Medical withdrawals in elite tennis in reference to playing standards, court surfaces and genders.

OBJECTIVES: To examine the relationships between medical withdrawals, playing standards, court surfaces and genders in tennis players participating in all elite tours. DESIGN: Descriptive epidemiology study. METHODS: Medical withdrawals of men and women tennis players from Association of Tennis Professionals, Women Tennis Association, Challengers and International Tennis Federation Futures tours' matches have been identified considering the court surfaces (fast vs. slow). Proportion comparison and the binomial regression model were used to determine the influence of playing standards, court surfaces and genders on tennis players' likelihoods to withdraw. RESULTS: A higher proportion of withdrawals was found for men in Challengers and Futures vs. Association of Tennis Professionals (4.8 %, 5.9 % vs 3.4 %; p < 0.001), but without difference between court surfaces (0.1 %, p > 0.05) whatever the playing standards. Women reported higher proportion of medical withdrawals sustained on slow surfaces (0.4 %, p < 0.001), but without different withdrawal rates between playing standards (3.9 %, p > 0.05). After adjustment, the odds of medical withdrawals were higher for Challengers (1.18, p < 0.001) and Futures (1.34, p < 0.001), with a higher likelihood to withdraw (1.04, p < 0.001) when playing on slow surfaces and with a gender-dependent effect indicating higher odds (1.29, p < 0.001) to withdraw for medical reasons in men in reference to women. CONCLUSIONS: These findings demonstrated a gender-dependent effect on medical withdrawals from an elite tennis tournament with higher likelihood for men participating in Challengers/Futures tours and for women playing on slow surfaces.

Corrective adjustment methods for relative age effects on French young swimmers' performances.

BACKGROUND: This study aimed to identify a Relative Age Effect (RAE) among French young swimmers and apply corrective adjustment procedures to rebalance performances according to categories and events. METHODS: 5,339,351 performances of French swimmers aged 10 to 18 were collected between 2000 and 2019. Birth quarters distribution was examined according to competitiveness level ('All', 'Top50%', 'Top25%' and 'Top10%'), event and age category. A linear relationship between the distribution of performances and calendar days provides a calibration coefficient allowing to rebalance performances by considering the effect of RAE for each event. Then, adjusted performances are recalculated using this coefficient, the initial performance and the relative age. RESULTS: Proportion of swimmers born in the first quarter was higher than the proportion of those born in the last quarter for all events and strokes (p < 0.01). RAE increases with the competitiveness level for all events. Indeed, among 'All' 12 years old 50m freestyle swimmers, the proportion born in the first quarter is 30.9% vs 19.2% in the fourth quarter, while among the "Top10%", 47.5% were born in the first quarter vs 10.3% in the last one. (p-value < 0.01). In average, each day represents a gap of 0.008 second, resulting in a difference of almost 3 seconds over a year. This tool is validated by comparing swimmers who have performed at least twice in a season. It provides a day by day rebalancing method for all swimming events and age categories. CONCLUSIONS: Relative age effect is present among French young male and female swimmers, and is strengthened by competitiveness level. A new corrective adjustment procedure to rebalance performances considering categories and events is proposed and validated. By applying such a tool, we are able to reveal the full potential of swimmers and make it possible to compare them at the same relative age.

The COVID-19 pandemic impact on the best performers in athletics and swimming among paralympic and non-disabled athletes.

BACKGROUND: The COVID 19 pandemic has greatly disrupted high performance sport and international competition. The aim of this study was to quantify the impact of the COVID-19 pandemic on the world's top 10 performances in Athletics and Swimming among non-disabled and Paralympic athletes. METHODS: The results of the 10-best world performers in 66 Olympic events since 1891 and 255 Paralympic events since 2010 were collected. To quantify the performance trend, the slopes of the 4 years moving average were calculated and analyzed by time period. The distribution of performances (in % of the world record) by year was analyzed to compare the 2020 values to the ten previous years. The stability rate (athletes joining and leaving each year) since 2010 and the number of annual competitions events were also measured. RESULTS: Over the study period, such declines in performance have only been observed during the two World Wars. In 2020, the level of performances has decreased significantly, corresponding to a 6 to 10 years setback. In 2020, the number of new athletes in the 10-best was significantly higher with a lower number of organized competitions. CONCLUSIONS: The impact on the performances of the best international non-disabled and Para athletes has been considerable.

