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

Preliminary Application of Infrared Thermography to Monitoring of Skin Temperature Asymmetries in Professional Padel Players

The aim of the present study was to evaluate skin temperature (Tsk) asymmetries, using infrared thermography, in professional padel players before (PRE), after (POST) and 10 min after training (POST10), and their relationship with perceptual variables and training characteristics. Thermal images were taken of 10 players before, after and 10 min after a standardized technical training. After training, Tsk of the dominant side was higher than before training in the anterior forearm (30.8 ± 0.4 °C vs. 29.1 ± 1.2 °C, p < 0.01; ES = 1.9), anterior shoulder (31.6 ± 0.6 °C vs. 30.9 ± 0.6 °C, p < 0.05; ES = 1.0) posterior arm (29.5 ± 1.0 °C vs. 28.3 ± 1.2 °C, p < 0.05; ES = 1.0), and posterior forearm (30.8 ± 0.9 °C vs. 29.3 ± 1.6 °C, p < 0.05; ES = 1.1). Likewise, these differences were significant POST10 in the anterior arm, anterior forearm, anterior shoulder, posterior arm and posterior forearm. Comparing the different moments of measurement (PRE, POST and POST10), the temperature was higher POST10 in all the regions analyzed except for the shoulder, abdominals, and lower back. Also, correlations were found between fatigue variation and temperature variation between limbs (Tsk dominance), and no correlation was found except between age and posterior thigh (|r| = 0.69; p < 0.05), and between the racket mass and anterior knee (|r| = 0.81; p < 0.01). In conclusion, infrared thermography allows monitoring of skin asymmetries between limbs in professional padel players, but these asymmetries were not related to overall fatigue variation, overall pain variation, years of experience and training hours.

Effects of a 6-week on-court training program on the International Tennis Number (ITN) and a range of physical fitness characteristics in young tennis players

The study aimed to (i) verify the effects of an on-court training program on the International Tennis Number (ITN) of young tennis players, as well as on a set of change of direction, linear sprint, and maximal oxygen uptake (VO2max) variables, and (ii) identify the main predictors of ITN. The sample consisted of 20 young male tennis players (mean age, 13.62 ± 0.23 years). Players underwent a 6-week on-court training program. The ITN and a number of change of direction variables (T-drill and repeated sprint ability), linear sprint (5 m, 10 m, and 20 m distances), and VO2max were measured. All variables improved significantly between the pre- and posttest (p < 0.001). The ITN (7.98 ± 6.06%, d = 0.82) and VO2max (6.77 ± 1.21%, d = 1.53) showed the greatest relative improvement with moderate to large effect sizes. The hierarchical linear model retained the time (estimate = 18.90, p < 0.001) and the T-drill (estimate = -64.77, p < 0.001) as significant predictors of the ITN. This indicates that the ITN improved significantly over the 6-week training program and that the T-drill test was the best and most significant predictor. Coaches and researchers are encouraged to monitor the ITN along with other physical fitness and technical variables. They can also use the T-drill test to understand the ITN of their players.

Upper extremity soft tissue stiffness measured with shear wave elastography: A between-day reliability study

Background

Imbalances in soft tissue stiffness (STS) of the pectoralis and common wrist extensors (CWEs) can adversely alter upper extremity function. Shear wave elastography (SWE) has the capacity to provide precise, repeatable, objective data on STS. The purpose of this study was to determine the between-day intrarater reliability for the pectoralis and CWE tendon stiffness as measured by SWE.

Methods

STS measured by the shear wave modulus (kilopascals (kPa)) was captured bilaterally on the pectoralis major, pectoralis minor, and CWE tendon using 2D SWE ultrasound imaging (GE Logiq S8, 9 L transducer) on two separate days. Within examiner intraclass correlation coefficients (ICC (3, 3)) with 95% confidence intervals, standard error of the measure, and minimal detectable changes were calculated.

