Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.246
Filtrar
1.
Phys Ther Sport ; 48: 83-90, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33395617

RESUMO

OBJECTIVES: The aim of this study was to describe the self-reported injury, training, and running technique choices of regular runners in four international regions. DESIGN AND SETTING: 756 participants began an expert derived self-report online survey in Ireland, USA, Hong Kong and Australia. PARTICIPANTS: 325 participants completed the survey (age = 38 ± 10 years; weight = 68.0 ± 13.1 kg; height = 1.70 ± 0.10 m). MAIN OUTCOME MEASURES: Descriptive statistics are reported examining injury incidence and location; shoe and orthosis choices; and training and technique practices. A backwards logistic regression was implemented to examine associations between injury and training choices. RESULTS: 68.3% reported having an injury in the last year. 81.45% of these injuries were believed to be running related. A large variation in training and footwear choices were observed for respondents. The regression (P ≤ 0.001) explained 20% of the variance in injury selection (Nagelkerke R2) and was able to identify 73% of cases accurately. Associated injury factors included competitive running, running on more than one surface, younger age, having a lower running age, and a higher proportion of running at an easy intensity. CONCLUSIONS: The high amount of variability in runner's choices highlights the lack of consistent information being presented to them and may be the reason for the high injury incidence.


Assuntos
Condicionamento Físico Humano/efeitos adversos , Condicionamento Físico Humano/métodos , Corrida/lesões , Adulto , Austrália/epidemiologia , Desenho de Equipamento , Feminino , Hong Kong/epidemiologia , Humanos , Incidência , Irlanda/epidemiologia , Masculino , Autorrelato , Sapatos , Inquéritos e Questionários , Estados Unidos/epidemiologia
2.
Phys Ther Sport ; 48: 154-168, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33486408

RESUMO

BACKGROUND: Research suggests that the frequency of training, combined with the repetitive motion involved in high volume swimming can predispose swimmers to symptoms of over-training. The prevention of pain, injury and illness is of paramount importance in competitive swimming in order to maximise a swimmer's ability to train and perform consistently. A significant factor in the prevention of pain, injury or illness is the appropriate load monitoring and management practices within a training programme. OBJECTIVE: The purpose of this systematic review is to investigate the relationship between training load and pain, injury and illness in competitive swimmers. METHODS: The databases SPORTDiscus, CINAHL, Scopus, MEDLINE and Embase were searched in accordance with PRISMA guidelines. Studies were included if they reported on competitive swimmers and analysed the link between training load and either pain, injury or illness. The methodological quality and study bias were assessed using the Joanna Briggs Institute Critical Appraisal Checklist. RESULTS: The search retrieved 1,959 articles, 15 of which were included for review. The critical appraisal process indicated study quality was poor overall. Pain was the most explored condition (N = 12), with injury (N = 2) and illness (N = 1) making up the remaining articles. There was no evidence of an association between training load and pain, while there may be some evidence to suggest a relationship between training load and injury or illness. CONCLUSIONS: The relationship between training load and pain, injury or illness is unclear owing to a host of methodological constraints. The review highlighted that youth, masters and competitive swimmers of a lower ability (e.g. club versus international) may need particular consideration when planning training loads. Winter periods, higher intensity sessions and speed elements may also need to be programmed with care. Monitoring practices need to be developed in conjunction with consensus guidelines, with the inclusion of internal training loads being a priority. Future research should focus on longitudinal prospective studies, utilising the session Rating of Perceived Exertion (sRPE) monitoring method and investigating the applicability of Acute/Chronic Workload Ratio (ACWR) and exponentially weighted moving average (EWMA). Improved methods and study design will provide further clarity on the relationship between load and pain, injury, and illness.


