Impact of Physical Performance and Anthropometric Characteristics on Serve Velocity in Elite Junior Tennis Players

Kinematics of the Tennis Serve Using an Optoelectronic Motion Capture System: Are There Correlations between Joint Angles and Racket Velocity?

The serve is the most important stroke in tennis. It is a complex gesture consisting of numerous rotations with a wide amplitude, which are important to manage for performance. The aim of this study was to investigate whether correlations exist between joint kinematic parameters and racket velocity. A quantitative kinematics analysis of four ranked players (two boys and two girls) was carried out using an optoelectronic system composed of 10 cameras (150 Hz). Five flat serves per player were analyzed. Eighty-two markers were located across the 15 body segments and on the racket. A descriptive statistical analysis including a correlation analysis was carried out between joint angles and racket kinematic parameters (vertical position, velocity, and acceleration) during the cocking and acceleration phases. Ten very high (0.7 < r < 0.9) and three almost perfect (r > 0.9) correlations were found. Shoulder and hip axial rotations, knee flexion, and trunk extension were correlated linearly with racket vertical position and velocity during the cocking phase. For the acceleration phase, elbow flexion, trunk flexion/extension, and trunk axial rotation were linked to racket kinematics. Some of these parameters showed differences between slow and fast serves. These parameters, which are involved in transmitting ball velocity, are important to consider for tennis players and coaches in training programs, education, and performance enhancement.

Neuromuscular Fitness Is Associated with Serve Speed in Young Female Tennis Players

In tennis, the serve plays a key role in determining the success of a player. The speed of a serve is influenced by a multitude of interconnected skills and abilities. The objective of this study was to establish the correlation between the explosive strength of the throwing type, the grip strength and flexibility of the arms, and the shoulder girdle with the serve speed in young female tennis players. Additionally, the study aimed to develop a regression model that accurately predicts the serve speed by analyzing the interplay among these variables. The study was carried out on a group of 20 tennis players, who had an average age of 13.10 ± 0.74 years. Additionally, their height was recorded as 165.70 ± 4.90 cm, and their body mass was measured at 51.45 ± 5.84 kg. To assess the motor abilities of the upper extremities, four tests were used that aimed to measure the explosive strength of the throwing type; one test was for the strength of the hand and forearm muscles, and one test was for the flexibility of the arms and shoulder girdle. Of all the variables examined, the medicine ball throw shot put (MBTSP) (r = 0.75), overhead medicine ball throw (OMBT) (r = 0.70), and grip strength (GS) (r = 0.71) displayed a notable correlation with serve speed (p < 0.05). The results obtained from the multiple regression analysis indicate that the combination of selected predictors (MBTSP-medicine ball throw shot put, OMBT-overhead medicine ball throw and GS-grip strength) explained 75% of the variability in serve speed. Significantly, MBTSP surfaced as the predominant predictor, autonomously elucidating 51% of the variability in serve speed. The importance of improving the analyzed motor skills of young female tennis players to enhance their serve in terms of speed is emphasized by the findings of this research.

Effects of plyometric training on measures of physical fitness in racket sport athletes: a systematic review and meta-analysis

Background

Over the past decade, the popularity of racket sports has surged. Plyometric training (PT) has been the focus of extensive research because of the proven benefits it provides to athletes. However, there is a lack of systematic reviews and meta-analyses specifically evaluating the impact of PT on physical fitness metrics in racket sport athletes. This study aimed to conduct a comprehensive review and analysis of evidence derived from randomized controlled trials (RCTs) to evaluate the effects of PT on measures of physical fitness among racket sports athletes.

Methods

The electronic databases PubMed, Web of Science, SCOPUS, and SPORTDiscus were systematically searched up to June 2023 without placing any restrictions on the publication dates. The PICOS method was adopted to establish the inclusion criteria: (a) healthy athletes who participate in racket sports; (b) a PT program; (c) a control group; (d) assessment of physical fitness components pre- and post-PT; and (e) RCTs. The records' methodological quality was assessed utilizing the Physiotherapy Evidence Database (PEDro) scale. The certainty in the evidence related to each outcome was evaluated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) assessment. A random-effects model was used to calculate effect sizes (ES; Hedges' g) between experimental and control groups.

Results

There were 14 eligible studies of moderate-to-high-quality, involving 746 athletes in total. The results revealed small-to-moderate effects (p < 0.05) of PT on muscle power (ES = 0.46), muscle strength (ES = 0.50), sprint speed (ES = 0.45), change of direction ability (ES = 0.76), and reaction time (ES = 0.67), while no clear evidence was found on balance and flexibility. The training-induced changes in muscle power showed no significant difference (p > 0.05) between youth (ES = 0.72) and adults (ES = 0.40). There were also similar muscle power improvements (ES = 0.36-0.54 vs 0.38-0.56, all p > 0.05) for a length of ≤7 weeks with ≤14 total PT sessions vs >7 weeks with >14 total PT sessions, and ≤2 weekly sessions vs >2 sessions. No adverse effects were reported in the included studies regarding the PT intervention. The certainty of evidence varied from very low to moderate. Conclusions: Our findings demonstrated that PT has positive effects on important indices of physical fitness among athletes participating in racket sports. Future studies are required to clarify the optimal doses and examine interactions among training variables to further promote the physical fitness of this specific population.

Effects of Upper-Body Plyometric Training on Physical Fitness in Healthy Youth and Young Adult Participants: A Systematic Review with Meta-Analysis

BACKGROUND

Upper-body plyometric training (UBPT) is a commonly used training method, yet its effects on physical fitness are inconsistent and there is a lack of comprehensive reviews on the topic.

OBJECTIVE

To examine the effects of UBPT on physical fitness in healthy youth and young adult participants compared to active, specific-active, and passive controls.

METHODS

This systematic review followed PRISMA 2020 guidelines and utilized the PICOS framework. PubMed, WOS, and SCOPUS were searched. Studies were assessed for eligibility using the PICOS framework. The effects of UBPT on upper-body physical fitness were assessed, including maximal strength, medicine ball throw performance, sport-specific throwing performance, and upper limb muscle volume. The risk of bias was evaluated using the PEDro scale. Means and standard deviations were used to calculate effect sizes, and the I2 statistic was used to assess heterogeneity. Publication bias was assessed using the extended Egger's test. Certainty of evidence was rated using the GRADE scale. Additional analyses included sensitivity analyses and adverse effects.

