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1.
Mymensingh Med J ; 29(1): 169-176, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31915354

RESUMO

This cross sectional analytical type of study was conducted at department of Anatomy, Dhaka Medical College, Dhaka, Bangladesh from July 2015 to June 2016 on 50 adult Bangladeshi male sprinters (Group A) and 50 adult Bangladeshi male cricket batsman (Group B). Sample collection was done by convenient purposive sampling technique. History of any injury of hand during playing was excluded to construct standard measurement. Hand breadth was measured with the help of slide calipers. Hand grip strength Dynamometer was used to measure the hand grip strength. Paired Student's 't' test, unpaired student's 't' test and Pearson's correlation coefficient test were done for statistical analysis of the result. The aim of the present study was to determine hand breadth and average hand grip strength of Bangladeshi male cricket batsman to find out correlation between them that may be used as a baseline for other professions as well for future research in our country. The mean right and left hand grip strength was significantly higher in the cricket batsman than in the sprinters. The mean right and left hand breadth was found to be significantly higher in the cricket batsman than in the sprinters. Right and left hand grip strength showed significant positive correlation with hand breadth in both hand. The study findings suggest that regular physical exercise and training increase hand grip strength.


Assuntos
Força da Mão , Mãos/anatomia & histologia , Adulto , Animais , Antropometria , Grupo com Ancestrais do Continente Asiático , Atletas , Bangladesh , Estudos Transversais , Grupos Étnicos , Humanos , Masculino , Dinamômetro de Força Muscular , Corrida
2.
Adv Exp Med Biol ; 1232: 245-251, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893417

RESUMO

Skeletal muscle metabolic function is known to respond positively to endurance exercise interventions, such as marathon training. Studies investigating skeletal muscle have typically used muscle biopsy samples or magnetic resonance spectroscopy (MRS) to interrogate metabolic function. We aimed to non-invasively detect exercise-training-induced improvements in muscle function using broadband near-infrared spectroscopy (NIRS). We used NIRS to determine concentration changes in oxygenated haemoglobin (HbO2) and the oxidation state of cytochrome-c-oxidase (oxCCO) in gastrocnemius during arterial occlusion in 14 volunteers. We also used a cardio-pulmonary exercise test (CPET) to assess peak total body oxygen uptake (peakVO2; a measure of fitness). Measurements were made at baseline (BL) which was prior to a period of at least 16 weeks of training for the 2017 London Marathon, and then within 3 weeks after completion of the marathon, follow-up (FU). We observed an increase in locally measured muscle oxygen consumption and rate of oxCCO concentration change, but not in cardio-respiratory fitness measured as whole-body peak oxygen consumption (peakVO2).


Assuntos
Músculo Esquelético , Consumo de Oxigênio , Corrida , Espectroscopia de Luz Próxima ao Infravermelho , Adulto , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Feminino , Humanos , Masculino , Músculo Esquelético/metabolismo , Oxiemoglobinas/metabolismo
3.
J Sports Sci ; 38(2): 187-191, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31783721

RESUMO

The popularity of pre-workout supplements is rising amongst professional athletes and fitness enthusiasts. Despite increased usage, the safety profile of pre-workout supplements is likely to be not well understood. Additionally, many different brands use various undisclosed proprietary blends of active ingredients creating safety regulation difficulties. This lack of oversight could prove unsafe for certain patients. This patient MK is a 33-year-old healthy housewife who presented with central chest tightness, pre-syncope and mild dyspnoea to the emergency department via ambulance. The presentation was in the context of recent strenuous exercise and ingestion of a pre-workout supplement (Alpha Lean-7). Most striking in her presentation was a troponin rise of 50 ng/L, while not very high it is unusual given her lack of cardiac risk factors. She had a 3-day uneventful admission with a downtrending troponin prior to discharge. This case highlights the possible dangers of pharmacologically active ingredients in pre-workout supplements.


