Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Sci Med Sport ; 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38944583

RESUMO

OBJECTIVES: To compare prevalence and change scores of disordered eating (DE) in combat sport athletes by sex and explore the potential relationship between rapid weight loss (RWL) and DE scores. DESIGN: Prospective study based on 24 events (September 2022-2023). METHODS: A body mass (BM) questionnaire was completed at ~1 day post-competition providing pre-competition BM data for -7 days, -24 h, and weigh-in. The Athletic Disordered Eating (ADE) online questionnaire was completed at ~7 and ~28 days post-competition, providing overall DE and four subscale scores (food and energy control, bingeing, body control, and body discontent). RESULTS: There were 122, 132, and 89 respondents for the BM (77 % male), and ADE questionnaires at 7 (79 % male), and 28 days (74 % male). A large proportion of males' (83 %) and females' (89 %) DE scores were moderate to very high; minimal (17 % vs. 11 %), moderate (36 % vs. 32 %), high (37 % vs. 36 %), and very high (11 % vs. 21 %). Comparing DE change scores in males and females indicated deterioration (5 % vs. 0 %), improvement (3 % vs. 25 %, p = 0.013), and no difference (92 % vs. 75 %). Body discontent change score showed a significant sex difference (p = 0.014), with females improving (42 % vs. 17 %, p = 0.035) and males deteriorating (35 % vs. 4 %, p = 0.008). Correlation analyses were significant for RWL -7 days and males' food control score (R = 0.22, p = 0.031). CONCLUSIONS: Moderate to very high DE indications were identified in 4 of every 5 combat sport competitors. A sex-specific change in body discontent is evident, and most competitors struggle with their food-body relationship post-competition, irrespective of RWL magnitude.

2.
Transl Sports Med ; 2024: 5531981, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38654722

RESUMO

This study aimed to investigate how overall competitive winningness in combat sports depended on patterns of victory and loss, as well as training habits. Competitors (N = 280) from several combat sports participated in the study. The online survey included questions on self-reported patterns of victory (and loss), training habits, general demographics (e.g., age), and sport-specific information (e.g., stage of career and competitive style). Overall, it was found across four models that reflected diversity of winningness in combat sports that the most important predictors of competitive winningness were loss by points (negative), loss by submission (negative), loss (negative) or victory (positive) by throw or technical fall, and loss (negative) or victory (positive) by knockout. The findings applied to amateur and regional/state athletes, and rarely to karate or tae kwon do. Findings around demographics or training habits were largely unremarkable, outside of a relationship between higher training loads and less career winning in wrestlers. Results show that while winning via a finishing sequence (e.g., knockout or submission) is preferable to the judge's decision or points, the matter of victory is less important than the methods by which an athlete loses. In grappling-only sports, we observed a trend that more losses via finishing sequence were worse for careers than losing by points. In fact, having most of one's losses coming via judge's decision or points was beneficial in wrestling and judo, perhaps due to athletes taking less risks and having better defence. These findings may aid practitioners developing effective tactics and training programs.

3.
Int J Sport Nutr Exerc Metab ; 34(2): 88-100, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38215737

RESUMO

This study investigated (a) differences between males and females for changes in serum, tear, and urine osmolality, hematocrit, and urine specific gravity following acute passive dehydration and (b) assessed the reliability of these biomarkers separately for each sex. Fifteen males (age: 26.3 ± 3.5 years, body mass: 76 ± 7 kg) and 15 females (age: 28.8 ± 6.4 years, body mass: 63 ± 7 kg) completed a sauna protocol twice (5-28 days apart), aiming for 4% body mass loss (BML). Urine, blood, and tear markers were collected pre- and postdehydration, and change scores were calculated. Male BML was significantly greater than that of females in Trial 1 (3.53% ± 0.55% vs. 2.53% ± 0.43%, p < .001) and Trial 2 (3.36% ± 0.66% vs. 2.53% ± 0.44%, p = .01). Despite significant differences in BML, change in hematocrit was the only change marker that displayed a significant difference in Trial 1 (males: 3% ± 1%, females: 2% ± 1%, p = .004) and Trial 2 (males: 3% ± 1%, females: 1% ± 1%, p = .008). Regression analysis showed a significant effect for sex (male) predicting change in hematocrit (ß = 0.8, p = .032) and change in serum osmolality (ß = -3.3, p = .005) when controlling for BML but not for urinary or tear measures. The intraclass correlation coefficients for females (ICC 2, 1) were highest for change in urine specific gravity (ICC = .62, p = .006) and lowest for change in tear osmolarity (ICC = -.14, p = .689), whereas for males, it was posthematocrit (ICC = .65, p = .003) and post tear osmolarity (ICC = .18, p = .256). Generally, biomarkers showed lower test-retest reliability in males compared with females but, overall, were classified as poor-moderate in both sexes. These findings suggest that the response and reliability of hydration biomarkers are sex specific and highlight the importance of accounting for BML differences.


