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1.
ABSTRACT

Participant and protocol factors affect post-activation potentiation response. Performance enhancement is more consistent in highly-trained participants following multiple sets of a biomechanically similar conditioning activity. Providing optimal conditions, 6 international-level sprint cyclists executed multiple sets of short maximal conditioning contractions on a high-inertia ergometer before metered sprint performance. Three trial conditions were completed on separate days after a standardised warm-up: dynamic (DYN: 4 × 4 crank-cycles), isometric (ISO: 4 × 5-sec maximal voluntary contraction (MVC)), and control (CON: rest). Performance was measured from standing start to maximum velocity on an inertial-load ergometer at baseline (Pre), 4 (Post4), 8 (Post8) and 16 (Post16) min post-conditioning. Performance and biomechanical measures were assessed across 4 sprint segments, with magnitude-based inferences used to assess the likelihood that any affect was beneficial. Performance time only improved in DYN Post4, a 3.9% reduction during the first crank cycle (92% likely). On the ascending limb of the power-cadence relationship, peak torque and average power increased by 6.2% (94% likely) and 4.0% (87% likely), respectively. In ISOPost16, optimal cadence increased (82% likely) and average power improved over the descending limb (76% likely). DYN and ISO potentiated extremities of the torque-cadence relationship at distinct recovery times post-conditioning. This study suggests merit in including a high-inertia warm-up for sprint cycling.  相似文献   

2.
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3.
ABSTRACT

Talent identification (TID) and development (TDE) are large fields in professional soccer and in science. However, TID and TDE processes in youth academies have not been assessed in detail. As such, our aim was to survey professional clubs from around the world about their youth academy TID and TDE processes, with 29 clubs responding to the survey. TID and TDE processes changed as a function of player age. TID processes involved finding the best players locally and regionally, but for older players the search widened to nationally and internationally for the needs of the first team. Clubs used a multidisciplinary approach to TID, but more so with older players. Median number of academy players was 80, 100, and 66 players at 8–11 years, 12–16 years, and 17–21 years, respectively. Annual player turnover in the most recent season (selections/de-selections) was 29% across all age groups, with competition from other clubs cited as a limitation to TID. TDE processes involved weekly matches and 3–5 training sessions per week led by experienced, well-qualified coaches, with most clubs providing players with academic education, residency and transportation services. Our findings extend previous research assessing professional soccer youth academy TID and TDE processes by quantifying worldwide practices.  相似文献   

4.
Abstract

The aim of the study was to assess the relationship between performance-based and laboratory tests for muscular strength and power assessment in older women. Thirty-two women aged 68.8 ± 2.8 years were recruited. All participants were asessed for: (a) two performance-based tests – the box-stepping test (mean 296 ± 51 J) and two-revolution maximum test (mean 7.1 ± 2 kg) performed while pedalling on a cycle ergometer; and (b) muscular function tests – maximal instantaneous peak power jumping on a force platform (mean 1528 ± 279 W); maximal voluntary contraction (MVC) during knee extension (mean 601 ± 571 N) and leg press (mean 626 ± 126 N), and leg press power (mean 483 ± 98 W) on a dynamometer. Using univariate analysis, performance-based tests were compared with laboratory muscle strength and power measurements. Muscle power correlated most strongly with the performance-based tests for both jumping and leg press power (r-values between 0.67 and 0.75; P < 0.01). The correlation with muscle strength measures ranged between 0.48 and 0.61 (P < 0.01). The proposed tests may have particular relevance in geriatric and rehabilitation environments as they represent an easy, practical, and inexpensive alternative for the assessment of muscular strength and power.  相似文献   

5.
Paralympic throwing events for athletes with physical impairments comprise seated and standing javelin, shot put, discus and seated club throwing. Identification of talented throwers would enable prediction of future success and promote participation; however, a valid and reliable talent identification battery for Paralympic throwing has not been reported. This study evaluates the reliability and validity of a talent identification battery for Paralympic throws. Participants were non-disabled so that impairment would not confound analyses, and results would provide an indication of normative performance. Twenty-eight non-disabled participants (13 M; 15 F) aged 23.6 years (±5.44) performed five kinematically distinct criterion throws (three seated, two standing) and nine talent identification tests (three anthropometric, six motor); 23 were tested a second time to evaluate test–retest reliability. Talent identification test–retest reliability was evaluated using Intra-class Correlation Coefficient (ICC) and Bland–Altman plots (Limits of Agreement). Spearman’s correlation assessed strength of association between criterion throws and talent identification tests. Reliability was generally acceptable (mean ICC = 0.89), but two seated talent identification tests require more extensive familiarisation. Correlation strength (mean rs = 0.76) indicated that the talent identification tests can be used to validly identify individuals with competitively advantageous attributes for each of the five kinematically distinct throwing activities. Results facilitate further research in this understudied area.  相似文献   

