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1.
Biol Sport ; 41(1): 201-205, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38188104

RESUMO

The use of Snus, an oral nicotine pouch, is becoming increasingly common in English professional football. As a nicotine product, Snus raises important questions about health and performance for practitioners. The purpose of this short communication is to explain the current regulatory status of Snus, performance relatedeffects, and associated health outcomes. Further, based on player statements and evidence from the general public, we argue that Snus is used as a coping mechanism to deal with the stressors of professional football. Accordingly, the communication concludes with guidance for club-level multidisciplinary interventions to support player welfare, aimed at reducing Snus use as well as future research recommendations.

2.
Biol Sport ; 40(4): 1003-1017, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37867748

RESUMO

Due to the lack of research in real-world sports competitions, the International Olympic Committee, in 2012, called for data characterising athletes' sport and event-specific thermal profiles. Studies clearly demonstrate that elite athletes often attain a core body temperature (Tc) ≥ 40°C without heat-related medical issues during competition. However, practitioners, researchers and ethical review boards continue to cite a Tc ≥ 40°C (and lower) as a threshold where athlete health is impacted (an assumption from laboratory studies). Therefore, this narrative review aims to: (i) summarise and review published data on Tc responses during competitive sport and identify key considerations for practitioners; (ii) establish the incidence of athletes experiencing a Tc ≥ 40°C in competitive sport alongside the incidence of heat illness/heat stroke (EHI/EHS) symptoms; and (iii) discuss the evolution of Tc measurement during competition. The Tc response is primarily based on the physical demands of the sport, environmental conditions, competitive level, and athlete disability. In the reviewed research, 11.9% of athletes presented a Tc ≥ 40°C, with only 2.8% of these experiencing EHI/EHS symptoms, whilst a high Tc ≥ 40°C (n = 172; Tc range 40-41.5°C) occurred across a range of sports and environmental conditions (including some temperate environments). Endurance athletes experienced a Tc ≥ 40°C more than intermittent athletes, but EHI/EHS was similar. This review demonstrates that a Tc ≥ 40°C is not a consistently meaningful risk factor of EHI/EHS symptomology in this sample; therefore, Tc monitoring alongside secondary measures (i.e. general cognitive disturbance and gait disruption) should be incorporated to reduce heat-related injuries during competition.

3.
Br J Sports Med ; 56(8): 439-445, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35165084

RESUMO

PURPOSE: To determine associations between thermal responses, medical events, performance, heat acclimation and health status during a World Athletics Championships in hot-humid conditions. METHODS: From 305 marathon and race-walk starters, 83 completed a preparticipation questionnaire on health and acclimation. Core (Tcore; ingestible pill) and skin (Tskin; thermal camera) temperatures were measured in-competition in 56 and 107 athletes, respectively. 70 in-race medical events were analysed retrospectively. Performance (% personal best) and did not finish (DNF) were extracted from official results. RESULTS: Peak Tcore during competition reached 39.6°C±0.6°C (maximum 41.1°C). Tskin decreased from 32.2°C±1.3°C to 31.0°C±1.4°C during the races (p<0.001). Tcore was not related to DNF (25% of starters) or medical events (p≥0.150), whereas Tskin, Tskin rate of decrease and Tcore-to-Tskin gradient were (p≤0.029). A third of the athletes reported symptoms in the 10 days preceding the event, mainly insomnia, diarrhoea and stomach pain, with diarrhoea (9% of athletes) increasing the risk of in-race medical events (71% vs 17%, p<0.001). Athletes (63%) who performed 5-30 days heat acclimation before the competition: ranked better (18±13 vs 28±13, p=0.009), displayed a lower peak Tcore (39.4°C±0.4°C vs 39.8°C±0.7°C, p=0.044) and larger in-race decrease in Tskin (-1.4°C±1.0°C vs -0.9°C±1.2°C, p=0.060), than non-acclimated athletes. Although not significant, they also showed lower DNF (19% vs 30%, p=0.273) and medical events (19% vs 32%, p=0.179). CONCLUSION: Tskin, Tskin rate of decrease and Tcore-to-Tskin gradient were important indicators of heat tolerance. While heat-acclimated athletes ranked better, recent diarrhoea represented a significant risk factor for DNF and in-race medical events.


