High-performance Tennis Players Research Articles

Determining Stroke and Movement Profiles in Competitive Tennis Match-Play From Wearable Sensor Accelerometry.

Perri, T, Reid, M, Murphy, A, Howle, K, and Duffield, R. Determining stroke and movement profiles in competitive tennis match-play from wearable sensor accelerometry. J Strength Cond Res 37(6): 1271-1276, 2023-This study determined stroke and movement accelerometry metrics from a wearable sensor and compared between court surface (grass vs. hard) and match outcome (win vs. loss) during competitive tennis match-play. Eight junior high-performance tennis players wore a trunk-mounted global positioning system, with in-built accelerometer, magnetometer, and gyroscope during singles matches on hard and grass courts. The manufacturer software calculated accelerometer-derived total player load (tPL). A prototype algorithm classified forehands, backhands, serves, and "other" strokes, thereby calculating stroke PL (sPL) from individual strokes. Movement PL (mPL) was calculated as the difference between tPL and sPL, with all metrics reported as absolute and relative (min -1 , %, and ·stroke). Analysis of accelerometer load and stroke count metrics was performed through a two-way (surface [grass vs. hard] × match outcome [win vs. loss]) analysis of variance ( p < 0.05) and effect sizes (Cohen's d ). No interaction effects for surface and match outcome existed for absolute tPL, mPL, and sPL ( p > 0.05). Increased mPL% featured on grass courts, whereas sPL% was increased on hard courts ( p = 0.04, d = 1.18[0.31-2.02]). Elevated sPL·min -1 existed on hard courts ( p = 0.04, d = 1.19[0.32-2.04]), but no differences in tPL·min -1 and mPL·min -1 were evident for surface or outcome ( p > 0.05). Relative forehand sPL (FH-sPL·min -1 ) was higher on hard courts ( p = 0.03, d = 1.18[0.31-2.02]) alongside higher forehand counts ( p = 0.01, d = 1.29[0.40-2.14]). Hitting demands are heightened on hard courts from increased sPL and counts. Conversely, increased mPL% on grass courts likely reflects the specific movement demands from point-play. Physical preparation strategies during training blocks can be tailored toward movement or hitting loads to suit competitive surfaces.

Prototype Machine Learning Algorithms from Wearable Technology to Detect Tennis Stroke and Movement Actions.

This study evaluated the accuracy of tennis-specific stroke and movement event detection algorithms from a cervically mounted wearable sensor containing a triaxial accelerometer, gyroscope and magnetometer. Stroke and movement data from up to eight high-performance tennis players were captured in match-play and movement drills. Prototype algorithms classified stroke (i.e., forehand, backhand, serve) and movement (i.e., "Alert", "Dynamic", "Running", "Low Intensity") events. Manual coding evaluated stroke actions in three classes (i.e., forehand, backhand and serve), with additional descriptors of spin (e.g., slice). Movement data was classified according to the specific locomotion performed (e.g., lateral shuffling). The algorithm output for strokes were analysed against manual coding via absolute (n) and relative (%) error rates. Coded movements were grouped according to their frequency within the algorithm's four movement classifications. Highest stroke accuracy was evident for serves (98%), followed by groundstrokes (94%). Backhand slice events showed 74% accuracy, while volleys remained mostly undetected (41-44%). Tennis-specific footwork patterns were predominantly grouped as "Dynamic" (63% of total events), alongside successful linear "Running" classifications (74% of running events). Concurrent stroke and movement data from wearable sensors allows detailed and long-term monitoring of tennis training for coaches and players. Improvements in movement classification sensitivity using tennis-specific language appear warranted.

Upper-Limb Force-Time Characteristics Determine Serve Velocity in Competition Tennis Players.

(1)To analyze the associations between serve velocity (SV) and various single-joint upper-limb isometric force-time curve parameters, (2)to develop a prediction model based on the relationship between these variables, and (3)to determine whether these factors are capable of discriminating between tennis players with different SV performances. A total of 17 high-performance tennis players performed 8 isometric tests of joints and movements included in the serve kinetic chain (wrist and elbow flexion [EF] and extension; shoulder flexion [SHF] and extension [SHE], internal [SHIR] and external rotation). Isometric force (IF), rate of force development (RFD), and impulse (IMP) at different time intervals (0-250ms) were obtained for analysis. Significant (P < .05 to P < .01) and moderate to very large correlations were found between SV and isometric force (IF), RFD and impulse (IMP) at different time intervals in all joint positions tested (except for the EF). Stepwise multiple regression analysis highlighted the importance of RFD in the SHIR from 0 to 50milliseconds and isometric force (IF) in the SHF at 250milliseconds on SV performance. Moreover, the discriminant analyses established SHIR RFD from 0 to 30milliseconds as the most important factor discriminating players with different serve performances. Force-time parameters in upper-limb joints involved in the serve moderate to very largely influence SV. Findings suggest that the capability to develop force in short periods of time (<250ms), especially in the shoulder joint, seems relevant to develop high SV in competition tennis players.

