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1.
Int J Exerc Sci ; 16(5): 458-468, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37122762

RESUMO

Exercise stimulates the production and secretion of testosterone, cortisol, and brain-derived neurotrophic factor (BDNF) and affects cognitive performance. However, the interaction of these variables is unknown. To investigate these interactions, 21 college-aged men completed two work-matched exercise protocols: continuous (CONT) exercise and an interval protocol (INT). Blood and saliva samples were collected before and after exercise to quantify BDNF, cortisol, and testosterone. Participants completed a battery of cognitive assessments after exercise. A MANOVA analysis of condition demonstrated that no domains were significantly different after CONT and INT (p > 0.05). A repeated measures ANOVA of time by condition demonstrated increases in BDNF in after both CONT and INT (p = 0.05), elevated cortisol after CONT (p = 0.05), and an interaction of testosterone (p = 0.027). Work matched continuous and interval exercise appears to promote serum BDNF but do not result in different post exercise cognitive performance.

2.
Int J Vitam Nutr Res ; 92(5-6): 357-365, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33143547

RESUMO

Caffeine has documented hypoalgesic effects during exercise. However, there is a lack of research focusing on caffeine's potential analgesic effects to ameliorate delayed onset muscle soreness. A placebo controlled randomized cross-over trial was carried out to determine if 5 mg/kg of body weight (mg/kgBW) of caffeine attenuates muscle pain and improves 5 k running performance following delayed onset muscle soreness. Prior to participating, eleven runners (9 male; 2 female; age, 24.5 ± 6.3 years; height, 173.6 ± 7.8 cm; body mass, 66.3 ± 7.5 kg; BMI, 23.18 kg/m2 ± 1.6; VO2max 61.0 ± 6.1 ml/kg/min-1), were asked to discontinue supplement use for 72 hours and abstain from caffeine consumption for 48 hours. Participants performed a 30-minute downhill run on a treadmill set at -10% grade at 70% VO2max to induce delayed onset of muscle soreness. Participants then returned 48 hours after to complete a 5 k time trial run where they consumed either 5 mg/kgBW of caffeine or a placebo. Rate of perceived exertion and heart rate were taken every two minutes during the trial. There was no detectable statistical difference between 5 k performance between caffeine (1074.9 ± 119.7 sec) or placebo (1053.8 ± 86.8 sec) (p = .41). Algometer readings were similar between both treatments for muscle soreness in the rectus femoris (p = .791) and the vastus medialis oblique (p = .371). Muscle soreness ratings were found to be greater in the caffeine condition compared to the placebo condition (p = .030). There was no effect of treatment on rating of perceived exertion between conditions (p = .574). The present study suggests that caffeine is not effective at reducing muscle soreness, rating of perceived exertion, or improving running performance in a time trial in the presence of muscle soreness.


Assuntos
Cafeína , Corrida , Adolescente , Adulto , Analgésicos , Cafeína/farmacologia , Método Duplo-Cego , Feminino , Humanos , Masculino , Músculos , Mialgia/tratamento farmacológico , Corrida/fisiologia , Adulto Jovem
3.
Front Nutr ; 8: 718936, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34621774

RESUMO

A distance runner's performance is generally limited by energy availability when competing or training. Modifying meal frequency and timing by abstaining from eating or drinking, from dawn to dusk, during Ramadan fasting is hypothesized to induce hypohydration and reduced caloric and nutrient intake. The purpose of this study was to investigate the impact of Ramadan fasting on runners' performances. Fifteen trained male distance runners who observed Ramadan participated in this study (Age = 23.9 ± 3.1 years; Peak VO2 = 71.1 ± 3.4 ml/kg/min). Each participant reported to the human performance lab on two testing occasions (pre-Ramadan and the last week of Ramadan). In each visit, participants performed a graded exercise test on the treadmill (Conconi protocol) and their VO2, Heart Rate, time to exhaustion, RPE, and running speed were recorded. Detailed anthropometrics, food records, and exercise logs were kept for the entire period of the study. Repeated measure ANOVA, paired t-test, and Cohen's effect size analysis were carried out. Results indicated no significant influence for Ramadan fasting on body mass (p = 0.201), body fat (p = 0.488), lean body mass (p = 0.525), VO2max (p = 0.960), energy availability (p = 0.137), and protein intake (p = 0.124). However, carbohydrate (p = 0.026), lipid (p = 0.009), water (p < 0.001), and caloric intakes (p = 0.002) were significantly reduced during Ramadan Fasting. Daily training duration (p < 0.001) and exercise energy expenditure (p = 0.001) were also reduced after Ramadan. Time to exhaustion (p = 0.049), and maximal running speed (p = 0.048) were improved. Overall, time to exhaustion and maximal running speed of the distance runners was improved during Ramadan fasting, independent of changes in nutrients intake observed during the current study. With proper modulation of training, distance runners performance can be maintained or even slightly improved following the month of Ramadan fasting.

