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The physiological adaptations to sauna bathing could enhance endurance performance. We have therefore performed a cross-over study in which six male distance runners completed 3 wk of post-training sauna bathing and 3 wk of control training, with a 3 wk washout. During the sauna period, subjects sat in a humid sauna at 89.9+/-2.0 degrees C (mean+/-standard deviation) immediately post-exercise for 31+/-5 min on 12.7+/-2.1 occasions. The performance test was a approximately 15 min treadmill run to exhaustion at the runner's current best speed over 5 km. The test was performed on the 1st and 2nd day following completion of the sauna and control periods, and the times were averaged. Plasma, red-cell and total blood volume were measured via Evans blue dye dilution immediately prior to the first run to exhaustion for each period. Relative to control, sauna bathing increased run time to exhaustion by 32% (90% confidence limits 21-43%), which is equivalent to an enhancement of approximately 1.9% (1.3-2.4%) in an endurance time trial. Plasma and red-cell volumes increased by 7.1% (5.6-8.7%) and 3.5% (-0.8% to 8.1%) respectively, after sauna relative to control. Change in performance had high correlations with change in plasma volume (0.96, 0.76-0.99) and total blood volume (0.94, 0.66-0.99), but the correlation with change in red cell volume was unclear (0.48, -0.40 to 0.90). We conclude that 3 wk of post-exercise sauna bathing produced a worthwhile enhancement of endurance running performance, probably by increasing blood volume.

Concerns about the value of physical testing and apparently declining test performance in junior basketball players prompted this retrospective study of trends in anthropometric and fitness test scores related to recruitment age and recruitment year. The participants were 1011 females and 1087 males entering Basketball Australia's State and National programmes (1862 and 236 players, respectively). Players were tested on 2.6 +/- 2.0 (mean +/- s) occasions over 0.8 +/- 1.0 year. Test scores were adjusted to recruitment age (14-19 years) and recruitment year (1996-2003) using mixed modelling. Effects were estimated by log transformation and expressed as standardized (Cohen) differences in means. National players scored more favourably than State players on all tests, with the differences being generally small (standardized differences, 0.2-0.6) or moderate (0.6-1.2). On all tests, males scored more favourably than females, with large standardized differences (1.2). Athletes entering at age 16 performed at least moderately better than athletes entering at age 14 on most tests (standardized differences, 0.7-2.1), but test scores often plateaued or began to deteriorate at around 17 years. Some fitness scores deteriorated over the 8-year period, most notably a moderate increase in sprint time and moderate (National male) to large (National female) declines in shuttle run performance. Variation in test scores between National players was generally less than that between State players (ratio of standard deviations, 0.83-1.18). More favourable means and lower variability in athletes of a higher standard highlight the potential utility of these tests in junior basketball programmes, although secular declines should be a major concern of Australian basketball coaches.

The purpose of this study was to examine the extent to which physical activity among adolescent female friends is interdependent. The participants were 318 adolescent girls with a mean age of 16.0 years (range: 15–18 years). Pedometry was used to assess physical activity over 4 days. The relationship between an individual girl and her first-nominated reciprocal friend's physical activity level was moderate (r = 0.45, 90% confidence interval = 0.31, 0.56), when the friendship was nonreciprocal it was trivial (r = -.06, 90% confidence interval = -.36. .25). Friends' physical activity levels explained between 27% and 32% of an individual's pedometer-determined physical activity level. Reciprocity of friendship is an important variable to consider when understanding the relationship between adolescent female friends' physical activity. When friendships are reciprocal, there is a stronger relationship between friends' physical activity.

Anecdotally many athletes use non-steroidal anti-inflammatory gels during competition to allow continued participation. To determine if this clinical practice is useful a randomised placebo-controlled study was conducted at the 5-day 2004 Red Cross Murray River Marathon. Forty-two kayakers presented with wrist extensor tenosynovitis while competing in the single and double kayak events. All subjects received standard treatment of ice, stretches and massage for wrist tenosynovitis before being randomised into a placebo or 1% diclofenac gel group. Evaluation was done by using a visual analogue scale (0-10) for pain and by clinical grading (0-3). The main outcome measurements were reduction in pain and clinical grading, the requirement for a rescue medication (paracetamol or diclofenac tablets) and effect on performance times. Both groups had similar pain scores and clinical grading on the first and fifth days of pain. On the second to fourth days of pain there was clearly no benefit and possibly a detrimental effect on pain with diclofenac gel relative to placebo. However, diclofenac tablets were possibly beneficial for pain relative to paracetamol tablets. The effects of pain and the various treatments on performance time were either trivial (

Purpose:Load monitoring in Australian football (AF) has been widely adopted, yet team-sport periodization strategies are relatively unknown. The authors aimed to quantify training and competition load across a season in an elite AF team, using rating of perceived exertion (RPE) and GPS tracking.Methods:Weekly totals for RPE and GPS loads (including accelerometer data; PlayerLoad) were obtained for 44 players across a full season for each training modality and for competition. General linear mixed models compared mean weekly load between 3 preseason and 4 in-season blocks. Effects were assessed with inferences about magnitudes standardized with between-players SD.Results:Total RPE load was most likely greater during preseason, where the majority of load was obtained via skills and conditioning. There was a large reduction in RPE load in the last preseason block. During in-season, half the total load came from games and the remaining half from training, predominantly skills and upper-body weights. Total distance, high-intensity running, and PlayerLoad showed large to very large reductions from preseason to in-season, whereas changes in mean speed were trivial across all blocks. All these effects were clear at the 99% level.Conclusions:These data provide useful information about targeted periods of loading and unloading across different stages of a season. The study also provides a framework for further investigation of training periodization in AF teams.

Purpose:Pacing has a substantial effect on endurance performance. The authors characterize pacing and identify its parameters for optimal performance in 1500-m freestyle swimming.Methods:Web sites provided 50-m lap and 1500-m race times for 330 swims of 24 elite male swimmers. Pacing for each swim was characterized with 7 parameters derived from a general linear model: linear and quadratic coefficients for the effect of lap number; reductions from predicted time for first, second, penultimate, and last laps; and lap-time variability. Scatter plots of race time vs each parameter for each swimmer were used to identify optimum values of parameters.Results:Most scatterplots showed only weak relationships between the parameter and performance, but one-third to one-half of swimmers had an optimum value of the parameter that was substantially different from their mean value. A large improvement in performance time (1.4% ± 0.9%, mean ± SD) could be achieved generally by reversing the sign of the linear parameter to make the slowest lap occur earlier in the race. Small to moderate improvements might also accrue by changing the quadratic parameter, by making the first and second laps slower and the penultimate and last laps faster, and reducing lap-time variability.Conclusions:This approach to analysis of pacing may help improve performance in swimmers and other endurance athletes in sports with multiple laps, but data from many competitions are required.