Assuntos
Regulação da Temperatura Corporal , Temperatura Alta , Aclimatação , Atletas , Regulação da Temperatura Corporal/fisiologia , Feminino , Nível de Saúde , Humanos , Masculino , Estudos Retrospectivos , Caminhada
4.
Biol Sport ; 39(3): 745-749, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35959322

RESUMO

Capillary dried blood spot (DBS) samples facilitate field-based collection without venipuncture. This pilot study aims to evaluate the viability of creatine (Cr) and creatinine (Crt) quantification using fresh capillary serum (CrS/CrtS) and DBS samples (CrDBS/CrtDBS), using Flow Injection Analysis Mass Spectrometry (FIA - MS). Nine Olympic Athletes provided a capillary blood sample to assess CrS/CrtS and CrDBS/CrtDBS quantified by FIA - MS. No difference between CrtS (mean ± SD: 813.6 ± 102.4 µmol/L) and CrtDBS (812.4 ± 108.1 µmol/L) was observed with acceptable variance [SEM 88.7; CV 10.7%; ICC 0.57 (CI 95% 0.06 - 0.84)] and agreement [very strong (Spearman: r = 0.77; p < 0.01) or strong (Pearson: r = 0.56; p = 0.04); Bland Altman: lower (-193) and upper (+196) limits of agreement]. CrS (mean ± SD: 691.8 ± 165.2 µmol/L) was significantly different to CrDBS (2911 ± 571.4 µmol/L) with unacceptable variance [SEM 171.6; CV 27%; ICC 0.002 (CI 95% -0.02 - 0.07)] and 'weak' agreement [Spearman: r = 0.21, p = 0.47 and Pearson: r = 0.06, p = 0.84; Bland Altman lower (-3367) and upper (-1072) limits of agreement]. Crt quantification is viable using both CrtS and CrtDBS (but not for Cr and CrS/CrDBS), with the DBS tissue handling technique offering several methodological and practice facing advantages. Future work should expand upon the sample size, explore sport/discipline relevant analytes across a full competitive season, including key training, recovery and performance blocks of their periodized performance plan.

5.
Biol Sport ; 39(4): 1103-1115, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36247962

RESUMO

Ramadan intermittent fasting during the COVID-19 lockdown (RIFL) may present unique demands. We investigated training practices (i.e., training load and training times) of athletes, using pre-defined survey criteria/questions, during the 'first' COVID-19 lockdown, comparing RIFL to lockdown-alone (LD) in Muslim athletes. Specifically, a within-subject, survey-based study saw athletes (n = 5,529; from 110 countries/territories) training practices (comparing RIFL to LD) explored by comparative variables of: sex; age; continent; athlete classification (e.g., world-class); sport classification (e.g., endurance); athlete status (e.g., professional); and level of training knowledge and beliefs/attitudes (ranked as: good/moderate/poor). During RIFL (compared to LD), athlete perceptions (ranges presented given variety of comparative variables) of their training load decreased (46-62%), were maintained (31-48%) or increased (2-13%). Decreases (≥ 5%, p < 0.05) affected more athletes aged 30-39 years than those 18-29 years (60 vs 55%); more national than international athletes (59 vs 51%); more team sports than precision sports (59 vs 46%); more North American than European athletes (62 vs 53%); more semi-professional than professional athletes (60 vs 54%); more athletes who rated their beliefs/attitudes 'good' compared to 'poor' and 'moderate' (61 vs 54 and 53%, respectively); and more athletes with 'moderate' than 'poor' knowledge (58 vs 53%). During RIFL, athletes had different strategies for training times, with 13-29% training twice a day (i.e., afternoon and night), 12-26% at night only, and 18-36% in the afternoon only, with ranges depending on the comparative variables. Training loads and activities were altered negatively during RIFL compared to LD. It would be prudent for decision-makers responsible for RIFL athletes to develop programs to support athletes during such challenges.