Covid-19 Mortality: A Matter of Vulnerability Among Nations Facing Limited Margins of Adaptation.

Context: The human development territories have been severely constrained under the Covid-19 pandemic. A common dynamics has been observed, but its propagation has not been homogeneous over each continent. We aimed at characterizing the non-viral parameters that were most associated with death rate. Methods: We tested major indices from five domains (demography, public health, economy, politics, environment) and their potential associations with Covid-19 mortality during the first 8 months of 2020, through a Principal Component Analysis and a correlation matrix with a Pearson correlation test. Data of all countries, or states in federal countries, showing at least 10 fatality cases, were retrieved from official public sites. For countries that have not yet finished the first epidemic phase, a prospective model has been computed to provide options of death rates evolution. Results: Higher Covid death rates are observed in the [25/65°] latitude and in the [-35/-125°] longitude ranges. The national criteria most associated with death rate are life expectancy and its slowdown, public health context (metabolic and non-communicable diseases (NCD) burden vs. infectious diseases prevalence), economy (growth national product, financial support), and environment (temperature, ultra-violet index). Stringency of the measures settled to fight pandemia, including lockdown, did not appear to be linked with death rate. Conclusion: Countries that already experienced a stagnation or regression of life expectancy, with high income and NCD rates, had the highest price to pay. This burden was not alleviated by more stringent public decisions. Inherent factors have predetermined the Covid-19 mortality: understanding them may improve prevention strategies by increasing population resilience through better physical fitness and immunity.

Involvement in Multiple Race Events Among International Para and Non-disabled Swimmers.

International elite Para swimmers form a large portion of the overall multi-medalist winning population. For the highest performing Para swimmers, world class performances were achieved across different strokes. The aim of this study was to quantify the level of involvement across different events and to examine this in relation to the level of performance. The performances in swimming speed of the top 100 females and males for both Para- and non-disabled swimmers were collected in 11 race events between 2009 and 2019 (4,400 performances for 307 Para females and 365 Para males, 605 non-disabled females, and 715 non-disabled males). We tallied the number of events in which each swimmer was involved. Swimmers were grouped according to the total number of race events in which they participated. Then the association between involvement and level of performance was investigated. Para swimmers with impairment from classes seven to 14 were involved in a range of race events across different strokes. The most common combination for both Para and non-disabled athletes was over similarly distanced races of the same stroke (50 and 100 m freestyle). The more race events in which Para swimmers involved, the higher the level of performance that was achieved. This trend can partially be explained by the less concentrated competition pool for Para swimmers compared to able-bodied swimmers. Para swimmers with minimal and no physical impairment perform in multiple race events more often than able-bodied swimmers. Fewer Para swimmers at the international level and a less concentrated competition pool could explain these differences.

Age-Related Changes in Para and Wheelchair Racing Athlete's Performances.

During the last decades, all para-athletes with disabilities have significantly increased their performance level due to technological progress and human investment, through better training or recovery protocols, medical care and nutritional monitoring. Among these elements, the athlete's age is one of the determining factors in performance. The aim of this study was to investigate the effect of age on maximal performances for para-athletes and wheelchair racing athletes, scaled on able-bodied records. We collected 53,554 results including athlete's best performance of the year, event, age and disability classification from the International Paralympic Committee competitions between 2009 and 2017 for both female and male para-athletics and wheelchair racing disciplines for a total of 472 sport events in Track and Field (considering each impairment type for each event) and gathered the all-time able-bodied records from the International Association of Athletics Federations (IAAF) at the end of 2017. Maximal performance by age was fitted with the Moore function for each para-athletics and wheelchair racing event. This study finds a similar age-related pattern in maximal performance among para-athletes and wheelchair racing athletes. The age at peak performance varies according to sex, impairment type and event and increases gradually from sprint to endurance events. The best Top 100 performances include a large age range suggesting that performance has probably not been optimized yet for most elite para-athletes and wheelchair racers. The next Paralympic Games of Tokyo 2020 and Paris 2024 will certainly offer exceptional performance.