4.
J Hum Kinet ; 79: 111-122, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34400991

RESUMO

Hydration plays an important role in performance, injury prevention, and recovery for athletes engaged in competitive sports. Therefore, it is important that strength and conditioning coaches understand an athlete's hydration needs to prevent illness and enhance performance. The purpose of this study was to identify hydration knowledge, attitudes, and behaviors of collegiate track and field throwers, as well as identify barriers to hydration and sources of nutritional information. The Rehydration and Refueling in Collegiate Track and Field Throwers Survey was sent to 271 track and field thrower coaches with a request to forward the email to current track and field throwers. Pearson correlation coefficients were calculated regarding knowledge, attitude, and behavior scores among the participants in this sample. Differences among response patterns were assessed via Chi-square analysis. Alpha level was set at p = .05. Results demonstrated that 97.3% (n = 287) of respondents knew that dehydration would decrease performance, but 50.5% (n = 149) erroneously believed thirst was the best indicator of dehydration. Chi-square analysis demonstrated a significant difference in reported values between participants who intended to eat a performance-enhancing diet and those who consumed less fluid than recomended values (207 - 295 m)l in the 2-3 hours prior to competition (χ2 = 10.87, p < .05). Pearson correlation coefficients demonstrated a large association between knowledge and behavior (r = .70, p < .05), a medium association between knowledge and attitude (r = .41, p < .05), and a small association between attitude and behavior (r = .21, p < .05). This suggests that strength and conditioning coaches and health staff need to educate and monitor hydration behaviors among collegiate track and field throwers to optimize performance.

5.
Int J Exerc Sci ; 14(6): 578-593, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34055175

RESUMO

Despite the continued growth of the Olympic Games (OG), the Youth Olympic Games (YOG) has received minimal attention from mainstream media since its introduction in 2010. The purpose of this study was to examine and compare event awareness and consumption intention for the 2012 Winter YOG to two international sport events occurring in the same year. A survey instrument was utilized to examine and compare event awareness, consumption intention, and logo identification for three international sport events within a millennial generation sample. The study showed significant differences in personal and public awareness between the three sport events, with personal (r = .313, p ≤ .001) and public (r = .331, p ≤ .001) awareness for the YOG demonstrating a positive correlation with consumption intention. This study is an important assessment of the YOG event awareness that can be utilized by the International Olympic Committee (IOC) to better understand and engage their participants and audience. Successful promotion of the YOG may require a transformation of the current marketing strategies that are utilized. The YOG has great opportunity for success in the global sport market to leave behind the status of the best kept secret in sport.

6.
J Hum Kinet ; 78: 271-281, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34025884

RESUMO

Researchers suggest that sport participation among athletes with disabilities promotes healthier lifestyles, increases self-esteem, and enhances peer acceptance. Ideally, coaches should be confident in teaching skills, tactics, and sportsmanship, while exhibiting appropriate leadership behaviors in order to positively impact the psychosocial development of any athlete. Thus, the present research examined sources of coaching efficacy that predict leadership behaviors in coaches who work with athletes who have physical disabilities. Seventy international Paralympic coaches of female and male sport teams completed a modified version of the Coaching Success Questionnaire-2, the Coaching Efficacy Scale and the Leadership Scale for Sports. Regression models indicated that total coaching efficacy was a significant predictor of instructional and positive feedback leadership behaviors, with prior success also being a significant predictor of instructional behavior.