Assuntos
Comportamento Competitivo , Dor/etiologia , Condicionamento Físico Humano/efeitos adversos , Natação/lesões , Adolescente , Transtornos Traumáticos Cumulativos/prevenção & controle , Humanos , Masculino , Dor/prevenção & controle , Condicionamento Físico Humano/métodos , Estudos Prospectivos , Natação/fisiologia
3.
PLoS One ; 15(9): e0239862, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32991633

RESUMO

The purpose of this study was to compare speed, sub-technique selection and temporal patterns between world-class male and female cross-country (XC) skiers and to examine the combined associations of sex and speed on sub-technique selection. Thirty-three XC skiers performed an international 10-km (women; n = 8) and 15-km (men; n = 25) time-trial competition in the classical style (with the first 10 km of the race being used for analyses). An integrated GNSS/IMU system was used to continuously track position speed and automatically classify sub-techniques and temporal patterns (i.e. cycle length and-rate). When comparing the eight highest ranked men and women, men spent less time than women (29±2 vs. 45±5% of total time) using diagonal stride (DIA), more time (44±4 vs. 31±4%) using double poling (DP) and more time (23±2 vs. 19±3%) using tucking and turning (all P < .01). Here, men and women used these sub-techniques at similar temporal patterns within the same speed-intervals; although men employed all sub-techniques at steeper uphill gradients (all P < .05). In subsequent analyses including all 33 skiers, adjustment for average racing speed did not fully attenuate the observed sex differences in the proportion of time using DIA (CI95% [-10.7, -1.6]) and DP (CI95% [0.8, 9.3]). Male world-class XC skiers utilized less DIA and more DP compared to women of equal performance levels. Although these differences coincided with men's higher speed and their ability to use the various sub-techniques at steeper uphill gradients, sexual dimorphism in the proportional use of DIA and DP also occurred independently of these speed-differences.


Assuntos
Condicionamento Físico Humano/métodos , Esqui/fisiologia , Adulto , Atletas , Desempenho Atlético , Comportamento Competitivo , Feminino , Humanos , Masculino , Condicionamento Físico Humano/normas , Fatores Sexuais
4.
PLoS One ; 15(8): e0227394, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32866148

RESUMO

The aim of this study was to assess the impact of a 6-week specialized training program aimed at strengthening core muscles to improve the effectiveness of selected elements of a swimming race on a group of Polish swimmers. Sixteen male national level swimmers (21.6 ± 2.2 years) participated in the research. The competitors were randomly assigned to 1 of 2 groups before the data collection process: an experimental (EG, n = 8) and a control (CG, n = 8) group. Both groups of swimmers underwent the same training program in the water environment (volume and intensity), while swimmers from the EG additionally performed specific core muscle training. The task of the swimmers was an individual front crawl swim of 50 m, during which the kinematic parameters of the start jump, turn and swimming techniques were recorded using a video camera system. In both groups, a minor increase in the flight phase was observed at the start (EG = 0.06 m, 1.8%; p = 0.088; CG = 0.08 m, 2.7%; p = 0.013). The time to cover a distance of 5 m after the turn and the recorded average speed in swimming this distance for the EG statistically significantly improved by 0.1 s (-28.6%; p < 0.001) and 3.56 m∙s-1 (23.2%; p = 0.001), respectively. In the EG, a statistically significant improvement in 50 m front crawl swimming performance of 0.3 s (-1.2%, p = 0.001) was observed. The results of the research show that the implementation of isolated strengthening of the stabilizing muscles seems to be a valuable addition to the standard training of swimmers.


Assuntos
Exercício Físico/fisiologia , Condicionamento Físico Humano/métodos , Natação/fisiologia , Desempenho Atlético/fisiologia , Fenômenos Biomecânicos , Terapia por Exercício , Humanos , Masculino , Força Muscular/fisiologia , Músculos , Polônia , Treinamento de Resistência/métodos , Adulto Jovem
5.
PLoS One ; 15(8): e0237027, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32745112