Assuntos
Desidratação , Caracteres Sexuais , Humanos , Masculino , Feminino , Adulto Jovem , Adulto , Reprodutibilidade dos Testes , Exercício Físico/fisiologia , Concentração Osmolar , Biomarcadores/urina
4.
J Strength Cond Res ; 37(12): 2397-2404, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37815246

RESUMO

ABSTRACT: Smolarek, T, Haff, GG, Poon, WCK, Nagatani, T, Barley, OR, and Guppy, SN. Dynamic and isometric force-time curve characteristics influencing change of direction performance of state-level netball players. J Strength Cond Res 37(12): 2397-2404, 2023-Although multiple lower-body strength capacities are required to change direction rapidly, there is limited knowledge about the relative importance of these factors. Therefore, the purpose of this study was to assess the relationship between dynamic and isometric lower-body strength capacities and change of direction (COD) time in state-league netball players. Seventeen female athletes completed maximal isometric midthigh pull (IMTP), countermovement jump (CMJ), and modified 5-0-5 COD tests. Pearson's product moment correlations were used to determine the relationship between COD time and several IMTP and CMJ force-time curve characteristics. To assess the level of contribution of each force-time curve characteristic to COD time, multivariate-linear stepwise regression analyses were performed. A significant moderate correlation was noted between net relative peak force (PF) during the IMTP and COD time ( r = 0.488, p = 0.047), accounting for 23.8% of the variance in COD time. Moreover, concentric relative impulse during the CMJ was strongly correlated with COD time ( r = 0.718; p = 0.001), explaining 81.9% of the variance in COD time when combined with net relative braking PF in a stepwise regression. Based on these findings, female netball players who display higher concentric and isometric strength, as well as the ability to express higher impulses during the concentric phase of the CMJ, are likely to perform CODs faster. This may occur because COD requires the generation of greater propulsive forces, as well as reduced braking and contact times, along with greater isometric strength enabling effective repositioning of center of mass during COD tasks.


Assuntos
Desempenho Atlético , Basquetebol , Humanos , Feminino , Contração Isométrica , Força Muscular , Músculo Esquelético , Teste de Esforço
5.
Psychol Rep ; : 332941231201951, 2023 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-37732934

RESUMO

The purpose of this study was to compare the psychometric properties of two measures of alexithymia - the Toronto Alexithymia Scale (TAS-20) and the Perth Alexithymia Questionnaire (PAQ) - as well as the Barratt Impulsiveness Scale 11 measure of behavioural impulsivity because the psychometric properties of these scales have not been established in athletes. As part of a larger study, 298 participants completed an online survey that included the TAS-20, PAQ, and BIS 11, as well personal- (age and gender) and sport-specific (primary combat sport and level of competition) demographic measures. A unidimensional model was retained for the TAS-20. A unidimensional model with the possibility of multidimensional measure was retained for the PAQ, with the viability of a subscale for Generalised Externally Orientated Thinking supported. The only versions of the BIS that were retainable were unidimensional models for the BIS-15 (a 15-item version of the BIS 11) and the BIS-Brief (an 8-item version of the BIS 11). As expected, the measures of alexithymia were highly correlated. The associations between impulsivity and alexithymia as well as age and alexithymia were small in nature, with none these associations moderated by level of gender, level of competition, or primary sport for the participants. No differences in alexithymia or impulsivity according to gender, level of competition, or primary sport were noted for the participants. Implications of these findings for the measures of alexithymia - the TAS-20 and PAQ - and impulsivity - the BIS-15 and BIS-Brief - examined in the present study with athletes (as well as with other populations) are discussed.