7.
Int J Vitam Nutr Res ; 91(3-4): 287-292, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31971089

RESUMO

The experiment examined the effects 4 weeks of vitamin D (Vit D) supplementation versus placebo on musculoskeletal and psychomotor performance. Thirty-two college age males (Age: 22 ± 4 y, Height: 177.7 ± 8.3 cm, Weight: 81.5 ± 14.6 kg, BF%: 19.6 ± 7.9, Vit D: 20.0 ± 7.2 ng/ml). Participants were assigned to group (Vit D vs placebo) and remained blind throughout the study. The treatments were 4000 IU of Vit D3 or placebo (dextrose) administered daily for 4 weeks. The participants underwent baseline testing for isometric strength, explosive ability and psychomotor performance, which was repeated at week 2 and week 4. Isometric tests consisted of an Isometric Mid Thigh Pull on a Force Plate (IMTP) and an upper body isometric test (UBIST) using a load cell. Peak force during a countermovement jump (CMJ) was also determined via force plate. A psychomotor vigilance test (PVT) was used to measure sustained reaction time. Analysis of the UBIST data did not reveal a significant group × time interaction (p = 0.14; Vit D pre: 553.7 ± 168.3 N, post: 585.5 ± 150.2 N; Placebo pre: 677.7 ± 182.3 N, post: 649.8 ± 236.9 N). For IMTP no significant group × time interaction (p = 0.83; Vit D pre: 2596.4 ± 342.3 N, post: 2606.9 ± 378.3 N; Placebo pre: 2684.0 ± 432.9 N, post: 2762.6 ± 440.4 N) was found. CMJ analysis did not reveal interaction effects for group × time (p = 0.21; Vit D pre: 4429.7 ± 1619.0 N, post: 4938.5 ± 2374.8 N; Placebo pre: 5537.3 ± 3027.0 N, post: 6266.9 ± 4577.3 N). For PVT (mean reaction time) there was no significant interaction effects for group × time (p = 0.35; Vit D pre: 0.304 ± 0.041 sec, post: 0.301 ± 0.053 sec; Placebo pre: 0.295 ± 0.044 sec, post: 0.284 ± 0.029 sec). In conclusion, four weeks of Vit D supplementation was not effective in increasing musculoskeletal or psychomotor performance.


Assuntos
Colecalciferol , Desempenho Psicomotor , Adolescente , Adulto , Peso Corporal , Humanos , Masculino , Vitamina D , Vitaminas , Adulto Jovem
8.
Medicina (Kaunas) ; 56(12)2020 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-33371366

RESUMO

Background and objectives: Striking a balance between maximizing performance and preventing injury remains elusive in many professional sports. The purpose of this study was to assess the relative risk of non-contact injuries in professional basketball players based on predictive cut scores on the Functional Movement Screen™ (FMS). Materials and Methods: Thirty-two professional basketball players from the National Basketball Association (NBA) and Women's National Basketball Association (WNBA) participated in this study. This observational pilot cohort study assessed and scored each participant using the FMS during training camp. Each athlete was then tracked throughout the season while recording the number, type, and time lost due to injuries. Possible exposures, actual exposures, and exposures missed due to non-contact injury (NCI) for each athlete were calculated and then used to determine the crude and specific incident rates for exposures missed due to NCI per 1000 exposures. Results: Linear regression models were used to evaluate the predictive ability of the FMS score for total missed exposures, NCI, and CI missed exposures. In all models, the FMS total score failed to attain significance as a predictor (p > 0.05). FMS scores ranged from 5 to 18. The recommended cut score of 14 showed a sensitivity of 0.474 and a specificity of 0.750. The cut score of 15 showed the best combination, exhibiting a sensitivity of 0.579 and specificity of 0.625. A total of 5784 exposures to NCI were possible for the men and women combined, and 681 possible exposures were missed. Of these, 23.5% were due to NCI, 16.5% were due to contact injuries (CI), and 60% were due to illnesses and personal reasons. Conclusions: The FMS proved to be a measure that was not associated with any injury measure in this sample of professional basketball players, suggesting the instrument lacks predictive validity in this population.


