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1.
Abstract

Low energy availability [(energy intake – exercise expenditure)/kg lean body mass], a component of the Female Athlete Triad, has been associated with menstrual disturbances and low bone mass. No studies have examined the energy availability of athletes across a season. The purpose of this study was to assess the prevalence of, and what contributes to, low energy availability in Division I female soccer players across a season. Nineteen participants aged 18–21 years (mean [Vdot]O2max: 57.0 ± 1.0 mL · kg?1 · min?1) were studied during the pre, mid, and post season. Mean energy availability was overall lowest at mid season, and lower at mid than post season (35.2 ± 3.7 vs. 44.5 ± 3.7 kcal · kg?1 lean body mass, P = 0.009). Low energy availability (<30 kcal · kg?1 lean body mass) was observed in 5/19 (26.3%), 5/15 (33.3%), and 2/17 (11.8%) of participants during the pre, mid, and post season. Dietary energy intake was lower mid (P = 0.008) and post season (P = 0.022) than it was pre season (pre: 2794 ± 233 kcal · day?1; mid: 2208 ± 156 kcal · day?1; post: 2161 ± 143 kcal · day?1). Exercise energy expenditure decreased significantly (P ≤ 0.001) over time (pre: 819 ± 57 kcal · day?1; mid: 642 ± 26 kcal · day?1; post: 159 ± 28 kcal · day?1). Low energy availability was due to lower dietary energy intake at lunch during pre season (P = 0.014) and during lunch and dinner during mid season (P ≤ 0.030). Energy availability was inversely related to body dissatisfaction (r = ?0.62, P = 0.017) and drive for thinness (r = ?0.55, P = 0.041) during mid season. Although most Division I female soccer players are not at risk for low energy availability, a concerning proportion exhibited low energy availability at pre or mid season. Further studies are needed to explore strategies to prevent and monitor low energy availability in these athletes.  相似文献   

2.
Abstract

The purpose of this study was to compare changes in aerobic condition, strength, and muscular endurance following 8 weeks of endurance rowing alone or in combination with weight-training. Twenty-two elite rowers were assigned to (1) rowing (n = 10, 250–270 km · week?1) or (2) rowing (n = 12, 190–210 km · week?1) plus four weight-training sessions each week. Pre and post mean and standardized effect-size (ES) differences in aerobic condition (watts at 4 mmol · L?1) and strength (isometric pull, N), prone bench-pull (6-repetition maximum, 6-RM), 5- and 30-repetition leg-press and 60-repetition seated-arm-pull (J, performed on a dynamometer) normalized by body mass and log-transformed were analysed, after adjusting for gender. The standardized differences between groups were trivial for aerobic condition (ES [±90% CI] = 0.15; ±0.28, P = 0.37) and prone bench-pull (ES = 0.27; ±0.33, P = 0.18), although a moderate positive benefit in favour of rowing only was observed for the seated-arm-pull (ES = 0.42; ±0.4, P = 0.08). Only the weight-training group improved isometric pull (12.4 ± 8.9%, P < 0.01), 5-repetition (4.0 ± 5.7%, P < 0.01) and 30-repetition (2.4 ± 5.4%, P < 0.01) leg-press. In conclusion, while gains in aerobic condition and upper-body strength were comparable to extensive endurance rowing, weight-training led to moderately greater lower-body muscular-endurance and strength gains.  相似文献   

3.
Abstract

The current study implemented a two-part design to (1) assess the vitamin D concentration of a large cohort of non-vitamin D supplemented UK-based athletes and 30 age-matched healthy non-athletes and (2) to examine the effects of 5000 IU · day?1 vitamin D3 supplementation for 8-weeks on musculoskeletal performance in a placebo controlled trial. Vitamin D concentration was determined as severely deficient if serum 25(OH)D < 12.5 nmol · l?1, deficient 12.5–30 nmol · l?1 and inadequate 30–50 nmol · l?1. We demonstrate that 62% of the athletes (38/61) and 73% of the controls (22/30) exhibited serum total 25(OH)D < 50 nmol · l?1. Additionally, vitamin D supplementation increased serum total 25(OH)D from baseline (mean ± SD = 29 ± 25 to 103 ± 25 nmol · l?1, P = 0.0028), whereas the placebo showed no significant change (53 ± 29 to 74 ± 24 nmol · l?1, P = 0.12). There was a significant increase in 10 m sprint times (P = 0.008) and vertical-jump (P = 0.008) in the vitamin D group whereas the placebo showed no change (P = 0.587 and P = 0.204 respectively). The current data supports previous findings that athletes living at Northerly latitudes (UK = 53° N) exhibit inadequate vitamin D concentrations (<50 nmol · l?1). Additionally the data suggests that inadequate vitamin D concentration is detrimental to musculoskeletal performance in athletes. Future studies using larger athletic groups are now warranted.  相似文献   