Assuntos
Suplementos Nutricionais/efeitos adversos , Isquemia Miocárdica/etiologia , Corrida/fisiologia , Adulto , Cafeína/efeitos adversos , Estimulantes do Sistema Nervoso Central/efeitos adversos , Dispneia/etiologia , Serviço Hospitalar de Emergência , Feminino , Produtos de Degradação da Fibrina e do Fibrinogênio/metabolismo , Humanos , Isquemia Miocárdica/sangue , Síncope/etiologia , Troponina/sangue
4.
Sports Health ; 12(1): 74-79, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31642726

RESUMO

BACKGROUND: Lower extremity overuse injuries are common among runners, especially first-time marathoners. Hip abductor and quadriceps strengthening is often recommended to reduce running-related injuries. HYPOTHESIS: A 12-week strength training program would decrease the rate of overuse injuries resulting in marathon noncompletion and improve race finishing time. STUDY DESIGN: Randomized trial. LEVEL OF EVIDENCE: Level 2. METHODS: Twelve weeks before the New York City Marathon, first-time marathon runners age 18 years and older were randomized into a strength training group or an observation group. The strength training group was instructed to perform a 10-minute program 3 times weekly using written and video instruction. This program targeted the quadriceps, hip abductor, and core muscle groups. Injuries were self-reported through biweekly surveys, with major injuries being those that resulted in marathon noncompletion and minor injuries being those that impaired training or race performance. RESULTS: A total of 720 runners were enrolled (mean age, 35.9 ± 9.4 years; 69.4% female), of whom 583 runners started the marathon and 579 completed it. The incidence of major injury was 8.9% and minor injury was 48.5%. Fifty two of 64 major injuries were overuse, of which 20 were bone stress injuries. The incidence of overuse injury resulting in marathon noncompletion was 7.1% in the strength training group and 7.3% in the observation group (risk ratio, 0.97; 95% CI, 0.57-1.63; P = 0.90). The mean finishing time was 5 hours 1 ± 60 minutes in the strength training group and 4 hours 58 ± 55 minutes in the observation group (P = 0.35). CONCLUSION: There is a high prevalence of injury among first-time marathon runners, but this self-directed strength training program did not decrease overuse injury incidence resulting in marathon noncompletion. CLINICAL RELEVANCE: Prevention strategies such as strength training need to be developed and evaluated through clinical trials to reduce the high prevalence of overuse injuries in runners, especially for high-risk populations such as first-time marathon runners.


Assuntos
Transtornos Traumáticos Cumulativos/prevenção & controle , Extremidade Inferior/lesões , Força Muscular/fisiologia , Resistência Física/fisiologia , Treinamento de Resistência , Corrida/lesões , Adulto , Transtornos Traumáticos Cumulativos/epidemiologia , Transtornos Traumáticos Cumulativos/fisiopatologia , Humanos , Cidade de Nova Iorque/epidemiologia , Fatores de Risco , Corrida/fisiologia
5.
J Sports Sci ; 38(1): 6-12, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31603027

RESUMO

This study aimed to examine the characteristics of electromyography (EMG) and kinematics of the supporting leg affecting energy cost while running at incline, level, and decline slopes. Twelve male Japanese middle- and long-distance runners volunteered for this study. The subjects were asked to run at 13.5 km·h-1 on a treadmill under three slope conditions. Sagittal plane kinematics and the EMG of the lower limb muscles, respiratory gases were recorded. Energy cost differed significantly between slopes, being the lowest in decline slope and the greatest in incline slope. Integrated EMG (iEMG) of leg extensor muscles was greater in the incline slope than in the decline slope, and iEMG of the gastrocnemius and soleus muscles correlated positively with energy cost. The knee and ankle joint kinematics were associated with energy cost during running. In incline slope, the knee and ankle joints were more extended (plantarflexed) to lift the body. These movements may disturb the coordination between the ankle and knee joints. The gastrocnemius muscle would do greater mechanical work to plantarflex the ankle joint rather than transfer mechanical energy as well as greater mechanical work of mono-articular muscles. These muscular activities would increase energy cost.


