all groups, with average differences of: LOW = 0.15 L/h; MOD = 0.14 L/h; HIGH = 0.16 L/h (p < 0.05). There were no significant differences in mean SR between LOW-MOD (p > 0.9), but significant differences between LOW-HIGH and MOD-HIGH (p < 0.03). The assessment of SR can provide useful data for determining hydration strategies. The significant differences in SR within each temperature range indicates a single assessment may not accurately represent an individual's typical SR even in similar environmental conditions.


Assuntos
Atletas , Desidratação , Treino Aeróbico , Suor , Ciclismo , Ingestão de Alimentos , Exercício Físico , Feminino , Humanos , Masculino , Raízes de Plantas , Corrida , Temperatura
7.
J Strength Cond Res ; 35(Suppl 1): S152-S157, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30694963

RESUMO

ABSTRACT: Krings, BM, Shepherd, BD, Swain, JC, Turner, AJ, Chander, H, Waldman, HS, McAllister, MJ, Knight, AC, and Smith, JW. Impact of fat grip attachments on muscular strength and neuromuscular activation during resistance exercise. J Strength Cond Res 35(2S): S152-S157, 2021-The purpose of this study was to examine the acute effects of Fat Gripz (FG) on muscular activation and strength. Resistance trained men (n = 15; age = 22.4 ± 2.3 years; mass = 83.2 ± 11.1 kg) performed 2 experimental trials in a randomized order. Subjects completed 1 repetition maximum (1RM) testing with an Olympic barbell (OB) and with FG attached to an OB during the exercises of deadlift, bent-over row, upright row, concentration curl, and completed maximum repetitions of pull-ups until failure. Surface electromyography (EMG) was used to measure muscle activity from 8 upper extremity muscles (trapezius, medial deltoid, biceps brachii, triceps brachii, flexor carpi radialis, flexor carpi ulnaris, extensor carpi radialis, and extensor carpi ulnaris), while performing maximal voluntary isometric contractions during 1RM trials and while performing maximum number of pull-ups. When using the FG, 1RM strength was significantly decreased for each exercise, and the maximal number of pull-ups completed was significantly lower. Electromyography muscle activity was significantly increased in the forearm and shoulder muscles, but significantly decreased in the upper arm muscles with the use of FG during deadlift, bent-over row, and pull-ups. However, there were no differences for EMG activity for upright row and concentration curl. Differences in maximal strength, pull-up performance, and EMG activity with FG use may be due to the different muscle length positions. Although FG training may increase neuromuscular activation, decrements in muscular strength may result in prescribing low training loads that may not be ideal for building muscular strength.


Assuntos
Treinamento Resistido , Adulto , Eletromiografia , Força da Mão , Humanos , Contração Isométrica , Masculino , Força Muscular , Músculo Esquelético , Adulto Jovem
8.
Appl Physiol Nutr Metab ; 46(6): 626-636, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33301383

RESUMO

The purpose of this investigation was to examine the importance of carbohydrate (CHO) timing while consuming a carbohydrate restricted diet (CRD) and completing a high-intensity exercise program. Eighteen males completed 6 weeks of training with the first 2 weeks serving as familiarization. During the final 4 weeks, subjects were randomized into 2 groups and completed 3 days of resistance training and 2 days of high-intensity interval training, while consuming a CRD (∼25%, ∼25%, and ∼50%, CHO, protein, and fat, respectively). The supplemented group (n = 9) ingested 30 g of CHO during exercise and 40 g of CHO immediately after each training session. The non-supplemented group (n = 9) consumed a non-caloric placebo during exercise. Pre- and post-testing measures included back squat and bench press 1-repetition maximums (1-RM), peak oxygen consumption (V̇O2peak), anaerobic power, body composition, fasted glucose, insulin, and total testosterone. Both groups significantly improved back squat and bench press 1-RM, V̇O2peak, and power output (p < 0.05), but there were no differences in blood markers or body composition. Our data suggests that CHO timing does not negatively impact training adaptations during a high-intensity exercise regimen when dietary CHO intake is restricted, but that favorable adaptations can be made while consuming a CRD. Novelty: Carbohydrate restricted dieting has no negative impact on resistance training adaptations. Short-term high-intensity interval training is effective in increasing peak oxygen consumption.