6.
Phys Sportsmed ; 51(3): 228-233, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-34989282

RESUMO

OBJECTIVES: The International Judo Federation (IJF) implemented new regulations in an attempt to regulate rapid weight loss in 2013. The body weight of the athletes cannot be more than 5% higher than the upper limits of their weight categories at the weight check for randomly selected athletes from each weight category before the competition. However, therea lack of studies demonstrating rapid weight loss and hydration status of elite judo athletes in a real match atmosphere under the current refereeing rules. Thus, this study aimed to examine the body mass and hydration changes of elite judo athletes a week before the competition, official weigh-in, and 24 hours after competition. METHODS: Eight high-level male judo athletes voluntarily participated in this study. Body mass and urinary measures of hydration status were collected a week before, at the official weigh-in and 24-hour post-weigh-in. RESULTS: The one-way repeated-measures ANOVA showed a significant main effect of time on body mass (p < 0.001). Body mass decreased by 5.4 ± 0.7 kg or 6.8% from a week before the competition to official weigh-in (p < 0.001) and increased by 3.0 ± 1.1 kg or 4.2% from official weigh-in to 24-h post-competition (p < 0.001). A significant effect of time was also found in both urine-specific gravity (USG) (p < 0.001) and urine color (UC) among the measurements (p = 0.001). Athletes' USG values were at the highest level (USG = 1.030 ± 0.001) at the official weigh-in, while they decreased significantly at 24-hour post-competition (USG = 1.017 ± 0.007). CONCLUSION: The results showed that elite judo athletes resort to rapid weight loss and present dehydration despite established regulations by the IJF.


Assuntos
Desidratação , Artes Marciais , Humanos , Masculino , Atletas , Urinálise , Redução de Peso
7.
Int J Exerc Sci ; 14(4): 941-961, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34567372

RESUMO

Mixed martial arts (MMA) is a combat sport that employs techniques from different combat disciplines. There are a multitude of technical and physiological characteristics that contribute to competitive success. Developing a single scientific assessment that can predict competitive outcomes poses great difficulty due to the complexity of MMA. While previous research has investigated some important physiological characteristics, there is no accepted best-practice for a comprehensive testing battery. As such, this study aimed to design and utilize a battery of physiological assessments to cover aerobic and anaerobic function, strength measures including explosive and maximal strength, body composition and repeat effort ability in Australian MMA athletes. Six participants with competitive experience were recruited. Testing involved a familiarization, three experimental sessions and including assessments such as the isometric midthigh pull, Wingate test, graded exercise test, countermovement jump and body composition scan. Results showed the testing battery in this study was realistic and able to be completed by the participants without issue and that regional Australian MMA athletes were similar physiologically to elite standard compared with previous research taken from a range of sources. However, future research with the testing battery is required with larger and more diverse samples to better understand the full profiles of MMA athletes. The results of the study can help inform athletes, researchers and support staff alike when deciding upon which testing protocols to use for MMA athletes. Future research should aim to develop normative data using the battery proposed in the current study.

8.
Sports Med Open ; 7(1): 63, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34432137

RESUMO

BACKGROUND: This study aimed to investigate the competitive history (the age when training and competing started), training habits and patterns of winning and losing of competitive combat sports athletes across different combat sports as well as the level of competition (e.g. amateurs, state-level and elite). METHODS: Competitors (N = 298) from mixed martial arts (MMA), Muay Thai/kickboxing, boxing, Brazilian jiu-jitsu (BJJ), wrestling, judo and traditional striking sports (TSS) completed an online questionnaire. RESULTS: Most athletes began competing in their mid-teenage years and competing soon after except for wrestlers who began earlier. Elite athletes began training earlier than amateurs (13.75 ± 7.75 years and 16.2 ± 7.45 years, p<0.01, respectively). Training habits were similar across sports (~4 combat and ~3 non-combat training sessions per week), except for MMA and wrestling which did more combat sports-specific training than Judo and TSS. Wrestlers did more non-combat sports-specific training than all other sports. Elite athletes completed more combat sessions per week than their lower-level contemporaries (4.64 ± 2.49 and 3.9 ± 1.44, p=0.01, respectively). Patterns of winning or losing were consistent across sports, except for amateur athletes who were more likely to report all their victories by points and none of their victories by submission or pin. Additionally, elite athletes are less likely to report none of their victories coming by knockout. CONCLUSIONS: Results may indicate that finishing ability is a key distinguisher of competitive level. The present study provides normative data for training and competing habits for athletes, support staff and regulators to use.