6.
ABSTRACT

This study investigated changes in body composition in relation to training load determined using RPE and duration (sRPE), and its relationship with physical qualities over a preseason period. Sixteen professional academy players (age = 17.2 ± 0.7 years; stature = 179.9 ± 4.9 cm; body mass = 88.5 ± 10.1 kg) participated in the study. Body composition was assessed before and after each training phase and physical qualities assessed at the start and end of preseason. Across the whole preseason period, skinfold thickness, body fat percentage and fat mass were most likely lower (ES = ?0.73 to ?1.00), and fat free mass and lean mass were likely to most likely higher (ES = 0.31 to 0.40). Results indicated that the magnitude of change appeared phase-dependent (ES = ?0.05 to ?0.85) and demonstrated large individual variability. Changes in physical qualities ranged from unclear to most likely (ES = ?0.50 to 0.64). Small to moderate correlations were observed between changes in body composition, and TL with changes in physical qualities. This study suggests training phase and TL can influence a player’s body composition; that large inter-participant variability exists; and that body composition and TL are related to the change in physical qualities.  相似文献   

7.
ABSTRACT

This study investigated whether a multi-dimensional assessment could assist with talent identification in junior Australian football (AF). Participants were recruited from an elite under 18 (U18) AF competition and classified into two groups; talent identified (State U18 Academy representatives; n = 42; 17.6 ± 0.4 y) and non-talent identified (non-State U18 Academy representatives; n = 42; 17.4 ± 0.5 y). Both groups completed a multi-dimensional assessment, which consisted of physical (standing height, dynamic vertical jump height and 20 m multistage fitness test), technical (kicking and handballing tests) and perceptual-cognitive (video decision-making task) performance outcome tests. A multivariate analysis of variance tested the main effect of status on the test criterions, whilst a receiver operating characteristic curve assessed the discrimination provided from the full assessment. The talent identified players outperformed their non-talent identified peers in each test (P < 0.05). The receiver operating characteristic curve reflected near perfect discrimination (AUC = 95.4%), correctly classifying 95% and 86% of the talent identified and non-talent identified participants, respectively. When compared to single assessment approaches, this multi-dimensional assessment reflects a more comprehensive means of talent identification in AF. This study further highlights the importance of assessing multi-dimensional performance qualities when identifying talented team sports.  相似文献   

8.
Abstract

Thirty-eight competitive cross-country skiers were divided into three groups to assess the reliability and validity of a new double poling ergometer. Group A (n = 22) performed two maximal 60-s tests, Group B (n = 8) repeated peak oxygen uptake tests on the double poling ergometer, and Group C (n = 8) performed a maximal 6-min test on the double poling ergometer and a double poling time-trial on snow. The correlation between the power calculated at the flywheel and the power applied at the base of the poles was r = 0.99 (P < 0.05). The power at the poles was 50 – 70% higher than that at the flywheel. There was a high test – retest reliability in the two 60-s power output tests (coefficient of variation = 3.0%) and no significant difference in peak oxygen uptake in the two 6-min all-out tests (coefficient of variation = 2.4%). There was a strong correlation between the absolute (W) and relative power (W · kg?1) output in the 6-min double poling ergometer test and the double poling performance on snow (r = 0.86 and 0.89 respectively; both P < 0.05). In conclusion, our results show that the double poling ergometer has both high reliability and validity. However, the power calculated at the flywheel underestimated the total power produced and needs to be corrected for in ergonomic estimations.  相似文献   

9.
Lumbar spine injury in rowers is common and ergometer rowing has been cited as a risk factor for this injury. The purpose of this study is to compare lumbar kinematics between ergometer and single scull rowing and to examine the effect of fatigue on kinematics. The sagittal lumbar spine motion of 19 elite male rowers (lumbar spine injury free in the previous six months) was measured with an electrogoniometer during a ‘step test’ on an ergometer and in a single sculling boat. Maximum range of lumbar flexion was recorded in standing for reference. Power output and heart rate were recorded during the ergometer tests. Heart rate was used as a surrogate for power output in the sculling test. Maximum lumbar flexion increased during the step test and was significantly greater on the ergometer (4.4° ± 0.9°change), compared with the boat (+1.3° ± 1.1°change), (3.1°difference, p = 0.035). Compared to the voluntary range of motion, there is an increase of 11.3% (ergometer) and 4.1% (boat). Lumbar spine flexion increases significantly during the course of an ergometer trial while changes in a sculling boat were minimal. Such differences may contribute to the recent findings linking ergometer use to lower-back injury.  相似文献   