Many athletes supplement with antioxidants in the belief this will reduce muscle damage, immune dysfunction and fatigue, and will thus improve performance, while some evidence suggests it impairs training adaptations. Here we review the effect of a range of dietary antioxidants and their effects on sport performance, including vitamin E, quercetin, resveratrol, beetroot juice, other food-derived polyphenols, spirulina and N-acetylcysteine (NAC). Older studies suggest vitamin E improves performance at altitude, with possible harmful effects on sea-level performance. Acute intake of vitamin E is worthy of further consideration, if plasma levels can be elevated sufficiently. Quercetin has a small beneficial effect for exercise of longer duration (>100 min), but it is unclear whether this benefits athletes. Resveratrol benefits trained rodents; more research is needed in athletes. Meta-analysis of beetroot juice studies has revealed that the nitrate component of beetroot juice had a substantial but unclear effect on performance when averaged across athletes, non-athletes and modes of exercise (single dose 1.4 ± 2.0 %, double dose 0.5 ± 1.9 %). The effect of addition of polyphenols and other components to beetroot juice was trivial but unclear (single dose 0.4 ± 3.2 %, double dose −0.5 ± 3.3 %). Other food-derived polyphenols indicate a range of performance outcomes from a large improvement to moderate impairment. Limited evidence suggests spirulina enhances endurance performance. Intravenous NAC improved endurance cycling performance and reduced muscle fatigue. On the basis of vitamin E and NAC studies, acute intake of antioxidants is likely to be beneficial. However, chronic intakes of most antioxidants have a harmful effect on performance.

Purpose: Lower barometric air pressure at altitude can affect competitive performance of athletes in some sports. Reported here are the effects of various altitudes on elite track-and-field athletes’ performance. Methods: Lifetime track-and-field performances of athletes placed in the top 16 in at least 1 major international competition between 2000 and 2009 were downloaded from the database at tilastopaja.org. There were 132,104 performances of 1889 athletes at 794 venues. Performances were logtransformed and analyzed using a mixed linear model with fixed effects for 6 levels of altitude and random quadratic effects to adjust for athlete age. Results: Men’s and women’s sprint events (100–400 m) showed marginal improvements of ~0.2% at altitudes of 500–999 m, and above 1500 m all but the 100- and 110-m hurdles showed substantial improvements of 0.3–0.7%. Some middle- and long-distance events (800–10,000 m) showed marginal impairments at altitudes above 150 m, but above 1000 m the impairments increased dramatically to ~2–4% for events >800 m. There was no consistent trend in the effects of altitude on field events up to 1000 m; above 1000 m, hammer throw showed a marginal improvement of ~1% and discus was impaired by 1–2%. Above 1500 m, triple jump and long jump showed marginal improvements of ~1%. Conclusions: In middle- and long-distance runners, altitudes as low as 150 to 299 m can impair performance. Higher altitudes (≥1000 m) are generally required before decreases in discus performance or enhancements in sprinting, triple and long jump, or hammer throw are seen.

Pacing offers a potential avenue for enhancement of endurance performance. We report here a novel method for characterizing pacing in 800-m freestyle swimming. Websites provided 50-m lap and race times for 192 swims of 20 elite female swimmers between 2000 and 2013. Pacing for each swim was characterized with five parameters derived from a linear model: linear and quadratic coefficients for effect of lap number, reductions from predicted time for first and last laps, and lap-time variability (standard error of the estimate). Race-to-race consistency of the parameters was expressed as intraclass correlation coefficients (ICCs). The average swim was a shallow negative quadratic with slowest time in the eleventh lap. First and last laps were faster by 6.4% and 3.6%, and lap-time variability was ±0.64%. Consistency between swimmers ranged from low-moderate for the linear and quadratic parameters (ICC = 0.29 and 0.36) to high for the last-lap parameter (ICC = 0.62), while consistency for race time was very high (ICC = 0.80). Only ~15% of swimmers had enough swims (~15 or more) to provide reasonable evidence of optimum parameter values in plots of race time vs. each parameter. The modest consistency of most of the pacing parameters and lack of relationships between parameters and performance suggest that swimmers usually compensated for changes in one parameter with changes in another. In conclusion, pacing in 800-m elite female swimmers can be characterized with five parameters, but identifying an optimal pacing profile is generally impractical.

OBJECTIVE—We sought to meta-analyze the effects of different modes of exercise training on measures of glucose control and other risk factors for complications of diabetes. RESEARCH DESIGN AND METHODS—The 27 qualifying studies were controlled trials providing, for each measure, 4–18 estimates for the effect of aerobic training, 2–7 for resistance training, and 1–5 for combined training, with 1,003 type 2 diabetic patients (age 55 ± 7 years [mean ± between-study SD]) over 5–104 weeks. The meta-analytic mixed model included main-effect covariates to control for between-study differences in disease severity, sex, total training time, training intensity, and dietary cointervention (13 studies). To interpret magnitudes, effects were standardized after meta-analysis using composite baseline between-subject SD. RESULTS—Differences among the effects of aerobic, resistance, and combined training on HbA1c (A1C) were trivial; for training lasting ≥12 weeks, the overall effect was a small beneficial reduction (A1C 0.8 ± 0.3% [mean ± 90% confidence limit]). There were generally small to moderate benefits for other measures of glucose control. For other risk factors, there were either small benefits or effects were trivial or unclear, although combined training was generally superior to aerobic and resistance training. Effects of covariates were generally trivial or unclear, but there were small additional benefits of exercise on glucose control with increased disease severity. CONCLUSIONS—All forms of exercise training produce small benefits in the main measure of glucose control: A1C. The effects are similar to those of dietary, drug, and insulin treatments. The clinical importance of combining these treatments needs further research.

To quantify the effects of adaptation to acutely intermittent hypoxia on running performance, we randomized 29 trained male hockey and soccer players in double-blind fashion to altitude or placebo groups for 15 days of daily use of a functional or placebo hypoxic re-breathing device. Each day's exposure consisted of alternately breathing stale and fresh air for 6 and 4 min respectively over 1 h. Oxygen saturation was monitored with pulse oximeters and progressively reduced in the hypoxia group (90% on Day 1, 77% on Day 15; equivalent to altitudes of ∼3600–6000 m above sea level). Performance tests were an incremental run to maximum speed followed by six maximal-effort running sprints; tests were performed 1 day before, 3 days after, and 12 days after the 15-day treatment. Relative to placebo, at 3 days post treatment the hypoxia group showed a mean increase in maximum speed of 2.0% (90% confidence limits, ±0.5%); sprint speed was relatively faster by 1.5% (±1.7%) in the first sprint through 7.0% ...

The purpose of this study was to characterize changes and variability in test performance of swimmers within and between seasons over their elite competitive career. Forty elite swimmers (24 male, 16 female) performed a 7×200-m incremental swimming step test several times each 6-month season (10±5 tests, spanning 0.5–6.0 y). Mixed linear modeling provided estimates of percent change in the mean and individual responses (within-athlete variation as a coefficient of variation) for measures based on submaximal performance (fixed 4-mM lactate), maximal performance (the seventh step) and lean mass (from skinfolds and body mass). Submaximal and maximal swim speed increased within each season from pre to taper phase by ∼2.2% for females and ∼1.5% for males (95% confidence limits ±1.0%), with variable contributions from stroke rate and stroke length. Most of the gains in speed were lost in the off-season, leaving a net average annual improvement of ∼1.0% for females and ∼0.6% for males (±1.0%). For subma...

Summary Intermittent hypoxic training and discontinuous exposure to altitude were used to improve performance at sea level in elite rowers. Altitude was simulated with a newly patented device which allowed athletes to experience altitude by re-breathing oxygen-depleted expired air. Seven elite rowers (five females, two males) used inhalers for a 90-min supervised daily session (alternating 6 min on and 4 min off) for 3 weeks, while four female elite rowers used placebo devices in the same sessions. The inhalers were adjusted to produce a progressive decrease in oxygen saturation over the 3 weeks (initially 90%; finally 80%). Immediately before and 7–10 days after altitude exposure, the rowers performed an incremental lactate test to determine power output equivalent to 4 mM [BLa], a 500-m time trial and a 5000-m time trial, all on a rowing ergometer. Relative to the control group, the altitude group showed a slight improvement in mean power for the 5000-m time trial (0.6%, 90% likely limits ±3.7%), and a substantial impairment in mean power for the 500-m trial (2.2%, ±4.1%). Power at 4-mM lactate declined in both groups, but overall the altitude group improved by 0.4% (±3.5%) relative to control. The device represents a practical way to simulate altitude exposure, but it is unlikely to have major effects on performance of elite rowers.