9.
Eur J Appl Physiol ; 121(4): 1087-1097, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33439308

RESUMO

PURPOSE: We examined changes in plasma creatine kinase (CK) activity, hydroxyproline and cell-free DNA (cfDNA) concentrations in relation to changes in maximum voluntary isometric contraction (MVIC) torque and delayed-onset muscle soreness (DOMS) following a session of volume-matched higher- (HI) versus lower-intensity (LI) eccentric cycling exercise. METHODS: Healthy young men performed either 5 × 1-min HI at 20% of peak power output (n = 11) or 5 × 4-min LI eccentric cycling at 5% of peak power output (n = 9). Changes in knee extensor MVIC torque, DOMS, plasma CK activity, and hydroxyproline and cfDNA concentrations before, immediately after, and 24-72 h post-exercise were compared between groups. RESULTS: Plasma CK activity increased post-exercise (141 ± 73.5%) and MVIC torque decreased from immediately (13.3 ± 7.8%) to 48 h (6.7 ± 13.5%) post-exercise (P < 0.05), without significant differences between groups. DOMS was greater after HI (peak: 4.5 ± 3.0 on a 10-point scale) than LI (1.2 ± 1.0). Hydroxyproline concentration increased 40-53% at 24-72 h after both LI and HI (P < 0.05). cfDNA concentration increased immediately after HI only (2.3 ± 0.9-fold, P < 0.001), with a significant difference between groups (P = 0.002). Lack of detectable methylated HOXD4 indicated that the cfDNA was not derived from skeletal muscle. No significant correlations were evident between the magnitude of change in the measures, but the cfDNA increase immediately post-exercise was correlated with the maximal change in heart rate during exercise (r = 0.513, P = 0.025). CONCLUSION: Changes in plasma hydroxyproline and cfDNA concentrations were not associated with muscle fiber damage, but the increased hydroxyproline in both groups suggests increased collagen turnover. cfDNA may be a useful metabolic-intensity exercise marker.


Assuntos
Ácidos Nucleicos Livres/sangue , Teste de Esforço/métodos , Hidroxiprolina/sangue , Contração Isométrica , Adulto , Creatina Quinase/sangue , Teste de Esforço/efeitos adversos , Frequência Cardíaca , Humanos , Masculino , Mialgia/sangue , Torque
10.
Artigo em Inglês | MEDLINE | ID: mdl-33255390

RESUMO

It is common practice in combat sports that athletes rapidly lose body weight before a match, by applying different practices-some safer and others possibly dangerous. The factors behind the choice of practices utilised have not been fully studied. This study aimed to investigate the weight loss strategies used by Italian boxers and to look at the difference between higher and lower risk practice adaptors. A modified version of a validated questionnaire has been sent to 164 amateur (88%) and professional (12%) boxers by email. A heatmap with hierarchical clustering was used to explore the presence of subgroups. Weight loss strategies were used by 88% of the athletes. Two clusters were found, defined by the severity of weight loss behaviours. Professional fighters, high-level athletes and females were more represented in Cluster 2, the one with more severe weight-loss practices. These athletes were characterised by a higher weight loss magnitude and frequency throughout the season and reported being more influenced by physicians and nutritionists, compared with the boxers in Cluster 1. Not all the weight loss practices are used with the same frequency by all boxers. The level of the athlete and the boxing style have an influence on the weight-cutting practices.


