Whole-body morphological asymmetries in high-level female tennis players: A cross­sectional study.

This cross-sectional study aimed to examine the degree of whole-body morphological asymmetries in female tennis players. Data were collected in 19 high-level female tennis players (21.3 ± 3.4 years). Based on anthropometric measurements (upper arm, lower arm, wrist, upper leg and lower leg circumferences as well as elbow and knee widths) and dual x-ray absorptiometry research scans (bone mineral density (BMD), bone mineral content (BMC), lean mass (LM), fat mass (FM) as well as humerus, radio-ulnar, femur and tibia bone lengths), within-subject morphological asymmetries for both upper (dominant vs. non-dominant) and lower (contralateral vs. ipsilateral) extremities were examined. Upper arm (p = 0.015), lower arm (p < 0.001) and wrist circumferences (p < 0.001), elbow width (p = 0.049), BMD (p < 0.001), BMC (p < 0.001), LM (p = 0.001), humerus (p = 0.003) and radio-ulnar bone length (p < 0.001) were all greater in the dominant upper extremity. BMC (p < 0.001) and LM (p < 0.001) were greater in the contralateral lower extremity, whereas FM (p = 0.028) was greater in the ipsilateral lower extremity. This is the first study to report significant side-to-side differences in both upper and lower extremities in high-level female tennis players.

Conceptual model of sport-specific classification for para-athletes with intellectual impairment.

The present paper describes the conceptual basis of evidence-based classification of para-athletes with intellectual impairment (II). An extensive description of the theoretical and conceptual foundation of the system as currently conceived is provided, as are examples of its applications in the three sports included in the Paralympic programme for II-athletes in 2020 (i.e., athletics, swimming and table tennis). Evidence-based classification for II-athletes is driven by two central questions: i. How can intellectual impairment be substantiated in a valid and reliable way, and ii. Does intellectual impairment limit optimal sport proficiency? Evolution of the system and current best practice for addressing these questions are described, and suggestions for future research and development are provided. Challenges of understanding and assessing a complex (multifaceted and intersectional) impairment in the context of sport also are considered.

Developing additional competition classes for athletes with intellectual impairments: Conceptual approach and efficacy of an ICF derived measure.

The purpose of para sport classification systems is to minimize the impact of impairment on competition outcome. Currently, athletes with intellectual impairment (II) compete in one class, regardless of the extent of activity limitation resulting from their impairment. Consequently, athletes with II that cause relatively minor difficulty in sport have a competitive advantage over athletes who have intellectual impairments that cause more significant advantage. This research investigated the efficacy of a measure of health-related functional impairment, derived from the World Health Organization International Classification of Functioning, Disability, and Health (ICF), as a tool to classify athletes with intellectual impairments (II) into groups with impairments that cause similar activity limitation. The first study used a Delphi technique to identify the most relevant codes within the ICF from which a measure of impairment presence and severity was derived. The second study investigated whether the measure could discriminate between groups of II athletes organized into three competition groups, and whether these groups could be predicted by ICF score. The ICF-based questionnaire shows promise as a conceptual approach and as a tool in this context, but this is a preliminary step before establishing a sport-specific approach to classification.

Kinematic Comparisons of the Shakehand and Penhold Grips in Table Tennis Forehand and Backhand Strokes when Returning Topspin and Backspin Balls.

Identifying the factors associated with table tennis performance may provide training information for competitive athletes and guide the general population for active participation. The purpose was to compare the joint, racket, and ball kinematics between the shakehand and penhold grips in table tennis forehand and backhand strokes when returning topspin and backspin balls in advanced male players. Nine penhold-grip players and 18 matched shakehand-grip players performed forehand and backhand strokes when returning topspin and backspin balls using their habitual grip styles, while the kinematics of the trunk, upper extremities, racket, and ball were collected. Racket angles were calculated as the relative motion of the racket to the forearm. For the forehand strokes, no significant differences were observed for ball or racket velocities between the two grips. The shakehand grip tended to demonstrate greater shoulder external rotation angles compared to the penhold grip. The shakehand grip resulted in racket flexion angular velocity compared to racket extension velocity for the penhold grip. For the backhand strokes, greater ball and racket velocities were observed for the shakehand grip. The shakehand grip generally demonstrated decreased final trunk left rotation angles, increased trunk right rotation angular velocities, decreased final shoulder abduction angles, increased shoulder adduction angular velocities, and increased forearm supination angular velocities. The two grips demonstrated similar peak racket and ball velocities but different shoulder rotation range of motion and racket motion in forehand strokes. The penhold grips resulted in decreased peak racket and ball velocities in backhand strokes, likely due to its decreased shoulder, elbow, and forearm motion and less aligned longitudinal axes between the racket and forearm. These findings may help understand the dominance of the shakehand grip over the penhold grip in elite athletes and provide information for grip selection, technique improvements, and exercise training.