RESULTS

Thirty-five studies were included in the systematic review and 30 studies in meta-analyses, involving 1412 male and female participants from various sport-fitness backgrounds. Training duration ranged from 4 to 16 weeks. Compared to controls, UBPT improved maximal strength (small ES = 0.39 95% CI = 0.15-0.63, p = 0.002, I2 = 29.7%), medicine ball throw performance (moderate ES = 0.64, 95% CI = 0.43-0.85, p < 0.001, I2 = 46.3%), sport-specific throwing performance (small ES = 0.55, 95% CI = 0.25-0.86, p < 0.001, I2 = 36.8%), and upper limbs muscle volume (moderate ES = 0.64, 95% CI = 0.20-1.08, p = 0.005, I2 = 0.0%). The GRADE analyses provided low or very low certainty for the recommendation of UBPT for improving physical fitness in healthy participants. One study reported one participant with an injury due to UBPT. The other 34 included studies provided no report measure for adverse effects linked to UBPT.

CONCLUSIONS

UBPT interventions may enhance physical fitness in healthy youth and young adult individuals compared to control conditions. However, the certainty of evidence for these recommendations is low or very low. Further research is needed to establish the optimal dose of UBPT and to determine its effect on female participants and its transfer to other upper-body dominated sports.

Effects of physical training programs on female tennis players' performance: a systematic review and meta-analysis

Background: Tennis is among the world's most popular and well-studied sports. Physical training has commonly been used as an intervention among athletes. However, a comprehensive review of the literature on the effects of physical training programs on female tennis players' performance is lacking. Therefore, this systematic review and meta-analysis aimed to determine the effects of physical training on performance outcomes in female tennis players. Methods: A comprehensive search was conducted on Web of Science, PubMed, SPORTDicus, Scopus, and CNKI from inception until July 2023 to select relevant articles from the accessible literature. Only controlled trials were included if they examined the effects of physical training on at least one measure of tennis-specific performance in female tennis players. The Cochrane RoB tool was employed to assess the risk of bias. The CERT scale was used to examine the quality of program information. The GRADE approach was adopted to evaluate the overall quality of the evidence. The Comprehensive Meta-Analysis software was used for the meta-analysis. Results: Nine studies were selected for the systematic review and seven for the meta-analysis, totaling 222 individuals. The study's exercise programs lasted 6-36 weeks, with training sessions ranging from 30 to 80 min, conducted one to five times per week. Muscle power (ES = 0.72; p = 0.003), muscle strength (ES = 0.65; p = 0.002), agility (ES = 0.69; p = 0.002), serve velocity (ES = 0.72; p = 0.013), and serve accuracy (ES = 1.14; p = 0.002) demonstrated significant improvement following physical training, while no notable changes in linear sprint speed (ES = 0.63; p = 0.07) were detected. Conclusion: Although research on physical training in sports is diversified, studies on training interventions among female tennis players are scarce. This review found that existing training programs yield some favorable outcomes for female tennis players. However, further research with high methodological quality is warranted on the tailoring of specific training programs for female tennis players. There should be more consistent measuring and reporting of data to facilitate meaningful data pooling for future meta-analyses.

Association of Selected Fitness Variables with Perceived Performance Levels in Lawn Tennis Players

Objectives Lawn tennis is an explosive sport that involves various fitness parameters such as explosive strength, endurance, power, and agility. Improved physical fitness leads to superior athletic performance. The coach's perception is contingent upon his perception of the player at the time the athlete is comparing himself to the coach. Thus, this study aimed to determine the association between chosen fitness factors and perceived performance by coach in lawn tennis players. Thus, the study aims to detect the relationship between different fitness variables and perceived level of performance in lawn tennis player.

Materials and Methods Fifty-two lawn tennis players from two sports academies were measured for various parameters of fitness and perceived performance level as rated by the coach.

Statistical Analysis The association between selected fitness metrics and perceived performance in lawn tennis players was investigated using Pearson's correlation test. Furthermore, the data were analyzed with paired t-test for male and female group, and ANOVA was used to analyze the difference between the levels of performance.

Results Fatigue index, closed kinetic chain upper extremity stability (CKCUEST) test, and peak power and energy expenditure taken by metabolic equivalent (MET) calculation was found to be statistically different between males and females. While comparing BMI with the peak power, there was a weak positive correlation for males, while for female there was no correlation. Metabolic equivalent, energy expenditure, and peak power were positively correlated with the level of performance; however, fatigue index and level of performance had a negative nonsignificant correlation.

Conclusion Peak power, fatigue index, energy expenditure, and BMI were found to be associated in males, but not in females. Peak power and energy expenditure were connected to performance in both genders.

Association of trunk and lower limb factors with shoulder complaints and sport performance in overhead athletes: A systematic review including GRADE recommendations and meta-analysis

OBJECTIVE

To identify the association of trunk and lower limb factors with shoulder complaints and sport performance in overhead athletes.

METHODS

Search performed at PubMed/Medline, Embase, CINAHL, LILACS, Cochrane, Web of Science and SPORTDiscus for observational studies. Methodological quality and strength of the evidence was assessed with the Newcastle-Ottawa Scale and GRADE. Meta-analysis and effects sizes analysis were calculated when possible.

RESULTS

Sixty-five studies were included. Low to very-low evidence suggests no association of trunk/lower limb strength, endurance, power, jump or balance with shoulder complaints and/or throwing performance. Athletes with shoulder complaints performed worse in trunk stability and endurance tests (mean difference: -6.83 (95%CI: -8.78, -4.88)). Athletes with high throwing performance presented better results in CMJ, horizontal jump, power measures and knee extension strength. For swimmers, there was no association of trunk/lower limb endurance with shoulder complaints (moderate evidence) and no association of balance and swimming performance (low evidence). Better trunk/lower limb strength, power and vertical jumps measures were associated with better swimming performance.

CONCLUSIONS

In methodologically similar studies, some trunk/lower limb outcomes are associated with shoulder complaint or sport/swimming performance. Results should be considered with caution and future studies should use better methodologies.