Age-Related Upper Limits in Physical Performances.

Maximal physical performances are powerful and accurate biomarkers in the understanding of age-related changes during the aging process. Previous studies have characterized age-related changes from Caenorhabditis elegans to Homo sapiens. We characterized changes in this pattern for H. sapiens, decade by decade, from 1970 to 2017. Using 286,916 performances related to age from the world's best performances in each age group, we measured the relative change of 10 different running and jumping events for both women and men. We compared the change in sexual dimorphism with age and showed that the gender gap in maximal performance regarding age increases gradually, especially after the age of 50. Between 1970 and 2017, the performances for all age groups in all events have slightly progressed. However, during the last decades, the relative progression of the best performances for all age groups has decreased in both range and frequency, suggesting that age-related maximal physical performances for H. sapiens are reaching their physiological limits.

Geographic enrolment of the top 100 in athletics running events from 1996 to 2012.

BACKGROUND: It is widely accepted in the literature that athletes of West African origins achieve the best sprint performances, while athletes originating from East Africa are the most efficient at long distances. So far, no study has measured the evolution of these groups' contribution from 100 m to the marathon. METHODS: Speed, morphology and geographic origin of the top 100 male and female athletes (from 100 m to the marathon) were collected and analyzed over the 1996-2012 period. RESULTS: The amount of male sprinters (100, 200 and 400 m) originating from West Africa increased from 57.7% in 1996 to 72.3% in 2012, while female sprinters from West Africa increased from 55% to 65% over the same period. This contribution gradually increases from 400 m to 100 m for both sexes. For long-distance runs (3000 m, 10,000 m and marathon), male athletes from East Africa represented 32% in 1996 ; this proportion increased to 65.7% in 2012. It also increased over the same period from 9% to 39% for women. In addition, male and female sprinters originating from West Africa have a significantly higher Body Mass Index (BMI, P<0.05) than athletes of other geographic origin. Conversely, long distances runners' with an East African origin have a significantly lower BMI (P<0.05). CONCLUSIONS: Running best performances are dominated by a few groups including runners with West African ancestry for the sprint distances and East African runners for the long distances. This dominance strengthened from 1996 to 2012 for both sexes in parallel with a reduction of Caucasian and Asian athletes contribution and in relation to muscle mass repartition.

Age-Related Changes in Locomotor Performance Reveal a Similar Pattern for Caenorhabditis elegans, Mus domesticus, Canis familiaris, Equus caballus, and Homo sapiens.

Locomotion is one of the major physiological functions for most animals. Previous studies have described aging mechanisms linked to locomotor performance among different species. However, the precise dynamics of these age-related changes, and their interactions with development and senescence, are largely unknown. Here, we use the same conceptual framework to describe locomotor performances in Caenorhabditis elegans, Mus domesticus, Canis familiaris, Equus caballus, and Homo sapiens. We show that locomotion is a consistent biomarker of age-related changes, with an asymmetrical pattern throughout life, regardless of the type of effort or its duration. However, there is variation (i) among species for the same mode of locomotion, (ii) within species for different modes of locomotion, and (iii) among individuals of the same species for the same mode of locomotion. Age-related patterns are modulated by genetic (such as selective breeding) as well as environmental conditions (such as temperature). However, in all cases, the intersection of the rising developmental phase and the declining senescent phase reveals neither a sharp transition nor a plateau, but a smooth transition, emphasizing a crucial moment: the age at peak performance. This transition may define a specific target for future investigations on the dynamics of such biological interactions.

Return to Sport Among French Alpine Skiers After an Anterior Cruciate Ligament Rupture: Results From 1980 to 2013.