10.
Purpose: The talent identification and selection process in young male soccer players is mainly focused on anthropometrics and physical performance, but social factors are also considered in this process. The purpose of this study was to test the existence of the relative age effect and its possible influence on anthropometrics and physical performance and to analyze coaches’ efficacy expectations. Method: Data for 564 young male soccer players (Mage = 13.7 ± 1.5 years; Mweight = 53.7 ± 11.6 kg; Mheight = 160.2 ± 11.6 cm) included their birth quartile, maturity status, anthropometrics, a physical test battery, and coaches’ efficacy expectations. Results: Early-born players were overrepresented (p < .05). Early-born players were not statistically taller, heavier, or better at physical performance (p > .05) when maturation and chronological age were controlled as confounding factors. However, coaches expected more from early-born players (p < .05), and the inferential analysis showed likely to very likely worthwhile differences between the coaches’ expectations for players born in the first quartile of the year and those born in the fourth quartile of the year. Conclusions: Anthropometrical and physical performance variables were not affected by birth quartile, and coaches’ efficacy expectations were related to the relative age effect.  相似文献   

11.
The aim of this current randomised controlled trial was to evaluate the effects of a home-based physical activity (PA) intervention on cardiorespiratory fitness in breast cancer survivors. Thirty-two post-adjuvant therapy breast cancer survivors (age = 52 ± 10 years; BMI = 27.2 ± 4.4 kg?m2) were randomised to a six-month home-based PA intervention with face-to-face and telephone PA counselling or usual care. Cardiorespiratory fitness and self-reported PA were assessed at baseline and at six-months. Participants had a mean relative V?O2max of 25.3 ± 4.7 ml?kg?1?min?1, which is categorised as “poor” according to age and gender matched normative values. Magnitude-based inference analyses revealed likely at least small beneficial effects (effect sizes ≥.20) on absolute and relative V?O2 max (d = .44 and .40, respectively), and total and moderate PA (d = .73 and .59, respectively) in the intervention compared to the usual care group. We found no likely beneficial improvements in any other outcome. Our home-based PA intervention led to likely beneficial, albeit modest, increases in cardiorespiratory fitness and self-reported PA in breast cancer survivors. This intervention has the potential for widespread implementation and adoption, which could considerably impact on post-treatment recovery in this population.  相似文献   

12.
The purpose of the study was to investigate the sensitivity of an alternative maximal accumulated oxygen deficit (MAODALT) method to discriminate the “anaerobic” capacity while comparing: least trained (LT) participants (n = 12), moderately trained (MT) participants (n = 12), endurance trained (ET) participants (n = 16), and rugby (RG) players (n = 11). Participants underwent a graded exercise test on a treadmill and a supramaximal effort for assessing MAODALT. MAODALT was calculated as the sum of oxygen equivalents from the phosphagen and glycolytic metabolic pathways. MAODALT was significantly higher (P < 0.05) in RG (64.4 ± 12.1 mL · kg?1) than in ET (56.8 ± 5.4 mL · kg?1; effect size [ES] = 0.77; +13.5%), MT (53.8 ± 5.3 mL · kg?1; ES = 1.08; +19.8%), and LT (49.9 ± 4.5 mL · kg?1; ES = 1.50; +36.4%). In addition, the magnitude-based inference analysis revealed that MAODALT was likely (LT vs. MT), very likely (MT vs. RG, and ET vs. RG) and most likely (LT vs. ET, and LT vs. RG) different between all groups, except for MT and ET, which presented an unclear difference. In conclusion, MAODALT was sensitive enough to distinguish the “anaerobic” capacity in individuals with different training status, especially for RG players compared with LT participants and MT participants.  相似文献   