RESUMO

The purpose of this study was to quantify training loads (TL) of high intensity sessions through original methods (TRIMP; session-RPE; Work-Endurance-Recovery) and their updated alternatives (TRIMPcumulative; RPEalone; New-WER). Ten endurance athletes were requested to perform five sessions until exhaustion. Session 1 composed by a 800m maximal performance and four intermittent sessions performed at the 800m velocity, three sessions with 400m of interval length and work:recovery ratios of 2:1, 1:1 and 1:2 and one with 200m intervals and 1:1. Total TL were quantified from the sessions' beginning to the cool-down period and an intermediate TL (TL800) was calculated when 800m running was accumulated within the sessions. At the end of the sessions high and similar RPE were reported (effect size, η2 = 0.12), while, at the intermediate 800m distance, the higher interval distances and work:recovery ratios the higher the RPE (η2 = 0.88). Our results show marked differences in sessions' total TL between original (e.g., lowest TL for the 800m and highest for the 200m-1:1 sessions) and alternative methods (RPEalone and New-WER; similar TL for each session). Differences appear in TL800 notably between TRIMP and other methods which are negatively correlated. All TL report light to moderate correlations between original methods and their alternatives, original methods are strongly correlated together, as observed for alternative methods. Differences in TL quantification between original and alternative methods underline that they are not interchangeable. Because of high exercise volume influence, original methods markedly enhance TL of sessions with higher exercise volumes although these presented the easiest interval distances and work-recovery ratios. Alternative methods based on exhaustion level (New-WER) and exertion (RPEalone) provided a new and promising point of view of TL quantification where exhaustion determines the highest TL whatever the exercise. This remains to be tested with more extended populations submitted to wider ranges of exercises.


Assuntos
Terapia por Exercício/métodos , Exercício Físico/fisiologia , Condicionamento Físico Humano/métodos , Adolescente , Atletas , Frequência Cardíaca , Humanos , Masculino , Consumo de Oxigênio , Esforço Físico , Corrida , Adulto Jovem
6.
Ann Endocrinol (Paris) ; 81(5): 493-499, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32768394

RESUMO

The present study examined the effectiveness of adding exercises with whole-body vibration (WBV) to aerobic training in terms of metabolic features and quality of life. Patients with non-alcoholic fatty liver disease (NAFLD), confirmed on imaging, underwent an 8-week individualized exercise program randomized between aerobic training with and without WBV. Training was performed at 60-80% heart rate workload for 165 min/week. The WBV amplitude was 2-4mm and the training frequency was 30Hz, for 15min. Assessments were carried out on surrogate scores of steatosis and fibrosis including transient elastography (FibroScan), metabolic features (biochemical analysis) and quality of life (SF-36). Insulin resistance was markedly reduced (-2.36; 95% CI: -4.96 to -0.24; P: 0.049) in aerobic training with WBV. The decrease in serum aspartate transaminase was significantly greater in aerobic training without WBV (-14.81; 95% CI: -23.36 to -6.25; P: 0.029). There were no significant differences between groups for the other metabolic features (P<0.05). All quality of life well-being domains improved in both groups (P<0.05). Given this reduction in insulin resistance, WBV can usefully be added to aerobic training. However, WBV did not provide further benefits in improving metabolic properties or quality of life.


Assuntos
Terapia por Exercício/métodos , Hepatopatia Gordurosa não Alcoólica/terapia , Condicionamento Físico Humano/métodos , Qualidade de Vida , Vibração/uso terapêutico , Adulto , Metabolismo Energético/fisiologia , Exercício Físico/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/fisiopatologia , Hepatopatia Gordurosa não Alcoólica/psicologia , Resultado do Tratamento
7.
Int J Sports Physiol Perform ; 15(5): 696-704, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32698124

RESUMO

PURPOSE: To investigate within-player effect, between-player effect, and individual response of external training load from player tracking devices on session rating of perceived exertion training load (sRPE-TL) in elite football players. METHODS: The authors collected sRPE-TL from 18 outfield players in 21 training sessions. Total distance, high-speed running distance (>14.4 m/s), very high-speed running distance (>19.8 m/s), PlayerLoad™, PlayerLoad2D™, and high-intensity events (HIE > 1.5, HIE > 2.5, and HIE > 3.5 m/s) were extracted from the tracking devices. The authors modeled within-player and between-player effects of single external load variables on sRPE-TL, and multiple levels of variability, using a linear mixed model. The effect of 2 SDs of external load on sRPE-TL was evaluated with magnitude-based inferences. RESULTS: Total distance, PlayerLoad™, PlayerLoad2D™, and HIE > 1.5 had most likely substantial within-player effects on sRPE-TL (100%-106%, very large effect sizes). Moreover, the authors observed likely substantial between-player effects (12%-19%, small to moderate effect sizes) from the majority of the external load variables and likely to very likely substantial individual responses of PlayerLoad™, high-speed running distance, very high-speed running distance, and HIE > 1.5 (19%-30% coefficient of variation, moderate to large effect sizes). Finally, sRPE-TL showed large to very large between-session variability with all external load variables. CONCLUSIONS: External load variables with low intensity-thresholds had the strongest relationship with sRPE-TL. Furthermore, the between-player effect of external load and the individual response to external load advocate for monitoring sRPE-TL in addition to external load. Finally, the large between-session variability in sRPE-TL demonstrates that substantial amounts of sRPE-TL in training sessions are not explained by single external load variables.