4.
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5.
Abstract

Major individual differences in the maximal oxygen uptake response to aerobic training have been documented. Vagal influence on the heart has been shown to contribute to changes in aerobic fitness. Whether vagal influence on the heart also predicts maximal oxygen uptake response to interval-sprinting training, however, is undetermined. Thus, the relationship between baseline vagal activity and the maximal oxygen uptake response to interval-sprinting training was examined. Exercisers (n?=?16) exercised three times a week for 12 weeks, whereas controls did no exercise (n?=?16). Interval-sprinting consisted of 20 min of intermittent sprinting on a cycle ergometer (8 s sprint, 12 s recovery). Maximal oxygen uptake was assessed using open-circuit spirometry. Vagal influence was assessed through frequency analysis of heart rate variability. Participants were aged 22 ± 4.5 years and had a body mass of 72.7 ± 18.9 kg, a body mass index of 26.9 ± 3.9 kg · m?2, and a maximal oxygen uptake of 28 ± 7.4 ml · kg?1 · min?1. Overall increase in maximal oxygen uptake after the training programme, despite being anaerobic in nature, was 19 ± 1.2%. Change in maximal oxygen uptake was correlated with initial baseline heart rate variability high-frequency power in normalised units (r?=?0.58; P < 0.05). Thus, cardiac vagal modulation of heart rate was associated with the aerobic training response after 12 weeks of high-intensity intermittent-exercise. The mechanisms underlying the relationship between the aerobic training response and resting heart rate variability need to be established before practical implications can be identified.  相似文献   

6.
This study examined effects of 4 weeks of caffeine supplementation on endurance performance. Eighteen low-habitual caffeine consumers (<75 mg · day?1) were randomly assigned to ingest caffeine (1.5–3.0 mg · kg?1day?1; titrated) or placebo for 28 days. Groups were matched for age, body mass, V?O2peak and Wmax (P > 0.05). Before supplementation, all participants completed one V?O2peak test, one practice trial and 2 experimental trials (acute 3 mg · kg?1 caffeine [precaf] and placebo [testpla]). During the supplementation period a second V?O2peak test was completed on day 21 before a final, acute 3 mg · kg?1 caffeine trial (postcaf) on day 29. Trials consisted of 60 min cycle exercise at 60% V?O2peak followed by a 30 min performance task. All participants produced more external work during the precaf trial than testpla, with increases in the caffeine (383.3 ± 75 kJ vs. 344.9 ± 80.3 kJ; Cohen’s d effect size [ES] = 0.49; P = 0.001) and placebo (354.5 ± 55.2 kJ vs. 333.1 ± 56.4 kJ; ES = 0.38; P = 0.004) supplementation group, respectively. This performance benefit was no longer apparent after 4 weeks of caffeine supplementation (precaf: 383.3 ± 75.0 kJ vs. postcaf: 358.0 ± 89.8 kJ; ES = 0.31; P = 0.025), but was retained in the placebo group (precaf: 354.5 ± 55.2 kJ vs. postcaf: 351.8 ± 49.4 kJ; ES = 0.05; P > 0.05). Circulating caffeine, hormonal concentrations and substrate oxidation did not differ between groups (all P > 0.05). Chronic ingestion of a low dose of caffeine develops tolerance in low-caffeine consumers. Therefore, individuals with low-habitual intakes should refrain from chronic caffeine supplementation to maximise performance benefits from acute caffeine ingestion.  相似文献   