Assuntos
Basquetebol , Atletas , Estudos de Coortes , Feminino , Humanos , Masculino , Movimento , Projetos Piloto
9.
Medicina (Kaunas) ; 56(9)2020 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-32824955

RESUMO

Background and Objectives: National Collegiate Athletic Association (NCAA) soccer coaches implement numerous warm-up and flexibility strategies to prepare athletes for training and competition. The Fédération Internationale de Football Association (FIFA) developed the 11+ injury prevention program to reduce non-contact injuries. This study aimed to analyze the level of familiarity with and implementation of the evidence-based FIFA 11+ amongst NCAA Division I (DI) and Division III (DIII) men's and women's soccer coaches. Materials and Methods: NCAA soccer coaches in the United States received an Institutional Review Board-approved survey hyperlink. A total of 240 coaches completed the survey. The respondents represented 47.5% men's and 52.5% women's teams distributed within DI and DIII programs. Descriptive statistics are reported as frequency counts and mean ± standard deviation where applicable. Pearson's chi-square tests were performed to assess potential differences with a significance level set at α < 0.05. Results: The results indicated that approximately 62% of the respondents reported being familiar with the FIFA 11+ program. Of those coaches familiar with the program, 15.0% reported full implementation, 57.5% reported partial implementation, and 27.5% reported no implementation. Chi-square analyses revealed significant differences in FIFA 11+ implementation based upon division level (χ2 = 4.56, p = 0.033) and coaching certification levels (χ2 = 13.11, p = 0.011). Conclusions: This study indicates that there is a gap between FIFA 11+ knowledge and actual implementation. To reduce the risk of non-contact injury, there is a need to educate coaches and athletic trainers on the purpose of the FIFA 11+ program and how to perform the exercises correctly.


Assuntos
Fidelidade a Diretrizes , Guias como Assunto , Tutoria , Exercícios de Alongamento Muscular , Futebol/fisiologia , Exercício de Aquecimento , Traumatismos em Atletas/prevenção & controle , Certificação , Feminino , Humanos , Masculino , Tutoria/normas , Futebol/classificação , Futebol/lesões , Estados Unidos
10.
Int J Exerc Sci ; 13(6): 260-272, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32148642

RESUMO

Current pre- and post-activity stretching guidelines are designed to optimize performance and reduce injury risk. However, it is unclear whether soccer coaches adhere to these recommendations. The purpose of this study was to determine if collegiate soccer coaches' perceptions and practices align with current scientific recommendations. A total of 781 questionnaires were electronically distributed to soccer coaches from NCAA Division I and III universities. The questionnaire obtained demographic, professional, and educational information, as well as stretching practices. Statistical analysis consisted of computing frequency counts and means where applicable. Pearson's Chi-square tests were performed to assess the potential differences in stretching perceptions and practices among the cohort of soccer coaches. Results suggest that soccer coaches are choosing some forms of stretching more frequently than other coaches (χ2 = 342.7, p < 0.001). Further analysis failed to determine significant associations between stretching type and coaching certification, level, sex, years of experience, and age. Of the 209 respondents, 84.9% believed pre-activity stretching to be of greater than average importance on a seven-point Likert scale. Dynamic stretching (68.7%) or a combination of static and ballistic stretching (18.0%) prior to athletic events was the most typical stretching prescribed. Current post-activity practices demonstrate that most coaches (95.4%) are using some form of a general cool-down following practice or competition. This study is an important assessment of the extent to which collegiate coaches administer appropriate stretching techniques. Most coaches adhere to current recommendations; however, they should continue to evaluate their practices against ongoing research and the practices of their peers.

11.
Res Q Exerc Sport ; 91(1): 92-101, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31609184

RESUMO

To promote student physical literacy, physical educators must teach and assess health-related fitness content knowledge (HRFK) and model healthy lifestyles. Individual HRFK is associated with lifetime physical activity (PA) and each may precede/predict both teaching and assessing of student HRFK. Purpose: The purpose of this study was to examine factors related to physical educators' teaching and assessment of student HRFK. Method: Physical educators (N = 796) representing each SHAPE America regional district completed a 33-item survey to determine their individual HRFK, weekly PA, and extent to which they teach (tHRFK) and assess (aHRFK) student HRFK. Results: Multiple regression was conducted to determine if tHRFK and aHRFK are predicted by teachers' individual HRFK, min/week of light, moderate, or vigorous PA, or any demographic variables. Overall, the tHRFK model was significant (F = 10.919, R2 = 0.100, p < .001) with all predictors significant, except weekly minutes of moderate PA and participant HRFK (p < .05). The aHRFK model was also significant (F = 45.736, R2 = 0.108, p < .022) with all predictors significant except weekly minutes of moderate PA, education level, and participant HRFK (p < .05). Conclusion: U.S. physical educators possess high levels of HRFK, however HRFK is not a significant predictor of their teaching and assessing HRFK. Weekly vigorous PA, was the strongest predictor, suggesting that teachers' commitment to their own personal PA is critical to teaching and assessing HRFK among their students. Further research should consider vigorous PA along with other potentially related variables to more fully describe and predict physical educators' teaching and assessment of HRFK.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Educação Física e Treinamento , Professores Escolares/psicologia , Feminino , Comportamentos Relacionados com a Saúde , Humanos , Masculino , Inquéritos e Questionários , Estados Unidos
12.
Int J Vitam Nutr Res ; 90(5-6): 403-410, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30932750