6.
Br J Sports Med ; 55(23): 1335-1341, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33579722

RESUMO

PURPOSE: To characterise hydration, cooling, body mass loss, and core (Tcore) and skin (Tsk) temperatures during World Athletics Championships in hot-humid conditions. METHODS: Marathon and race-walk (20 km and 50 km) athletes (n=83, 36 women) completed a pre-race questionnaire. Pre-race and post-race body weight (n=74), Tcore (n=56) and Tsk (n=49; thermography) were measured. RESULTS: Most athletes (93%) had a pre-planned drinking strategy (electrolytes (83%), carbohydrates (81%)) while ice slurry was less common (11%; p<0.001). More men than women relied on electrolytes and carbohydrates (91%-93% vs 67%-72%, p≤0.029). Drinking strategies were based on personal experience (91%) rather than external sources (p<0.001). Most athletes (80%) planned pre-cooling (ice vests (53%), cold towels (45%), neck collars (21%) and ice slurry (21%)) and/or mid-cooling (93%; head/face dousing (65%) and cold water ingestion (52%)). Menthol usage was negligible (1%-2%). Pre-race Tcore was lower in athletes using ice vests (37.5°C±0.4°C vs 37.8°C±0.3°C, p=0.024). Tcore (pre-race 37.7°C±0.3°C, post-race 39.6°C±0.6°C) was independent of event, ranking or performance (p≥0.225). Pre-race Tsk was correlated with faster race completion (r=0.32, p=0.046) and was higher in non-finishers (did not finish (DNF); 33.8°C±0.9°C vs 32.6°C±1.4°C, p=0.017). Body mass loss was higher in men than women (-2.8±1.5% vs -1.3±1.6%, p<0.001), although not associated with performance. CONCLUSION: Most athletes' hydration strategies were pre-planned based on personal experience. Ice vests were the most adopted pre-cooling strategy and the only one minimising Tcore, suggesting that event organisers should be cognisant of logistics (ie, freezers). Dehydration was moderate and unrelated to performance. Pre-race Tsk was related to performance and DNF, suggesting that Tsk modulation should be incorporated into pre-race strategies.


Assuntos
Atletas , Temperatura Corporal , Regulação da Temperatura Corporal , Temperatura Baixa , Feminino , Temperatura Alta , Humanos , Masculino , Caminhada
7.
J Sports Sci ; 39(18): 2080-2086, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33906585

RESUMO

Athletes physically overload to improve performance. Unbalanced stress/recovery may induce overtraining, which is difficult to diagnosis as no diagnostic marker exists. Hormonal responses to a 55/80 cycle (30-min of alternating blocks of 1-min at 55% and 4-min at 80% maximum work rate) may highlight early-stage overtraining (overreaching), as blunted cortisol and testosterone responses to 55/80 follows intensified training. However, the reliability of hormonal responses to 55/80 when not overreached is unknown. Therefore, reported blunted hormonal responses could be due to inconsistent cortisol and testosterone responses to 55/80. Participants (n = 23) completed three 55/80 bouts, >7 days apart, with no exercise 24 h pre-trials. Pre-exercise urine osmolality and stress questionnaire responses were measured. Pre, post, and 30-min post-exercise saliva samples were collected for cortisol and testosterone assessment. Salivary cortisol and testosterone responses, osmolality and well-being were not different between trials. Salivary cortisol and testosterone elevated from pre- to post-exercise [by 4.2 nmol.L-1 (cortisol) and 307 pmol.L-1 (testosterone)], and 30 min post-exercise [by 160 pmol.L-1 (testosterone) only]. Intraclass correlation coefficients for pre to peak post-exercise cortisol (0.89; good) and testosterone (0.53; moderate) were calculated. This demonstrates that 55/80 induces reliable elevations of salivary cortisol and testosterone when in a healthy state.


Assuntos
Ciclismo/fisiologia , Hidrocortisona/metabolismo , Resistência Física/fisiologia , Testosterona/metabolismo , Adolescente , Adulto , Teste de Esforço , Voluntários Saudáveis , Humanos , Masculino , Reprodutibilidade dos Testes , Saliva/química , Inquéritos e Questionários , Adulto Jovem
8.
BMC Med Res Methodol ; 20(1): 267, 2020 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-33115422

RESUMO

BACKGROUND: Aboriginal people are under-reported on administrative health data in Australia. Various approaches have been used or proposed to improve reporting of Aboriginal people using linked records. This cross-sectional study used self-reported Aboriginality from the NSW Patient Survey Program (PSP) as a reference standard to assess the accuracy of reporting of Aboriginal people on NSW Admitted Patient (APDC) and Emergency Department Data Collections (EDDC), and compare the accuracy of selected approaches to enhance reporting Aboriginality using linked data. METHODS: Ten PSP surveys were linked to five administrative health data collections, including APDC, EDDC, perinatal, and birth and death registration records. Accuracy of reporting of Aboriginality was assessed using sensitivity, specificity, and positive and negative predictive values (PPVs and NPVs) and F score for the EDDC and APDC as baseline and four enhancement approaches using linked records: "Most recent linked record", "Ever reported as Aboriginal", and two approaches using a weight of evidence, "Enhanced Reporting of Aboriginality (ERA) algorithm" and "Multi-stage median (MSM)". RESULTS: There was substantial under-reporting of Aboriginality on APDC and EDDC records (sensitivities 84 and 77% respectively) with PPVs of 95% on both data collections. Overall, specificities and NPVs were above 98%. Of people who were reported as Aboriginal on the PSP, 16% were not reported as Aboriginal on any of their linked records. Record linkage approaches generally increased sensitivity, accompanied by decrease in PPV with little change in overall F score for the APDC and an increase in F score for the EDDC. The "ERA algorithm" and "MSM" approaches provided the best overall accuracy. CONCLUSIONS: Weight of evidence approaches are preferred when record linkage is used to improve reporting of Aboriginality on administrative health data collections. However, as a substantial number of Aboriginal people are not reported as Aboriginal on any of their linked records, improvements in reporting are incomplete and should be taken into account when interpreting results of any analyses. Enhancement of reporting of Aboriginality using record linkage should not replace efforts to improve recording of Aboriginal people at the point of data collection and addressing barriers to self-identification for Aboriginal people.