Assuntos
Boxe , Análise por Conglomerados , Redução de Peso , Adolescente , Adulto , Peso Corporal/fisiologia , Boxe/estatística & dados numéricos , Feminino , Humanos , Itália , Masculino , Inquéritos e Questionários , Adulto Jovem
11.
J Int Soc Sports Nutr ; 17(1): 52, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-33126891

RESUMO

BACKGROUND: Despite a substantial body of research, no clear best practice guidelines exist for the assessment of hydration in athletes. Body water is stored in and shifted between different sites throughout the body complicating hydration assessment. This review seeks to highlight the unique strengths and limitations of various hydration assessment methods described in the literature as well as providing best practice guidelines. MAIN BODY: There is a plethora of methods that range in validity and reliability, including complicated and invasive methods (i.e. neutron activation analysis and stable isotope dilution), to moderately invasive blood, urine and salivary variables, progressing to non-invasive metrics such as tear osmolality, body mass, bioimpedance analysis, and sensation of thirst. Any single assessment of hydration status is problematic. Instead, the recommended approach is to use a combination, which have complementary strengths, which increase accuracy and validity. If methods such as salivary variables, urine colour, vital signs and sensation of thirst are utilised in isolation, great care must be taken due to their lack of sensitivity, reliability and/or accuracy. Detailed assessments such as neutron activation and stable isotope dilution analysis are highly accurate but expensive, with significant time delays due to data analysis providing little potential for immediate action. While alternative variables such as hormonal and electrolyte concentration, bioimpedance and tear osmolality require further research to determine their validity and reliability before inclusion into any test battery. CONCLUSION: To improve best practice additional comprehensive research is required to further the scientific understanding of evaluating hydration status.


Assuntos
Água Corporal/fisiologia , Ingestão de Líquidos , Esportes/fisiologia , Absorciometria de Fóton , Fenômenos Fisiológicos Sanguíneos , Índice de Massa Corporal , Desidratação/prevenção & controle , Impedância Elétrica , Hematócrito , Hormônios/sangue , Humanos , Análise de Ativação de Nêutrons , Concentração Osmolar , Saliva/química , Soro/fisiologia , Sódio/sangue , Lágrimas/química , Sede/fisiologia , Urinálise , Sinais Vitais
12.
Eur J Appl Physiol ; 120(5): 1015-1025, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32170443

RESUMO

PURPOSE: We compared high- and low-intensity eccentric cycling (ECC) with the same mechanical work for changes in muscle function and muscle soreness, and examined the changes after subsequent high-intensity ECC. METHODS: Twenty men performed either high-intensity ECC (1 min × 5 at 20% of peak power output: PPO) for two bouts separated by 2 weeks (H-H, n = 11), or low-intensity (4 min × 5 at 5% PPO) for the first and high-intensity ECC for the second bout (L-H, n = 9). Changes in indirect muscle damage markers were compared between groups and bouts. RESULTS: At 24 h after the first bout, both groups showed similar decreases in maximal isometric (70° knee angle, - 10.6 ± 11.8%) and isokinetic ( - 11.0 ± 8.2%) contraction torque of the knee extensors (KE), squat ( - 7.7 ± 10.4%) and counter-movement jump ( - 5.9 ± 8.4%) heights (p < 0.05). Changes in KE torque and jump height were smaller after the second than the first bout for both the groups (p < 0.05). Increases in plasma creatine kinase activity were small, and no significant changes in vastus lateralis or intermedius thickness nor ultrasound echo-intensity were observed. KE soreness with palpation was greater (p < 0.01) in H-H (peak: 4.2 ± 1.0) than L-H (1.4 ± 0.6) after the first bout, but greater in L-H (3.6 ± 0.9) than H-H (1.5 ± 0.5) after the second bout. This was also found for muscle soreness with squat, KE stretch and gluteal palpation. CONCLUSION: The high- and low-intensity ECC with matched mechanical work induced similar decreases in muscle function, but DOMS was greater after high-intensity ECC, which may be due to greater extracellular matrix damage and inflammation.