To evaluate the utility of fitness assessment and trends in drafting of players in the Australian Football League, we analysed height, mass, skinfolds, 20-m sprint, vertical jump, agility run and endurance assessed in the 495 players attending the annual national draft camps between 1999 and 2004. Effects of player position and assessment year were expressed as standardised mean differences (Cohen effect sizes) and interpreted qualitatively. Effect of birth month on chance of being drafted, which may be important in team sports, was also analysed. Compared with midfield players, ruckmen, tall forwards and tall defenders were decisively taller (effect-size range 1.33-1.95, large) and heavier (1.30-1.63, large), but had poorer sprint speed (0.23-0.57, small), aerobic ability (0.66-1.18, moderate) and agility (0.64-1.11, moderate). The only substantial changes in fitness scores over the 5-year period were an increase in height (0.76, moderate) and an increase in 20-m sprint time (0.39, small). A majority (65%) of players attending the camps were born in the first half of a given year, but their chance of being drafted (70%) was similar to that of players born in the second half (64%). We conclude that fitness assessment is useful for differentiating between player positions and identifying some annual trends in recruitment in Australian football, and that players with a second half birth month have been disadvantaged with lower representation at the national draft camp.

Objectives: To assess bone marrow edema at the pubic symphysis with magnetic resonance imaging (MRI), and its relation to training and osteitis pubis in an elite group of junior soccer players. Setting: Soccer players on scholarship at the Australian Institute of Sport (AIS). Patients: Nineteen players from an elite junior men’s soccer squad. Intervention/Assessment: Serial MRI examinations of the pubic symphysis over a 4-month training and playing period, training session questionnaire, and review of clinical diagnosis, investigations, and records on presentation of athletes with groin pain at the Department of Sports Medicine. Main Outcome Measures: Assessment of bone marrow edema (4-point scale) on MRI scans, review of athlete questionnaires, and review of clinical records. Results: Initial MRI scans showed moderate to severe bone marrow edema at the pubic symphysis in 11 of the 18 asymptomatic players. There was a greatly decreased risk of developing groin pain (osteitis pubis) with more training prior to entry of the AIS soccer program (odds ratio per 4 sessions of training, 0.003). The correlation between initial bone marrow edema grading and pre-AIS training was small. The increase in bone marrow edema grading from baseline over the scans was 0.5 (90% CL, 0.4). Conclusions: Substantial amounts of bone marrow edema at the pubic symphysis can occur in asymptomatic elite junior soccer players, but it is only weakly related to the development of osteitis pubis. Progressing training loads more slowly in athletes presenting with low current training loads may be a useful

A study of a sample provides only an estimate of the true (population) value of an outcome statistic. A report of the study therefore usually includes an inference about the true value. Traditionally, a researcher makes an inference by declaring the value of the statistic statistically significant or non significant on the basis of a P value derived from a null-hypothesis test. This approach is confusing and can be misleading, depending on the magnitude of the statistic, error of measurement, and sample size. The authors use a more intuitive and practical approach based directly on uncertainty in the true value of the statistic. First they express the uncertainty as confidence limits, which define the likely range of the true value. They then deal with the real-world relevance of this uncertainty by taking into account values of the statistic that are substantial in some positive and negative sense, such as beneficial or harmful. If the likely range overlaps substantially positive and negative values, they infer that the outcome is unclear; otherwise, they infer that the true value has the magnitude of the observed value: substantially positive, trivial, or substantially negative. They refine this crude inference by stating qualitatively the likelihood that the true value will have the observed magnitude (eg, very likely beneficial). Quantitative or qualitative probabilities that the true value has the other 2 magnitudes or more finely graded magnitudes (such as trivial, small, moderate, and large) can also be estimated to guide a decision about the utility of the outcome.

Background: The lean mass index (LMI) is a new empirical measure that tracks within-subject proportional changes in body mass adjusted for changes in skinfold thickness. Objective: To compare the ability of the LMI and other skinfold derived measures of lean mass to monitor changes in lean mass. Methods: 20 elite rugby union players undertook full anthropometric profiles on two occasions 10 weeks apart to calculate the LMI and five skinfold based measures of lean mass. Hydrodensitometry, deuterium dilution, and dual energy x ray absorptiometry provided a criterion choice, four compartment (4C) measure of lean mass for validation purposes. Regression based measures of validity, derived for within-subject proportional changes through log transformation, included correlation coefficients and standard errors of the estimate. Results: The correlation between change scores for the LMI and 4C lean mass was moderate (0.37, 90% confidence interval −0.01 to 0.66) and similar to the correlations for the other practical measures of lean mass (range 0.26 to 0.42). Standard errors of the estimate for the practical measures were in the range of 2.8–2.9%. The LMI correctly identified the direction of change in 4C lean mass for 14 of the 20 athletes, compared with 11 to 13 for the other practical measures of lean mass. Conclusions: The LMI is probably as good as other skinfold based measures for tracking lean mass and is theoretically more appropriate. Given the impracticality of the 4C criterion measure for routine field use, the LMI may offer a convenient alternative for monitoring physique changes, provided its utility is established under various conditions.

The race-to-race variation in performance of a top athlete determines the smallest change in performance affecting the athlete's chances of winning. We report here the typical variation in competition times of elite cyclists in various race series. Repeated-measures analysis of log-transformed official race times provided the typical variation in a cyclist's performance as a coefficient of variation. The typical variation of a top cyclist (and its 95% likely limits) was 0.4% (0.3–0.5%) in World Cup road races, 0.7% (0.7–0.8%) in Tour de France road races, 1.2% (0.8–2.2%) in the Kilo, 1.3% (0.9–2.4%) in road time trials, 1.7% (1.2–2.6%) in Tour de France time trials, and 2.4% (2.1–2.8%) in World Cup mountain biking. Cyclist interdependence arising from team tactics and pack riding probably accounts for the lower variability in performance of cyclists in road races and precludes estimation of the smallest worthwhile change in performance time for cyclists in these events. The substantial difference...

In a recent study competitive road cyclists experienced substantial gains in sprint and endurance performance when sessions of high-intensity interval training were added to their usual training in the competitive phase of a season. The current study reports the effect of this type of training on performance of 20 distance runners randomized to an experimental or control group for 5 to 7 weeks of training. The experimental group replaced part of their usual competitive-phase training with 10 × 30-minute sessions consisting of 3 sets of explosive single-leg jumps (20 for each leg) alternating with 3 sets of resisted treadmill sprints (5 × 30-second efforts alternating with 30-second recovery). Before and after the training period all runners completed an incremental treadmill test for assessment of lactate threshold and maximum running speed, 2 treadmill runs to exhaustion for prediction of 800- and 1500-m times, and a 5-km outdoor time trial. Relative to the control group, the mean changes (±90% confidence limits) in the experimental group were: maximum running speed, 1.8% (± 1.1%); lactate-threshold speed, 3.5% (±3.4%); predicted 800-m speed, 3.6% (± 1.8%); predicted 1500-m speed, 3.7% (± 3.0%); and 5-km time-trial speed, 1.2% (± 1.1%). We conclude that high-intensity resistance training in the competitive phase is likely to produce beneficial gains in performance for most distance runners.