Prognostic Validity of Statistical Prediction Methods Used for Talent Identification in Youth Tennis Players Based on Motor Abilities

(1) Background: The search for talented young athletes is an important element of top-class sport. While performance profiles and suitable test tasks for talent identification have already been extensively investigated, there are few studies on statistical prediction methods for talent identification. Therefore, this long-term study examined the prognostic validity of four talent prediction methods. (2) Methods: Tennis players (N = 174; n♀ = 62 and n♂ = 112) at the age of eight years (U9) were examined using five physical fitness tests and four motor competence tests. Based on the test results, four predictions regarding the individual future performance were made for each participant using a linear recommendation score, a logistic regression, a discriminant analysis, and a neural network. These forecasts were then compared with the athletes’ achieved performance success at least four years later (U13‒U18). (3) Results: All four prediction methods showed a medium-to-high prognostic validity with respect to their forecasts. Their values of relative improvement over chance ranged from 0.447 (logistic regression) to 0.654 (tennis recommendation score). (4) Conclusions: However, the best results are only obtained by combining the non-linear method (neural network) with one of the linear methods. Nevertheless, 18.75% of later high-performance tennis players could not be predicted using any of the methods.

Design and validation of a tennis tool to control on-court technical and tactical training content

In high performance tennis, different aspects like physical-conditioning, strategy-tactic, technical-biomechanical, psychology and skills acquisition have received large attention from the researchers. Nevertheless, the programming, periodization and planning of training sessions and competitions have not been as studied in depth. Coaches still use their experience, trial-error and subjective perceptions as methods of conducting these fundamental tasks. This article presents the design and validation of an instrument to control the technical and tactical training content on-court. The instrument was conceived by 9 experts and validated by 23 experienced coaches, who used on-court tennis exercises examples. The instrument is a useful tool for helping the coaches to improve the control of the on-court technical and tactical content and the tennis training session contents in high performance tennis players.

Acute effects of dynamic versus foam rolling warm-up strategies on physical performance in elite tennis players.

To date, there is a lack of information about the optimal conditions of the warm-up to lead to a better performance in elite tennis players. The aim of this study was to compare the effects of two different warm-up protocols (dynamic vs. self-myofascial release with foam rolling) on neuromuscular variables associated with physical determinants of tennis performance. Using a crossover randomised experimental design, eleven professional men tennis players (20.6 ± 3.5 years) performed either a dynamic warm-up (DWU) or a self-myofascial release with foam rolling (SMFR) protocol. DWU consisted of 8 min of dynamic exercises at increasing intensity and SMFR consisted of 8 min of rolling on each lower extremity unilaterally. Just before (baseline) and after completing warm-up protocols, players performed a countermovement jump (CMJ), the 5-0-5 agility test, a 10-m sprint test and the Straight Leg Raise and Thomas tests to assess range of motion. Compared to baseline, the DWU was more effective to reduce the time in the 5-0-5 test than SMFR (-2.23 vs. 0.44%, respectively, p = 0.042, ηp2 = 0.19). However, both warm-up protocols similarly affected CMJ (2.32 vs. 0.61%, p = 0.373, ηp2 = 0.04) and 10-m sprint time changes (-1.26 vs. 1.03%, p = 0.124, ηp2 = 0.11). Changes in range of motion tests were also similar with both protocols (p = 0.448–1.000, ηp2 = 0.00–0.02). Overall, both DWU and SMFR were effective to prepare well-trained tennis players for highly demanding neuromuscular actions. However, DWU offered a better preparation for performing change of direction and sprint actions, and hence, in high-performance tennis players, the warm-up should include dynamic exercises.

The influence of important conditions of professional high performance tennis players on psychological training and quality of their motor skills

The influence of important conditions of professional high performance tennis players on psychological training and quality of their motor skills

Differences in ball speed and accuracy of tennis groundstrokes between elite and high-performance players

