Estimation versus falsification approaches in sport and exercise science.

There has been a recent resurgence in debate about methods for statistical inference in science. The debate addresses statistical concepts and their impact on the value and meaning of analyses' outcomes. In contrast, philosophical underpinnings of approaches and the extent to which analytical tools match philosophical goals of the scientific method have received less attention. This short piece considers application of the scientific method to "what-is-the-influence-of x-on-y" type questions characteristic of sport and exercise science. We consider applications and interpretations of estimation versus falsification based statistical approaches and their value in addressing how much x influences y, and in measurement error and method agreement settings. We compare estimation using magnitude based inference (MBI) with falsification using null hypothesis significance testing (NHST), and highlight the limited value both of falsification and NHST to address problems in sport and exercise science. We recommend adopting an estimation approach, expressing the uncertainty of effects of x on y, and their practical/clinical value against pre-determined effect magnitudes using MBI.

Effects of a lifestyle intervention on endothelial function in men on long-term androgen deprivation therapy for prostate cancer.

BACKGROUND: Treatment of prostate cancer with androgen deprivation therapy (ADT) is associated with metabolic changes that have been linked to an increase in cardiovascular risk. METHODS: This randomised controlled trial investigated the effects of a 12-week lifestyle intervention that included supervised exercise training and dietary advice on markers of cardiovascular risk in 50 men on long-term ADT recruited to an on-going study investigating the effects of such a lifestyle intervention on quality of life. Participants were randomly allocated to receive the intervention or usual care. Cardiovascular outcomes included endothelial function (flow-mediated dilatation (FMD) of the brachial artery), blood pressure, body composition and serum lipids. Additional outcomes included treadmill walk time and exercise and dietary behaviours. Outcomes were assessed before randomisation (baseline), and 6, 12 and 24 weeks after randomisation. RESULTS: At 12 weeks, the difference in mean relative FMD was 2.2% (95% confidence interval (CI) 0.1-4.3, P=0.04) with an effect size of 0.60 (95% CI <0.01-1.18) favouring the intervention group. Improvements in skeletal muscle mass, treadmill walk time and exercise behaviour also occurred in the intervention group over that duration (P<0.05). At 24 weeks, only the difference in treadmill walk time was maintained. CONCLUSIONS: This study demonstrates that lifestyle changes can improve endothelial function in men on long-term ADT for prostate cancer. The implications for cardiovascular health need further investigation in larger studies over longer duration.

Misuse of "Power" and Other Mechanical Terms in Sport and Exercise Science Research.

Despite the Système International d'Unitès (SI) that was published in 1960, there continues to be widespread misuse of the terms and nomenclature of mechanics in descriptions of exercise performance. Misuse applies principally to failure to distinguish between mass and weight, velocity and speed, and especially the terms "work" and "power." These terms are incorrectly applied across the spectrum from high-intensity short-duration to long-duration endurance exercise. This review identifies these misapplications and proposes solutions. Solutions include adoption of the term "intensity" in descriptions and categorizations of challenge imposed on an individual as they perform exercise, followed by correct use of SI terms and units appropriate to the specific kind of exercise performed. Such adoption must occur by authors and reviewers of sport and exercise research reports to satisfy the principles and practices of science and for the field to advance.

Assessment of endothelial dysfunction by flow-mediated dilatation in men on long-term androgen deprivation therapy for prostate cancer.

