Influence of racket properties on injuries and performance in tennis

Tennis Injuries Among German League Players: Investigating Patterns and Epidemiology of Acute and Chronic Injuries

Purpose

While injuries among elite tennis athletes are extensively documented, a notable research gap exists regarding tennis injuries among club-level players. This study examines tennis injuries in German league players, with a particular emphasis on the impact of racquet properties and court surfaces, distinguishing between chronic and acute injuries.

Patients and Methods

Retrospectively analyzing data from 600 tennis players over a 1.5-year period, a standardized questionnaire covered anthropometrics, injury characteristics, equipment usage, and court surface conditions.

Results

The study identified 1012 tennis-related injuries, averaging 1.7 per player. Acute injuries predominantly affected the lower extremity (56%), with ankle injuries being the most prevalent, and ligaments were the most commonly affected structures (36.4%). Chronic complaints (reported by 364 athletes) focused on the upper extremity (63.2%), primarily tendon injuries (56.8%). Racket properties exhibited no significant impact on chronic upper extremity injuries.

Conclusion

This study highlights a high incidence of acute lower extremity injuries, especially ankle ligament injuries, among German league tennis players. It offers crucial insights for devising targeted injury prevention strategies applicable to amateur, semi-professional, and professional tennis players, despite finding no significant link between racquet material and chronic upper extremity injuries.

Comparison of Grip Strength, Forearm Muscle Activity, and Shock Transmission between the Forehand Stroke Technique of Experienced and Recreational Tennis Players Using a Novel Wearable Device

Upper limb tennis injuries are primarily chronic, resulting from repetitive overuse. We developed a wearable device which simultaneously measures risk factors (grip strength, forearm muscle activity, and vibrational data) associated with elbow tendinopathy development resulting from tennis players' technique. We tested the device on experienced (n = 18) and recreational (n = 22) tennis players hitting forehand cross-court at both flat and topspin spin levels under realistic playing conditions. Using statistical parametric mapping analysis, our results showed that all players showed a similar level of grip strength at impact, regardless of spin level, and the grip strength at impact did not influence the percentage of impact shock transfer to the wrist and elbow. Experienced players hitting with topspin exhibited the highest ball spin rotation, low-to-high swing path brushing action, and shock transfer to the wrist and elbow compared to the results obtained while hitting the ball flat, or when compared to the results obtained from recreational players. Recreational players exhibited significantly higher extensor activity during most of the follow through phase compared to the experienced players for both spin levels, potentially putting them at greater risk for developing lateral elbow tendinopathy. We successfully demonstrated that wearable technologies can be used to measure risk factors associated with elbow injury development in tennis players under realistic playing conditions.

There is no rush to upgrade the tennis racket in young intermediate competitive players: The effects of scaling racket on serve biomechanics and performance

Introduction

Scaling the equipment of young athletes is justified by the constraints-led approach introduced in motor learning. The aim of the present study is to analyze the effect of racket scaling on the serve biomechanics and performance parameters for young tennis players (between 8 and 11 years-old).

Methods

Nine young intermediate competitive tennis players (age: 9.9 ± 1.0 years) performed maximal effort flat serves with three different rackets (scaled 23 inches, scaled 25 inches and full-size 27 inches) in a randomized order. A radar measured ball speed while shoulder and elbow kinetics and upper and lower limb kinematics were calculated with a 20-camera optical motion capture system. Repeated measures ANOVAs were used to analyze the effect of the three rackets on ball speed, percentage of serve in, serve kinematics and kinetics.

Results

No significant differences in ball speed, maximal racket head velocity and percentage of serve in were observed between the three rackets. The lowest maximal upper limb kinetics and the highest upper limb maximal angular velocities were obtained with the scaled 23 inches racket.

Discussion

Using scaled rackets has the advantage to decrease shoulder and elbow loadings without reducing serve performance. Consequently, the present results incite tennis coaches and parents to not upgrade too soon the size of the racket in young intermediate tennis players to avoid overuse injury risks in the long term. Our results showed that the full-size 27 inches racket induced higher lower limb kinematics. As a consequence, occasionally serving with a fullsize racket can be a sparingly interesting intervention to help young tennis players to intuitively and immediately increase their leg drive action, allowing a more functional representation of the elite junior serve.