Results

The investigators recruited 10 healthy participants (mean age = 23.50  ±  1.43). Between day intrarater reliability values were obtained for the dominant pectoralis major ICC  =  0.70 (-0.15, -0.93), nondominant pectoralis major ICC  =  0.63 (-0.30, -0.91), dominant pectoralis minor ICC  = 0 .72(-0.04, -0.93), nondominant pectoralis minor ICC  = 0.75(0.08, -0.94), dominant CWE tendon ICC  =  0.75(-0.08, -0.94), and nondominant CWE tendon ICC  =  0.75(-0.12, -0.94).

Discussion

Our data demonstrate acceptable reliability but future studies should include methods that control for variables known to effect STS.

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.

Common Wrist-Extensor Tendon and Pectoralis Muscle Stiffness in Healthy Recreational Tennis Players

CONTEXT

Imbalances in upper-extremity soft tissue stiffness may play a role in the development of shoulder and elbow musculoskeletal injuries in tennis players. Ultrasound shear wave elastography provides quantifiable and specific data regarding muscle stiffness. The purpose of this study was to compare tendon and muscle stiffness in healthy tennis players to nontennis players.

DESIGN

Cross-sectional study.

METHODS

The shear wave modulus, measured in kilopascals, was obtained for the dominant pectoralis major, pectoralis minor, and common wrist-extensor tendon using 2-dimensional shear wave elastography ultrasound imaging (GE Logiq S8, L9 linear transducer). Independent t test was run to compare age, body mass index, and the activity index score between both groups. Within-day intrarater reliability was assessed using a within-examiner intraclass correlation coefficients (ICC [3, 1]) with 95% confidence intervals. A multivariate general linear model was run to compare the mean differences between the tennis and nontennis players for each of the soft tissues.

RESULTS

Twenty-six individuals (13 tennis players and 13 nontennis players) were recruited. Within-day ICCs were very good (ICC > .78 for the pectoralis musculature) and excellent (ICC > .94 for the common wrist extensor). Common extensor tendon stiffness was significantly higher in tennis players compared to nontennis players (mean difference = 114.8 [61.8], confidence interval, -22.8 to 252.5 kPa for the dominant arm [P = .039]). Mean pectoralis major and minor stiffness differences were not significant (P > .214).

CONCLUSIONS

Common wrist-extensor stiffness in healthy recreational tennis players is higher than those who do not play tennis. Therefore, clinicians may need to facilitate a greater soft tissue stiffness response with resistance training when rehabilitating recreational tennis players as compared to those not playing tennis. Additional normative data on a larger sample of recreational tennis players should be collected.

Biophysical characterization of the tennis serve: A systematic scoping review with evidence gap map

OBJECTIVES

We aimed to assess the available evidence on the biophysics of the tennis serve, mapping the populations, interventions, contexts and other relevant information to highlight what is already known and to identify gaps in the literature.

DESIGN

Systematic scoping review with evidence gap map.

METHODS

The protocol was designed according to PRISMA 2020, Prisma-ScR guidelines and the Cochrane Handbook. The searches were conducted on July 20, 2022 and updated on April 1, 2023, in PubMed, Scopus and Web of Science (core collection). The risk of bias assessment was performed using the Cochranes method for nonrandomized studies (RoBANS) and a narrative synthesis of the main findings was performed and supplemented with an evidence gap map.

RESULTS

Most trials were found on serve kinematics and kinetics (95 %), analyzing only flat serves (84 and 72 %, respectively). Few trials focused on physiology (20 %; e.g. biomarkers), under-19, left or both-handed, female and intermediate beginner or starter players (29, 17, 8 and 7 %, respectively). We found a preponderance of low and unclear risk of bias (63 and 31 %, respectively) and only 7 % high, particularly, on the assessment of confounding variables.

CONCLUSIONS

The current scoping review reveals a few trials on physiological rather than biomechanical variables, as well as the absence of the kick and slice serve, foot-back and foot-up serve, and left-handed, female, and young player analyses. We did not find systematic mistakes or limitations in the design, conduct, or analysis that would distort the results, since only 7 % presented a high risk of bias.

