INTEGRATING BIOMECHANICS AT THE ELITE LEVEL: THE TENNIS AUSTRALIA EXPERIENCE

Technical skill is key to tennis success. Qualitative critiques of technique are commonplace in the sport. The use of quantitative biomechanics analysis in aiding athlete development has been limited in tennis however, owing largely to its cost, the expertise required for implementation and/or the timeliness of meaningful feedback. Tennis Australia has nevertheless attempted to strategically deploy quantitative biomechanics analysis, often doubling as research opportunities, to facilitate a coach’s understanding of specific parts of his/her athlete’s technique. The organisation has also identified key research questions to improve the sport’s understanding of technique, skill development and injury prevention, generally through the use of motion analysis systems like VICON. The current paper provides some examples of the genesis and outcomes of this research in specific relation to the tennis serve

THE EFFECT OF A COMMON COACHING CUE ON BODY KINEMATICS IN THE TENNIS SERVE

The objective of this study was to quantify the kinematic changes promoted by instructing players to implement a common coaching constraint, an arabesque finish position, in the tennis serve. A 10 camera 500 Hz 3D VICON MX motion analysis system recorded the service action of 8 elite junior players as they performed 3 normal serves and 3 serves with an arabesque finish. The arabesque finish promoted greater frontal plane trunk range of motion and angular velocity (shoulder over shoulder rotation) as well as increased leg drive; variables established as important in the development of serve speed. Instructing players to finish in an arabesque position can therefore be considered an effective way to elicit the desired kinematic change, and is consequently an effective instructional cue

DIFFERENTIATING TOP-RANKED MALE TENNIS PLAYERS FROM LOWERRANKED PLAYERS USING HAWK-EYE DATA: AN INVESTIGATION OF THE 2012–2014 AUSTRALIAN OPEN TOURNAMENTS

The purpose of this study was to differentiate top- and lower-ranked professional tennis players, using Hawk-Eye derived performance metrics. Eighty players competing at the 2012–2014 Australian Open tournaments were assigned to either a top-ranked (n=40) or lower ranked (n=40) group, based on their ATP ranking. Hawk-Eye data from one of each player’s matches were obtained for analysis and compared between groups. Top-ranked players achieved more success on serve (with respect to aces, accuracy and points won) and possessed a faster first serve return, compared with lower-ranked players. Topranked players also played more groundstrokes from behind the baseline, delivered the ball deeper into their opponent’s court, and covered a greater distance during matches. Coaches may be able to use these findings to develop playing style and match tactics

Scaling the Equipment and Play Area in Children’s Sport to improve Motor Skill Acquisition: A Systematic Review

BACKGROUND: This review investigated the influence of scaling sports equipment and play area (e.g., field size) on children’s motor skill acquisition. METHODS: Peer-reviewed studies published prior to February 2015 were searched using SPORTDiscus and MEDLINE. Studies were included if the research (a) was empirical, (b) involved participants younger than 18 years, (c) assessed the efficacy of scaling in relation to one or more factors affecting skill learning (psychological factors, skill performance and skill acquisition factors, biomechanical factors, cognitive processing factors), and (d) had a sport or movement skills context. Risk of bias was assessed in relation to selection bias, detection bias, attrition bias, reporting bias and other bias. RESULTS: Twenty-five studies involving 989 children were reviewed. Studies revealed that children preferred using scaled equipment over adult equipment (n = 3), were more engaged in the task (n = 1) and had greater self-efficacy to execute skills (n = 2). Eighteen studies demonstrated that children performed skills better when the equipment and play area were scaled. Children also acquired skills faster in such conditions (n = 2); albeit the practice interventions were relatively short. Five studies showed that scaling led to children adopting more desirable movement patterns, and one study associated scaling with implicit motor learning. CONCLUSION: Most of the studies reviewed provide evidence in support of equipment and play area scaling. However, the conclusions are limited by the small number of studies that examined learning (n = 5), poor ecological validity and skills tests of few trials

HOW IMPORTANT IS PERCEPTION-ACTION COUPLING IN THE TENNIS SERVE?