NEW FINDINGS: What is the central question of this study? Androgen deprivation therapy (ADT) for prostate cancer has been linked with increased cardiovascular risk, but the mechanisms are unclear. Is there evidence that endothelial dysfunction, as evidenced by reduced flow-mediated dilatation (FMD), is associated with ADT? What is the main finding and its importance? Reduction in FMD with preservation of glyceryl trinitrate-mediated dilatation indicates endothelial dysfunction in men with prostate cancer on long-term ADT compared with well-matched control subjects. Vascular endothelial dysfunction associated with long-term ADT for prostate cancer might explain the observed epidemiological increases in adverse cardiovascular events. Assessment of FMD may be useful in the monitoring of cardiovascular risk in men with prostate cancer on ADT. Androgen deprivation therapy (ADT) in men with prostate cancer has been linked to an increased incidence of cardiovascular events and mortality, but the underpinning mechanisms are unclear. Endothelial dysfunction is considered a precursor for cardiovascular disease. Previous studies have reported variably on the association between ADT and endothelial function. This blinded case-control study examined endothelial function, using high-resolution ultrasound to measure flow-mediated dilatation (FMD) and glyceryl trinitrate (GTN)-mediated-dilatation in the brachial artery, in 20 men with prostate cancer (69 ± 7 years old) treated by ADT (median duration 22 months, range 6-133 months) and 20 men without prostate cancer (69 ± 5 years old) matched for age, physical activity, coexistent cardiovascular disease and body mass index. The magnitude of dilatation was calculated traditionally and allometrically scaled, adjusting for baseline diameter. There were no differences between groups for resting vascular measures (means ± SD). Flow-mediated dilatation was lower in men on ADT than in control subjects (3.9 ± 2.1 versus 5.9 ± 3.8% for traditional, P = 0.047; 3.7 ± 2.7 versus 6.0 ± 2.7% for allometrically scaled, P = 0.023). Response to GTN was similar in both groups (12.2 ± 4.2 versus 14.8 ± 5.7% for traditional, P = 0.113; 12.3 ± 4.6 versus 14.4 ± 4.6% for allometrically scaled, P = 0.163). The magnitude of difference in mean FMD between groups was marginally altered to 2.4% (95% confidence interval 0.3-4.5) after adjustment for the difference in body fat mass and concomitant cardiovascular medication, with the difference in FMD remaining significant (P = 0.029). There is evidence of endothelial dysfunction in men with prostate cancer on long-term ADT. Although a causal relationship is unproven, the findings are consistent with observational reports of adverse cardiovascular outcomes associated with long-term ADT for prostate cancer.

Nutrition for tennis: practical recommendations.

Tennis is a pan-global sport that is played year-round in both hemispheres. This places notable demands on the physical and psychological preparation of players and included in these demands are nutritional and fluid requirements both of training and match- play. Thus, the purpose of this article is to review nutritional recommendations for tennis. Notably, tennis players do not excel in any particular physiological or anthropometric characteristic but are well adapted in all areas which is probably a result of the varied nature of the training demands of tennis match play. Energy expenditures of 30.9 ± 5.5 and 45.3 ± 7.3 kJ·min(-1) have been reported in women and men players respectively regardless of court surface. Tennis players should follow a habitually high carbohydrate diet of between 6-10 g·kg(-1)·d(-1) to ensure adequate glycogen stores, with women generally requiring slightly less than men. Protein intake guidelines for tennis players training at a high intensity and duration on a daily basis should be ~1.6 g·kg(-1)·d(-1) and dietary fat intake should not exceed 2 g·kg(-1)·d(-1). Caffeine in doses of 3 mg·kg(-1) provides ergogenic benefit when taken before and/or during tennis match play. Depending on environmental conditions, sweat rates of 0.5 to and over 5 L·hr(-1) and sodium losses of 0.5 - 1.8 g have been recorded in men and women players. 200 mL of fluid containing electrolytes should be consumed every change-over in mild to moderate temperatures of < 27°C but in temperatures greater than 27°C players should aim for ≤ 400 mL. 30-60 g·hr(-1) of carbohydrate should be ingested when match play exceeds 2 hours. Key PointsTennis players should follow a habitually high carbohydrate diet of between 6-10 g·kg(-1) to ensure adequate glycogen stores, with women generally requiring slightly less than men. Protein intake guidelines for tennis players training at a high intensity and duration on a daily basis should be ~1.6 g·kg(-1)·d(-1). Dietary fat intake should not exceed 2 g·kg(-1)·d(-1).Caffeine in doses of 3 mg·kg(-1) can provide ergogenic benefit when taken before and/or during tennis match play.200 mL of fluid containing electrolytes should be consumed every change-over in mild to moderate temperatures of < 27°C but in temperatures greater than 27°C players should aim for ≥ 400 mL.30-60 g·hr(-1) of carbohydrate should be ingested when match play exceeds 2 hours.During periods of travel, specific dietary requirements can be communicated with agencies and hotels prior to arrival and in the event that suitably nutritious foods are not available in the host country, players can bring or send non-perishable foods and goods where customs and quarantine laws allow.