7.
Low energy availability, defined as low caloric intake relative to exercise energy expenditure, has been linked to endocrine alterations frequently observed in chronically energy-deficient exercising women. Our goal was to determine the endocrine effects of low energy availability in exercising men. Six exercising men (VO2peak: 49.3 ± 2.4 ml · kg?1 · min?1) underwent two conditions of low energy availability (15 kcal · kg?1 fat-free mass [FFM] · day?1) and two energy-balanced conditions (40 kcal · kg?1 FFM · day?1) in randomised order. During one low energy availability and one balanced condition, participants exercised to expend 15 kcal · kg?1 FFM · day?1; no exercise was conducted during the other two conditions. Metabolic hormones were assessed before and after each 4-day period. Following both low energy availability conditions, leptin (?53% to ?56%) and insulin (?34% to ?38%) were reduced (P < 0.05). Reductions in leptin and insulin were independent of whether low energy availability was attained with or without exercise (P > 0.80). Low energy availability did not significantly impact ghrelin, triiodothyronine, testosterone and IGF-1 (all P > 0.05). The observed reductions in leptin and insulin were in the same magnitude as changes previously reported in sedentary women. Further research is needed to understand why other metabolic hormones are more robust against low energy availability in exercising men than those in sedentary and exercising women.  相似文献   

8.
The aim was to assess the relationship between school rhythm and physical activity (PA) in adolescents. The study included 2024 adolescents (12.5–17.4 years). Participants wore an accelerometer for 7 days. A short school rhythm was defined as a short time at school with short recesses and less time in teaching per day (Group 1). A long school rhythm was defined as a longer time at school with more time in teaching and recess (Group 2). Adolescents in Group 1 performed less moderate to vigorous PA (MVPA) than those in Group 2 per week (P < .0001), especially during school days (recess: 3.9 ± 4.0 vs. 9.8 ± 7.9 min · day?1; P < .0001; teaching hours: 14.5 ± 9.8 vs. 19.1 ± 12.0 min · day?1; P < .0001). Adolescents in Group 1 were less likely to meet the PA recommendations than were adolescents in Group 2: 30.7% vs. 34.1% (P < .0001). During school days, the percentage of adolescents who spent more than 2 h · day?1 in sedentary activities was greater in the Group 1 (P < .001). Our results suggest that leisure-time out-of-school hours is used mainly for sedentary activities, and that school time provides a good opportunity for promoting PA.  相似文献   

9.
Abstract

This study was designed to investigate the effect of ingesting a glucose plus fructose solution on the metabolic responses to soccer-specific exercise in the heat and the impact on subsequent exercise capacity. Eleven male soccer players performed a 90 min soccer-specific protocol on three occasions. Either 3 ml · kg?1 body mass of a solution containing glucose (1 g · min?1 glucose) (GLU), or glucose (0.66 g · min?1) plus fructose (0.33 g · min?1) (MIX) or placebo (PLA) was consumed every 15 minutes. Respiratory measures were undertaken at 15-min intervals, blood samples were drawn at rest, half-time and on completion of the protocol, and muscle glycogen concentration was assessed pre- and post-exercise. Following the soccer-specific protocol the Cunningham and Faulkner test was performed. No significant differences in post-exercise muscle glycogen concentration (PLA, 62.99 ± 8.39 mmol · kg wet weight?1; GLU 68.62 ± 2.70; mmol · kg wet weight?1 and MIX 76.63 ± 6.92 mmol · kg wet weight?1) or exercise capacity (PLA, 73.62 ± 8.61 s; GLU, 77.11 ± 7.17 s; MIX, 83.04 ± 9.65 s) were observed between treatments (P > 0.05). However, total carbohydrate oxidation was significantly increased during MIX compared with PLA (P < 0.05). These results suggest that when ingested in moderate amounts, the type of carbohydrate does not influence metabolism during soccer-specific intermittent exercise or affect performance capacity after exercise in the heat.  相似文献   

10.
Abstract

The study investigated the effect of a school-based healthy lifestyles intervention on physical activity and dietary variables. In total 378 children (177 intervention, 201 control; age 9.75 ± 0.82 years (mean ± s)) took part in the 7-month intervention comprising: preparation for and participation in 3 highlight events (a dance festival, a walking event and a running event); an interactive website for pupils, teachers and parents; and vacation activity planners. Primary outcome measures were objectively measured physical activity (pedometers and accelerometers), endurance fitness and dietary variables. Multi-level modelling was employed for data analysis. The increase in physical activity was greater in the intervention group than the control group (steps: 1049 vs 632 daily steps each month; moderate to vigorous physical activity (MVPA) total: 4.6 min · day?1 · month?1 vs 1.3 min · day?1 · month?1; MVPA bouts: 5.4 min · day?1 · month?1 vs 2.6 min · day?1 · month?1; all P < 0.05). The increase in multi-stage fitness test distance was greater for intervention participants (46 vs 29 m · month?1 of intervention, group × month interaction, P < 0.05). There were no differences between groups in dietary variables, body composition, knowledge of healthy lifestyles or psychological variables. Thus an intervention centred around highlight events and including relatively few additional resources can impact positively on the objectively measured physical activity of children.  相似文献   