Assuntos
Metabolismo Energético/fisiologia , Extremidade Inferior/fisiologia , Corrida/fisiologia , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , Eletromiografia , Teste de Esforço/métodos , Articulação do Quadril/fisiologia , Humanos , Articulação do Joelho/fisiologia , Masculino , Movimento/fisiologia , Músculo Esquelético/fisiologia , Troca Gasosa Pulmonar/fisiologia , Adulto Jovem
6.
J Sports Sci ; 38(1): 53-61, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31623521

RESUMO

This study aimed 1) to examine the validity of inertial measurement unit (IMU)-based hip flexion strength test, and 2) to investigate the hip flexion strength test as an indicator of sprint performance. Eight males performed five repeated hip flexion-extension, while leg motion was recorded using an IMU and a motion capture system (Mocap). As the second experiment, 24 male athletes performed the IMU-based hip flexion strength test and sprinted 50 m, during which step-to-step ground reaction force (GRF) was recorded. The strength test variables were calculated using IMU and Mocap data including angular impulse, mean moment, and positive and negative work and power. Using GRF data, step-to-step spatiotemporal variables were obtained. The results showed high intra-class correlation coefficient and correlation coefficient (both >0.909) between IMU and Mocap for angular impulse, mean moment, positive work and power. The hip flexion mean moment showed significant correlation with running speed from the 5th-8th step section onwards. The angular impulse, mean moment, positive work and power are recommended to be used for the IMU-based hip flexion strength test variables in terms of accuracy and validity. Moreover, the proposed IMU-based hip flexion strength test can be an indicator for better sprinting performance.


Assuntos
Desempenho Atlético/fisiologia , Teste de Esforço/métodos , Quadril/fisiologia , Força Muscular/fisiologia , Corrida/fisiologia , Aceleração , Adulto , Fenômenos Biomecânicos , Humanos , Masculino , Reprodutibilidade dos Testes , Estudos de Tempo e Movimento , Adulto Jovem
7.
J Sports Sci ; 38(1): 29-37, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31631783

RESUMO

This study investigated the role of reactive and eccentric strength in stiffness regulation during maximum velocity sprinting (Vmax) in team sport athletes compared with highly trained sprinters. Thirteen team sport athletes and eleven highly trained sprinters were recruited. Vmax was measured using radar, and stiffness regulation was inferred from modelled vertical and leg spring stiffness. Reactive strength (RSI) was determined from a 0.50 m drop jump, and an eccentric back squat was used to assess maximum isoinertial eccentric force. Trained sprinters attained a higher Vmax than team sport athletes, partly due to a briefer contact time and higher vertical stiffness. Trained sprinters exhibited a moderately higher RSI via the attainment of a briefer and more forceful ground contact phase, while RSI also demonstrated large to very large associations with vertical stiffness and Vmax, respectively. Isoinertial eccentric force was largely correlated with Vmax, but only moderately correlated with vertical stiffness. Reactive and eccentric strength contribute to the ability to regulate leg spring stiffness at Vmax, and subsequently, the attainment of faster sprinting speeds in highly trained sprinters versus team sport athletes. However, stiffness regulation appears to be a task-specific neuromuscular skill, reinforcing the importance of specificity in the development of sprint performance.


Assuntos
Desempenho Atlético/fisiologia , Extremidade Inferior/fisiologia , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Condicionamento Físico Humano , Corrida/fisiologia , Aceleração , Adulto , Fenômenos Biomecânicos , Estudos Transversais , Feminino , Humanos , Masculino , Adulto Jovem
8.
Unfallchirurg ; 123(Suppl 1): 15-19, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31098646

RESUMO

Medial tibial stress syndrome is a common overuse injury in jumping and running athletes. It is defined as exercise-induced pain along the distal posteromedial border of the tibia and the presence of recognisable pain on palpation over a length of 5 or more centimetres. This overview article provides an evidence update on the diagnosis and management of athletes with medial tibial stress syndrome.