In this study of effects of simulated altitude exposure on sea-level performance, 10 competitive runners slept in a hypoxic environment achieved with tents for 9.8+/-1.3 h.d(-1) (mean+/-standard deviation) for 24 days-30 days at 2500-3500 m (PIO2=117-103 mmHg) above sea level. The altitude group and a control group of 10 runners performed usual training (PIO2=149 mmHg). At approximately 4-wk intervals before and after exposure both groups performed an incremental test for lactate threshold. The altitude group performed an additional test, a treadmill run to exhaustion lasting approximately 5 min. One week following exposure lactate threshold speed of the altitude group relative to the control group increased by 1.2% (90% likely limits +/-3.1%), but the effect became slightly negative after controlling for baseline differences in running speed between the groups. A 16% increase in time to exhaustion was observed in the altitude group, equivalent to a 1.9% (+/-1.4%) increase in speed in a time trial. Change in performance had an unclear relationship to total altitude exposure, genotype for angiotensin converting enzyme, and change in haemoglobin concentration. Our findings are consistent with little or no effect of use of altitude tents on sea-level performance.

We assessed the magnitude of changes in fitness and anthropometric test scores of well-trained basketball players between phases of a year and over several years. Players were 1011 females and 1087...

The volume of red blood cells (VRBC) is used routinely in the diagnostic workup of polycythemia, in assessing the efficacy of erythropoietin administration, and to study factors affecting oxygen transport. However, errors of various methods of measurement of VRBCand related parameters are not well characterized. We meta-analyzed 346 estimates of error of measurement of VRBCfor techniques based on Evans blue (VRBC,Evans),51chromium-labeled red blood cells (VRBC,51Cr), and carbon monoxide (CO) rebreathing (VRBC,CO), as well as hemoglobin mass with the carbon-monoxide method (MHb,CO), in athletes and active and inactive subjects undergoing various experimental and control treatments lasting minutes to months. Subject characteristics and experimental treatments had little effect on error of measurement, but measures with the smallest error showed some increase in error with increasing time between trials. Adjusted to 1 day between trials and expressed as coefficients of variation, mean errors for MHb,CO(2.2%; 90% confidence interval 1.4–3.5%) and VRBC,51Cr(2.8%; 2.4–3.2%) were much less than those for VRBC,Evans(6.7%; 4.9–9.4%) and VRBC,CO(6.7%; 3.4–14%). Most of the error of VRBC,Evanswas due to error in measurement of volume of plasma via Evans blue dye (6.0%; 4.5–7.8%), which is the basis of VRBC,Evans. Most of the error in VRBC,COwas due to estimates from laboratories with a relatively large error in MHb,CO, the basis of VRBC,CO. VRBC,51Crand MHb,COare the best measures for research on blood-related changes in oxygen transport. With care, VRBC,Evansis suitable for clinical applications of blood-volume measurement.

Relationships between fitness testing and career progression in the Australian Football League (AFL) are under-explored. This study investigated relationships between anthropometric and fitness tests conducted at the annual AFL National Draft Camp and subsequent career progression of players. A total of 283 players was tested over three consecutive camps (1999-2001). The anthropometric and fitness measures were: height, mass, sum of skinfolds, 20-m sprint test, vertical jump (standing and bilateral running), agility run and a multi-stage incremental shuttle run. The five outcome variables were: drafted (yes/no), AFL debut (yes/no), number of AFL games played to the end of 2003, and subjective ratings of career potential and career value (5-point scale). Of 205 players (72%) subsequently drafted, 166 (59%) eventually made their AFL debut. Players drafted to AFL clubs were faster over 5 m, 10 m and 20 m, ran further in the shuttle run and ran marginally faster in the agility test than players not drafted. Multi-regression analysis showed small to moderate correlations (r = 0.27-0.31) between the designated outcome variables and selected fitness tests: 20-m sprint time (faster), agility run test (faster), and running vertical jump (higher absolute height and smaller difference between left and ride sides). Regression analysis for the standing vertical jump relative to standing reach height showed a counterintuitive negative correlation with positive outcomes, possibly reflecting non-compliance with testing procedures by the less successful athletes. We conclude that the 20-m sprint, jump, agility and shuttle run tests have a small but important association with career progression of AFL footballers.

A popular method to attempt to enhance performance is for athletes to sleep at natural or simulated moderate altitude (SMA) when training daily near sea level. Based on our previous observation of periodic breathing in athletes sleeping at SMA, we hypothesised that athletes' sleep quality would also suffer with hypoxia. Using two typical protocols of nocturnal SMA (2650 m), we examined the effect on the sleep physiology of 14 male endurance-trained athletes. The selected protocols were Consecutive (15 successive exposure nights) and Intermittent (3x 5 successive exposure nights, interspersed with 2 normoxic nights) and athletes were randomly assigned to follow either one. We monitored sleep for two successive nights under baseline conditions (B; normoxia, 600 m) and then at weekly intervals (nights 1, 8 and 15 (N1, N8 and N15, respectively)) of the protocols. Since there was no significant difference in response between the protocols being followed (based on n=7, for each group) we are unable to support a preference for either one, although the likelihood of a Type II error must be acknowledged. For all athletes (n=14), respiratory disturbance and arousal responses between B and N1, although large in magnitude, were highly individual and not statistically significant. However, SpO2 decreased at N1 versus B (p0.001) and remained lower on N8 (p0.001) and N15 (p0.001), not returning to baseline level. Compared to B, arousals were more frequent on N8 (p=0.02) and N15 (p=0.01). The percent of rapid eye movement sleep (REM) increased from N1 to N8 (p=0.03) and N15 (p=0.01). Overall, sleeping at 2650 m causes sleep disturbance in susceptible athletes, yet there was some improvement in REM sleep over the study duration.

The effect of intermittent hypoxia on sea-level endurance performance was assessed by using hypoxic tents to simulate the live high-train low approach to altitude training. Eleven male sub-elite competitive runners and triathletes participated in a crossover study of usual training (control) and usual training with altitude exposure (altitude). Altitude treatment consisted of 25±3 d (mean±SD) of sleeping in tents for 8.1±0.6 h.d−1, progressing from a simulated altitude of 2500 m to 3500 m above sea level. Washout period between control and altitude treatments was 4 wk. Three treadmill runs to exhaustion lasting ∼2, ∼4 and ∼8 min were completed 7 and 12 d after control and altitude treatments. Times for standard competition distances (800, 1500 and 3000 m), were predicted using a log-log model, improved by 1.0% (90% confidence limits, ±1.3%), 1.4% (±1.2%) and 1.9% (±1.5%), respectively. Improvements were greater in the six athletes with an I allele for angiotensin converting enzyme (ACE): 2.3% (±1...