BACKGROUND: There is little known about return to sport and performance after anterior cruciate ligament (ACL) tear in high-level alpine skiers. PURPOSE: To analyze the parameters that influence the return to sport and performance after an ACL tear in French alpine skiers from 1980 to 2013. STUDY DESIGN: Descriptive epidemiology study. METHODS: The study population included 239 male and 238 female skiers who competed on the national French alpine ski team for at least 1 season between 1980 and 2013 in the speed (downhill and super-G) and technical disciplines (giant slalom and slalom). Two groups were formed: group 1 (G1) included athletes who had sustained an ACL rupture, and group 2 (G2) included athletes who had never sustained an ACL rupture. Three performance indicators were selected: International Ski Federation (FIS) points calculation, FIS ranking, and podium finishes in the World Cup, World Championships, and Olympic Games. RESULTS: The first-decile FIS points and international FIS ranking showed that G1 skiers obtained better performance than did G2 skiers. The mean ± SD career length of G1 skiers (men, 7.9 ± 4.7 years; women, 7.1 ± 4.1 years) was longer than that of G2 skiers (men, 4.5 ± 3.3 years; women, 4.2 ± 3.5 years). In addition, 12.8% (61 of 477) of the skiers achieved at least a podium finish during their careers: 23.0% (34 of 148) in G1 and 8.3% (27 of 329) in G2. The mean age at ACL rupture was 22.6 ± 4.1 years for men and 19.9 ± 3.5 years for women. In G1, 55 podiums were achieved before ACL rupture and 176 after in all competitions. Skiers who improved their performances after ACL rupture were significantly younger (men, 22.2 ± 3.0 years; women, 18.7 ± 2.2 years; P < .0001) at the time of injury than those showing a performance deterioration after ACL rupture (men, 25.3 ± 4.2 years; women, 22.4 ± 4.0 years). All skiers who had ACL tears continued their competitive careers after the injury. CONCLUSION: The overall results showed that it is possible to return to preinjury or even higher levels of performance after an ACL rupture and that age is the main element that guides postsurgical recovery.

Has Athletic Performance Reached its Peak?

Limits to athletic performance have long been a topic of myth and debate. However, sport performance appears to have reached a state of stagnation in recent years, suggesting that the physical capabilities of humans and other athletic species, such as greyhounds and thoroughbreds, cannot progress indefinitely. Although the ultimate capabilities may be predictable, the exact path for the absolute maximal performance values remains difficult to assess and relies on technical innovations, sport regulation, and other parameters that depend on current societal and economic conditions. The aim of this literature review was to assess the possible plateau of top physical capabilities in various events and detail the historical backgrounds and sociocultural, anthropometrical, and physiological factors influencing the progress and regression of athletic performance. Time series of performances in Olympic disciplines, such as track and field and swimming events, from 1896 to 2012 reveal a major decrease in performance development. Such a saturation effect is simultaneous in greyhound, thoroughbred, and frog performances. The genetic condition, exhaustion of phenotypic pools, economic context, and the depletion of optimal morphological traits contribute to the observed limitation of physical capabilities. Present conditions prevailing, we approach absolute physical limits and endure a continued period of world record scarcity. Optional scenarios for further improvements will mostly depend on sport technology and modification competition rules.

Mortality in female and male French Olympians: a 1948-2013 cohort study.

BACKGROUND: Whereas intense physical activity has been associated with deleterious effects on elite athletes' health, in particular due to cardiovascular anomalies, long-term follow-ups have suggested lower mortality rates among elite athletes. Causes of death for French Olympic athletes and female elite athletes have not been studied. HYPOTHESIS/PURPOSE: We aimed to measure overall and disease-specific mortality of French female and male Olympians compared with the French general population. We hypothesize that Olympians, both women and men, have lower mortality rates. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: French elite athletes (601 women and 1802 men) participating in summer or winter Olympic Games from 1948 to 2010 had their vital status verified by national sources and were followed until 2013. Causes of death were obtained via the National Death registry from 1968 to 2012. Overall and disease-specific mortalities of Olympians were compared with those of the French general population through standardized mortality ratios (SMRs) and 95% CIs. Olympians' observed and expected survivals were illustrated by Kaplan-Meier curves. RESULTS: At the endpoint of the study, 13 women and 222 men had died. Overall mortality in Olympians compared with that of their compatriots was 51% lower (SMR, 0.49; 95% CI, 0.26-0.85) among women and 49% lower (SMR, 0.51; 95% CI, 0.45-0.59) among men. Olympic athletes' survival is significantly superior to that of the French general population (women, P = .03; men, P < .001). According to the total deaths occurring from 1968 to 2012 (12 among women, 202 among men), female Olympians died from neoplasm (50.0%), external causes (33.3%), and cardiovascular diseases (16.6%). The main causes of death among men were related to neoplasms (36.1%), cardiovascular diseases (24.3%), and external causes (14.4%). Regarding the main causes of mortality among male Olympic athletes, the SMRs were as follows: 0.55 for neoplasms (95% CI, 0.43-0.69), 0.55 for cardiovascular diseases (95% CI, 0.41-0.73), and 0.66 for external causes (95% CI, 0.44-0.94). CONCLUSION: French Olympians live longer than their compatriots: A lower overall mortality of similar magnitude is observed among male and female athletes compared with the general population. The main causes of death in French Olympians are neoplasms, cardiovascular diseases, and external causes.