Assuntos
Ciclismo/fisiologia , Exercício Físico , Contração Muscular , Força Muscular , Músculo Esquelético/fisiopatologia , Mialgia/fisiopatologia , Adulto , Creatina Quinase/sangue , Humanos , Masculino , Fenômenos Mecânicos , Atividade Motora , Mialgia/sangue , Adulto Jovem
13.
Int J Sports Physiol Perform ; 15(2): 213-221, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31094260

RESUMO

PURPOSE: To examine the influence of fluid intake on heat acclimation and the subsequent effects on exercise performance following acute hypohydration. METHODS: Participants were randomly assigned to 1 of 2 groups, either able to consume water ad libitum (n = 10; age 23 [3] y, height 1.81 [0.09] m, body mass 87 [13] kg; HAW) or not allowed fluid (n = 10; age 26 [5] y, height 1.76 [0.05] m, body mass 79 [10] kg; HANW) throughout 12 × 1.5-h passive heat-acclimation sessions. Experimental trials were completed on 2 occasions before (2 baseline trials) and 1 following the heat-acclimation sessions. These sessions involved 3 h of passive heating (45°C, 38% relative humidity) to induce hypohydration followed by 3 h of ad libitum food and fluid intake after which participants performed a repeat sled-push test to assess physical performance. Urine and blood samples were collected before, immediately, and 3 h following hypohydration to assess hydration status. Mood was also assessed at the same time points. RESULTS: No meaningful differences in physiological or performance variables were observed between HANW and HAW at any time point. Using pooled data, mean sprint speed was significantly (P < .001) faster following heat acclimation (4.6 [0.7] s compared with 5.1 [0.8] s). Furthermore, heat acclimation appeared to improve mood following hypohydration. CONCLUSIONS: Results suggest that passive heat-acclimation protocols may be effective at improving short-duration repeat-effort performance following acute hypohydration.


Assuntos
Aclimatação , Desempenho Atlético/fisiologia , Desidratação/fisiopatologia , Ingestão de Líquidos/fisiologia , Temperatura Alta , Redução de Peso , Afeto , Desempenho Atlético/psicologia , Pressão Sanguínea , Cognição , Frequência Cardíaca , Humanos , Masculino , Análise e Desempenho de Tarefas
14.
Sports (Basel) ; 7(5)2019 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-31117325

RESUMO

In combat sports, athletes are divided into categories based on gender and body mass. Athletes attempt to compete against a lighter opponent by losing body mass prior to being weighed (i.e., 'weight-cutting'). The purpose of this narrative review was to explore the current body of literature on weight-cutting and outline gaps for further research. Methods of weight-loss include energy intake restriction, total body fluid reduction and pseudo extreme/abusive medical practice (e.g., diuretics). The influence of weight-cutting on performance is unclear, with studies suggesting a negative or no effect. However, larger weight-cuts (~5% of body mass in <24 h) do impair repeat-effort performance. It is unclear if the benefit from competing against a smaller opponent outweighs the observed reduction in physical capacity. Many mechanisms have been proposed for the observed reductions in performance, ranging from reduced glycogen availability to increased perceptions of fatigue. Athletes undertaking weight-cutting may be able to utilise strategies around glycogen, total body water and electrolyte replenishment to prepare for competition. Despite substantial discussion on managing weight-cutting in combat sports, no clear solution has been offered. Given the prevalence of weight-cutting, it is important to develop a deeper understanding of such practices so appropriate advice can be given.

15.
Front Physiol ; 10: 205, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30906267

RESUMO

Combat sports encompass a range of sports, each involving physical combat between participants. Such sports are unique, with competitive success influenced by a diverse range of physical characteristics. Effectively identifying and evaluating each characteristic is essential for athletes and support staff alike. Previous research investigating the relationship between combat sports performance and measures of strength and power is robust. However, research investigating the relationship between combat sports performance and assessments of endurance is less conclusive. As a physical characteristic, endurance is complex and influenced by multiple factors including mechanical efficiency, maximal aerobic capacity, metabolic thresholds, and anaerobic capacities. To assess endurance of combat sports athletes, previous research has employed methods ranging from incremental exercise tests to circuits involving sports-specific techniques. These tests range in their ability to discern various physiological attributes or performance characteristics, with varying levels of accuracy and ecological validity. In fact, it is unclear how various physiological attributes influence combat sport endurance performance. Further, the sensitivity of sports specific skills in performance based tests is also unclear. When developing or utilizing tests to better understand an athletes' combat sports-specific endurance characteristic, it is important to consider what information the test will and will not provide. Additionally, it is important to determine which combination of performance and physiological assessments will provide the most comprehensive picture. Strengthening the understanding of assessing combat sport-specific endurance as a physiological process and as a performance metric will improve the quality of future research and help support staff effectively monitor their athlete's characteristics.