Assuntos
Dieta com Restrição de Carboidratos , Metabolismo Energético , Treinamento Resistido , Adaptação Fisiológica , Biomarcadores/sangue , Glicemia/metabolismo , Composição Corporal , Carboidratos da Dieta/administração & dosagem , Teste de Esforço , Humanos , Insulina/sangue , Masculino , Consumo de Oxigênio/fisiologia , Testosterona/sangue , Adulto Jovem
9.
Int J Exerc Sci ; 13(7): 1251-1261, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33042385

RESUMO

Lifetime sports, such as tennis, provide opportunities for participation throughout the lifespan and has been linked with lower risk of cardiovascular disease, obesity, and depression. The objective of this study was to consider the influence of chronic tennis participation on various parameters of health. Members of the International Tennis Federation (ITF) completed a survey consisting of questions from International Physical Activity Questionnaire (IPAQ), Behavior Risk Factor Surveillance System (BRFSS), Satisfaction With Life Survey (SWLS), and specific tennis participation questions. Descriptive characteristics were calculated for all variables and a chi-squared analysis was used to compare prevalence of health variables of this sample and recent BRFSS data. Compared to the BRFSS greater proportion of study participants 45yrs and older frequently reported being in good or better health (χ2=7.946, p = 0.005); lower obesity rates (χ2=19.92, p = 0.0001); and a lower prevalence of heart disease than those of similar age who completed BRFSS (χ2= 8.759, p = 0.003). This study highlights the importance of activities that continue throughout the lifespan such as tennis.

10.
J Strength Cond Res ; 34(10): 2785-2792, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32740289

RESUMO

Waldman, HS, Smith, JW, Lamberth, J, Fountain, BJ, Bloomer, RJ, Butawan, MB, and McAllister, MJ. A 28-day carbohydrate-restricted diet improves markers of cardiovascular disease in professional firefighters. J Strength Cond Res 34(10): 2785-2792, 2020-This study compared the effects of a 4-week, nonketogenic, carbohydrate-restricted (<25% of calories) diet (CRD) on markers of inflammation and oxidative stress in professional firefighters (FF). Subjects (n = 15) reported to the laboratory for 2 sessions (i.e., baseline and post-CRD) where blood was drawn from an antecubital vein after a 10-hour overnight fast. Dependent variables measured at baseline and post-CRD included adiponectin, insulin, human growth hormone, cortisol, C-reactive protein, albumin, lipids, glucose, amylase, creatine kinase, malondialdehyde (MDA), advance oxidation protein products (AOPP), total nitrate + nitrite, and soluble intracellular adhesion molecule-1. Compared with baseline, the CRD resulted in dramatic improvements to subjects' cardiometabolic profiles, including decreases in AOPP (51.3 ± 27.3 vs. 32.9 ± 7.9 ng·ml), MDA (1.6 ± 0.6 vs. 1.1 ± 0.5 µmol·L), and triglycerides (84.4 ± 34.4 vs. 64.2 ± 14.4 mg·dl), respectively. In addition, the CRD increased total cholesterol (151.5 ± 23.0 vs. 167.7 ± 38.2 mg·dl) and high-density lipoprotein cholesterol (46.3 ± 12.7 vs. 50.6 ± 15.5 mg·dl), but no differences were found with low-density lipoprotein cholesterol. Overall, our results show a 4-week CRD can favorably improve some markers of cardiovascular health in male FF.