Secular trend: morphology and performance.

In a context of morphological expansion of the general population, how do athletes follow such a pattern of anthropometric growth? Is there any relation to performance? Biometric data including mass, height, body mass index (BMI) and age were collected for 50,376 American athletes representing 249,336 annual performers playing in professional baseball, football, ice hockey and basketball. Distributions by mass in National Football League (NFL) players are described by periods. Field goals have been studied in relation to players' height in the National Basketball Association (NBA). Between 1871 and 2011, athletes from the four sports have increased significantly in mass, height and BMI, following a multi-exponential function series. Consequently, biometric differences between athletes and the general population are increasing gradually. Changes in the mass distribution within the NFL show the emergence of a biometrical specificity in relation to the field position. At the professional level, performance remains structured around precise biometric values. In the NBA, a height-attractor at 201.3 ± 6.3 cm for the best scorers is invariant, regardless of the level of play. These results suggest that laws of growth and biometrics drive high-level sport and organise performance around the specific constraint of each field position. Discrepancies between some mass and height developments question the (disproportionate) large mass increase (relative to the height increase) during the 1980s and 1990s.

BMI, a performance parameter for speed improvement.

The purpose of this study is to investigate the association between anthropometric characteristics and performance in all track and field running events and assess Body Mass Index (BMI) as a relevant performance indicator. Data of mass, height, BMI and speed were collected for the top 100 international men athletes in track events from 100 m to marathon for the 1996-2011 seasons, and analyzed by decile of performance. Speed is significantly associated with mass (r = 0.71) and BMI (r = 0.71) in world-class runners and moderately with height (r = 0.39). Athletes, on average were continuously lighter and smaller with distance increments. In track and field, speed continuously increases with BMI. In each event, performances are organized through physique gradients. « Lighter and smaller is better ¼ in endurance events but « heavier and taller is better ¼ for sprints. When performance increases, BMI variability progressively tightens, but it is always centered around a distance-specific optimum. Running speed is organized through biometric gradients, which both drives and are driven by performance optimization. The highest performance level is associated with narrower biometric intervals. Through BMI indicators, diversity is possible for sprints whereas for long distance events, there is a more restrictive aspect in terms of physique. BMI is a relevant indicator, which allows for a clear differentiation of athletes' capacities between each discipline and level of performance in the fields of human possibilities.

Marathon progress: demography, morphology and environment.

As opposed to many other track-and-field events, marathon performances still improve. We choose to better describe the reasons for such a progression. The 100 best marathon runners archived from January 1990 to December 2011 for men and from January 1996 to December 2011 for women were analysed. We determined the impact of historical, demographic, physiological, seasonal and environmental factors. Performances in marathons improve at every level of performance (deciles). In 2011, 94% of the 100 best men athletes were African runners; among women athletes they were 52%. Morphological indicators (stature, body mass and Body Mass Index (BMI)) have decreased. We show a parabolic function between BMI and running speed. The seasonal distribution has two peaks, in spring (weeks 14 to 17) and autumn (weeks 41 to 44). During both periods, the average temperature of the host cities varies close to optimal value for long distance race. African men and women runners are increasingly dominating the marathon and pushing its record, through optimal eco-physiological conditions.

Environment and scheduling effects on sprint and middle distance running performances.