The Association Between Chronological Age and Maturity Status on Lower Body Clinical Measurements and Asymmetries in Elite Youth Tennis Players

BACKGROUND

Tennis is one of the most popular sports among youths. At elite levels, a notable increase in injury incidence and a temporary decline in performance may occur when children progress through puberty. However, limited research has explored maturity-associated variations in clinical measurements suggested as predictors of injury and tennis performance in elite youth players. Therefore, the main purpose of this study was to analyze the association between chronological age and maturity status on several measures of neuromuscular capability and physical performance as well as bilateral (interlimb) asymmetries in elite youth tennis players.

HYPOTHESIS

Youth tennis players around peak height velocity (PHV) will show higher growth-related impairments or deficits in measures of neuromuscular capability and physical performance than their less (pre-PHV) and more (post-PHV) mature counterparts irrespective of sex.

LEVEL OF EVIDENCE

Level 4.

METHODS

A total of 68 male (age, 13.7 ± 1.1 years; height, 162.4 ± 9.4 cm; body mass, 51.4 ± 10.3 kg [Mean values ± SD]) and 60 female (age, 13.6 ± 1.1 years; height, 162.8 ± 7.2 cm; body mass, 52.7 ± 7.5 kg [Mean values ± SD]) elite youth tennis players from 2 different age groups (under 13 [U13] and under 15 [U15]) and maturity status (pre-PHV, around PHV, and post-PHV), were tested during national training camps. Tests included the Y Balance Test, isometric hip abduction and adduction strength, hip ranges of motion (ROMs), and countermovement jump (CMJ) height. Bayesian analysis was used to establish any significant between-group differences.

RESULTS

Only dynamic balance (in boys; Bayesian factor [BF₁₀] = 88.2) and jump height (in both boys and girls; BF₁₀ >100) were significatively associated with chronological age, whereby the U15 group showed lower Y Balance Test reach distances (-6%; standardized effect size δ = 0.62) but higher CMJ height scores (+18%; δ = 0.73) than the U13 group. Although boys jump higher (+11%; δ = 0.62) and were stronger in isometric hip adduction strength (+14%; δ = 0.92) than girls, the latter had greater hip internal ROM values (+15%; δ = 0.75). Furthermore, relevant maturity-associated effects (BF₁₀ = 34.6) were solely observed for the CMJ test in boys, with the most mature players demonstrating higher jump height scores (+12%; δ = 0.93). Finally, a significant percentage (>25%) of tennis players, independent of sex, demonstrated bilateral asymmetries in hip ROM, hip strength, and jump height values.

CONCLUSION

The findings of this study show that in U13 and U15 male and female tennis players, there were neither positive nor negative maturity-associated variations in the clinical measurements analyzed (with the exception of jump height in male players). The high proportion of tennis players showing bilateral asymmetries in dynamic balance, hip ROM, and strength and jump performance highlight the need of future studies to analyze these factors in relation to unilateral tennis-specific adaptations in the musculoskeletal and sensorimotor systems.

CLINICAL RELEVANCE

These results may help to better understand how different clinical measurements are associated with the process of growth and maturation in elite youth tennis players and may aid in the design of specific training interventions during these stages of development.

Performance Outcomes Following Isoinertial or Machine-Based Training Interventions in Female Junior Tennis Players

PURPOSE

To evaluate changes in physical performance indicators after executing a flywheel or machine-based neuromuscular training program in young female tennis players.

METHODS

Twenty-four players were divided into a machine-based  group (MG), flywheel  group (FG), and control group. Countermovement jump (CMJ), sprint time (5, 10, and 15 m), change-of-direction (COD) performance (right and left), medicine-ball throws (overhead, forehand, and backhand), and serve velocity were included as tests at baseline, week 4, and week 8.

RESULTS

Both MG and FG largely improved from baseline to weeks 4 and 8 of training in CMJ (11.6, 10.6%; effect size [ES] = 1.24, 1.95). Also, sprint time 5 m and 10 m, COD performance-right, and COD performance-left improved moderately to very largely at week 4 in MG (-5.0% to -6.2%; ES = -1.79 to -4.19) and FG (-2.9% to -5.1%; ES = -1.13 to -1.64), respectively. Regarding medicine-ball throw, only FG improved moderately to very largely from weeks 4 to 8 in overhead (9.3%; ES = 1.46), forehand (8.0%; ES = 1.08), and backhand (6.1%; ES = 1.15). Serve velocity improved moderately from weeks 4 to 8 in MG (5.8%; ES = 0.87).

CONCLUSIONS

Four weeks of the tested programs seem sufficient to improve physical determinants in young female participants. Greater improvements in CMJ and medicine-ball throw following flywheel neuromuscular training indicate the importance of including exercises that emphasize the stretch-shortening cycle and involve the entire kinetic chain. Performing the same intervention with no load adjustments may stall or even decrease performance in some parameters from weeks 4 to 8.

Six-Week Joint-Specific Isometric Strength Training Improves Serve Velocity in Young Tennis Players

PURPOSE

Evaluate the effects of 6 weeks of specific-joint isometric strength training on serve velocity (SV), serve accuracy (SA), and force-time curve variables.

METHODS

Sixteen young competition tennis players were divided into an intervention (n = 10) or control group (n = 6). SV, SA, maximal voluntary isometric contraction, peak rate of force development, rate of force development, and impulse (IMP) at different time frames while performing a shoulder internal rotation (SHIR) or flexion were tested at weeks 0, 3, and 6.

RESULTS

The intervention group showed significant increases in SV from pretest to posttest (7.0%, effect size [ES] = 0.87) and no variations in SA. Moreover, the intervention group showed significant increases from pretest to posttest in shoulder-flexion rate of force development at 150 (30.4%, ES = 2.44), 200 (36.5%, ES = 1.26), and 250 ms (43.7%, ES = 1.67) and in SHIR IMP at 150 (35.7%, ES = 1.18), 200 (33.4%, ES = 1.19), and 250 ms (35.6%, ES = 1.08). Furthermore, significant increases were found in shoulder-flexion rate of force development from intertest to posttest at 150 ms (24.5%, ES = 1.07) and in SHIR IMP at 150 (13.5%, ES = 0.90), 200 (19.1%, ES = 0.98), and 250 ms (27.2%, ES = 1.16). SHIR IMP changes from pretest to intertest were found at 150 ms (25.6%, ES = 1.04). The control group did not show changes in any of the tested variables.

CONCLUSIONS

Six weeks of upper-limb specific-joint isometric strength training alongside habitual technical-tactical workouts results in significant increases in SV without SA detriment in young tennis players.