The purpose of this study was to examine how removing visual feedback affects ball and racket kinematics in the tennis serve. A 10-camera 500 Hz VICON MX motion analysis system recorded the service actions of 8 elite junior players as they performed three serves with eyes open and three serves with eyes closed. Removal of vision resulted in considerable differences in both racket and ball kinematics, and the interaction between the two. The results highlight that the service action is not pre-programmed, and that visual feedback is critical to the temporospatial regulation of the service action. These findings suggest that coaches need to be aware of the implications of removing perception-action couplings, and ensure that the drills that they prescribe represent the action being trained

REDEFINING SPATIAL CONSISTENCY IN THE BALL TOSS OF THE PROFESSIONAL FEMALE TENNIS SERVE

The objective of this study was to quantify the three-dimensional spatial variability of the ball toss in the female tennis serve and interpret its practical implications. A 500Hz optical motion capture system recorded the ball toss trajectory while eight professional female players performed flat 1st serves. The anteroposterior and lateral variability of ball location was smaller at ball zenith compared with impact. The impact height was the most consistent aspect of the ball toss. Given these findings, the prevailing coaching drills that emphasize consistency appear too stringent. Players should be granted more liberal constraints when rehearsing the ball toss and ball toss drills should retain a racket-ball impact component (as opposed to rehearsing the ball toss in isolation) to refine a consistent impact height

HITTING TO DIFFERENT SPOTS ON THE COURT: THE BALL KINEMATICS OF THE PROFESSIONAL TENNIS SERVICE

Of the component parts of the service (toss and swing) the swing has received disproportionate research attention. Consequently, the age-old question of whether players serve to different parts of the court from the same toss remains unanswered. A 22 camera, 250Hz VICON MX motion analysis system tracked six professionally ranked players as they hit first serves (FS) and second serves (SS) to three 2X1m target areas reflecting the landing locations of T, body and wide serves respectively, on the deuce court. The displacements of the front foot, ball zenith and ball impact were significantly different in the FS, while kinematics across SS were consistent. Front foot position was closer to the centre mark in the T serve and players impacted the ball further left in the wide serve compared to the T serve. Implications are practical for serving and returning

DIFFERENCES IN TENNIS SERVE KINEMATICS BETWEEN ELITE ADOLESCENT MALE AND FEMALE PLAYERS

The purpose of this study was to compare kinematic differences in elite adolescent male and female tennis serves. A 3D motion capture system was used to capture whole body, racquet and ball toss kinematics while twenty elite adolescent tennis players (male = 10, female = 10) performed flat and kick serves. Females had greater vertical front hip velocity (FS: 0.2 m/s, KS: 0.2 m/s greater than males), whilst males experienced larger peak shoulder external rotation displacements in both flat (10° greater) and kick (8° greater) serves compared to females. Females tossed the ball higher (FS: 18 cm, KS 19 cm) whilst males impacted the ball more laterally (across the body) (FS: 17cm, KS: 12) and more forward (FS: 10 cm, KS: 13 cm) into the court. Females had greater lower body kinematics whereas males tended to rely on shoulder external rotation to produce ball speed

IS THE KICK SERVE LINKED WITH PARS ABNORMALITIES IN ELITE ADOLESCENT TENNIS PLAYERS?

The purpose of this study was to compare lumbar kinetics in elite adolescent tennis players with and without pars abnormalities. A 3D motion capture system was used to capture lumbar spine kinetics while 24 right-handed elite adolescent tennis players (male = 14, female = 10, 9 players with pars abnormalities) performed kick serves. Players without pathology were found to have significantly greater peak lumbar posterior force (7.3 N/kg greater), left lateral flexion force (4 N/kg greater), right lateral flexion force (3.4 N/kg greater), flexion moment (2 Nm/kg greater) and left rotation moment (1.2 Nm/kg greater) during the drive phase. Interestingly, no differences were observed for peak kinetic values during the forward-swing phase. Those with pars abnormalities had lower lumbar loading overall compared with those without pars abnormalities