Assuntos
Doenças Cardiovasculares/prevenção & controle , Doenças Cardiovasculares/fisiopatologia , Dieta com Restrição de Carboidratos/métodos , Bombeiros , Adiponectina/sangue , Adulto , Biomarcadores , Glicemia/metabolismo , Pressão Sanguínea , Proteína C-Reativa/análise , Ingestão de Energia , Fatores de Risco de Doenças Cardíacas , Humanos , Insulina/sangue , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade
11.
J Diet Suppl ; 17(3): 261-272, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30580652

RESUMO

Firefighters and military personnel are exposed to a variety of stressors. The combination of mental and physical stress (i.e., dual stress challenges [DSCs]) results in significant oxidative stress (OS), which may contribute to cardiometabolic dysfunction. Curcumin (CUR) is an exogenous antioxidant that may attenuate such OS. Fourteen trained men participated in a randomized, cross-over design to investigate the impact of CUR on markers of OS resulting from DSC. CUR or placebo was ingested three days prior to, and the morning of, testing. The DSC involved 20 min of mental stress challenges during 35 min of cycling at 60% V̇O2 peak. Blood was sampled before, as well as immediately, 30 min, and 60 min after, exercise and analyzed for glutathione (GSH), superoxide dismutase (SOD), hydrogen peroxide (H2O2), and advanced oxidation protein products (AOPP). There was no treatment effect for any variable. However, the DSC resulted in significant reductions in SOD, H2O2, and AOPP at 30 and 60 min after exercise. Previous studies have shown that DSC results in significant OS compared to exercise alone. However, these data suggest the DSC was associated with reductions in postexercise markers of OS. Antioxidant therapy is likely not needed in trained men exposed to DSC.


Assuntos
Antioxidantes/administração & dosagem , Curcumina/administração & dosagem , Estresse Oxidativo/efeitos dos fármacos , Adulto , Produtos da Oxidação Avançada de Proteínas/sangue , Estudos Cross-Over , Método Duplo-Cego , Teste de Esforço , Glutationa/sangue , Humanos , Peróxido de Hidrogênio/sangue , Masculino , Estresse Fisiológico , Estresse Psicológico , Superóxido Dismutase/sangue , Adulto Jovem
12.
Int J Sport Nutr Exerc Metab ; 30(1): 42-47, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31563122

RESUMO

Carbohydrate mouth rinsing has been shown to enhance aerobic exercise performance, but there is limited research with resistance exercise (RE). Therefore, the purpose of this investigation was to examine the effects of carbohydrate mouth rinsing during a high-volume upper body RE protocol on performance, heart rate responses, ratings of perceived exertion, and felt arousal. Recreationally experienced resistance-trained males (N = 17, age: 21 ± 1 years, height: 177.3 ± 5.2 cm, mass: 83.5 ± 9.3 kg) completed three experimental sessions, with the first serving as familiarization to the RE protocol. During the final two trials, the participants rinsed a 25-ml solution containing either a 6% carbohydrate solution or an artificially flavored placebo in a randomized, counterbalanced, and double-blinded fashion. The participants rinsed a total of nine times immediately before beginning the protocol and 20 s before repetitions to failure with the exercises bench press, bent-over row, incline bench press, close-grip row, hammer curls, skull crushers (all completed at 70% one-repetition maximum), push-ups, and pull-ups. Heart rate, ratings of perceived exertion, and felt arousal were measured at the baseline and immediately after each set of repetitions to failure. There were no differences for the total repetitions completed (carbohydrate = 203 ± 25 repetitions vs. placebo = 201 ± 23 repetitions, p = .46, Cohen's d = 0.10). No treatment differences were observed for heart rate, ratings of perceived exertion, or felt arousal (p > .05). Although carbohydrate mouth rinsing has been shown to be effective in increasing aerobic performance, the results from this investigation show no benefit in RE performance in resistance-trained males.