Assuntos
Percepção/fisiologia , Condicionamento Físico Humano/métodos , Esforço Físico/fisiologia , Futebol/fisiologia , Adulto , Comportamento Competitivo/fisiologia , Monitores de Aptidão Física , Humanos , Masculino , Corrida/fisiologia
9.
Sports Health ; 12(5): 488-494, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32598234

RESUMO

BACKGROUND: Baseball pitching injuries are increasing at an alarming rate. While weighted ball throwing programs may be effective at increasing pitching velocity, previous research has identified a 24% injury rate and a 3.3° increase in shoulder external rotation (ER) range of motion (ROM) after performing a 6-week program. However, previous research has not investigated, separately, the immediate effects of throwing underloaded and overloaded balls on ROM. The purpose of this study was to examine the acute effects of throwing differently weighted baseballs on shoulder ROM. By analyzing these differences, it may be possible to determine the specific weight range that may lead to the greatest increase in ROM and potential injury risk. HYPOTHESIS: Throwing with weighted balls will result in an increase in shoulder ER ROM. STUDY DESIGN: Randomized controlled trial. LEVEL OF EVIDENCE: Level 2. METHODS: A total of 16 male high school baseball pitchers agreed to participate in this study. The participants were (mean ± SD) 17.1 ± 1.0 years of age, 1.81 ± 0.09 m tall, and had a mass of 79.2 ± 11.1 kg. Each participant was tested on 3 different days, 1 week apart, with 3 different conditions in random order: (1) underload throwing, using regulation 5-oz baseballs and 4- and 2-oz balls; (2) overload throwing, using 5-, 6-, and 9-oz balls; and (3) extreme overload throwing, using 5-, 16-, and 32-oz balls. Each testing session began by measuring passive shoulder ROM (external rotation and internal rotation) using standard goniometric measurements. Participants then performed 3 throws with each weighted ball from 3 different positions (kneeling, rocker, and run-and-gun) for a total of 27 throws each test session. ROM measurements were repeated at the end of each test session. The effect of each throwing condition on ROM was compared from pre- to posttraining using a paired t test (P ≤ 0.05). RESULTS: There was no significant difference in ER after throwing at underloaded weights. The overload condition showed a statistically significant increase of 3.3° in external rotation (P = 0.05). The extreme overload condition showed a statistically significant increase in ER of 8.4° (P < 0.001). There were no differences in internal rotation for any group. CONCLUSION: A significant increase in shoulder ER was observed immediately after throwing overload weighted balls. This effect increased as the weights of the balls increased. CLINICAL RELEVANCE: Throwing with overload weighted baseballs causes an immediate increase in shoulder ER ROM. It is unknown why these changes occur; however, the results may explain both the increase in velocity and injury rates previously observed from throwing weighted balls. The current study results may be used to develop more scientifically validated weighted ball programs. Heavier balls should be used with caution, and ROM should be monitored during implementation of these programs.