A Scoping Review on Shoulder Injuries of Wheelchair Tennis Players: Potential Risk-Factors and Musculoskeletal Adaptations

Wheelchair tennis players are prone to develop shoulder injuries, due to the combination of wheelchair propulsion, overhead activities and daily wheelchair activities. A methodical literature search was conducted to identify articles on shoulder complaints in wheelchair tennis, wheelchair sports and tennis. The aims were to identify (1) type of shoulder complaints; (2) possible risk factors for the development of shoulder injuries; (3) musculoskeletal adaptations in the shoulder joint in wheelchair tennis players. Fifteen papers were included in this review, five on wheelchair tennis, three on wheelchair sports and seven on tennis. Type of shoulder complaints were acromioclavicular pathology, osteoarthritic changes, joint effusion and rotator cuff tears. Possible risk factors for the development of shoulder injuries in wheelchair tennis are overhead movements, repetitive activation of the anterior muscle chain and internal rotators, as well as a higher spinal cord injury level. Muscular imbalance with higher values for the internal rotators, increase in external range of motion, decrease in internal range of motion and reduced total arc of motion were the most common proposed musculoskeletal adaptations due to an unbalanced load. These presented risk factors and musculoskeletal adaptations might help researchers, coaches and wheelchair tennis players to prevent shoulder injuries.

Lateral epicondylosis: A literature review to link pathology and tendon function to tissue-level treatment and ergonomic interventions

BACKGROUND

Common treatments for lateral epicondylosis (LE) focus on tissue healing. Ergonomic advice is suggested broadly, but recommendations based on biomechanical motion parameters associated with functional activities are rarely made. This review analyzes the role of body functions and activities in LE and integrates the findings to suggest motion parameters applicable to education and interventions relevant to activities and life roles for patients.

PURPOSE

This study examines LE pathology, tendon and muscle biomechanics, and population exposure outlining potentially hazardous activities and integrates those to provide motion parameters for ergonomic interventions to treat or prevent LE. A disease model is discussed to align treatment approaches to the stage of LE tendinopathy.

STUDY DESIGN

Integrative review METHODS: We conducted in-depth searches using PubMed, Medline, and government websites. All levels of evidence were included, and the framework for behavioral research from the National Institutes of Health was used to synthesize ergonomic research.

RESULTS

The review broadened the diagnosis of LE from a tendon ailment to one affecting the enthesis of the capitellum. It reinforced the continuum of severity to encompass degeneration as well as regeneration. Systematic reviews confirmed the availability of evidence for tissue-based treatments, but evidence of well-defined harm reducing occupational interventions was scattered amongst evidence levels. Integration of biomechanical studies and population information gave insight into types of potentially hazardous activities and provided a theoretical basis for limiting hazardous exposures to wrist extensor tendons by reducing force, compression, and shearing during functional activities.

CONCLUSIONS

These findings may broaden the first treatment approach from a passive, watchful waiting into an active exploration and reduction of at-risk activities and motions. Including the findings into education modules may provide patients with the knowledge to lastingly reduce potentially hazardous motions during their daily activities, and researchers to define parameters of ergonomic interventions.

Validity and reliability of a novel monitoring sensor for the quantification of the hitting load in tennis

Wearable sensor systems are a emerging tools for the evaluation of the sport's activity and can be used to quantify the external workload of the athlete. The main goal of this paper was to evaluate the validity and reliability of the "Armbeep inertial measurement unit" (IMU) sensor both in a closed tennis exercise and in open matchplay. Twentyfour junior tennis players performed a baseline drill and played matches, during which they wore a combined accelerometer and gyroscope sensor. Video footage was concomitantly recorded using a digital video camera. The agreement between the measurements was assessed with the intraclass correlation coefficient (ICC) and the standard error of measurement (SEM). A simple linear regression was used to predict the number of shots registered from the video and from the Armbeep IMU sensor's data. The number of total forehand and backhand shots during the drill repetitions showed an excellent test and re-test reproducibility (ICC≥0.90). There was a significant relationship between the Armbeep IMU sensor's number of contacts and the total number of shots (R2 = 0.938) which indicated the excellent reliability of the tested Armbeep IMU sensor for those parameters. Considering the accuracy of the total tennis shots and the small magnitude of error for wrist speed and acceleration, the Armbeep IMU sensor appears to be an appropriate on-court tool that can be used to monitor the hitting load during tennis practice and matches.

