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1.
Abstract

This study examined the influence of match-related fatigue on physical and technical skill performance in ball playing positions at two different levels of rugby league competition. Time-motion analyses were performed using global positioning systems from 6 elite National Rugby League (NRL) and 11 junior elite National Youth Competition (NYC) players from 45 matches. A standardised 5-point technical coding criteria was used to qualitatively assess skill involvements during match-play. The distance travelled in the 0–5 and 40–45 min period were significantly higher compared to the 30–35, 35–40, 70–75 and 75–80 min periods (P < 0.001). Skill rating and involvements were higher in the 0–5 and 40–45 min compared to 70–75 and 75–80 min periods (P < 0.001 and P < 0.001, respectively).There was no significant difference in the number of physical collisions between the 5-min periods (P = 0.051). Following the peak 5-min bout of exercise intensity there were reductions in distance (P < 0.001), quality of skill involvements (P < 0.001), number of involvements (P < 0.001) and collisions (P < 0.001). Elite NRL and NYC “ball players” exhibit reductions in physical performance towards the end of matches and following brief periods of intense exercise. There also appears to be a reduction in technical performance for NRL and NYC ball players, which may be attributable to match-related fatigue.  相似文献   

2.
Abstract

Squash is a popular racket sport that requires intermittent activity with frequent bursts of near maximal-intensity exercise. Consequently, effective physiological and thermoregulatory responses are important contributors to performance during squash match-play. Controlled field-based simulation protocols have been introduced in a growing number of sports, which allow sports scientists to investigate changes in physiology and the efficacy of various interventions in sport-specific contexts. This study aimed to develop an exercise protocol that simulates the physiological requirements of elite squash match-play. Eight elite junior squash players (age 16.2 ± 0.8 years, height 1.76 ± 0.06 m, body mass 61.3 ± 5.9 kg; mean ± s) completed the following in a randomized order: (1) a squash match against a player of similar standard and (2) a squash-specific incremental exercise protocol (multistage squash test [MST]) followed by the squash simulation protocol (SSP). The multistage squash test was continued for 18.0 ± 1.0 min and elicited near maximal post-MST heart rates, blood lactate concentrations and ratings of perceived exertion (198 ± 9 beats · min?1, 5.7 ± 1.7 mmol · l?1 and 18 ± 1, respectively). The SSP was 12.2 min in length compared with mean game length during competitive matches of 10.0 ± 1.6 min (P = 0.27). Peak heart rates were similar during the SSP and match-play (192 ± 11 and 189 ± 6 beats · min?1, respectively; P = 0.44). Mean exercising heart rates were similar during the SSP (180 ± 8 beats · min?1) and match-play (179 ± 13 beats · min?1; P = 0.73). Peak blood lactate concentrations during the SSP and match-play were 3.5 ± 1.5 and 2.4 ± 1.2 mmol · l?1 (P = 0.07), respectively. Peak ratings of perceived exertion during the SSP and match-play were similar (17 ± 2 and 17 ± 2, respectively; P = 0.64). It was concluded that the SSP closely replicated the demands of squash match-play in elite junior squash players. Furthermore, the SSP provides coaches and scientific support staff with a controlled squash-specific exercise protocol that has potential application in the objective investigation of a range of interventions such as training programmes, nutritional supplements and strategies to maintain core body temperature.  相似文献   

3.
Background:Football is the most practised sport in the world and is associated with the risk of injuries in the players.Some studies have been published that identify injury prevention programs,but there is no review of the full body of evidence on injury prevention programs for use by football coaches.The aim of this article was to carry out a systematic review of published studies on injury prevention programs for adult male footballers,identify points of common understanding and establish recommendations that should be considered in the design of injury prevention strategies.Methods:PubMed and EMBASE databases were used to identify relevant published articles using the following keywords:"soccer"AND"injury"AND"prevention".Results:A total of 2512 studies were identified initially,but only 11 studies met the inclusion criteria,and their outcomes are presented.Results revealed that injury prevention programs in football have focused on strength training,proprioceptive training,multicomponent programs(balance,core stability,and functional strength and mobility),and warm-up programs.Conclusion:Based on results from the studies analyzed,football players can lower the incidence of match and training injuries by participating in dynamic warm-up programs that include preventive exercises before games or during training sessions,and by adding strength,balance,and mobility training to the training sessions.  相似文献   