RESUMO

Aim: To determine the effects of short-term Montmorency cherry (MC) supplementation upon exercise performance, total blood nitrate levels, muscle oxygenation, and slow-component [Formula: see text]O2 kinetics. Methods: Twelve healthy male participants ingested a MC or placebo (PL) supplement in a randomized cross-over fashion over a six day period then cycled at a power output achieved at 70% of [Formula: see text]O2 peak for a maximum of 30 minutes or until exhaustion. Near-Infrared Spectroscopy sensors were used to determine muscle oxygenation. Blood was collected one hour post-supplement consumption on day one, day six, and one hour post-exercise. Results: All results are presented as mean ± SEM. Blood nitrate (µM/L) levels were not different one hour post-ingestion (MC = 8.30 ± 2.15, PL = 8.18 ± 1.86), following six days of supplementation (MC = 9.14 ± 1.89, PL = 7.24 ± 1.75) or one hour post-exercise (MC = 9.63 ± 1.61, PL = 7.97 ± 1.92) for treatment F = 0.26, p = 0.62; for time F = 0.45, p = 0.64; or treatment by time interaction F = 2.28, p = 0.13. Muscle oxygenation was not different between treatments for the right or left vastus lateralis, F = 0.68, p = 0.81 nor was time to respiratory compensation point (minutes) (MC = 18.40 ± 1.48, PL = 17.16 ± 1.78) F = 0.52, p = 0.60. MC supplement ingestion does not alter blood nitrate levels. Conclusion: Short-term MC ingestion does not increase muscle oxygenation during cycling exercise nor does it change slow-component [Formula: see text]O2 kinetics.


Assuntos
Suplementos Nutricionais , Músculo Esquelético , Estudos Cross-Over , Método Duplo-Cego , Exercício Físico , Humanos , Masculino
13.
J Diet Suppl ; 17(3): 309-320, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30887868

RESUMO

The purpose of the present study was to examine whether 14 days of supplementation with maritime pine extract leading up to and following an exercise test would increase performance and reduce biomarkers associated with muscle damage, inflammation, and oxidative stress. The study used a double-blind, placebo-controlled, cross-over design. Twenty apparently healthy young male participants ingested either 800 mg pine bark extract or placebo for 14 days prior to the first exercise trial and for 2 days postexercise. On the exercise day, participants submitted a pre-exercise blood sample then completed a VO2 peak test until volitional failure. A postexercise blood sample was collected 1 hour after completion of exercise. Participants returned at 24 and 48 hours after the exercise testing for measures of muscle pain in the lower body using an algometer. Participants then had a 7-day washout period before beginning to cross over to the alternate treatment. Analysis via ordinal regression demonstrated a significant difference in oxidative stress in the maritime pine extract group compared to placebo (ChiSq = 2.63; p = 0.045). Maritime pine extract was effective at affording protection from oxidative stress postexercise. Further work should be undertaken to evaluate the findings with other exercise modes or in participants with known metabolic syndrome.


Assuntos
Antioxidantes/farmacologia , Flavonoides/farmacologia , Inflamação , Mialgia , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/farmacologia , Adulto , Biomarcadores/sangue , Estudos Cross-Over , Método Duplo-Cego , Teste de Esforço , Humanos , Masculino , Músculo Esquelético/efeitos dos fármacos , Consumo de Oxigênio , Estados Unidos , Adulto Jovem
14.
J Therm Biol ; 85: 102399, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31657740