Risk Factors for Upper Limb Injury in Tennis Players: A Systematic Review

Studies in tennis injuries have successfully identified the incident rate, the location, and the type of the injury. The majority of the studies have multiple perspectives (epidemiology, biomechanics, performance), however only a few studies were able to identify risk factors or mechanisms that contribute to tennis injuries. Until now, there has not been a systematic literature review that identifies risk factors for tennis injuries. The objective of this review was to identify and critically appraise the evidence related to risk factors for upper limb injury in tennis players. A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework, using a research question developed by the Patient Problem, (or Population) Intervention, Comparison or Control, and Outcome (PICO) methodology. The quality of the studies included was moderate to low, indicating prolonged tennis (exposure to tennis), scapular dyskinesis, muscle fatigue, scapulothoracic properties, shoulder kinetics or kinematics, skill level, and technique as risk factors for upper limb injury in tennis players. In this review, it is evidenced that the majority of tennis injuries are associated with overuse and a chronic time course, however, tennis injuries do not arise from a linear combination of isolated and predictive factors. Therefore, the multifactorial and complex nature of tennis injuries has to be further examined. The necessity of more randomized control trial studies is highly recommended.

Hand-Arm Vibration Assessment and Changes in the Thermal Map of the Skin in Tennis Athletes during the Service

During recent years the number of tennis athletes has increased significantly. When playing tennis, the human body is exposed to many situations which can lead to human injuries, such as the so-called tennis elbow (lateral epicondylitis). In this work a biomechanical analysis of tennis athletes, particularly during the service, was performed, considering three different types of over-grip and the presence of one anti-vibrator device. One part of the study evaluates the exposure to hand-arm vibration of the athlete, based on the European Directive 2002/44/EC concerning the minimum health and safety requirements, regarding the exposure of workers to risks from physical agents. The second part of the study considers an infrared thermography analysis in order to identify signs of risk of injury, particularly tennis elbow, one of the most common injuries in this sport. The results show that the presence of the anti-vibrator influences the vibration values greatly in the case of athletes with more experience and also for athletes with less performance. The presence of the Cork and/or Tourna on the racket grip does not have any significant effect on the hand-arm vibration (HAV), similarly in the case of athletes with the best performance and athletes with less technique. The results indicated that the infrared thermography technique may be used to identify the risk of injuries in tennis players.

The Effect of an Arthroscopic Orthopaedic Procedure on a Professional Tennis Player's Career

Orthopaedic injuries can significantly impact the careers of professional tennis players. It is currently unknown how professional tennis players fare after arthroscopic surgery. For the purpose of this study, players ranked in the Association of Tennis Professionals (ATP) and Women’s Tennis Association (WTA) who underwent arthroscopic surgery of any joint between 1996 and 2016 were identified through a well-established, previously published protocol of injury reports and public archives. Performance statistics both before and after surgery, time to return (TTR) to play, and career length following surgery were collected for each player. Statistical analysis was performed with significance accepted at a probability value (p) of <0.05. A total of 55 (39 males and 16 females) players met the inclusion criteria (shoulder, n = 15; elbow, n = 15; wrist, n = 13; hip, n = 12). The average age of the players at the time of surgery was 25.8 (±4) years, and the average career length before surgery was 8.4 (±4) years. Tennis players who underwent arthroscopic shoulder surgery experienced a longer TTR to play (279 days, p <0.01), as well as a greater decline in their rankings, both in the first and second years postoperatively (p <0.01 and p = 0.01, respectively), compared to all other surgical cohorts. Players who underwent surgery on the elbow, wrist, and hip had no significant decline in the ranking by the second postoperative year. There were no significant differences between genders. This study represents the largest database of professional tennis players who have undergone arthroscopic surgery and may allow physicians to provide evidence-based recommendations about expectations after surgical treatment.