13.
This study investigated the effects of a mentally fatiguing test on physical tasks among elite cricketers. In a cross-over design, 10 elite male cricket players from a professional club performed a cricket run-two test, a Batak Lite reaction time test and a Yo-Yo-Intermittent Recovery Level 1 (Yo-Yo-IR1) test, providing a rating of perceived exertion (RPE) after completing a 30-min Stroop test (mental fatigue condition) or 30-min control condition. Perceived fatigue was assessed before and after the two conditions and motivation was measured before testing. There were post-treatment differences in the perception of mental fatigue (P < 0.001; d = ?7.82, 95% CIs = ?9.05–6.66; most likely). Cricket run-two (P = 0.002; d = ?0.51, 95% CIs = ?0.72–0.30; very likely), Yo-Yo-IR1 distance (P = 0.023; d = 0.39, 95% CIs = 0.14–0.64; likely) and RPE (P = 0.001; d = ?1.82, 95% CIs = ?2.49–1.14; most likely) were negatively affected by mental fatigue. The Batak Lite test was not affected (P = 0.137), yet a moderate (d = 0.41, 95% CIs = ?0.05–0.87) change was likely. Mental fatigue, induced by an app-based Stroop test, negatively affected cricket-relevant performance.  相似文献   

14.
The present investigation was performed to elucidate if the non-erythropoietic ergogenic effect of a recombinant erythropoietin treatment results in an impact on skeletal muscle mitochondrial and whole body fatty acid oxidation capacity during exercise, myoglobin concentration and angiogenesis. Recombinant erythropoietin was administered by subcutaneous injections (5000 IU) in six healthy male volunteers (aged 21 ± 2 years; fat mass 18.5 ± 2.3%) over 8 weeks. The participants performed two graded cycle ergometer exercise tests before and after the intervention where VO2max and maximal fat oxidation were measured. Biopsies of the vastus lateralis muscle were obtained before and after the intervention. Recombinant erythropoietin treatment increased mitochondrial O2 flux during ADP stimulated state 3 respiration in the presence of complex I and II substrates (malate, glutamate, pyruvate, succinate) with additional electron input from β-oxidation (octanoylcarnitine) (from 60 ± 13 to 87 ± 24 pmol · s?1 · mg?1 P < 0.01). β-hydroxy-acyl-CoA-dehydrogenase activity was higher after treatment (P < 0.05), whereas citrate synthase activity also tended to increase (P = 0.06). Total myoglobin increased by 16.5% (P < 0.05). Capillaries per muscle area tended to increase (P = 0.07), whereas capillaries per fibre as well as the total expression of vascular endothelial growth factor remained unchanged. Whole body maximal fat oxidation was not increased after treatment. Eight weeks of recombinant erythropoietin treatment increases mitochondrial fatty acid oxidation capacity and myoglobin concentration without any effect on whole body maximal fat oxidation.  相似文献   

15.
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   

16.
Abstract

Graded exercise tests are commonly used to assess peak physiological capacities of athletes. However, unlike time trials, these tests do not provide performance information. The aim of this study was to examine the peak physiological responses of female outrigger canoeists to a 1000-m ergometer time trial and compare the time-trial performance to two graded exercise tests performed at increments of 7.5 W each minute and 15 W each two minutes respectively. 17 trained female outrigger canoeists completed the time trial on an outrigger canoe ergometer with heart rate (HR), stroke rate, power output, and oxygen consumption ([Vdot]O2) determined every 15 s. The mean (± s) time-trial time was 359 ± 33 s, with a mean power output of 65 ± 16 W and mean stroke rate of 56 ± 4 strokes · min?1. Mean values for peak [Vdot]O2, peak heart rate, and mean heart rate were 3.17 ± 0.67 litres · min?1, 177 ± 11 beats · min?1, and 164 ± 12 beats · min?1 respectively. Compared with the graded exercise tests, the time-trial elicited similar values for peak heart rate, peak power output, peak blood lactate concentration, and peak [Vdot]O2. As a time trial is sport-specific and can simultaneously quantify sprint performance and peak physiological responses in outrigger canoeing, it is suggested that a time trial be used by coaches for crew selection as it doubles as a reliable performance measure and a protocol for monitoring peak aerobic capacity of female outrigger canoeists.  相似文献   