4.
Squash is a popular racket sport that requires intermittent activity with frequent bursts of near maximal-intensity exercise. Consequently, effective physiological and thermoregulatory responses are important contributors to performance during squash match-play. Controlled field-based simulation protocols have been introduced in a growing number of sports, which allow sports scientists to investigate changes in physiology and the efficacy of various interventions in sport-specific contexts. This study aimed to develop an exercise protocol that simulates the physiological requirements of elite squash match-play. Eight elite junior squash players (age 16.2+/-0.8 years, height 1.76+/-0.06 m, body mass 61.3+/-5.9 kg; mean+/-s) completed the following in a randomized order: (1) a squash match against a player of similar standard and (2) a squash-specific incremental exercise protocol (multistage squash test [MST]) followed by the squash simulation protocol (SSP). The multistage squash test was continued for 18.0+/-1.0 min and elicited near maximal post-MST heart rates, blood lactate concentrations and ratings of perceived exertion (198+/-9 beats.min-1, 5.7+/-1.7 mmol.l-1 and 18+/-1, respectively). The SSP was 12.2 min in length compared with mean game length during competitive matches of 10.0+/-1.6 min (P=0.27). Peak heart rates were similar during the SSP and match-play (192+/-11 and 189+/-6 beats.min-1, respectively; P=0.44). Mean exercising heart rates were similar during the SSP (180+/-8 beats.min-1) and match-play (179+/-13 beats.min-1; P=0.73). Peak blood lactate concentrations during the SSP and match-play were 3.5+/-1.5 and 2.4+/-1.2 mmol.l-1 (P=0.07), respectively. Peak ratings of perceived exertion during the SSP and match-play were similar (17+/-2 and 17+/-2, respectively; P=0.64). It was concluded that the SSP closely replicated the demands of squash match-play in elite junior squash players. Furthermore, the SSP provides coaches and scientific support staff with a controlled squash-specific exercise protocol that has potential application in the objective investigation of a range of interventions such as training programmes, nutritional supplements and strategies to maintain core body temperature.  相似文献   

5.
Abstract

In this paper we report on two studies that investigated the physical demands of professional rugby league match-play. Instudy one, National Rugby League (NRL) and National Youth Competition (NYC) players underwent global positioning system (GPS) analysis during competitive matches. No differences (P > 0.05) were observed between playing standards for minutes played, total distance covered, or the distances covered at low and high speeds. However, NRL players engaged in significantly more repeated high-intensity effort bouts than NYC players (13.1 ± 0.8 bouts vs. 9.7 ± 1.1 bouts). Reductions in physical performance occurred from the first to second half for both NRL and NYC players. In study two, we investigated, in the same players, the physical demands of professional rugby league match-play when players were competing in trial and regular fixture matches. The locomotor demands of trial matches were lower than fixture matches, with players covering less distance per minute of match-play, including less distance at low and high speeds. Players were also less likely to engage in repeated high-intensity effort bouts in trial matches than fixtures. These findings demonstrate that neither NYC matches nor NRL trial matches adequately reflect the intense physical demands of NRL fixture matches.  相似文献   

6.
ABSTRACT

Despite a growing body of evidence on the positive impact of sports science for golf, there is still a paucity of research investigating the “perceptions” and “practices” of high-skilled golfers. Professional Golfers’ Association Assistant Professionals (future-qualified coaches; n = 430) were surveyed on their “perceptions” and “practices” of “sports science”, “warm-ups”, “cool-downs” and “strength and conditioning” for golf. Participants perceived the discipline of sports science as beneficial to golfers but lacked implementation in coaching settings. Warm-up protocols were also perceived to be beneficial to all aspects of golf performance; however, the duration of tournament-based (37.84 ± 20.05 min), warm-ups was significantly greater (p < 0.001) than practice rounds (26.26 ± 18.63 min) and range sessions (13.00 ± 13.38 min). Education continues to be required to raise the understanding of warm-ups for golf. There were mixed perceptions regarding the benefits of a cool-down, with 62.1% of the high-skilled golfers omitting a cool-down following tournament play and practice. Strength and conditioning was perceived as beneficial, with 78.51% engaging in some form of training throughout the year. Results confirm, however, that certain misconceptions around surveyed sports science practices still exist and it is imperative that education disseminates research findings and validated applied practices to coaches and golfers alike.  相似文献   