Effectiveness and Kinematic Analysis of Initial Step Patterns for Multidirectional Acceleration in Team and Racquet Sports

The ability for quick multidirectional accelerations is crucial for athletic performance in team and racquet sports. So far, there has been little research dedicated to different initial step patterns usually applied by players. Therefore, the present study investigated the kinematic characteristics and effectiveness of the following step patterns: Jab Step (JS), Pivot Step (PS), Gravity Step (GS) and Counter Step (CS). Twenty-two male competitive team and racquet sport athletes completed maximum lateral accelerations utilizing the step patterns. Following familiarization with each step pattern, three 5 m sprints (5 m STs) into both directions (left & right) were completed. Sprint times, the translation of the center of mass (CoM) and joint angles were obtained using three-dimensional motion analysis. 5 m STs of the CS were faster compared to the GS and PS for both directions. A detailed distance-time analysis revealed that for shorter distances only the JS was faster than the GS. Regarding the sequence in which the maximum angular velocities (max. w → ) in the hip, the knee, and the ankle were reached during the push off, there was a proximal-to-distal sequence for the JS and the CS, but a distal-to proximal sequence for the GS and the PS. The results reveal that the JS and the CS are superior for accelerations towards the lateral direction. Specifically, they indicate that the JS is more suitable for covering very short distances and the CS is superior for covering further distances. In addition, the distal-to-proximal sequence of max. w → during the push-off in the GS and the PS might indicate lower kinematic efficiency.

SPECIAL TRAINING FOR ATHLETES TO IMPROVE THEIR PHYSICAL AND SPORTIVE CAPACITY

ABSTRACT Introduction: Athletes’ physical fitness is an important factor in achieving good results in the game. Exercise and physical skills training are important means of improving competitive sports. No matter the type of sporting event, there are strict regulations on players’ physical fitness. Objective: Analyze the special methods of physical exercise to improve the physical quality of athletes. The results can provide a reference for coaches to formulate more scientifically specific training programs for athletes. Methods: Several athletes with certain sports skills are selected as subjects. The objective of this work is to detect the level of physical fitness of the athletes. And based on this, a statistical analysis of their motor function was performed. Finally, an empirical study is conducted using mathematics and statistics. Results: The difference between the athletes was statistically significant (P<0.05). There were significant differences in athletic ability, physical attractiveness, and body mass among the special exercises for athletic ability (P<0.05). Conclusion: The methods for improving physical quality in male and female athletes were successful in athletes of different disciplines. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

STRENGTH TRAINING METHOD FOR TENNIS PLAYERS

ABSTRACT Introduction: Tennis is highly technical, and any error in its players’ strength training can exponentially impact the competition. A timely review and analysis of tennis players’ biomechanics will help to better understand the training system and reveal the basis for future scientific sports training strategies. Objective: Analyzes the effect of different strength training methods to design the best protocol considering tennis players’ speed and success rate. Methods: The effect of training on 40 tennis players is discussed. The volunteers were divided into the experimental and control group. The experimental group performed strength training for 40 minutes daily, thrice a week. The control group continued with conventional training. The trial lasted eight weeks. The speed and success rate of the training were tested before and after the experiment. Results: The experimental group players significantly improved serve speed (P<0.05). The success rate of the experimental group was also significantly improved (P<0.05). Conclusion: The proposed strength training significantly improved the success rates of speed in tennis players. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Relationship between Physical Performance, Anthropometric Measurements and Stroke Velocity in Youth Tennis Players

Given that serve velocity has been identified as one of the most important components influencing performance in tennis, identifying the factors associated with serve velocity is crucial for coaches and athletes. The aim of this study was to describe the relationship between physical performance, anthropometric characteristics and stroke velocity in youth tennis players. Twenty-seven youth players (male = 16, age = 15.69 ± 1.70 years; female = 11, age = 15.82 ± 1.40 years) underwent an anthropometric and physical performance assessment. On a tennis court, players were assessed for forehand, backhand and serve velocities. Pearson's correlation coefficient revealed that forehand velocity was significantly correlated with height (r = 0.58) and handgrip strength (right hand: r = 0.68; left hand: r = 0.57), whereas backhand velocity was significantly correlated with running time (r = 0.52) and handgrip strength (right hand: r = 0.67; left hand: r = 0.55) in males. Similarly, in males, serve velocity was significantly correlated with height (r = 0.60), running time (r = 0.62) and handgrip strength (right: r = 0.77, left hand: r = 0.71). In females, a significant correlation was only demonstrated between serve velocity and body weight (r = 0.69). These findings highlight that handgrip strength, running time and body height variables are positively associated with stroke velocities in male youth tennis players.

METHODS OF CORE STRENGTH TRAINING IN COLLEGE TENNIS PLAYERS

ABSTRACT Introduction Core strength training is essential for maintaining postural stability and explosive movement support, typical of tennis players. It has been proven that core strength training improves the motor coordination of the athlete’s whole body. Therefore, it is essential to develop specific approaches to strengthen the core in tennis players. Objective Analyze the effect of core strength training in college tennis players. Methods Twenty college tennis players were selected and randomly divided into two groups: core strength training and general training. Comparative results of the experiment were statistically processed for analysis on the effect of core strength training versus general strength training. Results There is a big difference in the level of fitness indicators before and after 14 weeks of core strength training (P < 0.05). The average gain in training speed of the athletes in the experimental group was 8.24% versus 1.05% in the control group. Conclusion Core strength training can improve the physical fitness of tennis players. Complementary core strengthening training can favor performance in matches and competition results. Evidence level II; Therapeutic Studies - Investigating the results.

Determinant Physical Factors of Tennis Serve Velocity: A Brief Review

PURPOSE

To review the main physical aspects that could positively or negatively influence serve velocity (SV).

METHODS

An examination of existing literature including studies analyzing positive (biomechanical aspects, anthropometrics, range of motion, strength, and power) and negative (competition-induced fatigue) associations to SV are summarized in this review.

RESULTS

Aspects such as lower-leg drive, hip and trunk rotations, upper-arm extension, and internal rotation seem to be the major contributors to racquet and ball speed. Favorable anthropometric characteristics, such as body height, arm length, and a greater lean body mass, seem to positively influence SV. Also, strength indicators such as maximal isometric strength and rate of force development in specific joint positions involved in the kinetic chain alongside upper-body power seem to be related to faster serves. On the other hand, the effects of prolonged or repetitive match play may impair the aforementioned factors and negatively influence SV.