11.
Abstract

This study examined the effects of combined glucose and sodium bicarbonate ingestion prior to intermittent exercise. Ninemales (mean ± s age 25.4 ± 6.6 years, body mass 78.8 ± 12.0 kg, maximal oxygen uptake ([Vdot]O2max) 47.0 ± 7ml · kg · min?1) undertook 4 × 45 min intermittent cycling trials including 15 × 10 s sprints one hour after ingesting placebo (PLA), glucose (CHO), sodium bicarbonate (NaHCO3) or a combined CHO and NaHCO3 solution (COMB). Post ingestion blood pH (7.45 ± 0.03, 7.46 ± 0.03, 7.32 ± 0.05, 7.32 ± 0.01) and bicarbonate (30.3 ± 2.1, 30.7 ± 1.8, 24.2 ± 1.2, 24.0 ± 1.8 mmol · l?1) were greater for NaHCO3 and COMB when compared to PLA and CHO, remaining elevated throughout exercise (main effect for trial; P < 0.05). Blood lactate concentration was greatest throughout exercise for NaHCO3 and COMB (main effect for trial; P < 0.05). Blood glucose concentration was greatest 15 min post-ingestion for CHO followed by COMB, NaHCO3 and PLA (7.13 ± 0.60, 5.58 ± 0.75, 4.51 ± 0.56, 4.46 ± 0.59 mmol · l?1, respectively; P < 0.05). Gastrointestinal distress was lower during COMB compared to NaHCO3 at 15 min post-ingestion (P < 0.05). No differences were observed for sprint performance between trials (P = 1.00). The results of this study suggest that a combined CHO and NaHCO3 beverage reduced gastrointestinal distress and CHO availability but did not improve performance. Although there was no effect on performance an investigation of the effects in more highly trained individuals may be warranted.  相似文献   

12.
Abstract

Individuals with impaired glucose tolerance (IGT) are at greater risk of developing diabetes than in normoglycaemia. The aim of this study was to examine the effects of 12-weeks exercise training in obese humans with IGT. Eleven participants (6 males and 5 females; 49±9 years; mean Body Mass Index (BMI) 32.4 kg · m?2), completed a 12-week brisk walking intervention (30 min per day, five days a week (d · wk?1), at 65% of age-predicted maximal heart rate (HRmax). Anthropometric measurements, dietary intake, pulse wave velocity (PWV, to determine arterial stiffness) and blood pressure (BP) were examined at baseline and post intervention. Fasting blood glucose, glycosylated haemoglobin, insulin, blood lipids, indices of oxidative stress and inflammation (lipid hydroperoxides; superoxide dismutase; multimeric adiponectin concentration and high-sensitivity C-reactive protein) were also determined. Post intervention, PWV (9.08±1.27 m · s?1 vs. 8.39±1.21 m · s?1), systolic BP (145.4±14.5 vs. 135.8±14.9 mmHg), triglycerides (1.52±0.53 mmol . L?1 vs. 1.31±0.54 mmol . L?1), lipid hydroperoxides (1.20±0.47 μM · L?1 vs. 0.79±0.32 μM · L?1) and anthropometric measures decreased significantly (P < 0.05). Moderate intensity exercise training improves upper limb vascular function in obese humans with IGT, possibly by improving triglyceride metabolism, which may subsequently reduce oxidative stress. These changes were independent of multimeric adiponectin modification and alterations in other blood biomarkers.  相似文献   