The effects of training with overweight and underweight cricket balls on fast-bowling speed and accuracy were investigated in senior club cricket bowlers randomly assigned to either a traditional (n = 9) or modified-implement training (n = 7) group. Both groups performed bowling training three times a week for 10 weeks. The traditional training group bowled only regulation cricket balls (156 g), whereas the modified-implement training group bowled a combination of overweight (161-181 g), underweight (151-131 g) and regulation cricket balls. A radar gun measured the speed of 18 consecutive deliveries for each bowler before, during and after the training period. Video recordings of the deliveries were also analysed to determine bowling accuracy in terms of first-bounce distance from the stumps. Bowling speed, which was initially 108 +/- 5 km h(-1) (mean +/- standard deviation), increased in the modified-implement training group by 4.0 km x h(-1) and in the traditional training group by 1.3 km x h(-1) (difference, 2.7 km x h(-1); 90% confidence limits, 1.2 to 4.2 km x h(-1)). For a minimum worthwhile change of 5 km x h(-1), the chances that the true effect on bowling speed was practically beneficial/trivial/harmful were 1.0/99/0.1%. For bowling accuracy, the chances were 1/48/51%. This modified-implement training programme is not a useful training strategy for club cricketers.

Estimates of progression and variability of athletic performance in competitions are useful for researchers and practitioners interested in factors that affect performance. We used repeated-measures mixed modelling to analyse 676 official race times of 26 US and 25 Australian Olympic swimmers in the 12-month period leading up to the 2000 Olympic Games. Progression was expressed as percent changes in mean performance; variability was expressed as the coefficient of variation in performance of an individual swimmer between races. Within competitions, both nations showed similar improvements in mean time from heats through finals (overall 1.2%; 95% confidence limits 1.1 to 1.3%). Mean competition time also improved over 12 months by a similar amount in both nations (0.9%; 95% confidence limits 0.6 to 1.2%). The US swimmers showed a greater improvement between the finals (a difference of 0.5%; 95% confidence limits -0.2 to 1.1%), which paralleled changes in the medal haul of the two nations. The coefficient of variation in performance time for a swimmer between races was 0.60% (95% confidence limits 0.56 to 0.65%) within a competition and 0.80% (95% confidence limits 0.73 to 0.86%) between competitions. Our results show that: (a) to stay in contention for a medal, an Olympic swimmer should improve his or her performance by approximately 1% within a competition and by approximately 1% within the year leading up to the Olympics; (b) an additional enhancement of approximately 0.4% (one-half the between-competition variability) would substantially increase the swimmer's chances of a medal.

Coaches believe world-ranking lists are a reliable tool for predicting international swimming performance. To examine the relationship between world-ranking and Olympic performance, we modelled world-ranking time and best time from the 2000 Olympic Games for 407 top-50 world-ranked swimmers. Analysis of log-transformed times yielded within-athlete and between-athlete coefficients of variation (CV) and percent changes in performance from world-rankings to Olympics. Variations and performance progressions were compared across sex, stroke, distance, nation and medal status. The within-athlete coefficient of variation of performance for all swimmers was 0.8% (95% confidence limits: 0.7 to 0.9%). Females were slightly less consistent, although not substantially different to males (ratio of female/male within-athlete CV: 1.1; 95% confidence limits: 1.0 to 1.2) and had a wider range of talent (ratio of female/male between-athlete CV: 1.2; 95% confidence limits: 1.1 to 1.4). Swimmers from Australia (AUS) were more consistent than those from the United States (USA) and other nations (OTHER) (ratio of within-athlete CV, USA/AUS: 1.5; 95% confidence limits: 1.0 to 2.2; OTHER/ AUS: 1.6; 95% confidence limits: 1.2 to 2.1). Most Olympic medallists (87%) had a top-10 world-ranking. Overall performance time at the Olympics was slower than world-ranking time by 0.3% (95% confidence limits: 0.2 to 0.4%), medallists improved by 0.6% (95% confidence limits: 0.4 to 0.9%) and non-medallists swam 0.6% slower (95% confidence limits: 0.5 to 0.7%). We conclude that a top-10 ranked swimmer who can improve performance time by 0.6%, equivalent to 0.13 s in the men's 50-m freestyle, will substantially increase their chance of an Olympic medal (the difference between first and fourth place).

We undertook a dietary survey of 167 Australian Olympic team athletes (80 females and 87 males) competing in endurance sports (n = 41), team sports (n = 31), sprint- or skill-based sports (n = 67), and sports in which athletes are weight-conscious (n = 28). Analysis of their 7-day food diaries provided mean energy intakes, nutrient intakes, and eating patterns. Higher energy intakes relative to body mass were reported by male athletes compared with females, and by endurance athletes compared with other athletes. Endurance athletes reported substantially higher intakes of carbohydrate (CHO) than other athletes, and were among the athletes most likely to consume CHO during and after training sessions. Athletes undertaking weight-conscious sports reported relatively low energy intakes and were least likely to consume CHO during a training session or in the first hour of recovery. On average, athletes reported eating on ~5 separate occasions each day, with a moderate relationship between the number of daily eating occasions and total energy intake. Snacks, defined as food or drink consumed between main meals, provided 23% of daily energy intake and were chosen from sources higher in CHO and lower in fat and protein than foods chosen at meals. The dietary behaviors of these elite athletes were generally consistent with guidelines for sports nutrition, but intakes during and after training sessions were often sub-optimal. Although it is of interest to study the periodicity of fluid and food intake by athletes, it is difficult to compare across studies due to a lack of standardized terminology.

Information on the incidence of injury, illness, and unexplained loss of athletic performance of 2345 Standardbred racehorses was gathered from a telephone survey of 177 trainers during the 1996-1997 season. Trainer-reported incidence of infection and illness (18%) was higher than the incidence of musculoskeletal problems (10%) or unexplained athletic performance loss (6%). Older horses (>5 years) were more likely to develop musculoskeletal problems (odds ratio [OR] = 3.9; confidence interval [CI] = 1.8-8.2) and performance loss (OR = 2.3, CI = 1.1-5.2) than 2-year-old horses. Horses were more likely to suffer musculoskeletal problems if fast-worked on tracks or surfaces with no banking compared with those fast-worked on tracks with banking similar to commercial racetracks (OR = 4.6, CI = 2.0-9.9). Horses given no warm-up before high-intensity exercise were more likely to suffer a musculoskeletal problem than horses given a light warm-up of 1 to 9 minutes (OR = 2.5, CI = 1.5-4.4). Horses trained for more than 164 min·wk–1 were more likely to suffer musculoskeletal problems (OR = 1.7, CI = 1.1-2.8) and athletic performance loss (OR = 2.5, CI = 1.4-4.4) than horses trained for shorter periods. Horses given a moderate weekly exercise duration (132-148 min·wk–1) had the lowest rates of infection and illness, but short (114-131 min·wk–1) or very long (>164 min·wk–1) weekly exercise duration increased the risk of horses suffering infection and illness

Athletes in sports requiring explosive movements might benefit from a unique form of training in which a limb is restrained while the athlete attempts ballistic (explosive) movements. We investigated the effects of such ballistic training and conventional resistance training on force and speed of front kicks, side kicks, and palm strikes of martial artists. We assigned subjects randomly to an experimental group (n = 13) or a control (normal martial art training) group (n = 9). Conventional resistance training produced a gain of 12% (95% likely limits +/- 13%) in front kick force relative to the control group. Overall ballistic training and conventional resistance training decreased side kick force by 15% (+/-14%), but movement speeds increased by 11-21% (+/-13-17%). Responses to ballistic training were generally more marked in more highly skilled athletes. Attempted ballistic training may be a beneficial adjunct to resistance training for skilled athletes in sports where speed rather than force is critical.