Assuntos
Desempenho Atlético/fisiologia , Carboidratos da Dieta/administração & dosagem , Antissépticos Bucais , Treinamento Resistido , Extremidade Superior/fisiologia , Levantamento de Peso/fisiologia , Nível de Alerta/fisiologia , Método Duplo-Cego , Frequência Cardíaca , Humanos , Masculino , Percepção/fisiologia , Esforço Físico/fisiologia , Adulto Jovem
13.
J Int Soc Sports Nutr ; 16(1): 50, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31699159

RESUMO

Background In this Position Statement, the International Society of Sports Nutrition (ISSN) provides an objective and critical review of the literature pertinent to nutritional considerations for training and racing in single-stage ultra-marathon. Recommendations for Training. i) Ultra-marathon runners should aim to meet the caloric demands of training by following an individualized and periodized strategy, comprising a varied, food-first approach; ii) Athletes should plan and implement their nutrition strategy with sufficient time to permit adaptations that enhance fat oxidative capacity; iii) The evidence overwhelmingly supports the inclusion of a moderate-to-high carbohydrate diet (i.e., ~ 60% of energy intake, 5-8 g·kg- 1·d- 1) to mitigate the negative effects of chronic, training-induced glycogen depletion; iv) Limiting carbohydrate intake before selected low-intensity sessions, and/or moderating daily carbohydrate intake, may enhance mitochondrial function and fat oxidative capacity. Nevertheless, this approach may compromise performance during high-intensity efforts; v) Protein intakes of ~ 1.6 g·kg- 1·d- 1 are necessary to maintain lean mass and support recovery from training, but amounts up to 2.5 g.kg- 1·d- 1 may be warranted during demanding training when calorie requirements are greater; Recommendations for Racing. vi) To attenuate caloric deficits, runners should aim to consume 150-400 Kcal·h- 1 (carbohydrate, 30-50 g·h- 1; protein, 5-10 g·h- 1) from a variety of calorie-dense foods. Consideration must be given to food palatability, individual tolerance, and the increased preference for savory foods in longer races; vii) Fluid volumes of 450-750 mL·h- 1 (~ 150-250 mL every 20 min) are recommended during racing. To minimize the likelihood of hyponatraemia, electrolytes (mainly sodium) may be needed in concentrations greater than that provided by most commercial products (i.e., > 575 mg·L- 1 sodium). Fluid and electrolyte requirements will be elevated when running in hot and/or humid conditions; viii) Evidence supports progressive gut-training and/or low-FODMAP diets (fermentable oligosaccharide, disaccharide, monosaccharide and polyol) to alleviate symptoms of gastrointestinal distress during racing; ix) The evidence in support of ketogenic diets and/or ketone esters to improve ultra-marathon performance is lacking, with further research warranted; x) Evidence supports the strategic use of caffeine to sustain performance in the latter stages of racing, particularly when sleep deprivation may compromise athlete safety.


Assuntos
Carboidratos da Dieta/administração & dosagem , Ingestão de Energia , Necessidades Nutricionais , Corrida/fisiologia , Fenômenos Fisiológicos da Nutrição Esportiva , Atletas , Desempenho Atlético , Comportamento Competitivo , Proteínas Alimentares/administração & dosagem , Humanos , Resistência Física , Corrida/classificação , Sociedades
14.
J Strength Cond Res ; 33(12): 3284-3294, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31469768

RESUMO

Waldman, HS, Smith, JW, Lamberth, J, Fountain, BJ, and McAllister, MJ. A 28-day carbohydrate-restricted diet improves markers of cardiometabolic health and performance in professional firefighters. J Strength Cond Res 33(12): 3284-3294, 2019-We investigated the effects of a 4-week ad-libitum, nonketogenic, carbohydrate-restricted (<25% of calories) diet (CRD) on cardiometabolic and performance markers in firefighters (FF). Subjects (n = 15) completed 9 sessions (trials 1-3 [familiarization], trials 4-6 [baseline], and trials 7-9 [post-CRD]). Following habitual western diet, anthropometric measures were assessed, glucose tolerance measured, and then completed a graded cycling test, maximal Wingate test, and conducted their FF physical performance assessment (FPPA) to measure performance while metabolic variables and perceptual responses were recorded. Subjects then adhered to a CRD for a 4-week duration and returned for repeat testing. Body fat as measured by BodPod, and 7-site skinfold thickness decreased (p < 0.01), and a decrease was observed in blood pressure (BP) (p < 0.01; ∼5 mm Hg) after CRD. There were no differences found for glucose tolerance, but an increase was found for fat oxidation rates (p < 0.01; ∼0.07 g·min) and a decrease in carbohydrate oxidation rates across a range of intensities (p < 0.01; ∼0.24 g·min). Finally, the 2.41-km run and pull-up performance during the FPPA improved (p < 0.01; ∼41 second and 3 repetitions, respectively) and with no differences observed between treatments regarding the Wingate test. To date, this is the first CRD implemented with FF and resulted in decreased fat mass (∼2.4 kg), BP, and improvements to performance on the FPPA while preserving high-intensity exercise. These data suggest that a 28-day CRD can benefit markers of health in professional FF without detriments to occupational performance.