16.
Front Physiol ; 9: 1562, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30450056

RESUMO

Introduction/Purpose: This study examined the influence of acute dehydration on neuromuscular function. Methods: On separate days, combat sports athletes experienced in acute dehydration practices (n = 14) completed a 3 h passive heating intervention (40°C, 63% relative humidity) to induce dehydration (DHY) or a thermoneutral euhydration control (25°C, 50% relative humidity: CON). In the ensuing 3 h ad libitum fluid and food intake was allowed, after which participants performed fatiguing exercise consisting of repeated unilateral knee extensions at 85% of their maximal voluntary isometric contraction (MVIC) torque until task failure. Both before and after the fatiguing protocol participants performed six MVICs during which measures of central and peripheral neuromuscular function were made. Urine and whole blood samples to assess urine specific gravity, urine osmolality, haematocrit and serum osmolality were collected before, immediately and 3 h after intervention. Results: Body mass was reduced by 3.2 ± 1.1% immediately after DHY (P < 0.001) but recovered by 3 h. Urine and whole blood markers indicated dehydration immediately after DHY, although blood markers were not different to CON at 3 h. Participants completed 28% fewer knee extensions at 85% MVIC (P < 0.001, g = 0.775) and reported a greater perception of fatigue (P = 0.012) 3 h after DHY than CON despite peak torque results being unaffected. No between-condition differences were observed in central or peripheral indicators of neuromuscular function at any timepoint. Conclusion: Results indicate that acute dehydration of 3.2% body mass followed by 3 h of recovery impairs muscular strength-endurance and increases fatigue perception without changes in markers of central or peripheral function. These findings suggest that altered fatigue perception underpins muscular performance decrements in recovery from acute dehydration.

17.
Int J Sports Physiol Perform ; 13(7): 933-939, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29283792

RESUMO

CONTEXT: Combat sports are typically divided into weight classes, and body-mass manipulation to reach a weight class is commonplace. Previous research suggests that weight loss practices in mixed martial arts (MMA) may be more extreme than in other combat sports. PURPOSE: To investigate the magnitude of weight loss and the prevalence of weight loss strategies in different combat sports. METHODS: Competitors (N = 637) from Brazilian jiu-jitsu, boxing, judo, MMA, Muay Thai/kickboxing, taekwondo, and wrestling completed an online questionnaire seeking information regarding their weight loss practices. RESULTS: Body-mass manipulation was commonly undertaken by all combat-sport athletes, with a particularly high incidence of gradual dieting, increased exercise, and fluid restriction. Skipping meals was higher in taekwondo and wrestling (84%) compared with the other combat sports (∼58%), whereas training in heated rooms and forced oral fluid loss (spitting) was higher in wrestling (83% and 47%, respectively) compared with other combat sports (∼45% and ∼19%, respectively). MMA athletes reported the highest usage of sauna (76%) and water loading (67%) while also reporting the second-highest use of training in rubber/plastic suits (63%). CONCLUSIONS: Body-mass manipulation was present in all combat sports, with the prevalence and magnitude of acute weight loss greater in MMA. The incidence of and practices reported will help support staff be fully aware of the variety of methods these athletes and coaches may use to achieve weight loss. Additionally, the results could aid regulatory bodies in the further development of policies on weight cutting.