Assuntos
Registro Médico Coordenado , Minorias Sexuais e de Gênero , Austrália , Estudos Transversais , Coleta de Dados , Feminino , Homossexualidade Masculina , Humanos , Masculino , Havaiano Nativo ou Outro Ilhéu do Pacífico , New South Wales , Gravidez , Web Semântica
9.
BMC Cardiovasc Disord ; 20(1): 224, 2020 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-32408860

RESUMO

BACKGROUND: Timely restoration of bloodflow acute ST-segment elevation myocardial infarction (STEMI) reduces myocardial damage and improves prognosis. The objective of this study was describe the association of demographic factors with hospitalisation rates for STEMI and time to angiography, Percutaneous Coronary Intervention (PCI) and Coronary Artery Bypass Graft (CABG) in New South Wales (NSW) and the Australian Capital Territory (ACT), Australia. METHODS: This was an observational cohort study using linked population health data. We used linked records of NSW and the ACT hospitalisations and the Australian Government Medicare Benefits Schedule (MBS) for persons aged 35 and over hospitalised with STEMI in the period 1 July 2010 to 30 June 2014. Survival analysis was used to determine the time between STEMI admission and angiography, PCI and CABG, with a competing risk of death without cardiac procedure. RESULTS: Of 13,117 STEMI hospitalisations, 71% were among males; 55% were 65-plus years; 64% lived in major cities, and 2.6% were Aboriginal people. STEMI hospitalisation occurred at a younger age in males than females. Angiography and PCI rates decreased with age: angiography 69% vs 42% and PCI 60% vs 34% on day 0 for ages 35-44 and 75-plus respectively. Lower angiography and PCI rates and higher CABG rates were observed outside major cities. Aboriginal people with STEMI were younger and more likely to live outside a major city. Angiography, PCI and CABG rates were similar for Aboriginal and non-Aboriginal people of the same age and remoteness area. CONCLUSIONS: There is a need to improve access to definitive revascularisation for STEMI among appropriately selected older patients and in regional areas. Aboriginal people with STEMI, as a population, are disproportionately affected by access to definitive revascularisation outside major cities. Improving access to timely definitive revascularisation in regional areas may assist in closing the gap in cardiovascular outcomes between Aboriginal and non-Aboriginal people.


Assuntos
Ponte de Artéria Coronária , Disparidades em Assistência à Saúde/etnologia , Havaiano Nativo ou Outro Ilhéu do Pacífico , Intervenção Coronária Percutânea , Infarto do Miocárdio com Supradesnível do Segmento ST/terapia , Adulto , Fatores Etários , Idoso , Território da Capital Australiana , Angiografia Coronária/tendências , Ponte de Artéria Coronária/tendências , Bases de Dados Factuais , Feminino , Disparidades em Assistência à Saúde/tendências , Humanos , Masculino , Pessoa de Meia-Idade , New South Wales/epidemiologia , Intervenção Coronária Percutânea/tendências , Fatores Raciais , Características de Residência , Fatores de Risco , Infarto do Miocárdio com Supradesnível do Segmento ST/diagnóstico por imagem , Infarto do Miocárdio com Supradesnível do Segmento ST/etnologia , Infarto do Miocárdio com Supradesnível do Segmento ST/mortalidade , Tempo para o Tratamento/tendências , Resultado do Tratamento
10.
J Strength Cond Res ; 33(4): 1043-1055, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29016478