Assuntos
Glicemia/metabolismo , Dieta com Restrição de Carboidratos , Carboidratos da Dieta/administração & dosagem , Bombeiros , Desempenho Físico Funcional , Tecido Adiposo , Adulto , Biomarcadores/sangue , Pressão Sanguínea , Dieta Ocidental , Ingestão de Energia , Teste de Esforço , Teste de Tolerância a Glucose , Humanos , Masculino , Dobras Cutâneas , Adulto Jovem
15.
Physiol Behav ; 198: 90-95, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30342058

RESUMO

PURPOSE: Those engaged in high stress occupations such as firefighters and military personnel are exposed to a variety of psychological and physiological stressors. The combination of mental and physical stress [i.e., dual stress challenges (DSC)] results in significant increases in stress hormones, which causes oxidative stress (OS) and contributes to elevated risk for cardiovascular disease. However, data are needed to determine the impact of DSC on markers of OS in exercise-trained individuals. METHOD: Fourteen healthy trained men aged 21-30 yrs. participated in a randomized, cross-over design to investigate the impact of DSC on blood markers of OS. The exercise alone condition (EA) consisted of 35 min of cycling at 60% V̇O2 peak. The DSC involved 20 min of mental stress challenges during exercise. Blood was sampled before exercise, as well as immediately, and 30 and 60 min after exercise and analyzed for glutathione (GSH), superoxide dismutase (SOD), hydrogen peroxide (H2O2) and advanced oxidation protein products (AOPP). RESULT: No significant treatment × time interactions were found. No time effects were noted for SOD, or H2O2; however, AOPP were reduced at 30 (p = .034) and 60 min post exercise (p = .006). GSH was reduced at 30 (p = .009) and 60 min post exercise (p = .031). CONCLUSION: These results indicate the OS response from DSC is not greater than that produced from EA in exercise trained men. Future work should investigate the impact of chronic resistance and endurance exercise training on OS resulting from DSC.


Assuntos
Exercício Físico/fisiologia , Estresse Oxidativo/fisiologia , Estresse Psicológico/metabolismo , Adulto , Biomarcadores/sangue , Estudos Cross-Over , Glutationa/sangue , Humanos , Peróxido de Hidrogênio/sangue , Masculino , Superóxido Dismutase/sangue , Adulto Jovem
16.
J Occup Environ Med ; 60(11): e595-e601, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30252723

RESUMO

OBJECTIVE: Firefighters (FFs) involved in fire suppression have the greatest on-duty risk of cardiovascular disease (CVD), which may be caused by oxidative stress (OS). METHODS: Healthy, active FFs performed a victim "search and clear" exercise involving three conditions: (1) no heat, (2) heat + antioxidant, and (3) heat + placebo. Blood samples were analyzed for OS markers glutathione (GSH), oxidized glutathione (GSSG), superoxide dismutase (SOD), catalase (CAT), and advanced oxidation protein products (AOPP). RESULTS: Increased GSH was found during both heat conditions compared with no heat. CAT activity was higher immediately post exercise. AOPP was reduced post exercise. CONCLUSIONS: Antioxidant supplementation did not impact the OS response to exercise. Added heat did not cause OS and exercise resulted in reductions in OS markers. These findings can be attributed to the training status of the FFs involved.