Assuntos
Transtornos Traumáticos Cumulativos , Síndrome da Tensão Tibial Medial/diagnóstico , Corrida , Humanos , Síndrome da Tensão Tibial Medial/terapia , Dor , Tíbia
9.
J Sports Sci ; 38(2): 214-230, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31795815

RESUMO

Injuries and lack of motivation are common reasons for discontinuation of running. Real-time feedback from wearables can reduce discontinuation by reducing injury risk and improving performance and motivation. There are however several limitations and challenges with current real-time feedback approaches. We discuss these limitations and challenges and provide a framework to optimise real-time feedback for reducing injury risk and improving performance and motivation. We first discuss the reasons why individuals run and propose that feedback targeted to these reasons can improve motivation and compliance. Secondly, we review the association of running technique and running workload with injuries and performance and we elaborate how real-time feedback on running technique and workload can be applied to reduce injury risk and improve performance and motivation. We also review different feedback modalities and motor learning feedback strategies and their application to real-time feedback. Briefly, the most effective feedback modality and frequency differ between variables and individuals, but a combination of modalities and mixture of real-time and delayed feedback is most effective. Moreover, feedback promoting perceived competence, autonomy and an external focus can improve motivation, learning and performance. Although the focus is on wearables, the challenges and practical applications are also relevant for laboratory-based gait retraining.


Assuntos
Desempenho Atlético/fisiologia , Desempenho Atlético/psicologia , Retroalimentação , Monitores de Aptidão Física , Motivação , Corrida/fisiologia , Corrida/psicologia , Traumatismos em Atletas/prevenção & controle , Fenômenos Biomecânicos , Marcha/fisiologia , Humanos , Percepção , Corrida/lesões
10.
Br J Sports Med ; 54(1): 51-57, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31511232

RESUMO

BACKGROUND: In randomised controlled trials (RCTs) of interventions that aim to prevent sports injuries, the intention-to-treat principle is a recommended analysis method and one emphasised in the Consolidated Standards of Reporting Trials (CONSORT) statement that guides quality reporting of such trials. However, an important element of injury prevention trials-compliance with the intervention-is not always well-reported. The purpose of the present educational review was to describe the compliance during follow-up in eight large-scale sports injury trials and address compliance issues that surfaced. Then, we discuss how readers and researchers might consider interpreting results from intention-to-treat analyses depending on the observed compliance with the intervention. METHODS: Data from seven different randomised trials and one experimental study were included in the present educational review. In the trials that used training programme as an intervention, we defined full compliance as having completed the programme within ±10% of the prescribed running distance (ProjectRun21 (PR21), RUNCLEVER, Start 2 Run) or time-spent-running in minutes (Groningen Novice Running (GRONORUN)) for each planned training session. In the trials using running shoes as the intervention, full compliance was defined as wearing the prescribed running shoe in all running sessions the participants completed during follow-up. RESULTS: In the trials that used a running programme intervention, the number of participants who had been fully compliant was 0 of 839 (0%) at 24-week follow-up in RUNCLEVER, 0 of 612 (0%) at 14-week follow-up in PR21, 12 of 56 (21%) at 4-week follow-up in Start 2 Run and 8 of 532 (1%) at 8-week follow-up in GRONORUN. In the trials using a shoe-related intervention, the numbers of participants who had been fully compliant at the end of follow-up were 207 of 304 (68%) in the 21 week trial, and 322 of 423 (76%), 521 of 577 (90%), 753 of 874 (86%) after 24-week follow-up in the other three trials, respectively. CONCLUSION: The proportion of runners compliant at the end of follow-up ranged from 0% to 21% in the trials using running programme as intervention and from 68% to 90% in the trials using running shoes as intervention. We encourage sports injury researchers to carefully assess and report the compliance with intervention in their articles, use appropriate analytical approaches and take compliance into account when drawing study conclusions. In studies with low compliance, G-estimation may be a useful analytical tool provided certain assumptions are met.