CONCLUSIONS

Following specific serving models that seem to enhance velocity production and efficient motion is highly recommended. Moreover, achieving a higher impact point, alongside shifting body composition toward a greater lean body mass, will most likely aid toward faster serves. Programs aiming at improving maximal isometric strength and rate of force development in specific positions involved in the kinetic chain including stretch-shortening cycle predominance and the mimicking of the serve motion seem of great interest to potentially increase SV. Effective recovery and monitoring of these variables appear to be essential to avoid impairments produced by continued or repetitive competition loads.

Grip position affects upper limb kinematic chain during tennis double-handed backhand topspin strokes: considerations for transitioning tennis grip position technique

The purpose of this study was to compare the upper limb kinematic chain of tennis players using either an eastern or continental non-dominant grip position during the forward swing of the double-handed backhand stroke. Sixteen right-handed tennis players performed backhands using two non-dominant grip positions (eastern and continental), aiming for two cross-court zones (deep and short). Trajectory data were captured using sixty reflective markers attached to the upper limb and racket using a 12-camera Vicon motion capture system (250 Hz). Peak angular velocity was significantly greater for multiple joint rotations at the dominant shoulder and entire non-dominant limb in the eastern grip. Subsequently, greater peak racket head angular velocity and post-impact ball speed were generated by the eastern grip, while shot accuracy was similar between grip types. There was delayed dominant shoulder peak adduction angular velocity for the continental grip, possibly due to a lack of skill familiarity causing changes in coordinative patterns. Collectively, the non-dominant grip position appears to influence proximal and distal upper limb movement. Future research should explore upper limb segment coordination comparing preferred and non-preferred double-handed backhand techniques and complete inter-disciplinary investigations to understand what grip positions are most effective for individuals to learn double-handed backhands.

Relationship between isometric force-time curve variables and serve velocity in young tennis players

This study aimed to investigate the associations between serve velocity (SV), maximal absolute and relative isometric voluntary contraction (MVC and RMVC), peak rate of force development (PRFD), rate of force development (RFD) and impulse (IMP) at different stages of contraction (≤200 ms). Sixteen players performed four maximum isometric tests in positions involved in the tennis serve motion. Variables tested included MVC, PRFD, RFD and IMP at 50, 100, 150 and 200 ms while performing a 90º shoulder internal rotation (SHIR), shoulder flexion (SHF), horizontal shoulder abduction (SHABD) and an isometric mid-thigh pull (IMTP). Significant (p ≤ 0.05) moderate-to-very-large correlations were found between SV, MVC and PRFD. RFD at different time intervals showed positive associations with SV, except in the SHF0-200 ms and IMTP0-200 ms. Accordingly, IMP values positively correlated with SV in all positions except in the SHIR0-50 ms and the IMTP in late contraction stages. Results indicate that the combination of maximum isometric strength in several body positions involved in the serve kinetic chain alongside RFD and IMP in short periods of time (≤200 ms) positively influences SV in young participants.

Physical fitness and stroke performance in healthy tennis players with different competition levels: A systematic review and meta-analysis

Differences in variables of physical fitness and stroke performance by competition level (i.e., elite vs. sub-elite players) have not been systematically investigated yet. Thus, the objective of the systematic review with meta-analysis was to characterize and quantify competition-level dependent differences in physical fitness and stroke performance in healthy tennis players. A systematic literature search was conducted in the databases PubMed, Web of Science, and SportDiscus from their inception date till May 2022. Studies were included if they investigated healthy tennis players and reported at least one measure of physical fitness (e.g., lower extremity muscle power, endurance, agility, speed) or stroke performance (e.g., stroke velocity). Weighted standardized mean differences (SMD) were calculated and reported according to their magnitude. The search identified a total of N = 12,714 records, 16 of which met the inclusion criteria. Competition-level dependent differences in physical fitness and stroke performance were investigated by 11 and 10 studies, respectively. For physical fitness, moderate (lower extremity muscle power: SMD = 0.53; endurance: SMD = 0.59; agility: SMD = 0.54) and small (speed: SMD = 0.35) effects were detected; all in favour of elite tennis players. However, sub-group analyses revealed an influence of players’ age showing higher SMD-values for adult than for young players. Further, a large effect (SMD = 1.00) was observed for stroke performance again in favour of elite tennis players. Lastly, a larger but not significantly different association between physical fitness and stroke performance was observed for elite (r = 0.562) compared to sub-elite (r = 0.372) tennis players. This systematic review and meta-analysis revealed better physical fitness and stroke performances in healthy elite compared to sub-elite tennis players. The greatest differences by competition level were shown in measures of lower extremity muscle power, endurance, and agility. Thus, training programs for sub-elite tennis players should place a special focus on these physical components.

Physical Fitness and Upper Limb Asymmetry in Young Padel Players: Differences between Genders and Categories

This study aimed to assess the physical fitness and upper body asymmetries of young padel players aged between 13 and 16 years and to determine the possible differences between genders and categories. A total of 60 padel players were divided into four groups: under-14 male (n = 15; age: 13.75 ± 0.45 years; height: 1.64 ± 0.07 m; weight: 54.7 ± 8.3 kg), under-14 female (n = 15; age: 13.75 ± 0.44 years; height: 1.60 ± 0.05 m; weight: 51.5 ± 6.0 kg), under-16 male (n = 15; age: 15.44 ± 0.51 years; height:1.71 ± 0.04 m; weight: 63.88 ± 6.2 kg) and under-16 female (n = 15; age:15.46 ± 0.52 years; height:1.63 ± 0.05 m; weight: 55.08 ± 3.6 kg). Handgrip strength, ischiosural flexibility, gestural speed of the dominant arm, vertical jump, cardiorespiratory capacity, lateral movement, lateral acceleration and reaction time were measured. Male players showed better results in manual grip strength, vertical jump power, cardiorespiratory capacity and lateral movement (p < 0.05). Moreover, males presented a higher percentage of asymmetry in upper limb strength. Female players showed better reaction time and greater flexibility (p < 0.05). Regarding the differences between categories, the under-16 players showed greater flexibility, gestural speed, vertical jump power, cardiorespiratory capacity and lateral movement compared to the under-14 players. These results can be used as reference values for coaches/physical trainers of younger categories to improve health control and physical performance planning.