The effect of pre-exercise meal composition on metabolism and performance in cycling were investigated in a crossover study. Twelve competitive cyclists ingested high-fat, high-carbohydrate, or high-protein meals 90 min before a weekly exercise test. The test consisted of a 1-hour pre-load at 55% peak power, five 10-min incremental loads from 55 to 82% peak power (to measure the peak fat-oxidation rate), and a 50-km time trial that included three 1-km and 4-km sprints. A carbohydrate supplement was ingested throughout the exercise. Relative to the high-protein and high-fat meals, the high-carbohydrate meal halved the peak fat-oxidation rate and reduced the fat oxidation across all workloads by a factor of 0.20 to 0.58 (p = .002–.0001). Reduced fat availability may have accounted for this reduction, as indicated by lower plasma fatty acid, lower glycerol, and higher pre-exercise insulin concentrations relative to the other meals (p = .04–.0001). In contrast, fat oxidation following the high-protein meal was similar to that following the high-fat meal. This similarity was linked to evidence suggesting greater lipolysis and plasma fat availability following high-protein relative to high-carbohydrate meals. Despite these substantial effects on metabolism, meal composition had no clear effect on sprint or 50-km performance.

We compared the effects of high-fat and high-carbohydrate dietary conditions on metabolism and short- and ultra-endurance cycling performance. Seven cyclists (VO(2)max 72 +/- 7 mL x kg(-1) x min(-1)) underwent a 2-week adaptation to each of the following 3 diets: 14-day high carbohydrate with 70 +/- 9 percent energy (%E) carbohydrate, 16 +/- 5%E fat, and 14 +/- 2%E protein; 14-day high fat with 66 +/- 10%E fat, 20 +/- 3%E protein, and 15 +/- 4%E carbohydrate; and 11.5-day high-fat diet followed by 2.5-day carbohydrate-loading. The conditions included a pre-exercise meal of the same composition as the preceding diet. Each diet condition was preceded by a 2-week standardizing normal diet. The exercise test lasted approximately 5 hours and comprised a 15-minute trial, an incremental test to measure the peak fat-oxidation rate, and a 100-km trial. Sports bars and a 5% carbohydrate solution were ingested during the tests. The diets had no statistically significant effect on 15-minute performance, although the high-fat condition tended to reduce distance covered by -2.4% (95% confidence interval: -5.4% to +0.6%, P =.11) relative to the fat with carbo-loading condition. In the 100-km time trial, the high-fat and the fat with carbohydrate-loading conditions attenuated the decline in power output observed in the high-carbohydrate condition (P =.03 to.07), although the corresponding improvement in performance time of 3% to 4% (-2% to 10%) was not statistically significant (P =.16 to.22). Power output during the final 5 km of the time trial in the fat with carbo-loading condition was 1.3-fold (1.0 to 1.6, P =.04) greater than in the high-carbohydrate condition. Overall, for every 10%E increase in dietary fat, 100-km mean power increased by 2% (-0.0% to 4%, P =.06). Relative to the high-carbohydrate condition, the high-fat conditions resulted in the following metabolic changes consistent with greater lipolysis and fuel availability: lower plasma insulin concentration before exercise (P

An editorial under the title Statistics: all together now, one step at a time appeared in this and other physiological journals earlier this year (Drummond et al., 2011) to announce a forthcoming series of 14 perspective articles on statistics. Two of the articles have now been published in six journals (Drummond and Vowler, 2011a; Drummond and Vowler, 2011b) and the third has started to appear (Drummond and Tom, 2011). The purpose of this letter is to identify what we consider to be substantial errors and omissions.

An editorial under the title All together now: one step at a time appeared in this and other physiological journals earlier this year (e.g. Drummond et al. 2011) to announce a forthcoming series of 14 perspective articles on statistics. Two of the articles have now been published in six journals (e.g. Drummond & Vowler, 2011a,b;) and the third has started to appear (Drummond & Tom, 2011). The purpose of this letter is to identify what we consider to be substantial errors and omissions.

Talent identification and development typically involve allocation of resources toward athletes selected on the basis of early-career performance.Purpose:To compare 4 methods for early-career selection of Australia’s 2012 Olympic-qualifying swimmers.Methods:Performance times from 5738 Australian swimmers in individual Olympic events at 101 competitions from 2000 to 2012 were analyzed as percentages of world-record times using 4 methods that retrospectively simulated early selection of swimmers into a talent-development squad. For all methods, squad-selection thresholds were set to include 90% of Olympic qualifiers. One method used each swimmer’s given-year performance for selection, while the others predicted each swimmer’s 2012 performance. The predictive methods were regression and neural-network modeling using given-year performance and age and quadratic trajectories derived using mixed modeling of each swimmer’s annual best career performances up to the given year. All methods were applied to swimmers in 2007 and repeated for each subsequent year through 2011.Results:The regression model produced squad sizes of 562, 552, 188, 140, and 93 for the years 2007 through 2011. Corresponding proportions of the squads consisting of Olympic qualifiers were 11%, 11%, 32%, 43%, and 66%. Neural-network modeling produced similar outcomes, but the other methods were less effective. Swimming Australia’s actual squads ranged from 91 to 67 swimmers but included only 50−74% of Olympic qualifiers.Conclusions:Large talent-development squads are required to include most eventual Olympic qualifiers. Criteria additional to age and performance are needed to improve early selection of swimmers to talent-development squads.

International industry standards set out requirements to mount ski bindings, test equipment functionality, provide guidelines on how to maintain the ski-binding-boot interface, and calculate correct release values. The standards call for the use of a torque testing device to assess functionality of the ski-binding with release values based on parameters of age, weight, height, boot-sole length, and skier type. To determine whether these standards were being applied in New Zealand a cross-sectional study was completed with a national survey of ski technicians and structured interviews with senior ski industry personnel. In setting up ski bindings, only 10 % of ski technicians used a torque-testing device, and substantial proportions did not take into account appropriate skier characteristics or check the boot-binding interface. Interviews of senior personnel indicated that there was good intent about quality of rental service; however, there were inconsistencies between operating procedures and international standards. The interviews also highlighted a need for better standardized questioning techniques for ski technicians to accurately determine skier type, and increased education for both ski technicians and skiers on correct setup to prevent injury related to non-release or inadvertent release. In conclusion, Ski-Binding-Boot (SBB) system inspection, routine torque testing to ensure safe functional ski-bindings, and consistent application of the international standards for correct setup of ski-binding-boot systems continues to be elusive in New Zealand. Assessment of the implementation of the international standards in other countries is also needed. KEYWORDS: alpine skiing, equipment, standards, ski-binding-boot system, torque, injury Language: en

This study evaluated release torque values for rental ski-binding-boot (S-B-B) systems that had one to four seasons use in a popular New Zealand commercial ski area. The proportions of S-B-B systems in classes of deviation from the reference release moment were determined according to the international equipment safety requirements from ASTM F1063-03, ASTM F1064-03, ASTM F939-06, ISO 13993: 2001, and ISO 11088-2006 (E). A randomly chosen sample of 9 % (124 skis/62 pairs) of S-B-B systems from the total ski rental fleet was tested using a Wintersteiger calibration machine. There were a high percentage of Class I deviations in the rental fleet: 50 % (2 seasons), 95 % (3 seasons), and 64 % (4 seasons). Class 1 deviations do not require corrective action; however, increased sampling is indicated. Based on the high percentage of Class I deviations the entire fleet should be inspected. Class II deviations that required immediate corrective action were found in 48 % of the S-B-B with two seasons of use. Only 8 % of the rental fleet had Class III deviations warranting removal from the rental fleet. The heel-pieces of S-B-B systems that had two or more seasons of use were nine times more likely to be out of tolerance than those with only one season of use; however, there was only a small increase in the proportion of toe-pieces out of tolerance for older compared to newer S-B-B systems. These differences may be due to age or to different models of S-B-B systems. The policy of retiring ski rental equipment after three or four seasons of use appears to be inadequate to ensure the supply of safe equipment. Language: en