RESUMO

It is important to identify potential underlying factors that can affect the variability of resting metabolic rate (RMR) measurements. The RMRs of 20 college-aged men were tested twice in stable environmental conditions, with each measurement separated by 40 min. Skin temperature, core temperature, and inter-beat interval were monitored throughout the study as identified factors that could affect RMR measurements. Since environmental conditions in a clinic or laboratory can vary, skin temperature and core temperature can be affected which may affect RMR. Similarly, prior physical activity, stress, sleep, and caffeine intake can affect inter-beat interval and may be a co-variable affecting RMR. Higher RMR measurements were compared to lower RMR measurements. RMR for the higher trial was 2068 ±â€¯66 kcal/day, the lower trial was 1975 ±â€¯65 kcal/day (t = 4.23; p < 0.01). Core temperature for higher trial was 37.1 ±â€¯0.1 °C, the lower trial was 36.8 ±â€¯0.1 °C (s = 105.00; p < 0.01). Skin temperature measurements were significantly different for the anterior bicep site (t = -2.52; p = 0.02), but not for any other site. Inter-beat interval for the higher measurement was 1038 ±â€¯33 ms, the lower measurement was 998 ±â€¯32 ms (t = 3.82; p < 0.01). However, regression analysis found that none of the variables were significant predictors for the higher RMR, lower RMR, or change in RMR. While the factors affecting RMR measurement variability remain unclear, the results suggest that typical fluctuations in core temperature, skin temperature, and inter-beat interval do not effectively predict changes in RMR in a thermoneutral environment.


Assuntos
Metabolismo Basal , Temperatura Corporal , Temperatura , Adulto , Calorimetria Indireta , Frequência Cardíaca , Humanos , Masculino , Adulto Jovem
15.
J Hum Kinet ; 64: 77-85, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30429901

RESUMO

Suspension exercise systems are being used in strength and conditioning facilities, fitness centers, rehabilitation centers and home gyms. Though some evidence exists regarding the impact of training with these systems, more work is needed for a better understanding. The purpose of the present investigation was to examine the acute effects of an exercise session with 2 (hands only) and 4 straps (hands and feet) in the push-up exercise compared to a work-matched bench press exercise session. The participants for this repeated measures, cross-over investigation were 18 healthy college-aged males (age: 24.8 ± 3.5 yrs, body mass: 81.8 ± 7.8 kg, body height: 178.9 ± 4.5 cm). The conditions were 6 sets of 10 repetitions of suspension push-ups using two straps (DUAL) for the hands, fours straps (QUAD) for hands and feet and a traditional bench press exercise matched to the average resistance during the suspension push-up. The participants performed all repetitions at a controlled cadence. Expired gases, and heart rate were monitored continuously during the exercise session. Pre and post exercise saliva samples were collected to quantify changes in testosterone and cortisol. Upper body isometric strength tests ( UBIST) were performed (Post, 1 hr, 24 hr, 48 hr) to evaluate changes in force production during recovery. Data analysis via repeated measures ANOVA revealed a significant trend for increased oxygen consumption in the QUAD condition compared to the bench press (p = 0.019). Additionally, both suspension conditions resulted in a reduced respiratory exchange ratio as compared to the bench press (p < 0.05). A significant main effect was noted for time in all conditions regarding isometric strength (p < 0.001), but no differences between conditions were revealed. Testosterone and cortisol responses did not differ between conditions. Based upon these data, it appears that when matched for work, suspension exercise results in equivalent reductions in muscle force, but greater oxygen consumption compared to isotonic exercise.

16.
Eur J Sport Sci ; 18(3): 357-366, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29364063

RESUMO

Mouth rinsing using a carbohydrate (CHO) solution has been suggested to improve physical performance in fasting participants. This study examined the effects of CHO mouth rinsing during Ramadan fasting on running time to exhaustion and on peak treadmill speed (Vpeak). In a counterbalanced crossover design, 18 sub-elite male runners (Age: 21 ± 2 years, Weight: 68.1 ± 5.7 kg, VO2max: 55.4 ± 4.8 ml/kg/min) who observed Ramadan completed a familiarization trial and three experimental trials. The three trials included rinsing and expectorating a 25 mL bolus of either a 7.5% sucrose solution (CHO), a flavour and taste matched placebo solution (PLA) for 10 s, or no rinse (CON). The treatments were performed prior to an incremental treadmill test to exhaustion. Three-day dietary and exercise records were obtained on two occasions and analysed. Anthropometric characteristics were obtained and recorded for all participants. A main effect for mouth rinse on peak velocity (Vpeak) (CHO: 17.6 ± 1.5 km/h; PLA: 17.1 ± 1.4 km/h; CON: 16.7 ± 1.2 km/h; P < .001, ηp2 = 0.49) and time to exhaustion (CHO: 1282.0 ± 121.3 s; PLA: 1258.1 ± 113.4 s; CON: 1228.7 ± 98.5 s; P = .002, ηp2 = 0.41) was detected, with CHO significantly higher than PLA (P < .05) and CON (P < .05). Oxygen consumption, heart rate, respiratory exchange ratio, and rating of perceived exertion were not significantly different between treatments or trials (P > .05). Energy availability from dietary analysis, body weight, and fat-free mass did not change during the last two weeks of Ramadan (P > .05). This study concludes that carbohydrate mouth rinsing improves running time to exhaustion and peak treadmill speed under Ramadan fasting conditions.