Prediction of Service Performance Based on Physical Strength in Elite Junior Tennis Players

In tennis, service requires a variety of complicated movements. Given the importance of taking the initiative to obtain points in a tennis match, it is crucial to make full use of speed and spin rate of service. Generally, a service that requires a higher spin rate would slow down, and a service that has increased speed would have a decreased spin rate. For players who are disadvantaged in height, although controlling spin rate is essential, slowing down service speed should be avoided. For these players, the challenge of service is to improve the speed without decreasing the spin rate. Players must also be trained to build physical strength required for this skill. It is not uncommon to work on physical training without a racket; however, few studies have reported on the effects of cultivated physical strength on on-court tennis performance. Therefore, this study aimed to propose physical measurements that could be used as indices to improve service performance in 58 elite Japanese junior male players. To test service performance, we used TrackMan tennis radar device to assess speed, spin rate, impact height, and impact depth. To test physical strength, we measured 5- and 20-m sprint, broad jump, medicine ball throw (forward, backward). We used a significant multiple regression equation to predict the first service speed obtained from the broad jump and the Medicine ball throw (backward). Additionally, a strong correlation was obtained between the predicted and measured values. In addition to physical strength, we suggest that the depth of the impact point (taking the hitting point forward toward the net) is important for improving the first service speed. However, we were not able to identify the physical strength test items that improve service spin rate. Other item should be examined in the future to determine the physical strength associated with spin rate. This result could help connect physical training and service performance.

Physical Education Teaching Strategy under Internet of Things Data Computing Intelligence Analysis

Racket sports such as tennis are amongst the most popular recreational sports activities. Optimizing tennis teaching methods and improving teaching modes can effectively improve the teaching quality of tennis. In this study, a video and image action recognition system based on image processing techniques and Internet of things is developed to overcome the shortcomings of the traditional tennis teaching methods. To validate its performance, the students of tennis courses are divided into experimental group and control group, respectively. The control group is taught by using the traditional tennis teaching method whereas the experimental group is taught by using the IoT video and image recognition teaching system. Three factors of students including service throwing height, arm elbow angle, and knee bending angles of both groups are measured and compared with those of world elite tennis players. The results show that the students' serving abilities in the experimental group are significantly improved using the video and image recognition system based on IoT, and they are better than those of the students in the control group. The proposed video and image processing technique can be applied in students' physical education and can be employed to provide the basis for the innovation of tennis teaching strategies in physical education.

Impact of HIIT Sessions with and without Cognitive Load on Cortical Arousal, Accuracy and Perceived Exertion in Amateur Tennis Players

The aim of the present study was to investigate the effects of high-intensity interval training (HIIT) exercises, with and without cognitive load, on the accuracy, critical flicker fusion threshold (CFFT), and rating of perceived exertion (RPE) on recreational tennis players. A total of 32 players of tennis at recreational level (25 men and 7 women) were enrolled in this cross-sectional the study. Participants had to perform, randomly, two HIIT sessions. In one of them, cognitive load was induced by conducting an incongruent Stroop during rests. After training accuracy of tennis serve, CFFT, and RPE were measured. Results showed that accuracy after baseline and HIIT without cognitive load were significantly higher than after HIIT with cognitive load. RPE significantly increased (p-value < 0.001) after HIIT sessions in both, with and without cognitive load. However, significant differences were not observed between the two sessions in the RPE (p-value = 0.405). Furthermore, differences were not obtained in the CFFT neither within nor between sessions (p-value > 0.05). Therefore, HIIT with and without cognitive load increased the RPE in recreational tennis players. Furthermore, HIIT sessions with cognitive load significant altered tennis serve accuracy.

Fitness testing in tennis: Influence of anthropometric characteristics, physical performance, and functional test on serve velocity in professional players

The aims of this study were to examine the relationship between anthropometric variables, physical performance, and functional test with serve velocity regarding tennis players’ level and to design regression models that effectively predict serve velocity. A sample of sixteen male tennis players participated in this study (national level = 8, professional level = 7). Anthropometric measurements (body mass, height, body mass index and body segments) and physical test (hand strength, countermovement jump, jump on serve, and serve velocity) and functional test (medicine ball throw overhead and shot put) were performed. No differences in anthropometrics and physical test were found between national and professional levels. A significant positive correlation (p < 0.05, ranging for 0.603 to 0.932) was found between some anthropometrics measurements (body mass, height, arm, forearm, and leg segments), physical parameters (hand strength, countermovement jump) and functional test (medicine ball throw shot put and overhead) with serve velocity for all tennis players. Multiple regression analysis indicated that medicine ball throw shot put was the most important test to explain serve velocity (r² = 0.869). The results showed how the combination of physical and anthropometric factors have an impact on serve velocity. In addition, a new functional fitness test (medicine ball throw shot put) is proposed as an alternative to traditional medicine ball throw overhead due to its high reproducibility (inter-trial reliability) and predictive validity values, as well as by multi-segmental coordination movement similar to tennis serve.

Shoulder Range of Motion, Rotator Strength, and Upper-Extremity Functional Performance in Junior Tennis Players

PURPOSE

Repetitive and asymmetric movements in tennis can result in biomechanical adaptation in shoulder joint. The aim of this study was to investigate the differences in shoulder range of motion (ROM), strength, and functional performance tests between the dominant and nondominant shoulders, as well as to identify gender differences in junior tennis players.

METHODS

Forty-two junior tennis players (age mean: 11.3 [1.2] y, body mass index 18.3 [2.4] kg/m2) were included in the study. Shoulder internal rotation (IR), external rotation (ER) ROM, and total ROM, IR and ER isokinetic strength and closed kinetic chain upper-extremity stability, seated medicine ball throw used, grip hold tests were applied bilaterally. Paired sample t test and Student t test were used to compare the differences.

RESULTS

ER ROM was greater, while IR ROM and total ROM were lower on the dominant shoulder (all P values < .05). Nineteen players had glenohumeral IR deficit (IR ROM difference >13°). The players had a greater ER strength on the dominant side and similar IR strength between shoulders. There was significant difference in seated medicine ball throw results between the dominant and nondominant sides (P < .001). The mean distance for bilateral seated medicine ball throw was 377.02 (85.70) m, and closed kinetic chain upper-extremity stability results were calculated as a mean of 15.85 (1.72) touches. Differences between the genders: total ROM of the dominant shoulder was higher in female players (P = .045), the IR PT/BW at 60°/s angular speed was higher in male players' dominant shoulder (P = .030), and closed kinetic chain upper-extremity stability performance was higher in male players (P = .019).