RESUMO

Fowler, PM, Murray, A, Farooq, A, Lumley, N, and Taylor, L. Subjective and objective responses to two rugby sevens world series competitions. J Strength Cond Res 33(4): 1043-1055, 2019-The purpose was to examine the utility of subjective and objective measures of player preparedness, interpreted at both group level and individual level, during 2 consecutive competitions of the World Rugby Sevens Series (WRSS). Subjective (sleep, energy, and muscle soreness ratings) and objective (heart rate [HR] at rest [HRREST] and in response to submaximal exercise [HREX]) measures were obtained from 16 male rugby 7s players from 1 team for 3 consecutive days (D1-3) at home (HOME) and on arrival at 4 tournament (T1-4) locations (T1-New Zealand; T2-USA; T3-Hong Kong; and T4-Tokyo) across 2 WRSS competitions (2 tournaments per competition) separated by 1 month. At a group level, energy ratings were significantly lower in T2 and T4 compared with HOME, and on D1 T2 compared with D1 T1 (p ≤ 0.05). Greatest variability in subjective ratings was observed during T1 and T3 at an individual level, particularly for sleep quality. Although at a group level HRREST and HREX significantly decreased in T1-4 compared with HOME (p ≤ 0.05), there was only a ∼50% agreement between the direction of change in HR indices at an individual level. Results from this study suggest that relocation between tournaments within WRSS competitions disrupts player preparedness measures to the largest degree. Hence, this period could be targeted by practitioners with appropriate recovery and/or sleep-promoting interventions or modulation of match-/training-load. Moreover, subjective rather than objective measures seem to be of greater use to inform player preparedness decision making, particularly at an individual level compared with a group level.


Assuntos
Fadiga/etiologia , Futebol Americano/fisiologia , Frequência Cardíaca , Mialgia/etiologia , Sono/fisiologia , Adulto , Exercício Físico/fisiologia , Teste de Esforço , Futebol Americano/psicologia , Humanos , Síndrome do Jet Lag/etiologia , Masculino , Descanso/fisiologia , Viagem , Adulto Jovem
11.
J Sports Sci ; 36(13): 1476-1484, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29099652

RESUMO

Currently, very little is known about the impact of short- or long-haul air travel on the sleep and wellbeing of wheelchair basketball athletes. Eleven national wheelchair basketball athletes wore actigraphy monitors prior, during, and after air travel to the United Kingdom. Upon arrival, participants rated their subjective jet-lag, fatigue, and vigor. Individuals traveled to the United Kingdom from different locations in Australia, the United States, and Europe and were categorised according to travel length [LONG (up to 30.2 h) or SHORT (up to 6.5 h)]. Linear mixed models determined effects of travel length on sleep and subjective ratings of jet-lag, fatigue, and vigor. During competition, subjective fatigue and jet-lag were substantially higher (ES = 0.73; ±0.77) and (ES = 0.57; ±0.60), subjective vigor was lower (ES = 1.94; ±0.72), and get-up time was earlier (ES = 0.57; ±0.60) for LONG when compared to SHORT. Travelling greater distances by airplane had a larger effect on subjective ratings of jet-lag, fatigue and vigor, rather than sleep. Irrespective of travel group, sleep and subjective responses were compromised, reflecting the travel requirements, competition-mediated influences, and/or due to a change in environment.


Assuntos
Desempenho Atlético/fisiologia , Basquetebol/fisiologia , Síndrome do Jet Lag/fisiopatologia , Sono/fisiologia , Viagem , Cadeiras de Rodas , Adulto , Humanos , Fatores de Tempo
12.
J Appl Clin Med Phys ; 19(4): 44-47, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29761625

RESUMO

A novel phantomless, EPID-based method of measuring the beam focal spot offset of a linear accelerator was proposed and validated for Varian machines. In this method, one set of jaws and the MLC were utilized to form a symmetric field and then a 180o collimator rotation was utilized to determine the radiation isocenter defined by the jaws and the MLC, respectively. The difference between these two isocentres is directly correlated with the beam focal spot offset of the linear accelerator. In the current work, the method has been considered for Elekta linacs. An Elekta linac with the Agility® head does not have two set of jaws, therefore, a modified method is presented making use of one set of diaphragms, the MLC and a full 360o collimator rotation. The modified method has been tested on two Elekta Synergy® linacs with Agility® heads and independently validated. A practical guide with instructions and a MATLAB® code is attached for easy implementation.