PVDF Nanofiber Sensor for Vibration Measurement in a String

Flexible, self-powered and miniaturized sensors are extensively used in the areas of sports, soft robotics, health care and communication devices. Measurement of vibration is important for determining the mechanical properties of a structure, specifically the string tension in strings. In this work, a flexible, lightweight and self-powered sensor is developed and attached to a string to measure vibrations characteristics in strings. Electrospun poly(vinylidene) fluoride (PVDF) nanofibers are deposited on a flexible liquid crystal polymer (LCP) substrate for the development of the sensor. The electrospinning process is optimized for different needle sizes (0.34–0.84 mm) and flow rates (0.6–3 mL/h). The characterization of the sensor is done in a cantilever configuration and the test results indicate the sensor’s capability to measure the frequency and strain in the required range. The comparison of the results from the developed PVDF sensor and a commercial Laser Displacement Sensor (LDS) showed good resemblance (±0.2%) and a linear voltage profile (0.2 mV/με). The sensor, upon attachment to a racket string, is able to measure single impacts and sinusoidal vibrations. The repeatability of the results on the measurement of vibrations produced by an impact hammer and a mini shaker demonstrate an exciting new application for piezoelectric sensors.

Quantifying hitting activity in tennis with racket sensors: new dawn or false dawn?

The non-invasive measurement of movement through sensor technologies is common in elite sport, yet only recently become possible in tennis. This study validated two commercial tennis racquet sensors compared to gold standards in VICON and expert notational analysis. One national-level male tennis player hit 24 shots (9 forehands and 9 backhands, hit with heavy topspin, flat and slice; 6 serves) using a Babolat Play racket with a Zepp sensor. Measures of shot type, impact location and racket speed were compared against those captured by a 500-Hz 12 camera VICON system. Cohen's kappa (κ) and a weighted kappa (κ _w) assessed the accuracy of stroke classification and impact location, respectively, and intraclass correlation coefficients (ICC) validated sensor-derived racket speed. Both sensors recorded the same total stroke volume as VICON, while Zepp racket speed displayed near perfect agreement with VICON (ICC = 0.983; p < 0.001). They exhibited moderate agreement with true stroke classification (Babolat: κ = 0.730; Zepp: κ = 0.612) and minimal agreement with true impact location (Babolat: κ _w = 0.412; Zepp: κ _w = 0.217). During match play, both sensors achieved near perfect accuracy for stroke volume but experienced difficulty discriminating the different stroke types. In sum, the Babolat Play and Zepp determined stroke volume and intensity accurately but were less effective in identifying specific strokes and impact locations.

Wrist Injuries in Tennis Players: A Narrative Review

The wrist/hand complex forms the crucial final link in the kinetic chain between the body and the racquet and therefore has a number of important roles in the production of all tennis strokes. However, the internal and external loads that are created at the wrist during these strokes have the potential to contribute to pain and injury. Therefore, the purposes of this narrative review are to (1) determine the extent of the problem of wrist pain/injury in tennis players, (2) identify bony and soft tissue structures of the wrist that are susceptible to damage as a result of tennis play and (3) explore factors that may influence the development of wrist pain/injury in tennis players. The epidemiological data revealed two important points. First, some evidence suggests wrist pain/injury accounts for a higher percentage of total injuries in more recent studies (2014-2015) than in early studies (1986-1995). Second, the relative frequency of wrist pain/injury compared with other well-recognized problem areas for tennis players such as the shoulder complex, elbow and lumbar spine is noticeably higher in more recent studies (2014-2015) than in early studies (1986-1995), particularly among females. Collectively, this would seem to indicate that the problem of wrist pain/injury has increased in the modern game. In fact, some wrist injuries appear to be related to the use of certain forehand grip types and the predominant use of the two-handed backhand. While the loads experienced at the wrist during tennis stroke production seem to be below threshold levels for a single event, the cumulative effects of these loads through repetition would appear to be an important consideration, especially when inadequate time is allowed to complete normal processes of repair and adaptation. This is supported by the evidence that most wrist injuries in tennis are associated with overuse and a chronic time course. The complex interaction between load, repetition, and training practices in tennis, particularly among young developing players who choose a path of early specialization, needs to be further explored.