CONCLUSIONS

Adolescent tennis players demonstrated differences in strength, ROM, and functional performance results between the dominant and nondominant shoulders. Gender differences were also seen in the aforementioned parameters in junior tennis players. Determining these differences may improve our understanding of sport-specific shoulder joint adaptations in tennis.

The Effects of Knee Flexion on Tennis Serve Performance of Intermediate Level Tennis Players

This study aimed to investigate the effects of knee flexion during the preparation phase of a serve on the tennis serve performance, using inertial sensors. Thirty-two junior tennis players were divided into two groups based on their maximum knee flexion during the preparation phase of serve: Smaller (SKF) and Greater (GKF) Knee Flexion. Their racket velocity, racket height, and knee extension velocity were compared during the tennis serve. Inertial sensors tracked participants’ shank, thigh, and racket motions while performing five first, flat, and valid serves. Knee flexion was analysed during the preparation phase of serve, knee extension velocity after this phase, racket velocity just before ball impact, and racket height at impact. Pre-impact racket velocity (mean difference [MD] = 3.33 km/h, p = 0.004) and the knee extension velocity (MD = 130.30 °/s, p = 0.012) were higher in the GKF than SKF; however, racket impact height was not different between groups (p = 0.236). This study’s findings support the importance of larger knee flexion during the preparation phase of serve-to-serve performance. This motion should be seen as a contributor to racket velocity.

An Enhanced Joint Hilbert Embedding-Based Metric to Support Mocap Data Classification with Preserved Interpretability

Motion capture (Mocap) data are widely used as time series to study human movement. Indeed, animation movies, video games, and biomechanical systems for rehabilitation are significant applications related to Mocap data. However, classifying multi-channel time series from Mocap requires coding the intrinsic dependencies (even nonlinear relationships) between human body joints. Furthermore, the same human action may have variations because the individual alters their movement and therefore the inter/intraclass variability. Here, we introduce an enhanced Hilbert embedding-based approach from a cross-covariance operator, termed EHECCO, to map the input Mocap time series to a tensor space built from both 3D skeletal joints and a principal component analysis-based projection. Obtained results demonstrate how EHECCO represents and discriminates joint probability distributions as kernel-based evaluation of input time series within a tensor reproducing kernel Hilbert space (RKHS). Our approach achieves competitive classification results for style/subject and action recognition tasks on well-known publicly available databases. Moreover, EHECCO favors the interpretation of relevant anthropometric variables correlated with players’ expertise and acted movement on a Tennis-Mocap database (also publicly available with this work). Thereby, our EHECCO-based framework provides a unified representation (through the tensor RKHS) of the Mocap time series to compute linear correlations between a coded metric from joint distributions and player properties, i.e., age, body measurements, and sport movement (action class).

Gender Differences in Physical Fitness Characteristics in Professional Padel Players

The aims of the present study were to examine the fitness characteristics of professional padel players and to determine differences in physical performance regarding players' gender. Thirty professional padel players (men: n = 15, age = 27.4 ± 6.8 years, height = 177.9 ± 4.0 cm; women: n = 15, age = 30.0 ± 4.2 years, height = 166.6 ± 4.8 cm) completed a 4-day evaluation process, including: isometric handgrip strength, sit and reach, 10 × 5 shuttle test, countermovement jump (CMJ), squat jump (SJ), Abalakov test, one-repetition maximum test (bench press, leg extension, leg curl, lat pulldowns, overhead press, and shoulder press), anthropometry and VO2 max tests. The men players had higher values in terms of weight, height, one maximum repetition, jump tests (CMJ and ABK) and VO2 max test than the women (p < 0.005). By contrast, the women had higher values for fat mass (p = 0.005; ES: 2.49). The values from this multifaceted test battery can be a useful guide for coaches regarding players' development in future evaluations and monitoring.

Key Physical Factors in the Serve Velocity of Male Professional Wheelchair Tennis Players

The aim of this study was to identify the physical factors related to serve speed in male professional wheelchair tennis players (WT). Nine best nationally-ranked Spanish male wheelchair tennis players (38.35 ± 11.28 years, 63.77 ± 7.01 kg) completed a neuromuscular test battery consisting of: isometric handgrip strength; serve velocity; 5, 10 and 20 m sprint (with and without racket); agility (with and without racket); medicine ball throw (serve, forehand and backhand movements); and an incremental endurance test specific to WT. Significantly higher correlations were observed in serve (r = 0.921), forehand (r = 0.810) and backhand (r = 0.791) medicine ball throws showing a positive correlation with serve velocity. A regression analysis identified a single model with the medicine ball throw serve as the main predictor of serve velocity (r² = 0.847, p < 0.001). In conclusion, it is recommended that coaches and physical trainers include medicine ball throw workouts in the training programs of WT tennis players due to the transfer benefits to the serve speed.

The value of technical characteristics for future performance in youth tennis players: A prospective study

The aim of this study is to examine whether technical characteristics predict current and future tennis performance of youth tennis players. Twenty-nine male youth tennis players (age 13.40 ± .51) were assessed on anthropometrical characteristics (height, weight, maturity status) and technical characteristics (ball speed, accuracy and percentage errors) using an on-court tennis test when they were under-14 (U14). Game situations were simulated, which were either fixed or variable. The variable game situations required players to consider the direction of the ball, as opposed to the fixed game situations where players needed to play every ball to the same side. Players’ tennis ratings were obtained U14 (‘current performance’) and under-18 (U18) (‘future performance’). According to their rating U18 players were classified as future elite (n = 9) or future competitive (n = 20). A multiple linear regression analysis showed that ball speed and accuracy were significant predictors of current and future performance (p < .001), with R² of .595 and .463, respectively. When controlling for age, a one-way MANCOVA revealed that future elite players were more accurate than future competitive players (p = .048, 95% CI [.000 to .489]), especially in variable compared to fixed game situations (p < .05). In conclusion, the current study is the first to show that technical characteristics are crucial for current as well as future performance in youth male tennis players. Findings of this prospective study provide essential information to coaches about characteristics that require most attention in performance development in youth players.