Assuntos
Aceleradores de Partículas , Imagens de Fantasmas , Radiometria , Rotação
13.
Biol Sport ; 35(3): 237-244, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30449941

RESUMO

To determine the effect of carbohydrate mouth rinsing (CHO-MR) on physical and cognitive performance during repeated-sprints (RS) after 3 days of intermittent fasting (abstaining from food and fluid 14 h per day). In a randomized and counter-balanced manner 15 active healthy males in a fasted state performed a RS-protocol [RSP; 2 sets (SET1 and SET2) of 5×5 s maximal sprints, with each sprint interspersed with 25 s rest and 3 min of recovery between SET1 and SET2] on an instrumented non-motorized treadmill with embedded force sensors under three conditions: i) Control (CON; no-MR), ii) Placebo-MR (PLA-MR; 0% maltodextrin) and iii) CHO-MR (10% maltodextrin). Participants rinsed their mouth with either 10 mL of PLA-MR or CHO-MR solution for 5 s before each sprint. Sprint kinetics were measured for each sprint and reaction time (RTI) tasks (simple and complex) were assessed pre-, during- and post-RSP. There was no statistical main effect of CHO-MR on mean power, mean speed, and vertical stiffness during the sprints between the PLA-MR and CON condition. Additionally, no statistical main effect for CHO-MR on accuracy, movement time and reaction time during the RTI tasks was seen. CHO-MR did not affect physical (RSP) or cognitive (RTI) performance in participants who had observed 3 days of intermittent fasting (abstaining from food and fluid 14 h per day).

14.
Eur J Appl Physiol ; 117(12): 2579-2585, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29058111

RESUMO

PURPOSE: Training with blood flow restriction (BFR) is known to enhance muscle mass and strength during resistance training activities. However, little is known about the BFR effects during aerobic training. This investigation examines the effects of running training performed with or without BFR on physiology and performance. METHOD: Sixteen subjects (age 24.9 ± 6.9 years, height 172.9 ± 7.8 cm, weight 75.1 ± 13.8 kg) were assigned to a BFR or control (CON) group for eight sessions of training. Before and after training, subjects completed an incremental test to determine peak running velocity (PRV) maximal oxygen uptake ([Formula: see text]) and running economy (RE), followed by a time to exhaustion run (TTE) performed at PRV. Training for both groups consisted of progressively increasing volumes of 30-s repetitions completed at 80% of PRV. RESULTS: The BFR and CON groups reported gains (6.3 ± 3.5 vs 4.0 ± 3.3%) in [Formula: see text] following training with only trivial (ES = 0.18) differences between groups. Similarly, PRV and incremental test time increased in both training groups with a small (ES ~ 0.3) additional enhancement in favour of the BFR group. Running economy improved in the BFR group but not in CON (ES = 0.4). TTE also increased in both BFR (27 ± 9%) and CON groups (17 ± 6%) with a small (ES = 0.31) additional benefit in favour of the BFR group. CONCLUSIONS: Using BFR during training appears to confer small but potentially worthwhile improvements in RE, PRV and TTE measures. The improvements following BFR training are likely due to muscular rather than cardiovascular function.


Assuntos
Limiar Anaeróbio , Músculo Esquelético/irrigação sanguínea , Condicionamento Físico Humano/métodos , Fluxo Sanguíneo Regional , Corrida/fisiologia , Adulto , Desempenho Atlético , Tolerância ao Exercício , Feminino , Humanos , Masculino , Força Muscular , Condicionamento Físico Humano/efeitos adversos
15.
J Sports Sci ; 35(8): 798-805, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27267974

RESUMO

This investigation compared the effects of external pre-cooling and mid-exercise cooling methods on running time trial performance and associated physiological responses. Nine trained male runners completed familiarisation and three randomised 5 km running time trials on a non-motorised treadmill in the heat (33°C). The trials included pre-cooling by cold-water immersion (CWI), mid-exercise cooling by intermittent facial water spray (SPRAY), and a control of no cooling (CON). Temperature, cardiorespiratory, muscular activation, and perceptual responses were measured as well as blood concentrations of lactate and prolactin. Performance time was significantly faster with CWI (24.5 ± 2.8 min; P = 0.01) and SPRAY (24.6 ± 3.3 min; P = 0.01) compared to CON (25.2 ± 3.2 min). Both cooling strategies significantly (P < 0.05) reduced forehead temperatures and thermal sensation, and increased muscle activation. Only pre-cooling significantly lowered rectal temperature both pre-exercise (by 0.5 ± 0.3°C; P < 0.01) and throughout exercise, and reduced sweat rate (P < 0.05). Both cooling strategies improved performance by a similar magnitude, and are ergogenic for athletes. The observed physiological changes suggest some involvement of central and psychophysiological mechanisms of performance improvement.