Assuntos
Carboidratos da Dieta/farmacologia , Jejum , Fadiga , Antissépticos Bucais/farmacologia , Resistência Física , Corrida/fisiologia , Estudos Cross-Over , Carboidratos da Dieta/administração & dosagem , Teste de Esforço , Humanos , Islamismo , Jordânia , Masculino , Consumo de Oxigênio , Adulto Jovem
17.
J Int Soc Sports Nutr ; 14: 39, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29042830

RESUMO

BACKGROUND: Recent studies have suggested that alpha glycerylphosphorylcholine (A-GPC) may be an effective ergogenic aid. The present study was designed to assess the efficacy of two doses of A-GPC in comparison to placebo and caffeine for increasing countermovement jump performance, isometric strength, and psychomotor function. METHODS: Forty-eight healthy, college aged males volunteered for the present study and underwent baseline assessment of countermovement jump (CMJ), isometric mid thigh pull (IMTP), upper body isometric strength test (UBIST), and psychomotor vigilance (PVT). Following this assessment participants were randomly assigned to groups consisting of 500 mg A-GPC, 250 mg A-GPC, 200 mg Caffeine or Placebo taken daily. Blood samples were collected 1 h and 2 h post initial dose to quantify serum free choline and thyroid stimulating hormone then subjects returned after 7 days of supplementation to repeat CMJ, IMTP, UBIST and PVT. RESULTS: No differences were noted between groups for IMTP, UBIST or PVT performance. Serum free choline was found to be elevated in the two A-GPC groups as compared to placebo (132% and 59% respectively). Serum TSH was found to be significantly depressed in the 500 mg A-GPC group compared to other treatments (p < 0.04). Group differences were noted for maximum velocity and maximum mechanical power on the CMJ (p < 0.05) with the 250 mg A-GPC group demonstrating the greatest improvements in result. CONCLUSIONS: Based upon this evidence, and previous evidence regarding A-GPC, it should be considered as an emerging ergogenic supplement.


Assuntos
Desempenho Atlético/fisiologia , Suplementos Nutricionais , Glicerilfosforilcolina/administração & dosagem , Glicerilfosforilcolina/farmacologia , Desempenho Psicomotor/efeitos dos fármacos , Método Duplo-Cego , Voluntários Saudáveis , Humanos , Contração Isométrica/efeitos dos fármacos , Contração Isométrica/fisiologia , Masculino , Força Muscular/efeitos dos fármacos , Força Muscular/fisiologia , Desempenho Psicomotor/fisiologia , Reprodutibilidade dos Testes , Fenômenos Fisiológicos da Nutrição Esportiva , Adulto Jovem
18.
Eur J Clin Invest ; 47(11): 853-859, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28881005

RESUMO

BACKGROUND: Determining predictive markers for the development of type 2 diabetes (T2D), particularly in young individuals, offers immense potential benefits in preventative medicine. Previous research examining serum fibroblast growth factor 21 (FGF21) in humans has revealed equivocal relationships with clinical markers of metabolic dysfunction. However, it is unknown to what extent, if any, first-degree family history of T2D (mother or father of the participant diagnosed with T2D) level affects serum FGF21 levels. The aim of this study was to determine whether in healthy individuals with FH+ (n = 18) and without FH- (n = 17) a family history of T2D affects serum FGF21. MATERIALS AND METHODS: Fasting serum and clinical, metabolic and anthropometric measures were determined using a cross-sectional design. RESULTS: Differences between groups for FGF21 were not significant (FH+ = 266 pg/mL ± 51·4, FH = 180 pg/mL ± 29; Z = 0·97, P = 0·33). Adiponectin values were lower in FH+ (8·81 µg/mL ± 2·14) compared to FH- (10·65 µg/mL ± 1·44; F = 8·83, P = 0·01). Resistin was negatively correlated with FGF21 for all participants (r = -0·38, P = 0·03), but no other clinical, metabolic, or serum markers were predictive for serum FGF21 in FH+ or FH-. CONCLUSIONS: Serum FGF21 is not significantly different between FH+ and FH- in young, healthy individuals. Based upon the data of this pilot study, it is unclear whether serum FGF21 can be used as a stand-alone predictive marker for T2D in healthy subjects.