A shot taxonomy in the era of tracking data in professional tennis.

Shots are an essential part of the language of tennis yet little is known about the distinct types of shots in the professional game. In this study, we build a taxonomy of shots for elite tennis players using tracking data from multiple years of men's and women's matches at the Australian Open. Our taxonomy is constructed using model-based multi-stage functional data clustering, an unsupervised machine learning approach. Among 270,023 men's and 178,136 women's shots, we found 13 distinct types of serves to both the Ad and Deuce court for male players and 17 and 15 types to the Ad and Deuce for female players. More variety was found among serve returns and rally shots compared to the serve; with less variety on the backhand than forehand. There was also more overlap in the physical characteristics of groundstroke shots between male and female players than on serve. Shot type was strongly associated with winning points and shots in the highest speed and lowest net clearance categories tended to be the most effective. This data-driven dictionary of shots provides a framework for analysis of elite player performance, characterizing playing style, and designing more representative practice.

Upper limb joint kinetic analysis during tennis serve: Assessment of competitive level on efficiency and injury risks.

The aim of this work was to compare the joint kinetics and stroke production efficiency for the shoulder, elbow, and wrist during the serve between professionals and advanced tennis players and to discuss their potential relationship with given overuse injuries. Eleven professional and seven advanced tennis players were studied with an optoelectronic motion analysis system while performing serves. Normalized peak kinetic values of the shoulder, elbow, and wrist joints were calculated using inverse dynamics. To measure serve efficiency, all normalized peak kinetic values were divided by ball velocity. t-tests were used to determine significant differences between the resultant joint kinetics and efficiency values in both groups (advanced vs professional). Shoulder inferior force, shoulder anterior force, shoulder horizontal abduction torque, and elbow medial force were significantly higher in advanced players. Professional players were more efficient than advanced players, as they maximize ball velocity with lower joint kinetics. Since advanced players are subjected to higher joint kinetics, the results suggest that they appeared more susceptible to high risk of shoulder and elbow injuries than professionals, especially during the cocking and deceleration phases of the serve.

Association of birthdate with success of nationally ranked junior tennis players in the United States.

The objective was to assess the effect of birthdate on successful performance in tennis by junior tennis players in the United States and to address the question of whether "birthdate effect" persisted with ongoing age toward adulthood. The national rankings and birthdates of junior tennis players in each age division were obtained from the United States Tennis Association. The number of male and female junior tennis players ranked within the top 100 in their respective age divisions with birthdates in the first half of the year were counted and compared with the number of junior athletes born in the second half of the year. A significant chi squared for birthdate by success in tennis was present in the 14 years and under and 16 years and under age divisions for boys. This effect was less for older ages. Among girls, the effect of birthdate on tennis ranking was not significant in any age group. Among male junior tennis players in the 14 years and under and 16 years and under age divisions, athletes born in the first half of the year had an advantage over those born in the second half, but not for girls.

Consumo alimentar e perfil antropométrico de adolescentes tenistas / Food intake and anthropometric profile of adolescent tennis players