7.
BackgroundIn recent years, much evidence has emerged to indicate that exercise can benefit people when performed properly. This review summarizes the exercise interventions used in studies involving mice as they are related to special diseases or physiological status. To further understand the effects of exercise interventions in treating or preventing diseases, it is important to establish a template for exercise interventions that can be used in future exercise-related studies.MethodsPubMed was used as the data resource for articles. To identify studies related to the effectiveness of exercise interventions for treating various diseases and organ functions in mice, we used the following search language: (exercise [Title] OR training [Title] OR physical activity [Title]) AND (mice [title/abstract] OR mouse [title/abstract] OR mus [title/abstract]). To limit the range of search results, we included 2 filters: one that limited publication dates to “in 10 years” and one that sorted the results as “best match”. Then we grouped the commonly used exercise methods according to their similarities and differences. We then evaluated the effectiveness of the exercise interventions for their impact on diseases and organ functions in 8 different systems.ResultsA total of 331 articles were included in the analysis procedure. The articles were then segmented into 8 systems for which the exercise interventions were used in targeting and treating disorders: motor system (60 studies), metabolic system (45 studies), cardio-cerebral vascular system (58 studies), nervous system (74 studies), immune system (32 studies), respiratory system (7 studies), digestive system (1 study), and the system related to the development of cancer (54 studies). The methods of exercise interventions mainly involved the use of treadmills, voluntary wheel-running, forced wheel-running, swimming, and resistance training. It was found that regardless of the specific exercise method used, most of them demonstrated positive effects on various systemic diseases and organ functions. Most diseases were remitted with exercise regardless of the exercise method used, although some diseases showed the best remission effects when a specific method was used.ConclusionOur review strongly suggests that exercise intervention is a cornerstone in disease prevention and treatment in mice. Because exercise interventions in humans typically focus on chronic diseases, national fitness, and body weight loss, and typically have low intervention compliance rates, it is important to use mice models to investigate the molecular mechanisms underlying the health benefits from exercise interventions in humans.  相似文献   

8.
ABSTRACT

Visual exploratory action, in which football players turn their head to perceive their environment, improves prospective performance with the ball during match-play. This scanning action, however, is relevant for players throughout the entire match, as the information perceived through visual exploration is needed to guide movement around the pitch during both offensive and defensive play. This study aimed to understand how a player’s on-pitch position, playing role and phase of play influenced the visual exploratory head movements of players during 11v11 match-play. Twenty-two competitive-elite youth footballers (M = 16.25 years) played a total of 1,623 minutes (M = 73.8). Inertial measurement units, global positioning system units and notational analysis were used to quantify relevant variables. Analyses revealed that players explored more extensively when they were in possession of the ball, and less extensively during transition phases, as compared to team ball-possession and opposition ball-possession phases of play. Players explored most extensively when in the back third of the pitch, and least when they were in the middle third of the pitch. Playing role, pitch position and phase of play should be considered as constraints on visual exploratory actions when developing training situations aimed at improving the scanning actions of players.  相似文献   

9.
Abstract

Four groups of male subjects participated in anaerobic testing on a Repco EX 10 cycle ergometer to determine the effectiveness of sodium bicarbonate (0.3 g kg‐1 body mass) as an ergogenic aid during exercise of 10, 30, 120 and 240 s duration. Blood was collected 90 min prior to ingestion of sodium bicarbonate (NaHCO3), after ingestion of NaHCO3 and immediately post‐exercise from a heated (43–46°C) fingertip and analysed immediately post‐collection for pH, base excess, bicarbonate and lactate. The total work undertaken (kj) and peak power achieved during the tests were also obtained via a Repco Work Monitor Unit. Blood bicarbonate levels were again increased above the control and placebo conditions (P< 0.001) and blood lactate levels were also increased following the bicarbonate trials. The pH levels fell significantly (P<0.05) below the control and placebo conditions in all trials. The results indicate that NaHCO3 at this dosage has no ergogenic benefit for work of either 10 or 30 s duration, even though blood bicarbonate levels were significantly increased (P<0.05) following ingestion of NaHCO3. For work periods of 120 and 240 s, performance was significantly increased (P<0.05) above the control and placebo conditions following NaHCO3 ingestion.  相似文献   