Sedentary behavior is associated with overweight and obesity in children, and distance to school has been negatively associated with active commuting to school. It is not known how distance to school relates to sedentary behavior in children. The aim of this study was to investigate the association between distance to school and children’s sedentary behavior during weekdays at times where children interact with the neighborhood environment. Children (5–13 years, n = 295) who participated in the understanding relationships between activity and neighborhoods study (2008–2010) across four New Zealand cities wore a hip-mounted accelerometer for 7 days. Minutes spent sedentary (accelerometer count

Many national sporting organizations recruit talented athletes to well-resourced centralized training squads to improve their performance.Purpose: To develop a method to monitor performance progression of swimming squads and to use this method to assess the progression of New Zealand’s centralized elite swimming squad.Methods: Best annual long-course competition times of all New Zealand swimmers with at least 3 y of performances in an event between 2002 and 2013 were downloaded from takeyourmarks.com (~281,000 times from ~8500 swimmers). A mixed linear model accounting for event, age, club, year, and elite-squad membership produced estimates of mean annual performance for 175 swim clubs and mean estimates of the deviation of swimmers’ performances from their individual quadratic trajectories after they joined the elite squad. Effects were evaluated using magnitude-based inferences, with a smallest important improvement in swim time of –0.24%.Results: Before 2009, effects of elite-squad membership were mostly unclear and trivial to small in magnitude. Thereafter, both sexes showed clear additional performance enhancements, increasing from large in 2009 (males –1.4% ± 0.8%, females –1.5% ± 0.8%; mean ± 90% confidence limits) to extremely large in 2013 (males –6.8% ± 1.7%, females –9.8% ± 2.9%). Some clubs also showed clear performance trends during the 11-y period.Conclusions: Our method of quantifying deviations from individual trends in competition performance with a mixed model showed that Swimming New Zealand’s centralization strategy took several years to produce substantial performance effects. The method may also be useful for evaluating performance-enhancement strategies introduced at national or club level in other sports.

The purpose of this study was to assess the possible contribution of 1RM leg-press strength and jump peak power to 20-m sprint time in young athletes in three maturity groups based on age relative to predicted age of peak height velocity (PHV): Pre (− 2.5 to −1.0 years; n=25), Mid (− 1.0 to 0.5 years; n=26) and Post (0.5 to 2.0 years; n=15). Allometric scaling factors, representing percent difference in 20-m time per percent difference in strength and peak power, were derived by linear regression and were similar in the three maturity groups (−0.16%/% and −0.20%/% for strength and peak power, respectively). The moderate increase in sprint performance Pre to Mid PHV (5.7%) reduced to small (1.9%) and trivial but unclear (0.9%) magnitudes after adjustment for 1RM and peak power, while the moderate increase Mid to Post PHV (4.6%) were still moderate (3.4 and 3.0%) after adjustment. Thus percent differences in strength or power explained most of the maturity-related improvements in sprint performance before PHV age but only some improvements after PHV age. Factors in addition to strength and power should be identified and monitored for development of speed in athletes during puberty.

Background Low-volume high-intensity interval training (HIT) appears to be an efficient and practical way to develop physical fitness. Objective Our objective was to estimate meta-analysed mean effects of HIT on aerobic power (maximum oxygen consumption [VO2max] in an incremental test) and sprint fitness (peak and mean power in a 30-s Wingate test). Data Sources Five databases (PubMed, MEDLINE, Scopus, BIOSIS and Web of Science) were searched for original research articles published up to January 2014. Search terms included ‘high intensity’, ‘HIT’, ‘sprint’, ‘fitness’ and ‘VO2max’. Study Selection Inclusion criteria were fitness assessed pre- and post-training; training period ≥2 weeks; repetition duration 30–60 s; work/rest ratio 18 years. Data Extraction The final data set consisted of 55 estimates from 32 trials for VO2max, 23 estimates from 16 trials for peak sprint power, and 19 estimates from 12 trials for mean sprint power. Effects on fitness were analysed as percentages via log transformation. Standard errors calculated from exact p values (where reported) or imputed from errors of measurement provided appropriate weightings. Fixed effects in the meta-regression model included type of study (controlled, uncontrolled), subject characteristics (sex, training status, baseline fitness) and training parameters (number of training sessions, repetition duration, work/rest ratio). Probabilistic magnitude-based inferences for meta-analysed effects were based on standardized thresholds for small, moderate and large changes (0.2, 0.6 and 1.2, respectively) derived from between-subject standard deviations (SDs) for baseline fitness. Results A mean low-volume HIT protocol (13 training sessions, 0.16 work/rest ratio) in a controlled trial produced a likely moderate improvement in the VO2max of active non-athletic males (6.2 %; 90 % confidence limits ±3.1 %), when compared with control. There were possibly moderate improvements in the VO2max of sedentary males (10.0 %; ±5.1 %) and active non-athletic females (3.6 %; ±4.3 %) and a likely small increase for sedentary females (7.3 %; ±4.8 %). The effect on the VO2max of athletic males was unclear (2.7 %; ±4.6 %). A possibly moderate additional increase was likely for subjects with a 10 mL·kg−1·min−1 lower baseline VO2max (3.8 %; ±2.5 %), whereas the modifying effects of sex and difference in exercise dose were unclear. The comparison of HIT with traditional endurance training was unclear (−1.6 %; ±4.3 %). Unexplained variation between studies was 2.0 % (SD). Meta-analysed effects of HIT on Wingate peak and mean power were unclear. Conclusions Low-volume HIT produces moderate improvements in the aerobic power of active non-athletic and sedentary subjects. More studies are needed to resolve the unclear modifying effects of sex and HIT dose on aerobic power and the unclear effects on sprint fitness.

Purpose:The implications of undertaking DXA scans using best practice protocols (subjects fasted and rested) or a less precise but more practical protocol in assessing chronic changes in body composition following training and a specialized recovery technique were investigated.Methods:Twenty-one male cyclists completed an overload training program, in which they were randomized to four sessions per week of either cold water immersion therapy or control groups. Whole-body DXA scans were undertaken with best practice protocol (Best) or random activity protocol (Random) at baseline, after 3 weeks of overload training, and after a 2-week taper. Magnitudes of changes in total, lean and fat mass from baseline-overload, overload-taper and baseline-taper were assessed by standardization (Δmean/SD).Results:The standard deviations of change scores for total and fat-free soft tissue mass (FFST) from Random scans (2–3%) were approximately double those observed in the Best (1–2%), owing to extra random errors associated with Random scans at baseline. There was little difference in change scores for fat mass. The effect of cold water immersion therapy on baseline-taper changes in FFST was possibly harmful (-0.7%; 90% confidence limits ±1.2%) with Best scans but unclear with Random scans (0.9%; ±2.0%). Both protocols gave similar possibly harmful effects of cold water immersion therapy on changes in fat mass (6.9%; ±13.5% and 5.5%; ±14.3%, respectively).Conclusions:An interesting effect of cold water immersion therapy on training-induced changes in body composition might have been missed with a less precise scanning protocol. DXA scans should be undertaken with Best.