Anthropometric profile and food intake affect sports performance. The objective of this work was to describe and compare the food consumption and anthropometric profile of tennis players between 11 and 19 years old. A total of 48 tennis players were rated with the following age distribution: 11-14 years old (n=20) and 15 to 19 years old (n=28). The athletes were evaluated in relation with the anthropometric variables. Diets were as-sessed from 24-hour recall. There were significant differences in the an¬thropometric profile of athletes aged 15-19 years old compared to those aged 11-14 years old (body mass: 63.80±6.86kg and 54.29±11.33kg; height: 1.75±0,07m and 1.64±0.11m; right forearm: 26.14±1.41cm and 23.70±2.62cm; left forearm: 24.64±1.38cm and 22.48±2.38cm; right wrist: 16.71±0.72cm and 15.69±1.01cm; left wrist: 16.37±0.74cm and 15.36±1.12cm). There was no significant difference in the percentage of fat, 18.33±5.94 for 11-14 year-olds and 16.79±4.60 for 15-19 year-olds. An energy deficit was observed between the estimated energy needs and the energy consumption reported. There was significant difference in the consumption of carbohydrate, fat and protein between the age groups. Among the minerals, the main concern was the low consumption of calcium (11-14 years old: 724.36±397.94mg/day and 15-19 years old: 927.04±413.35mg/day). It was possible to observe significant differences in the anthropometric profile and food intake in relation to energy needs between the age groups. The deviations observed reinforce the need for nutritional guidance, technical training and fitness.

El perfil antropométrico y el consumo de alimentos afectan el rendimiento deportivo. El objetivo de este trabajo fue describir y comparar el consumo de alimentos y el perfil antropométrico de jugadores de tenis de 11 a 19 años. Se evaluaron las variables antropométricas de 48 jugadores, con la siguiente distribución: 11-14 años (n=20) y 15-19 años (n=28). Se evaluaron sus dietas a partir de recordatorio de 24 horas. Se encontraron diferencias significativas en el perfil antropométrico de los atletas de 15-19 años en comparación con los de 11-14 años (masa corporal: 63,80±6,86kg y 54,29±11,33kg, talla: 1,75±0,07m y 1,64±0,11m; antebrazo derecho: 26,14±1,41cm y 23.70±2.62cm; antebrazo izquierdo 24,64±1,38cm y 22,48±2,38cm; muñeca derecha 16,71±0,72cm y 15,69±1,01cm; muñeca izquierda: 16.37±0.74cm y 15.36cm y 1.12). No hubo diferencia significativa en el porcentaje de grasa en los jugadores de 11- 14 años (18,33±5,94) y en los de 15-19 años (16,79±4,60). Se observó déficit energético entre el requerimiento de energía estimado y el consumo de energía informado. Se encontraron diferencias significativas entre los grupos de edad en cuanto al consumo de hidratos de carbono, grasa y proteínas. Se observó baja ingesta de calcio (11-14 años: 724,36±397,94mg/día y 15-19 años: 927,04±413,35mg/día). Los desvíos observados refuerzan la necesidad de mayor educación nutricional, entrenamiento técnico y preparación física.

O perfil antropométrico e o consumo alimentar afetam o desempenho esportivo. O objetivo deste trabalho foi descrever e comparar o consumo alimentar e o perfil antropométrico de tenistas de 11 a 19 anos. Foram avaliados 48 tenistas, com a seguinte distribuição: 11-14 anos (n=20) e de 15 a 19 anos (n=28). Os atletas foram avaliados quanto às variáveis antropométricas. As dietas foram avaliadas a partir de recordatórios 24 horas. Houve diferença significativa no perfil antropométrico dos atletas de 15-19 anos em relação aos de 11-14 anos (massa corporal: 63,80±6,86kg e 54,29±11,33kg; estatura: 1,75±0,07m e 1,64±0,11m; antebraço direito: 26,14±1,41cm e 23,70±2,62cm e antebraço es¬querdo 24,64±1,38cm e 22,48±2,38cm; punho direito 16,71±0,72cm e 15,69±1,01cm; punho esquerdo: 16,37±0,74cm e 15,36cm e 1,12cm. Não houve diferença significativa quanto ao percentual de gordura, 18,33±5,94 para os de 11-14 anos e 16,79±4,60 para os de 15-19 anos. Observou-se déficit energético entre a necessidade energética estimada e a ingestão energética relatada. Houve diferença significativa quanto ao consumo de carboidrato, lipídio e proteína entre as faixas etárias. Entre os minerais, a principal preocupação foi a baixa ingestão de cálcio (11-14 anos: 724,36±397,94mg/dia e 15-19 anos: 927,04±413,35mg/dia). Desvios observa¬dos reforçam a necessidade de orientação nutricional, treinamento técnico e preparo físico.