Effects of in-play cooling during simulated tennis match play in the heat on performance, physiological and perceptual measures

BACKGROUND

The aim of this crossover study was to investigate whether a cooling intervention during simulated tennis match play in the heat could affect players' performance, physiology, perception of effort, and well-being.

METHODS

Eight competitive male tennis players performed two testing sessions of 45-minute simulated tennis match play on a hard court at 31.8±2.1°C and 48.5±9.6% relative humidity. During change-of-end breaks, the cooling interventions (COL) consisted of cold-water ingestion (ad libitum) and an electric fan facing the players at a distance of 1 m combined with an ice-filled damp towel around the neck and on the thighs or no cooling (CON) were applied. Measures of performance, heart rate, blood lactate concentration, tympanic and local skin temperature, sweat loss, perceived exertion, and thermal sensation as well as ratings of recovery were recorded in both sessions.

RESULTS

Paired-samples t-tests showed no significant differences (P>0.05) in any of the measures between COL and CON. Effect size (ES) calculations indicated moderate evidence that COL was beneficial to local skin temperature (ES=-0.95) and thermal sensation (ES=-0.77). At the individual level, a positive response to COL was found in some players for heart rate, local skin temperature, thermal sensation, and ratings of recovery.

CONCLUSIONS

A likely inability of COL to improve players' performance or reduce thermal strain during tennis match play in hot humid conditions was found at the group level. However, some players may be more likely to benefit from COL. Therefore, the use of COL should be individualized.

Influence of Strength, Power, and Muscular Stiffness on Stroke Velocity in Junior Tennis Players

Objective

The main aim of this study was to establish the relationship between strength, power characteristics, individual muscle stiffness, international tennis number (ITN), and stroke velocity (StV) in junior tennis players.

Methods

Twenty one junior male tennis players (mean ± SD; age, 17.0 ± 0.8 years; height, 1.8 ± 0.1 m; body mass, 72.3 ± 5.8 kg; BMI 22.1 ± 1.5 kg/m²), with an ITN ranging from 2 to 4, performed measurements regarding muscle stiffness of selected muscles involved in tennis strokes. StV (serve, forehand, and backhand), strength (maximum isometric strength) and power (medicine ball throws, squat jump, countermovement jump, and bench press) measurements were also performed (ICC = 0.803–0.998; CV = 0.3–6.4).

Results

Moderate inverse correlations were found between serve velocity (SV) and ITN (r = −0.43; p = 0.05), and large positive correlations were observed between pectoralis majoris stiffness (PMStiff) (r = 0.53; p = 0.01), isometric wrist flexion (r = 0.58; p = 0.006) and ITN, respectively. PMStiff was moderately inversely correlated to forehand velocity (FV) (r = −0.45; p = 0.03) and gastrocnemius (GStiff) and infraspinatus stiffness (IStiff) positively to SV (r = 0.45; p = 0.04; r = 0.42; p = 0.05). No significant correlations were found regarding strength and power measurements.

Conclusion

Greater stiffness values may enhance StV, especially when transferring power from lower to upper body. On the other hand, high scores could interfere in technical parameters that are key for velocity production in complex tennis strokes. Strength and power values proved to correlate poorly to StV in this particular sample of junior tennis players, possibly due to the multifactorial nature of tennis strokes and the possibility that they become more important as age and level increase.

Change of Direction Performance in Young Tennis Players: A Comparative Study Between Sexes and Age Categories

Fernandez-Fernandez, J, Loturco, I, Pereira, LA, Del Coso, J, Areces, F, Gallo-Salazar, C, and Sanz-Rivas, D. Change of direction performance in young tennis players: a comparative study between sexes and age-categories. J Strength Cond Res XX(X): 000-000, 2019-The aim of this study was to examine the differences in linear sprint, change of direction (COD) performance, and COD deficit in a large sample of under-13 (U13) and under-15 (U15) male and female tennis players. One hundred and twenty-eight junior tennis players grouped into 2 age-groups (U13 years [32 boys and 28 girls] and U15 [36 boys and 32 girls]) participated in this study. Tests included anthropometric measurements, sprints (5-, 10- and 20-m), and a modified version of the 505 COD test. The differences in performance between age-categories and sex were assessed via an independent t-test. The differences in the physical tests between U13 and U15 players were tested using a univariate analysis, with age and anthropometric variables as covariates. Effect sizes (ESs) were calculated for pairwise comparisons. Results showed that boys presented lower 20-m sprint times than girls in the U13 (ES: 0.54; p < 0.05), and lower linear sprint (5-20-m) and COD times than girls in the U15 category (ES varying from 0.67 to 1.60; p < 0.05). Comparing age-groups, U15 girls demonstrated a higher COD deficit than the U13 (p < 0.05), whereas no differences were found in the other variables. In boys, no significant differences were observed in any variable when comparing both categories. These results could be of great interest for coaches and researchers involved in the development and training of elite tennis players, suggesting the need to include strategies able to improve sprint and COD performance throughout the players' specialization process.

Age and sex-related upper body performance differences in competitive young tennis players

Objective

The aims of this study were to analyze the shoulder functional profile of young male and female tennis players and to establish the relationship among physical variables and serve speed.

Methods

A total of 128 Spanish tennis players (Under-13 (n = 32/32 males/females) and Under-15 (n = 36/28 males/females), were tested during National training camps. Tests included passive shoulder range of motion (ROM) for both internal (IR) and external rotation (ER) and isometric strength (i.e., IR and ER) of the dominant/non-dominant shoulders, medicine ball throws (MBT), and serve speed. Age and sex pairwise comparisons were carried using the Hedges’ g index (d_g).

Results

Results showed age and sex effects on serve speed and all MBT, with males showing greater changes (1.51≤d_g≤1.98) with age than females (0.92≤d_g≤1.35; p<0.05). U15 males showed higher (p<0.05) absolute shoulder IR and ER strength than U13, with only significant differences between males and females in the U15. Regarding ROM, U15 males showed a decreased IR ROM compared to U13 (d_g = -0.84; p<0.05) and higher significant IR bilateral deficit (d_g = 0.51; p<0.05). The distances obtained in the different MBT were the variables more correlated to serve speed.

Conclusion

The present results suggest that shoulder strength, medicine ball throws and serve speed increased along with age in young elite tennis players of both sexes. However, a decreased range of motion and bilateral deficit for glenohumeral internal rotation is evident in male under-15 tennis players. Muscle strength, power and shoulder range of motion are key factors for serve speed in young tennis players.