Assuntos
Diabetes Mellitus Tipo 2/genética , Fatores de Crescimento de Fibroblastos/metabolismo , Adiponectina/metabolismo , Adolescente , Adulto , Análise de Variância , Biomarcadores/metabolismo , Diabetes Mellitus Tipo 2/sangue , Feminino , Voluntários Saudáveis , Humanos , Masculino , Linhagem , Adulto Jovem
19.
J Hum Kinet ; 57: 73-83, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28713460

RESUMO

The purpose of this study was to determine the appropriateness of using an elastic hamstring assistance device to reduce perceived levels of soreness, increase isometric strength, increase passive range of motion, and decrease biomarkers of muscle damage after eccentric exercise, specifically, downhill running This study was conducted in a university exercise physiology laboratory placing sixteen apparently healthy males (X = 21.6 ± 2.5 years) into two groups using a pre-test/post-test design. Pre-intervention measures taken included participants' body height, body mass, body fat, capillary blood samples, VO2max, isometric hamstring strength at 45 and 90 degrees of flexion and passive hamstring range of motion. Post-intervention measures included blood biomarkers, passive range of motion, the perceived level of soreness and isometric strength. An analysis of normality of data was initially conducted followed by multivariate analysis of variance (MANOVA) of hamstring strength at 45 and 90 degrees of flexion, blood myoglobin and passive range of motion of the hamstrings. Statistically significant changes were noted in subject-perceived muscle soreness and isometric strength at 90 degrees at the 24-hour post-exercise trial measure between the two groups. Results would suggest the findings could be explained by the decrease in muscle soreness from utilizing the device during the exercise trial. Further research should be conducted to address sample size issues and to determine if the results are comparable on different surfaces.

20.
J Diet Suppl ; 14(6): 697-705, 2017 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-28429998

RESUMO

There is a limited supply of sport nutrition supplements currently available for vegan or vegetarian athletes. In addition, the efficacy of a vegan or vegetarian pre-workout supplement that does not contain any processed ingredients or stimulants is currently unknown. The purpose of the current study was to examine the effects of an unprocessed vegan pre-workout supplement on high-intensity cycling performance. Participants completed three separate cycling trials following the consumption of a vegan pre-workout supplement, an isocaloric processed supplement, or a zero-calorie placebo supplement. Each supplement was consumed 30 minutes prior to each trial, and each cycling trial was separated by a minimum of 72 hours. Supplements were administered using a randomized, double-blind cross-over design. Each cycling trial was performed at a workload equal to 80% VO2peak until exhaustion. The average time in seconds (s) until exhaustion values for the vegan, isocaloric, and zero-calorie supplements were 482 ± 163, 480 ± 157, and 496 ± 238, respectively. Consumption of the vegan supplement did not significantly improve performance compared to an isocaloric and zero-calorie supplement (F = 0.12, p =.89). The results of this study indicate that individuals who choose a vegan pre-workout supplement (over an isocaloric or zero-calorie product) will not experience any acute decrements or ergogenic benefits in cycling performance. Although the present study does not support performance benefits of the tested vegan pre-workout supplement before cycling, additional research examining various exercise intensities and modalities is warranted.


Assuntos
Ciclismo , Suplementos Nutricionais , Resistência Física , Fenômenos Fisiológicos da Nutrição Esportiva , Veganos , Atletas , Índice de Massa Corporal , Estudos Cross-Over , Dieta , Método Duplo-Cego , Exercício Físico , Humanos , Masculino , Músculo Esquelético/fisiologia , Consumo de Oxigênio , Vegetarianos , Adulto Jovem
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