Assuntos
Traumatismos em Atletas/prevenção & controle , Cooperação do Paciente , Condicionamento Físico Humano/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto/normas , Interpretação Estatística de Dados , Humanos , Análise de Intenção de Tratamento , Ensaios Clínicos Controlados Aleatórios como Assunto/estatística & dados numéricos , Corrida/lesões , Sapatos
12.
Sports Biomech ; 19(1): 120-140, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31456487

RESUMO

Dynamic stability of locomotion plays an important role in running injuries, particularly during trail running where ankle injuries occur frequently. Several studies have investigated dynamic stability of locomotion using wearable accelerometer measurements. However, no study has reviewed how dynamic stability of locomotion is quantified using accelerometry. Therefore, the present review aims to synthetise the methods and findings of studies investigating stability related parameters measured by accelerometry, during locomotion on various surfaces, and among asymptomatic participants. A systematic search of studies associated with locomotion was conducted. Only studies including assessment of dynamic stability parameters based on accelerometry, including at least one group of asymptomatic participants, and conditions that occur during trail running were considered relevant for this review. Consequently, all retrieved studies used a non-obstructive portable accelerometer or an inertial measurement unit. Fifteen studies used a single tri-axial accelerometer placed above the lumbar region allowing outdoor recordings. From trunk accelerations, a combination of index of cycle repeatability and signal dispersion can adequately be used to assess dynamic stability. However, as most studies included indoor conditions, studies addressing the biomechanics of trail running in outdoor conditions are warranted.


Assuntos
Acelerometria/métodos , Corrida/fisiologia , Caminhada/fisiologia , Fenômenos Biomecânicos , Meio Ambiente , Marcha/fisiologia , Humanos , Fatores de Risco , Corrida/lesões , Caminhada/lesões
13.
Equine Vet J ; 52(1): 52-58, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30989701

RESUMO

BACKGROUND: Epiglottic entrapment can occur in yearling Thoroughbreds (TB); however, race performance following surgical correction is unknown. OBJECTIVES: To determine the race performance of horses treated surgically for epiglottic entrapment as yearlings as compared to an untreated cohort. A second objective was to identify risk factors for treated horses not racing post-operatively. STUDY DESIGN: Retrospective cohort and case-control studies. METHODS: Medical (1989-2014) and race records of 66 treated TB racehorses were reviewed. Observed abnormalities on pre- and post-operative endoscopic images and surgical method were recorded. Race records (EquineLine) were recorded. Racing performance of treated yearling TBs and two of their maternal half-siblings, which were used as the untreated cohort, was evaluated in a cohort study. A case-control study was used to investigate risk factors for not racing post-operatively among treated horses. Quarterly starts and earnings were compared to an untreated cohort. Survival analysis was used to assess career longevity. Rates of racing and earnings were compared between groups using Poisson and negative binomial regression respectively. Associations between clinical variables and not racing post-surgery were evaluated using logistic regression. RESULTS: Sixty-six treated horses were identified, 65 of which had at least one half-sibling. Proportions of horses that raced were similar for treated and maternal cohorts (70.0 vs. 70.8%, P = 0.9). Treated horses performed similarly to untreated horses. In treated horses, epiglottic entrapment with abnormal right arytenoid movement was associated with never racing (OR 15.40, 95% CI 1.64-144.23, P = 0.02). More females were affected by epiglottic entrapment than males (47/66 vs. 19/66 respectively, P<0.001). MAIN LIMITATIONS: The retrospective design over a prolonged period of time with cases obtained from a single hospital population. Low case numbers likely influenced the outcome of the multivariable analysis. CONCLUSIONS: Thoroughbred racehorses treated in their yearling year for epiglottic entrapment had no differences in performance variables compared to their untreated cohort. Epiglottic entrapment with abnormal right arytenoid movement might decrease odds of racing post-operatively.