Physiological correlates of multiple-sprint ability and performance in international-standard squash players.

From measures on a battery of fitness tests in elite-standard squash players on different tiers of a national performance program, we examined the relationships among test scores and player rank, and fitness factors important for squash-specific multiple-sprint ability. Thirty-one (20 men, 11 women) squash players from the England Squash performance program participated: n = 12 senior; n = 7 transition; n = 12 talented athlete scholarship scheme (TASS) players. In 1 test session and in a fixed order, the players completed a battery of tests to assess countermovement jump height, reactive strength, change-of-direction speed, and multiple-sprint ability on squash-specific tests and endurance fitness. Two-way analysis of variance compared senior, transition, and TASS players by sex on all measures except jump height where only senior and transition players were compared. Effect size (ES) was calculated for all comparisons. Pearson's correlation examined relationships among test scores and multiple-sprint ability. Spearman's ρ investigated relationships among test scores and players' rank in men and women separately. Regardless of sex, seniors outperformed TASS players on all except the endurance test (p < 0.05, ES at least 1.1). Seniors had better multiple-sprint ability than did transition players (p < 0.01, ES = 1.2). Transition outperformed TASS players on the reactive-strength test (p < 0.05, ES = 1.0). Men outperformed women in all tests at all performance program tiers (p < 0.05, ES at least 0.5). In men, rank was related to multiple-sprint ability, fastest-multiple-sprint-test repetition, and change-of-direction speed (ρ = 0.78, 0.86, 0.59, respectively). In women, rank was related to fastest multiple-sprint-test repetition (ρ = 0.65). In men and women, multiple-sprint ability was related to change-of-direction speed (r = 0.9 and 0.84) and fastest-multiple-sprint-test repetition (r = 0.96 for both) and to reactive strength in men (r = -0.71). The results confirm that high-intensity variable-direction exercise capabilities are important for success in elite squash.

Adjusting athletes' body mass index to better reflect adiposity in epidemiological research.

The aim of the present study was to identify when body mass index (BMI) is unlikely to be a valid measure of adiposity in athletic populations and to propose a simple adjustment that will allow the BMI of athletes to reflect the adiposity normally associated with non-athletic populations. Using data from three previously published studies containing 236 athletes from seven sports and 293 age-matched controls, the association between adiposity (sum of 4 skinfold thicknesses, in millimetres) and BMI was explored using correlation, linear regression, and analysis of covariance (ANCOVA). As anticipated, there were strong positive correlations (r = 0.83 for both men and women) and slope parameters between adiposity and BMI in age-matched controls from Study 1 (all P < 0.001). The standard of sport participation reduced these associations. Of the correlations and linear-regression slope parameters between adiposity and BMI in the sports from Studies 2 and 3, although still positive in most groups, less than half of the correlations and slope parameters were statistically significant. When data from the three studies were combined, the ANCOVA identified that the BMI slope parameter of controls (5.81 mm (kg m(-2))(-1)) was greater than the BMI slope parameter for sports (2.62 mm (kg m(-2))(-1)) and middle-distance runners (0.94 mm (kg m(-2))(-1)) (P < 0.001). Based on these contrasting associations, we calculated how the BMI of athletes can be adjusted to reflect the same adiposity associated with age-matched controls. This simple adjustment allows the BMI of athletes and non-athletes to be used with greater confidence when investigating the effect of BMI as a risk factor in epidemiological research.

Validity of a squash-specific test of multiple-sprint ability.