Assuntos
Desempenho Atlético/fisiologia , Regulação da Temperatura Corporal/fisiologia , Temperatura Baixa , Temperatura Alta , Imersão , Corrida/fisiologia , Água , Adulto , Desempenho Atlético/psicologia , Estudos Cross-Over , Face , Humanos , Masculino , Músculo Esquelético/fisiologia , Percepção , Corrida/psicologia
16.
J Strength Cond Res ; 31(3): 620-629, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27379961

RESUMO

Stevens, CJ, Bennett, KJM, Sculley, DV, Callister, R, Taylor, L, and Dascombe, BJ. A comparison of mixed-method cooling interventions on preloaded running performance in the heat. J Strength Cond Res 31(3): 620-629, 2017-The purpose of this investigation was to assess the effect of combining practical methods to cool the body on endurance running performance and physiology in the heat. Eleven trained male runners completed 4 randomized, preloaded running time trials (20 minutes at 70% V[Combining Dot Above]O2max and a 3 km time trial) on a nonmotorized treadmill in the heat (33° C). Trials consisted of precooling by combined cold-water immersion and ice slurry ingestion (PRE), midcooling by combined facial water spray and menthol mouth rinse (MID), a combination of all methods (ALL), and control (CON). Performance time was significantly faster in MID (13.7 ± 1.2 minutes; p < 0.01) and ALL (13.7 ± 1.4 minutes; p = 0.04) but not PRE (13.9 ± 1.4 minutes; p = 0.24) when compared with CON (14.2 ± 1.2 minutes). Precooling significantly reduced rectal temperature (initially by 0.5 ± 0.2° C), mean skin temperature, heart rate and sweat rate, and increased iEMG activity, whereas midcooling significantly increased expired air volume and respiratory exchange ratio compared with control. Significant decreases in forehead temperature, thermal sensation, and postexercise blood prolactin concentration were observed in all conditions compared with control. Performance was improved with midcooling, whereas precooling had little or no influence. Midcooling may have improved performance through an attenuated inhibitory psychophysiological and endocrine response to the heat.


Assuntos
Desempenho Atlético/fisiologia , Temperatura Corporal/fisiologia , Crioterapia/métodos , Temperatura Alta/efeitos adversos , Corrida/fisiologia , Adulto , Regulação da Temperatura Corporal/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Resistência Física/fisiologia , Temperatura Cutânea , Água
17.
Res Sports Med ; 25(1): 11-25, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27855493

RESUMO

Pretest guidelines typically stipulate that no exercise should be performed 48 h prior to a maximal incremental exercise [Formula: see text] test. However, no study has specifically investigated if this timescale alters key outcome variables associated with [Formula: see text]. Twenty apparently healthy males split into two equal groups performed [Formula: see text] during three visits (visits 1 - [Formula: see text]EXP1, 2 - [Formula: see text]EXP2 and 4 - [Formula: see text]EXP3). The experimental group only, performed muscle-damaging exercise during visit 3. From [Formula: see text]EXP2 to [Formula: see text]EXP3 average time to exhaustion (TTE) decreased by 45 s (9%) (p < 0.01), maximum blood lactate decreased by 1.2 mmol/L (11%) (p = 0.03), and perceived readiness decreased by 8 mm (18%) (p = 0.01). There were no changes in any [Formula: see text] variables in the control group (p ≥ 0.37). Performing [Formula: see text] 48 h following muscle-damaging exercise impairs specific, but not all, physiological outcome variables.


Assuntos
Teste de Esforço/métodos , Fadiga Muscular/fisiologia , Mialgia/etiologia , Corrida/fisiologia , Adolescente , Adulto , Voluntários Saudáveis , Humanos , Modelos Lineares , Masculino , Contração Muscular/fisiologia , Dinamômetro de Força Muscular , Músculo Esquelético/fisiologia , Músculo Esquelético/fisiopatologia , Mialgia/fisiopatologia , Consumo de Oxigênio , Adulto Jovem
18.
Mycologia ; 2016 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-27549617