17.
Abstract

The aims of this study were to examine the use of the critical velocity test as a means of predicting 2000-m rowing ergometer performance in female collegiate rowers, and to study the relationship of selected physiological variables on performance times. Thirty-five female collegiate rowers (mean ± s: age 19.3 ± 1.3 years; height 1.70 ± 0.06 m; weight 69.5 ± 7.2 kg) volunteered to participate in the study. Rowers were divided into two categories based on rowing experience: varsity (more than 1 year collegiate experience) and novice (less than 1 year collegiate experience). All rowers performed two continuous graded maximal oxygen consumption tests (familiarization and baseline) to establish maximal oxygen uptake ([Vdot]O2max), peak power output, and power output at ventilatory threshold. Rowers then completed a critical velocity test, consisting of four time-trials at various distances (400 m, 600 m, 800 m, and 1000 m) on two separate days, with 15 min rest between trials. Following the critical velocity test, rowers completed a 2000-m time-trial. Absolute [Vdot]O2max was the strongest predictor of 2000-m performance (r = 0.923) in varsity rowers, with significant correlations also observed for peak power output and critical velocity (r = 0.866 and r = 0.856, respectively). In contrast, critical velocity was the strongest predictor of 2000-m performance in novice rowers (r = 0.733), explaining 54% of the variability in performance. These findings suggest the critical velocity test may be more appropriate for evaluating performance in novice rowers.  相似文献   

18.
Abstract

We evaluated (1) the test–retest reliability of the Wingate test conducted on a rowing ergometer, and (2) the sensitivity of this test in determining the differences in performance attained by 12- to 18-year-old rowers. Altogether, 297 male rowers aged 12.0–18.9 years (mean ± s: 14.8 ± 1.7) completed a maximal 30-s test on a rowing ergometer, and 80 rowers representing all age groups were retested after 5–7 days. No change was evident in participants' performance in terms of mean power output (P = 0.726; Cohen's d = 0.04), maximal power output (P = 0.567; Cohen's d = 0.06), and minimum power output (P = 0.318; Cohen's d = 0.11) in the second test. The intra-class correlation coefficients were high (≥0.973) and coefficients of variation were low (≤7.3%). A series of analyses of variance were used to compare the performances among 12- to 18-year-old rowers, and age-related increases in performance were evident (P < 0.001; Cohen's d = 1.91–1.96). The age-related increases in performance were similar, although reduced, when the effects of body mass were partitioned out when using analysis of covariance (P < 0.001; Cohen's d = 0.82–0.85). The results suggest that: (1) the described test is reliable and can be used for maximal-intensity exercise assessment in youth rowing, and (2) it discriminates performance among 12- to-18-year-old rowers.  相似文献   

19.
Abstract

The purpose of this study was to evaluate the effects of a realistic, feasible, and commonly used fitness training programme on cardiac autonomic control in 14 sedentary men aged 62.0 ± 6.1 years (mean ± s). All participants performed a one-year fitness training programme in which training intensity and frequency were specifically chosen to be compliant for the majority of the participants (2 – 3 sessions per week at moderate intensity). At the same time, a reference group consisting of 15 sedentary age-matched men (age 64.2 ± 6.5 years) did not change their habitual physical activity. Measurements were performed before and after the training intervention. Cardiac autonomic control was inferred from resting values (supine and standing) of heart rate variability (HRV) computed in the frequency domain over 10-min intervals. Endurance capacity was evaluated during a maximal incremental bicycle ergometer test. In spite of an increase in peak oxygen consumption ([Vdot]O2peak) by 6.4% after training, heart rate in the training group remained unchanged at rest and at the same metabolic demand. No changes in resting parameters of HRV were shown for either groups or positions. Results from this study provide no evidence of a clinically meaningful increase in the vagal modulation to the sinus node at rest after one year of low-volume and moderate-intensity fitness training in men aged 55 – 75 years.  相似文献   

20.
This study investigated the change in body composition and bone mineral content (BMC) of senior rugby league (RL) players between 2008 and 2014. Twelve male professional RL players (age, 24.6 ± 4.0 years; stature, 183.4 ± 8.4 cm) received a dual-energy X-ray absorptiometry scan during preseason in 2008 and 2014. Between 2008 and 2014, very likely increases in leg lean mass (LM), total trunk and leg BMC, and a likely increase in arm BMC and possible increases in body mass (BM), total and trunk fat mass (FM), and total, trunk and arm LM were observed. Unlikely decreases and unclear changes in leg and arm FM were also found. Large negative correlations were observed between age and BM (r = ?0.72), LM (r = ?0.70), FM (r = ?0.61) and BMC (r = ?0.84) change. Three participants (19.1 ± 1.6 years) increased LM by 7.0–9.3 kg. Younger players had the largest increases in LM during this period, although an older player (30-year old) still increased LM. Differences in body composition change were also observed for participants of the same age, thus contextual factors should be considered. This study demonstrates the individuality of body composition changes in senior professional rugby players, while considering the potential change in young athletes.  相似文献   

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