Epigenomic regulation of the transcriptome by DNA methylation and posttranscriptional gene silencing by miRNAs are potential environmental modulators of skeletal muscle plasticity to chronic exercise in healthy and diseased populations. We utilized transcriptome networks to connect exercise-induced differential methylation and miRNA with functional skeletal muscle plasticity. Biopsies of the vastus lateralis were collected from middle-aged Polynesian men and women with morbid obesity (44 kg/m2 ± 10) and Type 2 diabetes before and following 16 wk of resistance ( n = 9) or endurance training ( n = 8). Longitudinal transcriptome, methylome, and microRNA (miRNA) responses were obtained via microarray, filtered by novel effect-size based false discovery rate probe selection preceding bioinformatic interrogation. Metabolic and microvascular transcriptome topology dominated the network landscape following endurance exercise. Lipid and glucose metabolism modules were connected to: microRNA (miR)-29a; promoter region hypomethylation of nuclear receptor factor ( NRF1) and fatty acid transporter ( SLC27A4), and hypermethylation of fatty acid synthase, and to exon hypomethylation of 6-phosphofructo-2-kinase and Ser/Thr protein kinase. Directional change in the endurance networks was validated by lower intramyocellular lipid, increased capillarity, GLUT4, hexokinase, and mitochondrial enzyme activity and proteome. Resistance training also lowered lipid and increased enzyme activity and caused GLUT4 promoter hypomethylation; however, training was inconsequential to GLUT4, capillarity, and metabolic transcriptome. miR-195 connected to negative regulation of vascular development. To conclude, integrated molecular network modelling revealed differential DNA methylation and miRNA expression changes occur in skeletal muscle in response to chronic exercise training that are most pronounced with endurance training and topographically associated with functional metabolic and microvascular plasticity relevant to diabetes rehabilitation.

Objectives: Identifying performance indicators related to rugby sevens competition outcomes will inform development of team tactics that increase the likelihood of success. This study characterized 16 team performance indicators and quantified the effect of changes and differences in performance indicators within and between teams on team ranking in international tournaments.

Analyses of elite competitive performance provide useful information for research and practical applications.Purpose:Here the authors analyze performance times of cross-country skiers at international competitions (World Cup, World Championship, and Olympics) in classical and free styles of women’s and men’s distance and sprint events, each with a total of 410–569 athletes competing in 1–44 races at 15–25 venues from seasons 2002 to 2011.Methods:A linear mixed model of race times for each event provided estimates of within-athlete race-to-race variability expressed as a coefficient of variation (CV) after adjustment for fixed or random effects of snow conditions, altitude, race length, and competition terrain.Results:Within-athlete variability was similar for men and women over various events for all athletes (CV of 1.5–1.8%) and for the annual top-10 athletes (1.1–1.4%). Observed effects of snow conditions and altitude on mean time were substantial (~2%) but mostly unclear, owing to large effects of terrain (CV of 4–10% in top-10 analyses). Predictability of performance was extremely high for all athletes (intraclass correlations of .90–.96) but only trivial to poor for top-10 athletes (men .00–.03, women .03–.35).Conclusion:The race-to-race variability of top-ranked skiers is similar to that of other elite endurance athletes. Estimates of the smallest worthwhile performance enhancement (0.3× within-athlete variability) will help researchers and practitioners evaluate strategies affecting performance of elite skiers.

The athlete biological passport for the fight against doping is currently based on longitudinal monitoring for abnormal changes in cellular blood parameters. Serum parameters related to altered erythropoiesis could be considered for inclusion in the passport. The aim of this study was to quantify the changes in such parameters in athletes during a period of intense exercise.12 highly trained cyclists tapered for 3 days before 6 days of simulated intense stage racing.Morning and afternoon blood samples were taken on most days and analysed for total protein,albumin, soluble transferrin receptor andferritin concentrations. Plasma volume wasdetermined via total haemoglobin mass measuredby carbon-monoxide rebreathing. Percent changes in means from baseline and percent standard errors of measurement (analytical error plus intra-athlete variation) on each measurement occasion were estimated with mixed linear modelling of log-transformed measures.Means of all variables changed substantially in the days following the onset of racing, ranging from − 13 % (haemoglobin concentration) to + 27 %(ferritin). After the second day, errors of measurement were generally twice those at baseline.Plasma variables were affected by heavy exercise,either because of changes in plasma volume(total protein, albumin, haemoglobin), acute phase/inflammatory reactions (ferritin) or both(soluble transferrin receptor). These effects need to be taken into consideration when integrating a plasma parameter into the biological passportmodel for athletes. Refereed/Peer-reviewed

The effect of caffeine ingestion on sprint performance is unclear. We have therefore investigated its effect on performance in a test that simulates the repeated sprints of team sports.In a randomized double-blind crossover experiment, 16 male team-sport athletes ingested either caffeine (6 mg.kg-1 of body mass) or a placebo 60 min before performing a repeated 20-m sprint test. The test consisted of 10 sprints, each performed within 10 s and followed by rest for the remainder of each 10 s. The caffeine and placebo trials followed a familiarization trial, and the time between consecutive trials was 2-3 d. To allow estimation of variation in treatment effects between individuals, nine subjects performed three more trials without a supplement 7-14 d later. We estimated the smallest worthwhile effect on sprint time in a team sport to be approximately 0.8%.Mean time to complete 10 sprints increased by 0.1% (95% likely range -1.5 to 1.7%) with caffeine ingestion relative to placebo. Individual variation in this effect was a standard deviation of 0.7% (-2.7 to 2.9%). Time to complete the 10th sprint was 14.4% longer than the first; caffeine increased this time by 0.7% (-1.8 to 3.2%) relative to placebo, and individual variation in this effect was 2.4% (-3.4 to 4.9%).The observed effect of caffeine ingestion on mean sprint performance and fatigue over 10 sprints was negligible. The true effect on mean performance could be small at most, although the true effects on fatigue and on the performance of individuals could be somewhat larger. Pending confirmatory research, team-sport athletes should not expect caffeine to enhance sprint performance.

The reliability of power in tests of physical performance affects the precision of assessment of athletes, patients, clients and study participants. In this meta-analytic review we identify the most reliable measures of power and the factors affecting reliability. Our measures of reliability were the typical (standard) error of measurement expressed as a coefficient of variation (CV) and the percent change in the mean between trials. We meta-analysed these measures for power or work from 101 studies of healthy adults. Measures and tests with the smallest CV in exercise of a given duration include field tests of sprint running (approximately 0.9%), peak power in an incremental test on a treadmill or cycle ergometer (approximately 0.9%), equivalent mean power in a constant-power test lasting 1 minute to 3 hours on a treadmill or cycle ergometer (0.9 to 2.0%), lactate-threshold power (approximately 1.5%), and jump height or distance (approximately 2.0%). The CV for mean power on isokinetic ergometers was relatively large (4%). CV were larger for nonathletes versus athletes (1.3 x), female versus male nonathletes (1.4 x), shorter (approximately 1-second) and longer (approximately 1-hour) versus 1-minute tests (or = 1.6 x), and respiratory- versus ergometer-based measures of power (1.4 to 1.6 x). There was no clear-cut effect of time between trials. The importance of a practice trial was evident in studies with2 trials: the CV between the first 2 trials was 1.3 times the CV between subsequent trials; performance also improved by 1.2% between the first 2 trials but by only 0.2% between subsequent trials. These findings should help exercise practitioners and researchers select or design good measures and protocols for tests of physical performance.