RESUMO

Fungal species with a broad distribution may exhibit considerable genetic variation over their geographic ranges. Variation may develop among populations based on geographic isolation, lack of migration, and genetic drift, though this genetic variation may not always be evident when examining phenotypic characters. Fomitopsis pinicola is an abundant saprotrophic fungus found on decaying logs throughout temperate regions of the Northern Hemisphere. Phylogenetic studies have addressed the relationship of F. pinicola to other wood-rotting fungi, but pan-continental variation within F. pinicola has not been addressed using molecular data. While forms found growing on hardwood and softwood hosts exhibit variation in habit and appearance, it is unknown if these forms are genetically distinct. In this study, we generated DNA sequences of the nuc rDNA internal transcribed spacers (ITS), the TEF1 gene encoding translation elongation factor 1-α, and the RPB2 gene encoding the second largest subunit of RNA polymerase II for collections across all major geographic regions where this fungus occurs, with a primary focus on North America. We used Bayesian and maximum likelihood analyses and evaluated the gene trees within the species tree using coalescent methods to elucidate evolutionarily independent lineages. We find that F. pinicola sensu lato encompasses four well-supported, congruent clades: a European clade, southwestern US clade, and two sympatric northern North American clades. Each clade represents distinct species according to phylogenetic and population-genetic species concepts. Morphological data currently available for F. pinicola do not delimit these species, and three of the species are not specific to either hardwood or softwood trees. Originally described from Europe, F. pinicola appears to be restricted to Eurasia. Based on DNA data obtained from an isotype, one well-defined and widespread clade found only in North America represents the recently described Fomitopsis ochracea The remaining two North American clades represent previously undescribed species.

19.
J Sports Sci ; 34(24): 2338-2349, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27842463

RESUMO

Soccer players are required to have well-developed physical, technical and cognitive abilities. The present systematic review, adhering to Preferred Reporting Items for Systematic reviews and Meta-Analysis guidelines, examined the effects of cognitive training strategies on motor and positive psychological skills development in soccer performance and identified the potential moderators of the "cognitive training-soccer performance" relationship. Thirteen databases were systematically searched using keywords related to psychological or cognitive training in soccer players. The review is based on 18 studies, employing 584 soccer players aged 7-39 years. Cognitive strategies, particularly imagery, appear to improve sports performance in soccer players. Regarding imagery, the combination of two different types of cognitive imagery training (i.e., cognitive general and cognitive specific) has a positive influence on soccer performance during training, whereas motivational imagery (i.e., motivational general-arousal, motivational general-mastery and motivational specific) enhance competition performance. Younger soccer players employ cognitive general and cognitive specific imagery techniques to a greater extent than older soccer players. Combined cognitive training strategies were more beneficial than a single cognitive strategy relative to motor skills enhancement in elite (particularly midfielders) and amateur (i.e., when practising complex and specific soccer skills in precompetitive period) soccer players. In conclusion, it appears that there are differences in cognitive/psychological training interventions, and their efficacy, according to whether they are directed towards training or competition, and the age, standard and playing position of the players.


Assuntos
Desempenho Atlético/psicologia , Cognição , Motivação , Destreza Motora , Educação Física e Treinamento/métodos , Futebol/psicologia , Humanos , Imaginação
20.
Res Sports Med ; 24(2): 130-44, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27031165

RESUMO

This study determined the effectiveness of antioxidant supplementation on high-intensity exercise-heat stress. Six males completed a high-intensity running protocol twice in temperate conditions (TEMP; 20.4°C), and twice in hot conditions (HOT; 34.7°C). Trials were completed following7 days supplementation with 70 ml·day(-1) effective microorganism-X (EM-X; TEMPEMX or HOTEMX) or placebo (TEMPPLA or HOTPLA). Plasma extracellular Hsp72 (eHsp72) and superoxide dismutase (SOD) were measured by ELISA. eHsp72 and SOD increased pre-post exercise (p < 0.001), with greater eHsp72 (p < 0.001) increases observed in HOT (+1.5 ng·ml(-1)) compared to TEMP (+0.8 ng·ml(-1)). EM-X did not influence eHsp72 (p > 0.05). Greater (p < 0.001) SOD increases were observed in HOT (+0.22 U·ml(-1)) versus TEMP (+0.10 U·ml(-1)) with SOD reduced in HOTEMX versus HOTPLA (p = 0.001). Physiological and perceptual responses were all greater (p < 0.001) in HOT versus TEMP conditions, with no difference followed EM-X (p > 0.05). EM-X supplementation attenuated the SOD increases following HOT, potentiating its application as an ergogenic aid to ameliorate oxidative stress.


Assuntos
Antioxidantes/farmacologia , Resposta ao Choque Térmico/efeitos dos fármacos , Temperatura Alta/efeitos adversos , Umidade/efeitos adversos , Estresse Oxidativo/efeitos dos fármacos , Corrida/fisiologia , Superóxido Dismutase/sangue , Antioxidantes/administração & dosagem , Biomarcadores/sangue , Estudos Cross-Over , Suplementos Nutricionais , Método Duplo-Cego , Proteínas de Choque Térmico HSP72/sangue , Resposta ao Choque Térmico/fisiologia , Humanos , Modelos Lineares , Masculino , Estresse Oxidativo/fisiologia , Adulto Jovem
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