We examined the validity and reproducibility of a squash-specific multiple-sprint test. Eight male squash and 8 male soccer players performed Baker's 8 × 40-m sprints and a squash-specific-multiple-sprint test on separate days. The sum of individual sprint times in each test was recorded. Six squash and 6 soccer players repeated the tests 7 days later to assess reproducibility using intraclass correlation. In addition, 2 England Squash coaches independently ranked the squash players using knowledge of the player and recent performances in local leagues. Performance on the squash-specific (r = 0.97 and 0.90) and Baker's test (r = 0.95 and 0.83) was reproducible in squash and soccer players, respectively, and did not differ on Baker's test (mean ± SD 72.9 ± 3.9 and 72.9 ± 2.8 seconds for squash and soccer players, p = 0.969, effect size = 0.03). Squash players (232 ± 32 seconds) outperformed soccer players (264 ± 14 seconds) on the squash-specific test (p = 0.02, effect size = 1.39). Performance on Baker's and the squash-specific test were related in squash players (r = 0.98, p < 0.001) but not in soccer players (r = -0.08, p = 0.87). Squash-player rank correlated with performance on the squash-specific (ρ = 0.79, p = 0.02) but not the Baker's test (ρ = 0.55, p = 0.16). The squash-specific test discriminated between groups with similar non-sport-specific multiple-sprint ability and in squash players. In conjunction with the relationship between test performances, the results suggest that the squash-specific test is a valid and reproducible measure of multiple-sprint ability in squash players and could be used for assessing and tracking training-induced changes in multiple-sprint ability.

Effects of acute dehydration on brain morphology in healthy humans.

Dehydration can affect brain structure which has important implications for human health. In this study, we measured regional changes in brain structure following acute dehydration. Healthy volunteers received a structural MRI scan before and after an intensive 90-min thermal-exercise dehydration protocol. We used two techniques to determine changes in brain structure: a manual point counting technique using MEASURE, and a fully automated voxelwise analysis using SIENA. After the exercise regime, participants lost (2.2% +/- 0.5%) of their body mass. Using SIENA, we detected expansion of the ventricular system with the largest change occurring in the left lateral ventricle (P = 0.001 corrected for multiple comparisons) but no change in total brain volume (P = 0.13). Using manual point counting, we could not detect any change in ventricular or brain volume, but there was a significant correlation between loss in body mass and third ventricular volume increase (r = 0.79, P = 0.03). These results show ventricular expansion occurs following acute dehydration, and suggest that automated longitudinal voxelwise analysis methods such as SIENA are more sensitive to regional changes in brain volume over time compared with a manual point counting technique.

Considerations for the Scientific Support Process and Applications to Case Studies.

Case studies are vehicles to bridge the gap between science and practice because they provide opportunities to blend observations and interventions that have taken place in real-world environments with scientific rigor. The purpose of this invited commentary is to present considerations for those providing applied sport science support to athletes with the intention of broadcasting this information to the scientific community. The authors present a 4-phased approach (1: athlete overview; 2: needs analysis; 3: intervention planning; and 4: results, evaluation, and conclusion) for scientific support to assist practitioners in the development and implementation of scientific support. These considerations are presented in the form of "performance questions" designed to guide and critically evaluate the scientific support process and aid the transfer of this knowledge through case studies.

Modeling maximum oxygen uptake of elite endurance athletes.

PURPOSE: To compare the maximum oxygen uptake V0(2max) of elite endurance athletes and to explain why the body mass exponent, necessary to render V0(2max) independent of body mass, appears to be greater than 0.67. METHODS: Study 1: V0(2max) of 174 international sportsmen and women was assessed. Athletes were recruited from seven sports (middle- and long-distance runners, heavyweight and lightweight rowers, triathletes, and squash and badminton players). Study 2: calf and thigh leg muscle masses were estimated in 106 male and 30 female athletes from 11 sports. Differences in V0(2max) and leg muscle masses between "sports" and "sex" were analyzed independent of body mass by using allometric log-linear ANCOVA. RESULTS: Heavyweight rowers had the greatest V0(2max) when expressed in L.min but long-distance runners had the highest V0(2max)in mL.kg.min. However, the ANCOVA identified no difference in "mass independent" V0(2max) between the five "pure" endurance sports (runners, rowers, and triathletes) (P > 0.05) with the two racket sports being significantly lower. The body mass covariate exponent was inflated, estimated as 0.94. The results from study 2 estimated calf and thigh leg muscle masses to increase in proportion to body mass, and, respectively. CONCLUSIONS: After having controlled for differences in body mass, V0(2max) did not differ between pure endurance sports (P > 0.05). Assuming that athletes' thigh muscle mass increases in proportion to body mass as observed in study 2, a similar disproportional increase in V0(2max) would be anticipated, providing a plausible explanation for the inflated mass exponent associated with V0(2max) identified in this and other studies.