Assuntos
Beisebol/fisiologia , Condicionamento Físico Humano/instrumentação , Condicionamento Físico Humano/métodos , Ombro/fisiologia , Equipamentos Esportivos , Adolescente , Beisebol/lesões , Humanos , Masculino , Amplitude de Movimento Articular , Estresse Mecânico
11.
J Sports Med Phys Fitness ; 60(6): 889-894, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32487983

RESUMO

BACKGROUND: CrossFit® is usually composed of high intensity workout routines and is executed quickly, repetitively and with limited rest time. Previous studies have identified a high prevalence of injuries in CrossFit®. This study aimed to determine the prevalence of CrossFit-related musculoskeletal injuries and to identify potential associated factors. METHODS: A cross-sectional study was conducted with 413 CrossFitters. Participants completed a questionnaire containing personal data, training characteristics and injury history in the last 12 months. Data were analyzed by descriptive statistics and logistic regression models. RESULTS: The prevalence of CrossFit-related musculoskeletal injuries was 24.0%; and the injury rate was of 0.80 injuries per 1,000 hours of exposure. The regions of the body most affected were the lumbar spine (33.3%), shoulders (31.3%) and knees (14.1%). The majority of CrossFitters participated in competitions (74.6%), had more than 12 months of experience in CrossFit® (62.7%), and trained up to 90 minutes a day (82.3%) for more than 4 days a week (76.8%). The variables that showed a significant association with CrossFit®-related musculoskeletal injuries were weekly training frequency (OR=2.25; 95% CI: 1.13-4.48) and regular physiotherapeutic care (OR=1.85; 95% CI: 1.11-3.07). CONCLUSIONS: The prevalence of musculoskeletal injury was 24.0%, and the most affected regions of the body were the lumbar spine, shoulders and knees. Training more than four days a week and do not receive regular physiotherapeutic care were associated with CrossFit-related musculoskeletal injuries.


Assuntos
Traumatismos em Atletas/epidemiologia , Sistema Musculoesquelético/lesões , Adulto , Traumatismos em Atletas/fisiopatologia , Brasil/epidemiologia , Estudos Transversais , Feminino , Humanos , Vértebras Lombares/fisiopatologia , Masculino , Sistema Musculoesquelético/fisiopatologia , Condicionamento Físico Humano/efeitos adversos , Condicionamento Físico Humano/métodos , Prevalência , Inquéritos e Questionários , Adulto Jovem
12.
J Sports Sci ; 38(19): 2177-2185, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32520644

RESUMO

The aim of this study was to compare the effects of 20 min neuromuscular training with a programme of 10 min in youth football players. 342 (15.4 ± 1.7 years) male football players from 18 teams were included, and cluster-randomized by team into two intervention groups. Both groups performed an injury prevention programme twice a week over five months using the same exercises but a different duration. The first intervention group (INT10, n = 175) performed the programme for 10 min, the second intervention group (INT20, n = 167) for 20 min. Primary outcomes were lower extremity (LE) injuries. Secondary outcomes were injury type, severity, mechanism and compliance to the intervention. 13 teams with 185 players were included for final analysis. No significant group difference was found between INT10 (6.37 per 1000 h) and INT20 (7.20 per 1000 h) for the incidence rate ratio of the lower extremities (IRR = 1.03, 95% confidence interval 0.59, 1.79), nor for the distribution of injury location, type, severity or mechanism. The results show that performing preventive exercises for 10 min is no less effective than 20 min in youth football players. Shorter training sessions can, therefore, be effectively used for injury prevention. TRIAL REGISTRATION: DRKS00015282.


Assuntos
Extremidade Inferior/lesões , Condicionamento Físico Humano/métodos , Futebol/lesões , Adolescente , Antropometria , Traumatismos em Atletas/epidemiologia , Traumatismos em Atletas/prevenção & controle , Alemanha/epidemiologia , Humanos , Incidência , Masculino , Fatores de Tempo , Adulto Jovem
13.
PLoS One ; 15(6): e0234027, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32497061