Assuntos
Epiglote/cirurgia , Doenças dos Cavalos/cirurgia , Animais , Estudos de Casos e Controles , Estudos de Coortes , Feminino , Cavalos , Doenças da Laringe/veterinária , Masculino , Condicionamento Físico Animal , Estudos Retrospectivos , Corrida , Esportes
14.
Chin J Physiol ; 62(6): 279-284, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31793465

RESUMO

The aim of this study was to investigate the plasma dopamine and serum serotonin levels in humans with and without caffeine (CAFF) ingestion during treadmill running exercise. Thirty male volunteers participated in the randomized experiment involving two groups: CON (n = 15, 200 mL of tap water) versus CAFF (n = 15, 3 mg/kg CAFF and 200 mL tap water). After treadmill running, the dopamine level was significantly increased in the CAFF group (P < 0.01) and was significantly higher than in the CON group (P < 0.01). Serotonin was significantly increased in both groups after treadmill running (P < 0.05). However, serotonin levels showed no significant statistical difference between the groups. Prolactin and cortisol were significantly increased in both groups after treadmill running (P < 0.01). However, there was no significant statistical difference between groups. ß-endorphin level was significantly increased in the CAFF group at after treadmill running (P < 0.01) and was significantly higher than in CON after treadmill running (P < 0.01). In conclusion, 3 mg/kg CAFF ingestion before treadmill running stimulated dopamine release without inhibiting serotonin, which may reduce central fatigue.


Assuntos
Corrida , Cafeína , Dopamina , Teste de Esforço , Humanos , Masculino , Homens
16.
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 na Dieta/administração & dosagem , Humanos , Resistência Física , Corrida/classificação , Sociedades
17.
J Sports Med Phys Fitness ; 59(10): 1601-1607, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31694361

RESUMO

BACKGROUND: Outdoor exercise often proceeds in rainy conditions. However, there are very few studies reporting the physiological effects of cold with rain or wet-cold exposure on humans during exercise. The purpose of this study was to investigate the effects of rain on physiological responses during running exercise at 80% V̇Omax in the cold. METHODS: Twelve healthy men (age: 21.7±3.3 years; height: 1.760±0.085 m; body weight: 68.8±7.1 kg; maximal oxygen consumption: 67.3±5.00 mL/kg/min) exercised on a treadmill at 80% V̇Omax intensity for 60 minutes with rain (RAIN) or not (CON) at 5 °C. RESULTS: Rectal temperature was significantly lower in RAIN than in CON at 10, 40, 50, and 60 minutes (P<0.05). Mean weighted skin temperature was significantly lower in RAIN than in CON during exercise (P<0.05). Oxygen consumption and rating of perceived exertion were significantly higher in RAIN than in CON at 50 and 60 minutes (P<0.05). Plasma lactate was significantly higher in RAIN than in CON at 10 minutes and from 40 to 60 minutes (P<0.05). Plasma norepinephrine levels were significantly higher in RAIN than in CON at 10 minutes and from 40 to 60 minutes (P<0.05). CONCLUSIONS: These results suggest that rain increased heat loss during the early phase of exercise in the cold, then heat production increased and transiently suppressed cold stress. However, with time, body heat loss intensified due to increasing wet area, and then energy expenditure and plasma lactate increased due to cold stress. Therefore, rain may decrease exercise performance and affect sport safety.