Assuntos
Boxe/fisiologia , Comportamento Competitivo/fisiologia , Artes Marciais/fisiologia , Redução de Peso , Luta Romana/fisiologia , Adulto , Índice de Massa Corporal , Boxe/classificação , Desidratação/etiologia , Feminino , Hábitos , Humanos , Masculino , Artes Marciais/classificação , Luta Romana/classificação , Adulto Jovem
18.
J Strength Cond Res ; 32(9): 2555-2561, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28930879

RESUMO

Barley, OR, Iredale, F, Chapman, DW, Hopper, A, and Abbiss, C. Repeat effort performance is reduced 24 hours after acute dehydration in mixed martial arts athletes. J Strength Cond Res 32(9): 2555-2561, 2018-This study sought to determine the influence of acute dehydration on physical performance and physiology in mixed martial arts (MMA). Mixed martial arts athletes (n = 14; age: 23 ± 4 years) completed in a randomized counterbalanced order a dehydration protocol, (DHY: 3-hour cycling at 60 W in 40° C to induce 5% dehydration) or thermoneutral control (25° C: CONT) exercise, followed by ad libitum fluid/food intake. Performance testing (a repeat sled push test, medicine ball chest throw, and vertical jump) was completed 3 hours and 24 hours after the intervention, whereas urine and blood samples were collected before, 20 minutes, 3 hours, and 24 hours after the intervention. Body mass was reduced (4.8 ± 0.8%) after DHY (p < 0.001) and remained lower than CONT at 3 hours and 24 hours after DHY (p = 0.003 and p = 0.024, respectively). Compared with CONT, average sled push times were slower 3 hours and 24 hours after DHY (19 ± 15%; p = 0.001; g = 1.229 and 14 ± 15%; p = 0.012; g = 0.671, respectively). When compared with the CONT, handgrip was weaker 3 hours after DHY (53 ± 8 and 51 ± 8 kg; p = 0.044, g = 0.243, respectively) and medicine ball chest throw distances were shorter 24 hours after DHY (474 ± 52 and 449 ± 44 cm; p = 0.016, g = 0.253, respectively). No significant differences were observed in vertical jump (p = 0.467). Urine specific gravity was higher than CONT 20 minutes (p = 0.035) and 24 hours (p = 0.035) after DHY. Acute dehydration of 4.8% body mass results in reduced physical performance 3 and 24 hours after DHY. There is need for caution when athletes use dehydration for weight loss 24 hours before competition.


Assuntos
Desempenho Atlético/fisiologia , Desidratação/fisiopatologia , Artes Marciais/fisiologia , Adolescente , Adulto , Estudos Cross-Over , Humanos , Masculino , Fatores de Tempo , Adulto Jovem
19.
J Strength Cond Res ; 31(5): 1165-1176, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28135219

RESUMO

Hopper, A, Haff, EE, Barley, OR, Joyce, C, Lloyd, RS, and Haff, GG. Neuromuscular training improves movement competency and physical performance measures in 11-13-year-old female netball athletes. J Strength Cond Res 31(5): 1165-1176, 2017-The purpose of this study was to examine the effects of a neuromuscular training (NMT) program on movement competency and measures of physical performance in youth female netball players. It was hypothesized that significant improvements would be found in movement competency and physical performance measures after the intervention. Twenty-three junior female netball players (age, 12.17 ± 0.94 years; height, 1.63 ± 0.08 m; weight, 51.81 ± 8.45 kg) completed a test battery before and after a 6-week training intervention. Thirteen of these athletes underwent 6 weeks of NMT, which incorporated plyometrics and resistance training. Trained athletes showed significant improvements in 20-m sprint time, 505 agility time, countermovement jump height, and peak power (p ≤ 0.05, g > 0.8). In addition, trained athletes significantly improved their score in the Netball Movement Screening Tool (NMST) (p < 0.05, g > -1.30); while the athletes also demonstrated increased reach in the anterior and posteromedial directions for the right leg and left leg, and in the posterolateral direction for the left leg only in the Star Excursion Balance Test (SEBT) (p < 0.05, g > -0.03). Control subjects did not exhibit any significant changes during the 6-week period. Significant negative correlations were found between improved score on the NMST and decreased 5-, 10-, and 20-m sprint time, and 505 change of direction time (r > 0.4, p ≤ 0.05). Results of the study affirm the hypothesis that a 6-week NMT intervention can improve performance and movement competency in youth netball players.


Assuntos
Desempenho Atlético/fisiologia , Movimento/fisiologia , Exercício Pliométrico , Treinamento Resistido , Esportes/fisiologia , Adolescente , Criança , Teste de Esforço , Feminino , Humanos , Extremidade Inferior , Masculino
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...