RESUMO

INTRODUCTION: We repeated our study of intensified training on a ketogenic low-carbohydrate (CHO), high-fat diet (LCHF) in world-class endurance athletes, with further investigation of a "carryover" effect on performance after restoring CHO availability in comparison to high or periodised CHO diets. METHODS: After Baseline testing (10,000 m IAAF-sanctioned race, aerobic capacity and submaximal walking economy) elite male and female race walkers undertook 25 d supervised training and repeat testing (Adapt) on energy-matched diets: High CHO availability (8.6 g∙kg-1∙d-1 CHO, 2.1 g∙kg-1∙d-1 protein; 1.2 g∙kg-1∙d-1 fat) including CHO before/during/after workouts (HCHO, n = 8): similar macronutrient intake periodised within/between days to manipulate low and high CHO availability at various workouts (PCHO, n = 8); and LCHF (<50 g∙d-1 CHO; 78% energy as fat; 2.1 g∙kg-1∙d-1 protein; n = 10). After Adapt, all athletes resumed HCHO for 2.5 wk before a cohort (n = 19) completed a 20 km race. RESULTS: All groups increased VO2peak (ml∙kg-1∙min-1) at Adapt (p = 0.02, 95%CI: [0.35-2.74]). LCHF markedly increased whole-body fat oxidation (from 0.6 g∙min-1 to 1.3 g∙min-1), but also the oxygen cost of walking at race-relevant velocities. Differences in 10,000 m performance were clear and meaningful: HCHO improved by 4.8% or 134 s (95% CI: [207 to 62 s]; p < 0.001), with a trend for a faster time (2.2%, 61 s [-18 to +144 s]; p = 0.09) in PCHO. LCHF were slower by 2.3%, -86 s ([-18 to -144 s]; p < 0.001), with no evidence of superior "rebound" performance over 20 km after 2.5 wk of HCHO restoration and taper. CONCLUSION: Our previous findings of impaired exercise economy and performance of sustained high-intensity race walking following keto-adaptation in elite competitors were repeated. Furthermore, there was no detectable benefit from undertaking an LCHF intervention as a periodised strategy before a 2.5-wk race preparation/taper with high CHO availability. TRIAL REGISTRATION: Australia New Zealand Clinical Trial Registry: ACTRN12619000794101.


Assuntos
Desempenho Atlético , Dieta Hiperlipídica , Dieta Cetogênica , Condicionamento Físico Humano , Caminhada , Adaptação Fisiológica , Atletas , Feminino , Humanos , Masculino , Condicionamento Físico Humano/métodos , Resistência Física
14.
Int J Sports Med ; 41(11): 759-765, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32492734

RESUMO

A combination of yoga and blood flow restriction, each of which elicits marked pressor responses, may further increase blood pressure and myocardial oxygen demand. To determine the impact of a combination of yoga and blood flow restriction on hemodynamic responses, twenty young healthy participants performed 20 yoga poses with/without blood flow restriction bands placed on both legs. At baseline, there were no significant differences in any of the variables between the blood flow restriction and non-blood flow restriction conditions. Blood pressure and heart rate increased in response to the various yoga poses (p<0.01) but were not different between the blood flow restriction and non-blood flow restriction conditions. Rate-pressure products, an index of myocardial oxygen demand, increased significantly during yoga exercises with no significant differences between the two conditions. Rating of perceived exertion was not different between the conditions. Blood lactate concentration was significantly greater after performing yoga with blood flow restriction bands (p=0.007). Cardio-ankle vascular index, an index of arterial stiffness, decreased similarly after yoga exercise in both conditions while flow-mediated dilation remained unchanged. In conclusion, the use of lower body blood flow restriction bands in combination with yoga did not result in additive or synergistic hemodynamic and pressor responses.


Assuntos
Pressão Sanguínea , Hemodinâmica , Condicionamento Físico Humano/métodos , Fluxo Sanguíneo Regional , Coxa da Perna/irrigação sanguínea , Ioga , Adolescente , Adulto , Estudos Cross-Over , Endotélio Vascular/fisiologia , Feminino , Frequência Cardíaca , Humanos , Ácido Láctico/sangue , Masculino , Miocárdio/metabolismo , Consumo de Oxigênio , Percepção/fisiologia , Condicionamento Físico Humano/fisiologia , Esforço Físico/fisiologia , Rigidez Vascular , Vasodilatação , Adulto Jovem
16.
Int J Sports Med ; 41(12): 839-845, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32590846