13.
Abstract

The aim of this study was to quantify the physiological loads of programmed “pre-season” and “in-season” training in professional soccer players. Data for players during each period were included for analysis (pre-season, n = 12; in-season, n = 10). We monitored physiological loading of training by measuring heart rate and rating of perceived exertion (RPE). Training loads were calculated by multiplying RPE score by the duration of training sessions. Each session was sub-categorized as physical, technical/tactical, physical and technical/tactical training. Average physiological loads in pre-season (heart rate 124 ± 7 beats · min?1; training load 4343 ± 329 Borg scale · min) were higher compared with in-season (heart rate 112 ± 7 beats · min?1; training load 1703 ± 173 Borg scale · min) (P < 0.05) and there was a greater proportion of time spent in 80–100% maximum heart rate zones (18 ± 2 vs. 5 ± 2%; P < 0.05). Such differences appear attributable to the higher intensities in technical/tactical sessions during pre-season (pre-season: heart rate 137 ± 8 beats · min?1; training load 321 ± 23 Borg scale · min; in-season: heart rate 114 ± 9 beats · min?1; training load 174 ± 27 Borg scale · min; P < 0.05). These findings demonstrate that pre-season training is more intense than in-season training. Such data indicate that these adjustments in load are a direct attempt to deliver training to promote specific training adaptations.  相似文献   

14.
Strenuous physical exercise of the limb muscles commonly results in damage, especially when that exercise is intense, prolonged and includes eccentric contractions. Many factors contribute to exercise-induced muscle injury and the mechanism is likely to differ with the type of exercise. Competitive sports players are highly susceptible to this type of injury. AM3 is an orally administered immunomodulator that reduces the synthesis of proinflammatory cytokines and normalizes defective cellular immune fractions. The ability of AM3 to prevent chronic muscle injury following strenuous exercise characterized by eccentric muscle contraction was evaluated in a double-blind and randomized pilot study. Fourteen professional male volleyball players from the First Division of the Spanish Volleyball League volunteered to take part. The participants were randomized to receive either placebo (n?=?7) or AM3 (n?=?7). The physical characteristics (mean±s) of the placebo group were as follows: age 25.7±2.1 years, body mass 87.2±4.1?kg, height 1.89±0.07?m, maximal oxygen uptake 65.3±4.2?ml?·?kg?1?·?min?1. Those of the AM3 group were as follows: age 26.1±1.9 years, body mass 85.8±6.1?kg, height 1.91±0.07?m, maximal oxygen uptake 64.6±4.5?ml?·?kg?1?·?min?1. All participants were evaluated for biochemical indices of muscle damage, including concentrations of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatine kinase (CK) and its MB fraction (CK-MB), myoglobin, lactate dehydrogenase, urea, creatinine and γ-glutamyltranspeptidase, both before and 30 days after treatment (over the peak of the competitive season). In the placebo group, competitive exercise (i.e. volleyball) was accompanied by significant increases in creatine kinase (494±51 to 560±53?IU?·?l?1, P?<?0.05) and myoglobin (76.8±2.9 to 83.9±3.1?μg?·?l?1, P?<?0.05); aspartate aminotransferase (30.8±3.0 to 31.1±2.9?IU?·?l?1) and lactate dehydrogenase (380±31 to 376±29?IU?·?l?1) were relatively unchanged after the 30 days maximum effort. AM3 not only inhibited these changes, it led to a decrease from baseline serum concentrations of creatine kinase (503±49 to 316±37?IU?·?l?1, P?<?0.05) and myoglobin (80.1±3.2 to 44.1±2.6?IU?·?l?1, P?<?0.05), as well as aspartate aminotransferase (31.1±3.3 to 26.1±2.7?IU?·?l?1, P?<?0.05) and lactate dehydrogenase (368±34 to 310±3?IU?·?l?1, P?<?0.05). The concentration of CK-MB was also significantly decreased from baseline with AM3 treatment (11.6±1.2 to 5.0±0.7?IU?·?l?1, P?<?0.05), but not with placebo (11.4±1.1 to 10.8±1.4?IU?·?l?1). In conclusion, the use of immunomodulators, such as AM3, by elite sportspersons during competition significantly reduces serum concentrations of proteins associated with muscle damage.  相似文献   