Objective Methods of Muscle Tone Diagnosis and Their Application-A Critical Review

"Muscle tone" is a clinically important and widely used term and palpation is a crucial skill for its diagnosis. However, the term is defined rather vaguely, and palpation is not measurable objectively. Therefore, several methods have been developed to measure muscle tone objectively, in terms of biomechanical properties of the muscle. This article aims to summarize these approaches. Through database searches, we identified those studies related to objective muscle tone measurement in vivo, in situ. Based on them, we described existing methods and devices and compared their reliability. Furthermore, we presented an extensive list of the use of these methods in different fields of research. Although it is believed by some authors that palpation cannot be replaced by a mechanical device, several methods have already proved their utility in muscle biomechanical property diagnosis. There appear to be two issues preventing wider usage of these objective methods in clinical practice. Firstly, a high variability of their reliability, and secondly, a lack of valid mathematical models that would provide the observed mechanical characteristics with a clear physical significance and allow the results to be compared with each other.

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.

Influence of lower-limb muscular and tendon mechanical properties and strength on countermovement jump performance

BACKGROUND

The aim of the study is to examine the relationship between measures of muscle and tendon mechanical properties and strength on countermovement jump (CMJ) performance.

METHODS

Twenty-six physically active participants (males; N.=16: females; N.=10) were tested. Testing comprised of measuring the mechanical properties of lower limb muscles and tendons using myotonometry, isometric and isokinetic knee extensor strength through dynamometry, and CMJ's with a force platform.

RESULTS

Large positive correlations were observed between CMJ jump height and Achilles tendon stiffness (N/m) (r=0.56) and Achilles tendon tone (Hz) (r=0.553). Large negative correlations were found between CMJ height and Achilles tendon elasticity (r=-0.658), and Achilles tendon relaxation (r=-0.572), and Achilles tendon creep (r=-0.589). Large correlations (r=0.592 to 0.659) were observed between CMJ height and all measures of isometric and isokinetic dynamometry measures. Achilles tendon stiffness, elasticity level and relaxation, and isokinetic peak concentric torque (N.m) explained 63% of this variance.

CONCLUSIONS

Greater stiffness of the Achilles tendon may improve CMJ performance due to the improved transfer of concentric and eccentric force of the knee extensor muscles. Practitioners need to implement specific interventions to target increasing Achilles tendon stiffness to improve countermovement jump performance.

Influence of anthropometric, ball impact and landing location parameters on serve velocity in elite tennis competition

This study aimed (i) to analyse the associations between serve velocity (SV) and anthropometric, ball impact and landing location parameters in total serves (TS) and fastest serves (FS) performed during an ATP Tour event; (ii) to observe differences between first (S1) and second (S2) serves, and (iii) to determine a SV prediction model based on the relationship between the observed variables. Using Foxtenn technology, 30 S1 and 15 S2 were registered in 14 matches in twenty-one male professional tennis players. Ball impact (impact height [IH], impact projection angle [IPA] and relative impact height [RIH]), bounce landing (width and depth) location parameters, S1 and S2 SV in TS (TSV1 and TSV2) and FS (FSV1 and FSV2) alongside anthropometric characteristics of tennis players (body height [BH], body mass [BM] and body mass index [BMI]) were analysed. Significant moderate to large associations were found between BH and BM and TSV1, FSV1 and FSV2 (r = 0.315 to 0.593; p < 0.001), and between IH and IPA and TSV1 and TSV2 (r = 0.294 to -0.409; p < 0.001). BH and BM were the unique significant contributors of FS explaining 22 to 35% of FSV1 and FSV2. Only BM appears in the model to predict FSV1 and FSV2 (r² = 0.48 and 0.21). We concluded that all three anthropometric, ball impact and bounce landing location parameters small to moderately influence TSV. Anthropometric parameters show an impact on SV when tennis players serve at or near maximal speed, highlighting the influence of BM above BH.