10.
BackgroundIncreasing caloric expenditure in physical education is considered an effective school-based approach to addressing the child obesity epidemic. This study was designed to determine synergistic influences of student characteristics and lesson factors on caloric expenditure in elementary and middle school physical education.MethodsThe study used a multi-level design. Level-1 factors included personal characteristics: age, gender, and body mass index. Level-2 factors included lesson length, content, and school level. Based on the Center for Disease Control and Prevention age–gender adjusted growth chart, students in 87 classes from 14 elementary and 15 middle schools were pre-screened into “Overweight”, “Healthy weight”, or “Thin” groups. One boy and one girl were randomly selected from each group in each class as data providers (264 elementary and 294 middle school students). Caloric expenditure was measured in 243 physical education lessons using accelerometers.ResultsAnalysis of variance revealed and hierarchical linear modeling confirmed separate age by body mass index, age by gender, and content by lesson–length interaction effects, suggesting that the personal and lesson factors influenced caloric expenditure independently. Older male and heavier students burned more calories in all lessons. Students burned more calories in 45–60 min sport skill or fitness lessons than in shorter (30 min) or longer (75–90 min) game or multi-activity lessons.ConclusionsThe hypothesized cross-level interaction was not observed in the data. Caloric expenditure can be optimized in 45–60 min sport skill or fitness development lessons. It can be recommended that schools adopt 45–60 min lesson length and provide skill and fitness development tasks in physical education to maximize caloric expenditure.  相似文献   

11.
Background:Exercise is considered as an important intervention for treatment and prevention of several diseases,such as osteoarthritis,obesity,hypertension,and Alzheimer's disease.This review summarizes decadal exercise intervention studies with various rat models across 6 major systems to provide a better understanding of the mechanisms behind the effects that exercise brought.Methods:PubMed was utilized as the data source.To collect research articles,we used the following terms to create the search:(exercise[Title]OR physical activity[Title]OR training[Title])AND(rats[Title/Abstract]OR rat[Title/Abstract]OR rattus[Title/Abstract]).To best cover targeted studies,publication dates were limited to"within 11 years."The exercise intervention methods used for different diseases were sorted according to the mode,frequency,and intensity of exercise.Results:The collected articles were categorized into studies related to 6 systems or disease types:motor system(17 articles),metabolic system(110 articles),cardiocerebral vascular system(171 articles),nervous system(71 articles),urinary system(2 articles),and cancer(21 articles).Our review found that,for different diseases,exercise intervention mostly had a positive effect.However,the most powerful effect was achieved by using a specific mode of exercise that addressed the characteristics of the disease.Conclusion:As a model animal,rats not only provide a convenient resource for studying human diseases but also provide the possibility for exploring the molecular mechanisms of exercise intervention on diseases.This review also aims to provide exercise intervention frameworks and optimal exercise dose recommendations for further human exercise intervention research.  相似文献   

12.
Abstract

The contextual interference (CI) effect has been replicated many times since its first demonstration by Shea and Morgan (1979) in the motor learning domain (see Brady, 1998; Magill&;Hall, 1990). The CI effect is characterized by the observation that experiencing greater interference during acquisition is detrimental to immediate performance but enhances delayed performance as measured on retention or transfer tests. High CI is most often created by random practice in which the learning of multiple tasks occurs in a single training. In contrast, low CI is frequently created by using a blocked practice format in which all the practice trials of one task are completed before another task is introduced. One theoretical account that has been forwarded to account for the CI effect is labeled the action plan reconstruction hypothesis (Lee&;Magill, 1983, 1985). This position intimates that before a movement occurs an “action plan” must be prepared. In blocked practice, a previously prepared “action plan” is readily available from trial to trial, but it suffers from lack of attention on trials following initial retrieval from working memory. In random practice, however, each time a task must be executed a “reconstruction” of the action plan must be processed, because the interchange of information from trial to trial never allows the same information to remain in working memory for an extended amount of time. Presumably, the additional trial-to-trial preparation used by the random practice participant during practice results in a more resilient memory representation that better supports long-term recall efforts compared to their blocked practice counterparts.  相似文献   

13.
This study examined contributions of different types of sport activities to the development of elite youth soccer performance. Match-play performance of 44 German male players was assessed by expert coaches twice, 24 months apart (age 11.1–13.1 years), based on videotaped 5v5 matches. Player pairs were matched by identical age and initial performance at t1. Each player was assigned to a group of either “Strong” or “Weak Responders” based on a higher or lower subsequent performance improvement at t2 within each pair (mean Δperformance 29% vs. 7%). A questionnaire recorded current and earlier amounts of organised practice/training and non-organised sporting play, in soccer and other sports, respectively. Group comparison revealed that “Strong Responders” accumulated more non-organised soccer play and organised practice/training in other sports, but not more organised soccer practice/training. Subsequent multivariate analyses (multiple linear regression analyses (MLR)) highlighted that higher resultant match-play performance at t2 was accounted for R2adj = 0.65 by performance at t1, together with more non-organised soccer play and organised engagement in other sports, respectively, and greater current, but less earlier volume of organised soccer. The findings suggest that variable early sporting experience facilitates subsequent soccer performance development in German elite youth footballers.  相似文献   