RESUMO

The effects of wearing an intra-oral device on several ventilatory and fatigue markers have been reported for a variety of sports. The quality of the figures performed in synchronized swimming is directly affected by fatigue, and can be monitored during training sessions (TS). The aim of the study was to investigate the acute effects of wearing customized intra-oral devices on heart rate variability, rating of perceived exertion, blood lactate accumulation, and salivary cortisol production during a competitive training session. Twelve highly trained elite female athletes (age: 21.0±3.6 years) participated in the study. Fatigue markers were assessed at the beginning and at the end of the 3rd and 5th afternoon TS for that week, once with and once without an intra-oral device, in random order. Salivary cortisol levels were higher in relation to the baseline in the intra-oral device condition (P<0.05) but not in athletes without an intra-oral device. No differences between conditions were found in rating of perceived exertion (P=0.465) and blood lactate (P=0.711). No time or condition interactions or main effects were shown for heart rate variability. Thus, there is no evidence that wearing a low-arch intra-oral device is a good recommendation for high-standard athletes performing long and stressful routines.


Assuntos
Comportamento Competitivo/fisiologia , Protetores Bucais , Condicionamento Físico Humano/fisiologia , Natação/fisiologia , Desenho de Equipamento , Feminino , Frequência Cardíaca , Humanos , Hidrocortisona/metabolismo , Arcada Osseodentária , Ácido Láctico/sangue , Percepção/fisiologia , Condicionamento Físico Humano/métodos , Esforço Físico/fisiologia , Ventilação Pulmonar , Saliva/metabolismo , Adulto Jovem
17.
Int J Sports Med ; 41(12): 824-831, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32599642

RESUMO

This study investigated acute hemodynamic, plasma volume and immunological responses to four loading protocols: sauna only, and sauna after endurance, strength or combined endurance and strength exercise. Twenty-seven healthy, slightly prehypertensive men (age 32.7±6.9 years) were measured at PRE, MID (after exercise), POST, POST30min and POST24h. The measurements consisted systolic and diastolic blood pressure, heart rate, body temperature and concentrations of high-sensitive C-reactive protein, white blood cells and plasma volume measurements. Endurance+sauna showed significant decreases in systolic blood pressure at POST (-8.9 mmHg), POST30min (-11.0 mmHg) and POST24h (-4.6 mmHg). At POST30min, significant decreases were also observed in sauna (-4.3 mmHg) and combined+sauna (-7.5 mmHg). Diastolic blood pressure decreased significantly from -5.4 to -3.9 mmHg at POST in all loadings. Plasma volume decreased significantly at MID in all exercise loadings and at POST in endurance+sauna and strength+sauna. Plasma volume increased significantly (p < 0.01) in endurance+sauna and combined+sauna at POST24h. White blood cells increased following all exercise+sauna loadings at MID, POST and POST30min, whereas high sensitive C-reactive protein showed no changes at any measurement point. The combination of endurance exercise and sauna showed the greatest positive effects on blood pressure. Both loadings including endurance exercise increased plasma volume on the next day.


Assuntos
Exercício Físico/fisiologia , Hemodinâmica , Banho a Vapor , Adulto , Pressão Sanguínea , Temperatura Corporal , Proteína C-Reativa/metabolismo , Frequência Cardíaca , Humanos , Contagem de Leucócitos , Masculino , Neutrófilos , Condicionamento Físico Humano/métodos , Condicionamento Físico Humano/fisiologia , Resistência Física/fisiologia , Volume Plasmático , Treinamento de Resistência
18.
Med Sci Sports Exerc ; 52(7): 1629-1638, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32541378