Shoulder Torque Production and Muscular Balance after Long and Short Tennis Points

Tennis is an asymmetric sport characterized by a systematic repetition of specific movements that may cause disturbances in muscular strength, power, and torque. Thus, we assessed (i) the torque, power, ratio production, and bilateral asymmetries in the shoulder's external and internal rotations at 90 and 180°/s angular velocities, and (ii) the point duration influence of the above-mentioned variables. Twenty competitive tennis players performed external and internal shoulder rotations; an isokinetic evaluation was conducted of the dominant and non-dominant upper limbs before and after five and ten forehands. A higher torque production in the shoulder's internal rotations at 90 and 180°/s was observed for the dominant vs. non-dominant sides (e.g., 63.1 ± 15.6 vs. 45.9 ± 9.8% and 62.5 ± 17.3 vs. 44.0 ± 12.6% of peak torque/body mass, p < 0.05). The peak torque decreased only after ten forehands (38.3 ± 15.8 vs. 38.2 ± 15.8 and 39.3 ± 16.1 vs. 38.1 ± 15.6 Nm, respectively, p < 0.05), but without impacting speed or accuracy. Unilateral systematic actions of tennis players caused contralateral asymmetries, evidencing the importance of implementing compensatory training. The forehand kinematic assessment suggests that racket and wrist amplitude, as well as speed, are important success determinants in tennis.

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.

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.

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.

Inter-Limb Muscle Property Differences in Junior Tennis Players

The goal of this study was to investigate side-to-side differences and asymmetries regarding muscle characteristics in young tennis players. Thirty-four participants performed contractile property measurements (stiffness, tone, elasticity and time to relaxation) on the dominant and non-dominant extremities including nine muscle groups involved in the kinetic chain of main tennis strokes. Significant differences (p≤0.05) and small-to-moderate effect sizes for greater stiffness and tone were found for the dominant biceps femoris (-11.1% and -5.6%; ES=0.53 and 0.54) and the non-dominant vastus medialis (5.4% and 3.2%; ES=-0.33 and -0.41), while greater tone was present in the non-dominant pectoralis major (4.0%; ES=-0.56). Time to relaxation was increased in the dominant biceps femoris (10.3%; ES=-0.58), the non-dominant pectoralis major (5.1%; ES=-0.56) and the gastrocnemius (9.1%; ES=-0.5). The non-dominant infraspinatus and dominant rectus abdominis showed greater elasticity than contralateral muscles (9.9% and -8.0%; ES=-0.58 and 0.6, respectively). These results reflect the existence of small-to-moderate differences when comparing side-to-side values of contractile characteristics in a small amount of the muscle groups tested. However, passive measurements of a relaxed muscle do not seem to fully reflect possible adaptation and changes derived from gameplay in young tennis players.

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.

Alterations in mechanical muscle characteristics and postural control induced by tennis match-play in young players

Background

Central and peripheric fatigue indicators are among the main reasons for performance decline following competition. Because of the impact of these factors on performance, how these variables are affected by match-play could be of interest, especially in young tennis players.

Objective

This study aimed to investigate alterations induced by a simulated tennis match on postural control and muscle characteristics in young tennis players.

Method

Seventeen male junior players took part in pre- and post-competition testing sessions performing postural control (displacement, speed and surface area of center of pressures) and muscle characteristics measurements (tone, stiffness, time to relaxation and elasticity). Between trials, participants played an 80-min simulated tennis match.

Results

No significant differences were observed in any of the tested variables. Moderate-to-large effect sizes (ES) for decreased stiffness and tone and greater time to relaxation were found between pre- and post-conditions in the right rectus abdominis (−9.8%, −4.4% and 7.8%; ES = 0.8, 0.54 and −0.85). Also, a decrease in tone was found in the right vastus medialis (−7.1%; ES = 0.56), while surface area of the center of pressures with eyes open showed trends towards increasing in post-match measurements (55.9%; ES = 0.56).

Conclusion

An 80-min simulated tennis match seems insufficient to elicit significant changes in postural control and mechanical muscle characteristics. Results suggest that physiological responses triggered by match-play were closer to those seen after a moderate activity than those present following a strenuous task.

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.