PURPOSE: Achievement of athletes' performances is related to several factors including physiological, environmental and institutional cycles where physical characteristics are involved. The objective of this study is to analyse the performance achieved in professional sprint and middle-distance running events (100 m to 1500 m) depending on the organization of the annual calendar of track events and their environmental conditions. METHODS: From 2002 to 2008, all performances of the Top 50 international athletes in the 100 m to 1500 m races (men and women) are collected. The historical series of world records and the 10 best annual performances in these events, amounted to a total of 26,544 performances, are also included in the study. RESULTS: Two periods with a higher frequency of peak performances are observed. The first peak occurs around the 27.15(th) ±0.21 week (first week of July) and the second peak around 34.75(th) ±0.14 week (fourth week of August). The second peak tends to be the time of major international competitions (Olympic Games, World Championships, and European Championships) and could be characterized as an institutional moment. The first one, however, corresponds to an environmental optimum as measured by the narrowing of the temperature range at the highest performance around 23.25±3.26°C. CONCLUSIONS: This is the first study to demonstrate that there are two performance peaks at a specific time of year (27th and 34th weeks) in sprint and middle distance. Both institutional and ecophysiological aspects contribute to performance in the 100 m to 1500 m best performances and define the contours of human possibilities. Sport institutions may take this into account in order to provide ideal conditions to improve the next records.

Impact of environmental parameters on marathon running performance.

PURPOSE: The objectives of this study were to describe the distribution of all runners' performances in the largest marathons worldwide and to determine which environmental parameters have the maximal impact. METHODS: We analysed the results of six European (Paris, London, Berlin) and American (Boston, Chicago, New York) marathon races from 2001 to 2010 through 1,791,972 participants' performances (all finishers per year and race). Four environmental factors were gathered for each of the 60 races: temperature (°C), humidity (%), dew point (°C), and the atmospheric pressure at sea level (hPA); as well as the concentrations of four atmospheric pollutants: NO(2)-SO(2)-O(3) and PM(10) (µg x m(-3)). RESULTS: All performances per year and race are normally distributed with distribution parameters (mean and standard deviation) that differ according to environmental factors. Air temperature and performance are significantly correlated through a quadratic model. The optimal temperatures for maximal mean speed of all runners vary depending on the performance level. When temperature increases above these optima, running speed decreases and withdrawal rates increase. Ozone also impacts performance but its effect might be linked to temperature. The other environmental parameters do not have any significant impact. CONCLUSIONS: The large amount of data analyzed and the model developed in this study highlight the major influence of air temperature above all other climatic parameter on human running capacity and adaptation to race conditions.

How they won Rugby World Cup through height, mass and collective experience.

OBJECTIVES: To investigate the evolution of anthropometric characteristics in World Cup rugby players and identify elements associated with performance. DESIGN: Age, weight and height were collected for 2692 World Cup rugby players as well as rankings in each World Cup, and collective experience of winners, finalists, semifinalists and quarter finalists in comparison to the rest of the competitors. Anthropometric parameters were compared according to age and position (back and forwards). RESULTS: From 1987 to 2007, forwards and backs have become heavier by 6.63 and 6.68 kg and taller by 0.61 and 1.09 cm, respectively. The collective experience of the forwards' pack is a value increasing with the final ranking attained, as well as the weight of forwards and the height of backs. CONCLUSIONS: For all Rugby World Cups, the highest performing teams have the tallest backs and heaviest forwards with the highest percentage of collective experience.

Exponential growth combined with exponential decline explains lifetime performance evolution in individual and human species.

The physiological parameters characterizing human capacities (the ability to move, reproduce or perform tasks) evolve with ageing: performance is limited at birth, increases to a maximum and then decreases back to zero at the day of death. Physical and intellectual skills follow such a pattern. Here, we investigate the development of sport and chess performances during the lifetime at two different scales: the individual athletes' careers and the world record by age class in 25 Olympic sports events and in grandmaster chess players. For all data sets, a biphasic development of growth and decline is described by a simple model that accounts for 91.7% of the variance at the individual level and 98.5% of the variance at the species one. The age of performance peak is computed at 26.1 years old for the events studied (26.0 years old for track and field, 21.0 years old for swimming and 31.4 years old for chess). The two processes (growth and decline) are exponential and start at age zero. Both were previously demonstrated to happen in other human and non-human biological functions that evolve with age. They occur at the individual and species levels with a similar pattern, suggesting a scale invariance property.