Assuntos
Antioxidantes/administração & dosagem , Curcumina/administração & dosagem , Bombeiros , Temperatura Alta , Estresse Oxidativo , Esforço Físico/fisiologia , Adulto , Produtos da Oxidação Avançada de Proteínas/sangue , Biomarcadores/sangue , Catalase/sangue , Estudos Cross-Over , Método Duplo-Cego , Incêndios , Dissulfeto de Glutationa/sangue , Frequência Cardíaca , Humanos , Masculino , Superóxido Dismutase/sangue
17.
Appl Physiol Nutr Metab ; 43(7): 711-717, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29451991

RESUMO

This study examined the effects of a d-ß-hydroxybutyrate (ßHB) containing beverage on cognitive and performance measures during a bout of repeated Wingates. Fifteen healthy, college-aged males (mean ± SD; age: 23.1 ± 2.4 years, height: 165.4 ± 2.0 cm, mass: 81.4 ± 9.2 kg) volunteered for the present study. Trial 1 consisted of baseline measures and familiarization for the protocol. During trials 2 and 3, subjects reported to the laboratory, after a 10-h fast, and ingested 11.38 g of ßHB or a placebo (PLA) beverage 30 min before exercise. Participants then completed a cognitive challenge (CC), consisting of a 5-min FitLight response task while cycling. At the cessation of the test, participants then completed four 15-s repeated Wingates with 4 min of rest between, followed by another 5-min CC response task. Blood ketones, glucose, and lactate were measured pre-CC and post-Wingates. ßHB levels were significantly higher compared with PLA (0.53 vs. 0.21 mmol/L), respectively. A significant order effect was observed across trials 2 and 3 for total FitLight misses and hits, regardless of treatment. Further, there were no significant differences among Wingate power output between treatments, although fatigue index was higher in the ßHB group compared with PLA (32.3 vs. 29.4 W/s), respectively. In conclusion, ßHB did not improve high-intensity cycling or cognitive performance measures; however, these findings might be partially explained by the absolute dosing protocol used for ßHB in the present study as opposed to a relative (g/kg) dosing protocol used in previous research.


Assuntos
Ácido 3-Hidroxibutírico/administração & dosagem , Cognição/efeitos dos fármacos , Exercício Físico , Ácido 3-Hidroxibutírico/sangue , Adulto , Bebidas , Glicemia/metabolismo , Aptidão Cardiorrespiratória , Estudos Cross-Over , Método Duplo-Cego , Humanos , Ácido Láctico/sangue , Masculino , Resistência Física/efeitos dos fármacos , Adulto Jovem
18.
Nutrition ; 46: 33-35, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29290352

RESUMO

OBJECTIVE: Investigations into the relationship between dietary carbohydrate restriction and health are mixed. Current guidelines for nutrition promote low-fat foods and higher carbohydrate consumption for optimal health and weight loss. However, high-fat, low-carbohydrate diets are revealing both intra- and extracellular adaptations that have been shown to elicit favorable cardiometabolic changes associated with obesity. Moreover, dietary fat is associated with higher satiety levels from the hormones adiponectin, leptin, and cholecystokinin. Additionally, insulin responses from high-glycemic carbohydrates are known to alter these pathways, potentially leading to an increase in energy consumption and a possible mechanism for obesity. CONCLUSION: There is convincing evidence of beneficial effects of controlled trials implementing high-fat, low-carbohydrate diets in both sedentary and obese individuals, but longer duration clinical trials are required to confirm this hypothesis.