Analysis of the tennis racket vibrations during forehand drives: Selection of the mother wavelet

The time-frequency analysis of the tennis racket and hand vibrations is of great interest for discomfort and pathology prevention. This study aimed to (i) to assess the stationarity of the vibratory signal of the racket and hand and (ii) to identify the best mother wavelet to perform future time-frequency analysis, (iii) to determine if the stroke spin, racket characteristics and impact zone can influence the selection of the best mother wavelet. A total of 2364 topspin and flat forehand drives were performed by fourteen male competitive tennis players with six different rackets. One tri-axial and one mono-axial accelerometer were taped on the racket throat and dominant hand respectively. The signal stationarity was tested through the wavelet spectrum test. Eighty-nine mother wavelet were tested to select the best mother wavelet based on continuous and discrete transforms. On average only 25±17%, 2±5%, 5±7% and 27±27% of the signal tested respected the hypothesis of stationarity for the three axes of the racket and the hand respectively. Regarding the two methods for the detection of the best mother wavelet, the Daubechy 45 wavelet presented the highest average ranking. No effect of the stroke spin, racket characteristics and impact zone was observed for the selection of the best mother wavelet. It was concluded that alternative approach to Fast Fourier Transform should be used to interpret tennis vibration signals. In the case where wavelet transform is chosen, the Daubechy 45 mother wavelet appeared to be the most suitable.

Active tuning of stroke-induced vibrations by tennis players

This paper investigates how tennis players control stroke-induced vibration. Its aim is to characterise how a tennis player deals with entering vibration waves or how he/she has the ability to finely adjust them. A specific experimental procedure was designed, based on simultaneously collecting sets of kinematic, vibration and electromyographic data during forehand strokes using various commercial rackets and stroke intensities. Using 14 expert players, a wide range of excitations at spectral and temporal levels were investigated. Energetic and spectral descriptors of stroke-induced vibration occurring at the racket handle and at the player's wrist and elbow were computed. Results indicated that vibrational characteristics are strongly governed by grip force and to a lower extent by the racket properties. Grip force management drives the amount of energy, as well as its distribution, into the forearm. Furthermore, hand-grip can be assimilated to an adaptive filter which can significantly modify the spectral parameters propagating into the player's upper limb. A significant outcome is that these spectral characteristics are as much dependent on the player as on the racket. This contribution opens up new perspectives in equipment manufacture by underlining the need to account for player/racket interaction in the design process.

The effects of player grip on the dynamic behaviour of a tennis racket

The aim of this article is to characterise the extent to which the dynamic behaviour of a tennis racket is dependent on its mechanical characteristics and the modulation of the player's grip force. This problem is addressed through steps involving both experiment and modelling. The first step was a free boundary condition modal analysis on five commercial rackets. Operational modal analyses were carried out under "slight", "medium" and "strong" grip force conditions. Modal frequencies and damping factors were then obtained using a high-resolution method. Results indicated that the dynamic behaviour of a racket is not only determined by its mechanical characteristics, but is also highly dependent on the player's grip force. Depending on the grip force intensity, the first two bending modes and the first torsional mode frequencies respectively decreased and increased while damping factors increased. The second step considered the design of a phenomenological hand-gripped racket model. This model is fruitful in that it easily predicts the potential variations in a racket's dynamic behaviour according to the player's grip force. These results provide a new perspective on the player/racket interaction optimisation by revealing how grip force can drive racket dynamic behaviour, and hence underlining the necessity of taking the player into account in the racket design process.