14.
ABSTRACT

Purpose: Badminton is a sport characterized by high-intensity activity interspersed with short rests requiring specific physiological fitness, skills and game tactics. This study aimed to develop, describe and establish the reliability of a novel badminton intermittent exercise protocol, to simulate singles match-play (Part A) and assess match-fitness (Part B). Method: Twelve well-trained male badminton players performed a two-part protocol, mimicking the demands and activity of match-play, on two occasions with at least 72-h recovery. Part A imitated match-play and consisted of 40 stages alternating between 20 s work – receiving shuttlecocks from a launcher and ghosting (simulated) actions – and 40 s rest. Part B was an open-ended period, challenging match-fitness, designed to exhaust participants within 10 min. Physiological responses (heart rate, blood lactate and ratings of perceived exertion) (Part A and B) and time to exhaustion (Part B) were determined both times. Results: There were no differences in performance and physiological responses between trials (p > .05). The protocol demonstrated excellent reliability (intraclass correlation coefficient > 0.89) for all variables. Time to exhaustion (Part B) was 198 ± 98 s and 194 ± 82 s, respectively. Mean (Part A) and peak (Part B) heart rates were 166 ± 9; 191 ± 8 b?min?1 and 166 ± 9; 191 ± 7 b?min?1 and blood lactate concentrations (Part B) 11.8 ± 2.3 and 11.5 ± 2.1 mmol?l?1 for trials 1 and 2, respectively. Conclusion: The protocol reliably induces match-like responses and can be used to assess match-fitness for training/research purposes.  相似文献   

15.
Abstract

Three hundred male subjects, assigned in systematic rotation to five experimental groups (N = 60 in each) which differed in amount of distribution of practice, were tested on a discrete-trial motor learning task, the peg turn. All subjects were given 120 practice trials (60 trials a day), on two days separated by a 48-hour rest. Even though the peg turn task is inherently distributed, reminiscence did occur when the massing was made as large as practically possible. The amount of reminiscence depended upon the stage of practice. Warm-up decrement occurred in the peg turn under both massed and distributed practice conditions; the longer the rest, the greater the amount. Performance of the task under nonrhythmical conditions reduced the development of “set” during practice and thus decreased the amount of warm-up decrement after rest. Increased amounts of massing did have a deleterious effect on performance, but did not reduce the amount learned.  相似文献   

16.
Abstract

The synergistic stimulating effect of combined intake of carbohydrate and protein on plasma insulin concentration has been reported previously. However, it remains unclear whether the amount of protein ingested after exercise affects the concentrations of plasma insulin and amino acids. This study of trained men compared the effects of post-exercise co-ingestion of carbohydrate plus different amounts of whey protein hydrolysates (WPHs) with carbohydrate alone on (1) blood biochemical parameters of carbohydrate metabolism during the post-exercise phase, and (2) endurance performance. Eight trained men exercised continuously for 70 min. Immediately after exercise and 30, 60, 90, and 120 min later, the participants received supplements containing: (1) 17.5 g carbohydrate, (2) 3.0 g WPHs and 17.5 g carbohydrate (L-WPH), or (3) 8.0 g WPHs and 17.5 g carbohydrate (H-WPH). After a 2-h recovery period, the participants performed an endurance performance test. The concentrations of blood glucose were lower and plasma insulin significantly higher in the H-WPH trial compared with the carbohydrate trial. The concentrations of plasma amino acids were increased in a dose-dependent manner following ingestion of different amounts of WPHs with carbohydrate. Endurance performance was not significantly different between the three trials. Co-ingestion of carbohydrate and H-WPH was more effective than ingestion of carbohydrate alone for stimulating insulin secretion and increasing the availability of plasma amino acids. These results suggest that plasma concentrations of amino acids during the recovery period are determined by the amount of dietary protein ingested, and that it is necessary to increase the concentration of plasma amino acids above a certain level to stimulate insulin secretion.  相似文献   