Assuntos
Temperatura Baixa/efeitos adversos , Metabolismo Energético/fisiologia , Chuva , Corrida/fisiologia , Adolescente , Adulto , Regulação da Temperatura Corporal/fisiologia , Estudos de Casos e Controles , Teste de Esforço/métodos , Humanos , Ácido Láctico/sangue , Masculino , Consumo de Oxigênio/fisiologia , Temperatura Cutânea , Adulto Jovem
18.
J Sports Med Phys Fitness ; 59(10): 1684-1690, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31694362

RESUMO

BACKGROUND: Athletes in jumping and running sports have a high incidence of Achilles tendon (AT) injuries. We compared AT loading during jumping and landing phases in anteroposterior (AP) and mediolateral (ML) directions. METHODS: Sixteen males (age: 21.6±1.8 years, height: 178.4±6.4 cm, weight: 76.4±11.2 kg) performed single leg AP and ML jump-landings during both propulsive (jump) and braking (land) phases. Inverse dynamics and static optimization were used to determine muscle forces. AT cross sectional area was measured with ultrasound. AT force was divided by cross sectional area to determine stress while strain was determined from previous data. Two-way repeated measures analysis of variance (α=0.05) compared several variables (vertical ground reaction force (VGRF), ankle and knee angle, ankle joint muscle moment arm, external ankle moment arm, AT tendon force, stress, and strain) between movements (jump-landings) and directions (AP/ML). RESULTS: AT loading was higher during jump than land in the ML compared to AP direction. VGRF was higher during land versus jump with no direction effect (AP/ML). An interaction showed a higher VGRF during the AP land and ML jump. The ankle joint moment arm was lower in jump and AP direction at peak tendon stress. External ankle moment arm at peak tendon stress was higher in jump and ML direction with an interaction. A larger external ankle moment arm occurred in ML but the change was less in the jump. CONCLUSIONS: Higher tendon loading occurred during the jump and ML direction. This may provide insight into both injuries and rehabilitation efforts.


Assuntos
Tendão do Calcâneo/química , Tendão do Calcâneo/fisiologia , Adulto , Traumatismos do Tornozelo , Articulação do Tornozelo/fisiologia , Atletas , Fenômenos Biomecânicos/fisiologia , Humanos , Articulação do Joelho/fisiologia , Masculino , Movimento , Corrida , Adulto Jovem
19.
J Sports Med Phys Fitness ; 59(10): 1709-1715, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31694363

RESUMO

BACKGROUND: The purpose of this study was to investigate the effects of an Ironman-distance triathlon on bone metabolism. METHODS: Nine recreational male triathletes (39.7±8.2 years old) were voluntarily recruited before a 226-km Ironman triathlon race. Baseline blood samples were collected >1 hour before race. Serial post-race blood sampling time points included immediately (0hr), 1 hour (1hr), 1 day (d), 3 d, and 5 d after the Ironman race. RESULTS: Serum muscle damage markers, serum myoglobin, creatine kinase (CK) and lactate dehydrogenase (LDH) revealed significant post-race peak values immediately, 1hr and 1d after the race, respectively. Except for the marginally higher serum CK and myoglobin at 5d (P=0.01~0.05), all post-race serum levels of muscle damage markers were significantly higher than baseline levels (P<0.01). Serum phosphorus values were significantly higher immediately (0hr) after the Ironman race. Serum osteocalcin, an index specific to bone formation, showed a significant decrease at time points 0hr and 1hr, but a significant increase 1 day after (P<0.01) and a marginal increase 3 and 5 days after (P=0.01~0.05) the race. No difference was shown in type I collagen C-telopeptide (CTX-1), a bone resorption marker. Pearson's correlation between serum osteocalcin and CTX-1 was done at each time point, and significant correlation was shown on the 5th d after the race (r=0.591, P<0.05). CONCLUSIONS: An Ironman-distance contest induces a bone-formative-favoring turnover during the post-race period for amateur male triathletes.


Assuntos
Desempenho Atlético , Osso e Ossos/metabolismo , Adulto , Atletas , Ciclismo/fisiologia , Biomarcadores/análise , Creatina Quinase/sangue , Humanos , L-Lactato Desidrogenase/sangue , Masculino , Pessoa de Meia-Idade , Mioglobina/sangue , Resistência Física/fisiologia , Corrida/fisiologia , Natação/fisiologia
20.
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