Tennis Racket Vibrations and Shock Transmission to the Wrist during Forehand Drive

This study aimed to investigate the effects of two different racket models and two different forehand drive velocities on the three-dimensional vibration behavior of the racket and shock transmission to the player’s wrist under real playing conditions. Nine tennis players performed a series of crosscourt flat forehand drives at two velocities, using a lightly and a highly vibrant racket. Two accelerometers were fixed on the racket frame and the player’s wrist. The analysis of vibration signals in both time and frequency domains showed no interaction effect of velocity and racket conditions either on the racket vibration behavior or on shock transmission. An increase in playing velocity enlarged the amount of vibrations at the racket and wrist, but weakly altered their frequency content. As compared to a racket perceived as highly vibrating, a racket perceived as lightly vibrating damped longer in the out-of-plane axis of the racket and shorter on the other axis of the racket and on the wrist, and displayed a lower amount of energy in the high frequency of the vibration signal at the racket and wrist. These findings indicated that the playing velocity must be controlled when investigating the vibration loads due to the racket under real playing conditions. Similarly, a reduced perception of vibration by the tennis player would be linked to decreased amplitude of the racket vibration signal, which may concentrate the signal energy in the low frequencies.

Tennis injuries: epidemiology, pathophysiology, and treatment

Tennis places high loads on the joints of players, with supraphysiologic forces being generated at the shoulder and elbow hundreds of times per match. Acute injuries tend to affect the lower extremity; chronic injuries usually involve the upper extremity. Commonly encountered upper extremity conditions include rotator cuff injury, internal impingement, superior labral tears, and epicondylitis of the elbow. Serving is the most strenuous stroke in tennis, with the highest peak muscle activity in the shoulder and forearm occurring during this stroke. The kinetic chain links upper extremity, lower extremity, and core muscle segments by transmitting coordinated activation and motion; in this regard, any pathologic process that disturbs the groin, hip, and abdominal musculature can further result in an increased risk of injury to the shoulder and upper extremity. Evolution in equipment and in play surfaces has also affected the type and frequency of injuries. Prevention programs that address the muscular imbalances throughout the kinetic chain may help reduce the incidence of both acute and chronic injuries experienced by tennis athletes.

Evaluation of a Subject-Specific, Torque-Driven Computer Simulation Model of One-Handed Tennis Backhand Ground Strokes

A torque-driven, subject-specific 3-D computer simulation model of the impact phase of one-handed tennis backhand strokes was evaluated by comparing performance and simulation results. Backhand strokes of an elite subject were recorded on an artificial tennis court. Over the 50-ms period after impact, good agreement was found with an overall RMS difference of 3.3° between matching simulation and performance in terms of joint and racket angles. Consistent with previous experimental research, the evaluation process showed that grip tightness and ball impact location are important factors that affect postimpact racket and arm kinematics. Associated with these factors, the model can be used for a better understanding of the eccentric contraction of the wrist extensors during one-handed backhand ground strokes, a hypothesized mechanism of tennis elbow.

Lower and Upper Extremity Loading in Nordic Walking in Comparison with Walking and Running

Nordic walking (NW) was compared with walking (W) and running (R) with respect to upper and lower limb injury risks. 24 NW-instructors performed W, NW, and R trials on a runway covered with artificial turf at controlled speeds. Foot pronation and ground reaction forces were measured as well as shock wave transmission to the right wrist. Comparison of NW and W shows similar results for all of the four chosen velocities (5 km/h, 7 km/h, 8 km/h, 8.5 km/h). Except for the 2nd peak of the vertical ground reaction force, NW results in higher loading rates and horizontal forces as well as higher pronation and pronation velocity values as compared with W. Wrist acceleration values up to 7.6 times gravitational acceleration were recorded in NW. Compared with R at the same speeds (8 km/h and 8.5 km/h), NW can be recommended as low impact sport with 36% lower loading rates and 59% lower pronation velocities. However, the high wrist accelerations in NW reveal that the upper extremities are exposed to considerable repetitive shocks, which may cause overuse injuries of the upper extremities. Thus, additional preventive exercises for the upper limb muscles are recommended as well as using shock absorbing walking poles.