15.
Abstract

Spinning is a type of indoor fitness activity performed on stationary bikes by participants who pedal together to the rhythm of music and the motivating words of an instructor. Despite worldwide popularity of this type of recreational activity, to date there have been few, mainly non-scientific, studies of the impact of spinning on metabolic, respiratory, and cardiovascular functions. The main aim of this study was to evaluate a number of metabolic and cardiovascular variables during a standard 50-min class performed by Spinning® instructors of both sexes: six males (age 30 ± 4.8 years, body mass index 24 ± 2.5 kg · m?2; mean ± s) and six females (age 34 ± 6.3 years, body mass index 21 ± 1.9 kg · m?2). The mean power output, heart rate, and oxygen uptake during the performance were 120 ± 4 W, 136 ± 13 beats · min?1, and 32.8 ± 5.4 ml · kg?1 · min?1 respectively for males, and 73 ± 43 W, 143 ± 25 beats · min?1, and 30 ± 9.9 ml · kg?1 · min?1 respectively for females. Analysis of individual performances showed that they were compatible with physical exercise that ranged from moderate-to-heavy to very heavy, the latter conditions prevailing. The results show that this type of fitness activity has a high impact on cardiovascular function and suggest that it is not suitable for unfit or sedentary individuals, especially the middle aged or elderly, who are willing to begin a recreational physical activity programme.  相似文献   

16.
Kinetics and full body kinematics were measured in ten elite goalkeepers diving to save high and low balls at both sides of the goal, aiming to investigate their starting position, linear and angular momentum, and legs' contribution to end-performance. Our results showed that goalkeepers adopted a starting position with a stance width of 33 ± 1% of leg length, knee flexion angle of 62 ± 18° and hip flexion angle of 63 ± 18°. The contralateral leg contributed more than the ipsilateral leg to COM velocity (p < 0.01), both for the horizontal (2.7 ± 0.1 m·s?1 versus 1.2 ± 0.1 m·s?1) and for the vertical component (3.1 ± 0.3 m·s?1 versus 0.4 ± 0.2 m·s?1). Peak horizontal and peak angular momenta were significantly larger (p < 0.01) for low dives than for high dives with a mean difference of 55 kg·m·s?1 and 9 kg·m2·s?1, respectively. In addition, peak vertical momentum was significantly larger (p < 0.01) for high dives with a mean difference between dive heights of 113 kg·m·s?1. Coaches need to highlight horizontal lateral skills and exercises (e.g. sideward push-off, sideward jumps), with emphasis on pushing-off with the contralateral leg, when training and assessing goalkeeper’s physical performance.  相似文献   

17.
Abstract

The aim of this study was to determine sprint profiles of professional female soccer players and evaluate how various speed thresholds impact those outcomes. Seventy-one professional players competing in full matches were assessed repeatedly during 12 regular season matches using a Global Positioning System (GPS). Locomotion ≥18 km · h?1 was defined as sprinting and each event was classified into: Zone 1: 18.0–20.9 km· h?1; Zone 2: 21.0–22.9 km · h?1; Zone 3: 23.0–24.9 km · h?1 and Zone 4: >25 km · h?1. Outcomes included: duration (s), distance (m), maximum speed (km · h?1), duration since previous sprint (min) and proportion of total sprint distance. In total 5,019 events were analysed from 139 player-matches. Mean sprint duration, distance, maximum speed and time between sprints were 2.3 ± 1.5 s, 15.1 ± 9.4 m, 21.8 ± 2.3 km· h?1, and 2.5 ± 2.5 min, respectively. Mean sprint distances were 657 ± 157, 447 ± 185, and 545 ± 217 m for forwards, midfielders and defenders, respectively (P ≤ 0.046). Midfielders had shorter sprint duration (P = 0.023), distance (P ≤ 0.003) and maximum speed (P < 0.001), whereas forwards performed more sprints per match (43 ± 10) than midfielders (31 ± 11) and defenders (36 ± 12) (P ≤ 0.016). Forty-five percent, 29%, 15%, and 11% of sprints occurred in sprint Zones 1, 2, 3 and 4, respectively. This group of professional female soccer players covered 5.3 ± 2.0% of total distance ≥18 km · h?1 with positional differences and percent decrements distinct from other previously identified elite players. These data should guide the development of high intensity and sprint thresholds for elite-standard female soccer players.  相似文献   