The main aim of this study was to identify and compare ball speed and hitting accuracy of forehand and backhand groundstrokes between ATP professionals (elite) and high-performance youth players when shots were played cross-court and down the line to a target square. Six elite and seven high-performance tennis players volunteered to participate in the study. A Doppler-radar device and a digital video camera, operating at 120 frames per second, were used to measure ball speed and accuracy of forehand and backhand groundstrokes in the respective situation (cross-court and down the line). The results of 1040 measured groundstrokes indicate that the ball speed of the forehand and the backhand ground stroke was higher in the elite group when analysing (1) all valid shots, (2) the six fastest shots, and (3) the six most accurate shots (all P < 0.05). In addition, all players achieved a higher forehand speed compared with their backhand when balls were directed cross-court (P < 0.01). The participants demonstrated similar ability when considering accuracy of their groundstrokes (P > 0.05). However, a group difference for accuracy was identified when considering the six fastest forehand shots (P<0.05), and the forehand cross-court stroke was played more accurately than the backhand cross-court stroke by both groups (valid shots and six most accurate shots, P<0.05). Moreover, there was no evidence that players who impacted the ball faster were any less accurate than those who impacted the ball more slowly. Analyses for participants actually revealed a negative correlation between ball speed and mean radial error (accuracy) for the backhand down the line (r= − 0.77, P<0.01). According to the results of this study, ball speed seems to be the determining factor that separates elite from sub-elite tennis players.

Effect of a rehydration intervention on markers of hydration status in tennis players

Tennis players have repeatedly been shown to present with signs of dehydration before training or competition. To date no study has investigated the role of post-exercise rehydration in tennis players. Therefore the aim of this study was to assess the efficacy of a post-training rehydration strategy on markers of hydration status in high-performance tennis players. Using a nonblinded randomised crossover design the participants (12 male elite tennis players; mean±SD; age 21±2 years, national ranking 13±8; range 2-25) completed their normal daily training and dietary routine followed by ad libitium consumption (CON) of a commercially available carbohydrate-electrolyte solution (Lucozade Sport Hydro Active PLUS; 4 g carbohydrate and 91 mg sodium per 100 ml) or 20 ml per kg body mass (EXP) of the same solution. An array of markers of hydration status were assessed after rest days (baseline) and each training and intervention day (CON, EXP) including but not limited to: urine osmolality (first morning void, freezing point depression method); total body water, intra and extracellular water (multifrequency bioelectrical impedance). All markers of hydration status were measured in the morning before any activity or meals and normalised as a percentage of baseline. A magnitude-based inferences approach1 was used to determine the main effect of the intervention on the markers of hydration status. The mean (±SD% normalised to baseline) in CON vs EXP for urine osmolality, total body water, extracellular and intracellular water were 104±25% vs 95±31%; 99±2% vs 100±2%; 100±2% vs 102±7% and 98±5% vs 100±2%. The probability of a beneficial or positive effect on these markers of hydration status was 87%, 67%, 84% and 59%, respectively. The probability of a harmful or negative effect was 2%, 3%, 8% and 4%, respectively. Therefore this post-exercise rehydration intervention has an unclear effect as the probability of a negative effect on these markers of hydration status was too great.

Kinematic differences of elite and high-performance tennis players in the cross court and down the line forehand

This study identified and compared the full body kinematics of different skill levels in the forehand groundstroke when balls were hit cross court and down the line. Forty-three three-dimensional retro-reflective marker trajectories of six elite and seven high-performance players were recorded using an eight-camera 400 Hz, Vicon motion analysis system. The six highest horizontal velocity forehands with reliable kinematics of all participants were analysed for each specific situation (a total of 156 analysed shots). Significant differences (p < 0.01) and large effect sizes were observed between elite and high-performance players in linear velocity of the shoulder (2.0 vs. 1.2 m/s), angular velocity of the pelvis (295 vs. 168 °/s), and angular velocity of the upper trunk (453 vs. 292 °/s) at impact. The elite group showed a tendency towards higher racquet velocities at impact (p < 0.05). No significant differences were found in angular displacement of the racquet, hip alignment, or shoulder alignment at the completion of the backswing; nor did angular displacement vary significantly at impact. Irrespective of the group, different shoulder, hip, and racquet angles were found at impact, depending on the situation. The results should assist coaches when striving to improve their players' forehand.

The phenomenon of twisted growth: humeral torsion in dominant arms of high performance tennis players

This manuscript is driven by the need to understand the fundamental mechanisms that cause twisted bone growth and shoulder pain in high performance tennis players. Our ultimate goal is to predict bone mass density in the humerus through computational analysis. The underlying study spans a unique four level complete analysis consisting of a high-speed video analysis, a musculoskeletal analysis, a finite element based density growth analysis and an X-ray based bone mass density analysis. For high performance tennis players, critical loads are postulated to occur during the serve. From high-speed video analyses, the serve phases of maximum external shoulder rotation and ball impact are identified as most critical loading situations for the humerus. The corresponding posts from the video analysis are reproduced with a musculoskeletal analysis tool to determine muscle attachment points, muscle force vectors and overall forces of relevant muscle groups. Collective representative muscle forces of the deltoid, latissimus dorsi, pectoralis major and triceps are then applied as external loads in a fully 3D finite element analysis. A problem specific nonlinear finite element based density analysis tool is developed to predict functional adaptation over time. The density profiles in response to the identified critical muscle forces during serve are qualitatively compared to X-ray based bone mass density analyses.