RESUMO

INTRODUCTION: Regulatory efforts toward reducing concussion risk have begun to focus on decreasing the number of head impacts (i.e., head impact burden) sustained by athletes in contact sports. To that end, in 2018, the NCAA decreased the number of preseason on-field team activities for Division I teams from 29 to 25. The objective of the current study was to quantify changes in practice schedule and head impact exposure between the 2017 and 2018 football preseasons. METHODS: Athletes from five NCAA Division I football teams (n = 426) were consented and enrolled. RESULTS: On average, athletes participated in 10% fewer contact practices in 2018. However, the effect of this ruling on preseason head impact burden was mixed. Across all athletes, the total preseason head impact burden was essentially the same from 2017 to 2018. However, this study revealed significant team-by-team differences in preseason head impact burden, with one team demonstrating a 35% increase in the average number of recorded head impacts from 2017 to 2018, despite a modest decrease in the number of contact practices. Other teams had similar or decreased head impact burden. CONCLUSIONS: Team-based differences in total preseason head impact burden were attributable to changes in daily practice schedule, with longer practice durations and more intense contact practice sessions contributing to increases in daily head impact exposure that, in turn, led to greater preseason head impact burden. Results of this study have highlighted the difficulty in decreasing contact sport head impact exposure through rule changes targeted at limiting on-field team activities. Future efforts aimed specifically at contact practice duration, daily head impact exposure, or limiting time in specific drills may be more effective at reducing total preseason head impact burden.


Assuntos
Concussão Encefálica/prevenção & controle , Futebol Americano/fisiologia , Cabeça/fisiologia , Condicionamento Físico Humano , Fenômenos Biomecânicos , Concussão Encefálica/fisiopatologia , Humanos , Política Organizacional , Condicionamento Físico Humano/métodos , Condicionamento Físico Humano/fisiologia , Comportamento de Redução do Risco , Esportes , Fatores de Tempo
19.
J Sports Sci ; 38(18): 2155-2160, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32543286

RESUMO

Imitation jumps are frequently used in training for ski jumping. Yet, the dynamics of these jumps differ considerably. Thus, the relevance of imitation jumps for ski jumping performance is not elucidated. The aim of this study was to investigate the relationship between the technical execution of imitation jumps and ski jumping performance level. We compared the imitation jumps of 11 ski jumpers of different performance levels using a Spearman correlation transform of time traces of the kinetics (measured using force cells and motion capture) of imitation jumps. The kinetic aspects that were related to performance centred on the moment arm of ground reaction force to the centre of mass before the onset of the push-off, angular momentum early in push-off, thigh angle during the main period of push-off and vertical velocity towards the end of push-off. We propose that the thigh angle may be a key element allowing high development of linear momentum while preparing for appropriate aerodynamic position. Furthermore, the findings suggest that the kinetic development prior to (and during) push-off is more important than the kinematic end state at take-off.


Assuntos
Desempenho Atlético/fisiologia , Destreza Motora/fisiologia , Condicionamento Físico Humano/métodos , Esqui/fisiologia , Fenômenos Biomecânicos , Comportamento Competitivo/fisiologia , Humanos , Masculino , Análise e Desempenho de Tarefas , Adulto Jovem
20.
Int J Sports Med ; 41(11): 736-743, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32485779

RESUMO

Injuries of runners reduce the ability to train and hinder competing. Literature shows that the relation between potential risk factors and injuries are not definitive, limited, and inconsistent. In team sports, workload derivatives were identified as risk factors. However, there is an absence of literature in running on workload derivatives. This study used the workload derivatives acute workload, chronic workload, and acute: chronic workload ratios to investigate the relation between workload and injury risk in running. Twenty-three competitive runners kept a daily training log for 24 months. The runners reported training duration, training intensity and injuries. One-week (acute) and 4-week (chronic) workloads were calculated as the average of training duration multiplied by training intensity. The acute:chronic workload ratio was determined dividing the acute and chronic workloads. Results show that a fortnightly low increase of the acute:chronic workload ratio (0.10-0.78) led to an increased risk of sustaining an injury (p<0.001). Besides, a low increase of the acute:chronic workload ratio (0.05-0.62) between the second week and third week before an injury showed an association with increased injury risk (p=0.013). These findings demonstrate that the acute:chronic workload ratio relates to injury risk.


Assuntos
Comportamento Competitivo/fisiologia , Condicionamento Físico Humano/fisiologia , Corrida/lesões , Traumatismos em Atletas/fisiopatologia , Feminino , Humanos , Masculino , Percepção/fisiologia , Condicionamento Físico Humano/métodos , Esforço Físico/fisiologia , Fatores de Risco , Fatores de Tempo , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...