Assuntos
Dieta com Restrição de Carboidratos , Dieta Hiperlipídica , Obesidade/dietoterapia , Obesidade/metabolismo , Adiponectina/sangue , Colecistocinina/sangue , Ingestão de Energia , Humanos , Insulina/sangue , Leptina/sangue , Política Nutricional , Saciação , Redução de Peso
19.
Appl Physiol Nutr Metab ; 43(5): 504-509, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29244956

RESUMO

The purpose of this investigation was to examine the individual and combined effects of ingesting carbohydrates (CHO) and branched-chain amino acids (BCAA) during high-volume upper body resistance exercise (RE) on markers of catabolism and performance. Thirteen resistance-trained males completed 4 experimental trials with supplementation, ingesting beverages containing CHO, BCAA, CHO+BCAA, or placebo (PLA) in a randomized, double-blind design. The beverages were ingested in 118-mL servings 6 times during an ∼60-min RE session consisting of bench press, bent-over row, incline press, and close-grip row. Each RE was performed with 5 sets of repetitions at 65% 1-repetition maximum until volitional fatigue. Blood samples were collected at baseline, immediately postexercise, and 60 min postexercise to assess glucose and insulin. Cortisol was assessed immediately and at 60 min postexercise. No significant performance benefits were observed for any RE. CHO+BCAA (152.4 ± 71.4 ng/mL) resulted in the lowest cortisol levels, which was lower than BCAA and PLA (193.7 ± 88.5, 182.8 ± 67.5 ng/mL, p < 0.05), but not different from CHO (165 ± 76.5 ng/mL, p = 0.342). Postexercise insulin concentrations were significantly higher with CHO (4.79 ± 3.4 mU/L) compared with BCAA and PLA (3.7 ± 2.0, 3.5 ± 1.8 mU/L, p < 0.05), but not different from CHO+BCAA (4.3 ± 2.5 mU/L, p = 0.339). There was no treatment effect for glucose, but glucose significantly increased from baseline to immediately postexercise and significantly decreased at 60 min postexercise. Ingesting beverages containing CHO with or without BCAA during upper body resistance exercise may promote a more favorable postexercise less catabolic environment.


Assuntos
Aminoácidos de Cadeia Ramificada/administração & dosagem , Carboidratos da Dieta/administração & dosagem , Hidrocortisona/sangue , Insulina/sangue , Treinamento Resistido , Adulto , Bebidas , Glicemia/metabolismo , Estudos Cross-Over , Dieta , Gorduras na Dieta/administração & dosagem , Proteínas Alimentares/administração & dosagem , Suplementos Nutricionais , Método Duplo-Cego , Humanos , Masculino , Músculo Esquelético/fisiologia , Resistência Física , Adulto Jovem
20.
J Strength Cond Res ; 32(1): 205-210, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28195977

RESUMO

Cummings, PM, Waldman, HS, Krings, BM, Smith, JW, and McAllister, MJ. Effects of fat grip training on muscular strength and driving performance in division I male golfers. J Strength Cond Res 32(1): 205-210, 2018-Fat grip (FG) training is implemented into strength and conditioning programs with the overall goal of increasing grip strength. Previous research assessing the effect of training with increased grip diameters compared with standard Olympic bar diameters has mainly been in acute settings. Therefore, the purpose of this study was to examine to effects FG training compared with normal diameter grip (CON) training during an 8-week periodized resistance training (RT) program in division I male golfers. Subjects (n = 10) were randomly assigned into 2 groups: the FG group (n = 5, scoring average: 75.4 ± 2.0) and CON group (n = 5, scoring average: 75.0 ± 0.5). Both groups participated in 8 weeks of RT (3 d·wk). The FG group completed every lift and repetition using FG, compared with the CON training group which used normal diameter bars. Pretraining and posttraining performance variables included swing speed, ball speed, driving distance, driving carry, maximum pull-ups to failure, right and left hand grip strength, and 1 repetition max trap-bar deadlift. The FG group demonstrated significant increases (p ≤ 0.05) in ball speed, carry, drive distance, and left hand grip strength after 8 weeks of RT. In a population, such as low-handicap division I male golfers, FG training may allow for athletes to increase golf-specific performance after 8 weeks of periodized RT. Strength and conditioning coaches may use FG training over the course of a training program with athletes who require adequate grip strength to further elicit training adaptations.


Assuntos
Desempenho Atlético/fisiologia , Golfe/fisiologia , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Treinamento Resistido/métodos , Adaptação Fisiológica , Adolescente , Força da Mão/fisiologia , Humanos , Masculino , Universidades , Adulto Jovem
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