17.
Abstract

On four separate occasions resting, fasted adults ingested 10 oz of a cola-flavored soft drink containing either 0, 22.5, 35, or 150 mg caffeine. Heart rate, blood pressure, and plasma free fatty acid (FFA) and glucose values were obtained before and at 15, 30, 60, 90, 120, 180 and 360 min after the feeding. All urine was collected during the 6 hr following ingestion and was later assayed for total catecholamine (CA) content. Urine volume and total CA excretion increased as the amount of caffeine ingested increased. Only the 150 mg solution resulted in significant increases (over control) in 6 hr CA output, or FFA concentration and mean arterial pressure early after the feeding. The 150 mg drink also maintained blood glucose at pre–ingestion levels for the entire course of the experiment. The moderate increase in circulating FFA following ingestion of a commercially available cola (22 to 35 mg caffeine/bottle) is similar to the change seen in resting, nonfed subjects. These data suggest that ingestion of caffeine in an amount typically found in a single bottle of cola drink does not increase factors associated with coronary risk, nor will it have a positive influence on parameters associated with enhanced athletic performance, should those same changes occur during exercise.  相似文献   

18.
Abstract

Previous investigations regarding activity during the post-knowledge of results (KR) interval have considered the performance of interference groups over KR-supplied acquisition trials as indicative of effects upon learning. The absence of transfer tests in these studies, however, preclude such an assumption. Indeed, the use of a retention test in the present investigation (no-KR trials following an interpolated phase) provided evidence suggesting that, while activity during the post-KR interval is detrimental to performance, no such assumption can be made regarding this effect upon learning. These findings are discussed relative to recent arguments that some of the commonly accepted “Laws of KR” may be contradictory when applied simultaneously to motor learning and performance.  相似文献   

19.
Abstract

The aim of this study was to adapt a performance measurement tool, the Team Sport Assessment Procedure (TSAP), to ice hockey during match-play. In addition to the six categories included in the original observational procedure, the ice hockey TSAP contained four new categories. Twelve Pee-Wee ice hockey matches were video-recorded during a regional championship tournament. The game play of 103 of the 11- to 12-year-old players was then analysed on video by three trained observers, based on all 10 ice hockey TSAP categories. The observational data were thereafter used to compute, for each player, a “volume of play per minute” and an efficiency index. Finally, volume of play per minute and the efficiency index were combined to obtain a composite score, the TSAP performance score. Additional measurements for each player were playing time during the observed matches, coaches’ assessments (dominant, good, less decisive), and player tournament statistics (number of points, based on assists and goals). The mean TSAP performance score was substantially higher for players rated by their coaches as dominant and for players who accumulated more than one tournament point, findings that provide evidence of the validity of the TSAP measure. In inter-observer reliability analyses of TSAP observational data provided by the trained observersfrom video recordings, the level of agreement between each pair of observers was 80–82%. Reliability correlations over a series of three matches (r=0.26, 0.59, and 0.16 respectively) showed that the TSAP performance score was relatively unstable. Ice hockey coaches may use this adapted Team Sport Assessment Procedure to better understand the offensive implication of each player in a given match, since the 10 observational variables provide more extensive information on performance than traditional statistical measures. Due to low performance stability of the TSAP performance score, coaches ought to use the observational assessment data for the formative rather than the summative assessment of their players unless they cumulate information over a series of several matches. Formative assessment can be conducted either during training camps or even during the regular season.  相似文献   

20.
Abstract

This study examined the relationship between intensity of training and changes in hydration status, core temperature, sweat rate and composition and fluid balance in professional football players training in the heat. Thirteen professional football players completed three training sessions; “higher-intensity” (140 min; HI140), “lower-intensity” (120 min; LI120) and “game-simulation” (100 min; GS100). Movement demands were measured by Global Positioning System, sweat rate and concentration were determined from dermal patches and body mass change. Despite similar environmental conditions (26.9 ± 0.1°C and 65.0 ± 7.0% relative humidity [Rh]), higher relative speeds (m · min?1) and increased perceptions of effort and thermal strain were observed in HI140 and GS100 compared with LI120 (P < 0.05). Significantly (P < 0.05) greater sweat rate (L · h?1) and electrolyte losses (g) were observed in HI140 and GS100 compared with LI120. Rate of rise in core temperature was correlated with mean speed (r = 0.85), session rating of perceived exertion (sRPE) (r = 0.61), loss of potassium (K+) (r = 0.51) sweat rate (r = 0.49), and total sweat loss (r = 0.53), with mean speed the strongest predictor. Sodium (Na+) (r = 0.39) and K+ (r = 0.50) losses were associated with total distance covered. In hot conditions, individualised rehydration practices should be adopted following football training to account for differences in sweat rate and electrolyte losses in response to intensity and overall activity within a session.  相似文献   

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