Glenoid Labrum Lesion in an Elite Tennis Player: A Clinical Challenge in Diagnosis

Shoulder pain among overhead-sport athletes is common and often presents a challenge to clinicians in making an accurate diagnosis. A case report of a young college tennis player is presented, with emphasis on the clinical examination process leading to the diagnosis of a superior labrum anteroposterior lesion. The current literature regarding the clinical diagnosis of glenoid labrum lesion in the shoulder with respect to specific clinical tests was reviewed. It is recommended that clinicians consider glenoid labral lesions in the context of shoulder instability. Glenohumeral internal-rotation deficit should be routinely evaluated and corrected in high-performance tennis players.

MUSCULAR DYSBALANCES IN DIFFERENT SHOULDER EXERCISES

229 Functionally, the shoulder is considered a ball joint, whereby high mobility is attended by low stability. Therefore, muscular balance is decisive for stability. Altered strength ratios are frequently described as "muscular dysbalances" and considered one of the causes of various shoulder pathologies, whereby objective quantification is difficult. In order to define muscular balance first, the strength ratios of reciprocal muscle groups (quotient of peak torque) for extension/flexion (EX/FL), abduction/adduction (AB/AD) and rotation movements (ERO/IRO) were determined in 166 untrained men (UM) and 83 untrained women (UF). Determination was made isometric, concentric (60°/s, 180°/s) and eccentric (60°/s, 120°/s, LIDO-Active). The influence on this norm of one-sided (25 high-performance tennis players, TPH; 18 leisure tennis players, TPL) and two-sided (32 gymnasts, GY) athletic exercise, altered daily exercise (11 paraplegics with paralysis time < 4 mo., PP; 11 Paraplegics with paralysis time > 2 years, PU) and a combination of longer existing, altered daily exercise and increased athletic exercise (16 trained paraplegics, PT) was examined (ANOVA, α=0.05). The definition of the sex-specific norm showed no differences in reciprocal strength ratios between UM and UF (p>0.05) in spite of different absolute torque values (p<0.05). EX, AD and ERO showed higher torques, so that the quotients were < 1. Morcover, there was a decrease in the sequence AB/AD > FL/EX > ERO/IRO. Shoulder stress in sports led to a decrease in quotients compared to UM due to a relatively increased maximum strength in EX, AD and ERO (p<0.01). At the beginning of a paraplegia (PP), the quotient of FL/EX and AB/AD is elevated (p<0.05). This altered ratio decreases with increasing duration of paralysis (PU). The combination of paraplegia and athletic exercise (PT) showed no difference in ratios to UM. With increased shoulder stress, the altered strength ratios reflect specific requirements of the performance attained. However, the importance of muscular dysbalances for the onset of shoulder complaints must be considered more important than their influence on athletic performance capacity.

The Influence of Grip Position on Upper Limb Contributions to Racket Head Velocity in a Tennis Forehand

In tennis groundstrokes, the speed of the racket head depends on the rotational velocities of the upper limb segments and the corresponding instantaneous position of the racket. The method of holding the racket may influence these factors. Six high-performance tennis players who preferred the eastern method of holding the racket and a further 6 who preferred the western method were filmed. The displacement histories of 16 selected landmarks were calculated using the direct linear transformation approach and were used to calculate the contribution that the three-dimensional individual segment rotations for the upper limb made to racket head velocity. Horizontal flexion/abduction and internal rotation of the upper arm, in addition to linear velocity of the shoulder, were the primary contributors to racket head speed at impact, regardless of grip. Significant variations, however, were recorded for the contribution of the hand segment to racket head speed for the different grip positions.

Contributions of Upper Limb Segment Rotations during the Power Serve in Tennis

In the high-velocity tennis serve, the contributions that the upper limb segments' anatomical rotations make to racket head speed at impact depend on both their angular velocity and the instantaneous position of the racket with respect to the segments' axes of rotation. Eleven high-performance tennis players were filmed at a nominal rate of 200 Hz by three Photosonics cameras while hitting a high-velocity serve. The three-dimensional (3-D) displacement histories of 11 selected landmarks were then calculated using the direct linear transformation approach, and 3-D individual segment rotations for the upper limb were calculated using vector equations (Sprigings, Marshall, Elliott, &amp; Jennings, 1994). The major contributors to the mean linear velocity of the center of the racket head of 31.0 m · s-1 at impact were internal rotation of the upper arm (54.2%), flexion of the hand (31.0%), horizontal flexion and abduction of the upper arm (12.9%), and racket shoulder linear velocity (9.7%). Forearm extension at the elbow joint played a negative role (-14.4%) and reduced the forward velocity of the center of the racket at impact.