18.
Abstract

In this study, we investigated the effect of ingesting carbohydrate alone or carbohydrate with protein on functional and metabolic markers of recovery from a rugby union-specific shuttle running protocol. On three occasions, at least one week apart in a counterbalanced order, nine experienced male rugby union forwards ingested placebo, carbohydrate (1.2 g · kg body mass?1 · h?1) or carbohydrate with protein (0.4 g · kg body mass?1 · h?1) before, during, and after a rugby union-specific protocol. Markers of muscle damage (creatine kinase: before, 258 ± 171 U · L?1 vs. 24 h after, 574 ± 285 U · L?1; myoglobin: pre, 50 ± 18 vs. immediately after, 210 ± 84 nmol · L?1; P < 0.05) and muscle soreness (1, 2, and 3 [maximum soreness = 8] for before, immediately after, and 24 h after exercise, respectively) increased. Leg strength and repeated 6-s cycle sprint mean power were slightly reduced after exercise (93% and 95% of pre-exercise values, respectively; P < 0.05), but were almost fully recovered after 24 h (97% and 99% of pre-exercise values, respectively). There were no differences between trials for any measure. These results indicate that in experienced rugby players, the small degree of muscle damage and reduction in function induced by the exercise protocol were not attenuated by the ingestion of carbohydrate and protein.  相似文献   

19.
Purpose: The purpose of this study was to quantify and compare training and competition demands in basketball. Methods: Fifteen semiprofessional male basketball players wore microsensors during physical conditioning training (PCT), games-based training (GBT), and competition to measure absolute and relative (·min?1) PlayerLoadTM (PL) and estimated equivalent distance (EED). Internal responses were calculated using absolute and relative session rating of perceived exertion (sRPE) and summated heart rate zones (SHRZ). Integrated measures were calculated as sRPE:PL and SHRZ:PL ratios. Results: PlayerLoad (arbitrary units [AU]) and EED (m) were statistically significantly (p < .05) higher during PCT (632 ± 139 AU, d = 1.36; 5,964 ± 1,312 m, d = 1.36; 6.50 ± 0.81 AU·min?1, d = 2.44; 61.88 ± 7.22 m·min?1, d = 2.60) and GBT (624 ± 113 AU, d = 1.54; 5,892 ± 1,080 m, d = 1.53; 6.10 ± 0.77 AU·min?1, d = 2.14; 56.76 ± 6.49 m·min?1, d = 2.22) than they were during competition (449 ± 118 AU; 3,722 ± 1474 m; 4.35 ± 1.09 AU·min?1; 41.01 ± 10.29 m·min?1). Summated heart rate zones were statistically significantly (p < .05) higher during PCT (314 ± 86 AU, d = 1.05; 3.22 ± 0.50 AU·min?1, d = 1.94) and GBT (334 ± 79 AU, d = 1.38; 3.19 ± 0.54 AU·min?1, d = 1.83) than they were during competition (225 ± 77 AU; 2.17 ± 0.69 AU·min?1). The ratio of sRPE:PL was statistically significantly (p < .05) higher during competition (1.58 ± 0.85) than during PCT (0.98 ± 0.22, d = 1.44) and GBT (0.91 ± 0.24, d = 1.90). Conclusion: Training demands exceeded competition demands.  相似文献   

20.
Participation in youth sport is assumed to promote and contribute towards more physically active lifestyles among children and adolescents. The aim of this study was to examine inter-participant variability in objectively measured habitual physical activity (PA) behaviours and sedentary time among youth sport participants and their implications for health. One-hundred-and-eighteen male youth sport footballers (Mean ± s = 11.72 ± 1.60) wore a GT3X accelerometer for 7 days. Average daily PA [min · day?1, in light (LPA), moderate (MPA), vigorous (VPA) and combined moderate-to-vigorous (MVPA)] and sedentary time were calculated. Participants’ body mass index adjusted for age and sex (BMI–standard deviation score), per cent body fat (BF%), waist circumference and cardiorespiratory fitness were assessed. Results revealed that variability in daily PA behaviours and sedentary time (min · day?1) was associated with BMI–standard deviation score [VPA (?), MVPA (?)], BF% [sedentary time (+), VPA (?), MVPA (?)], waist circumference [sedentary time (+), LPA (?)] and cardiorespiratory fitness [sedentary time (?), MPA (+), VPA (+), MVPA (+)]. Whilst sedentary time and MVPA were not related to health outcomes independent of one another, associations with markers of adiposity and cardiorespiratory fitness were stronger for sedentary time. Sedentary time was also significantly positively related to waist circumference independent of VPA. Results demonstrate inter-participant variability in habitual PA and sedentary time among youth sport participants which holds implications for their health. Thus, promoting PA and, in particular, reducing sedentary time may contribute towards the prevention of adverse health consequences associated with a physically inactive lifestyle for children and adolescents active in the youth sport context.  相似文献   

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