Stuart Miller

Consensus statement on epidemiological studies of medical conditions in tennis, April 2009

Background: The reported incidence, severity and nature of injuries sustained in tennis vary considerably between studies. While some of these variations can be explained by differences in sample populations and conditions, the main reasons are related to differences in definitions and methodologies employed in the studies. Objective: This statement aims to review existing consensus statements for injury surveillance in other sports in order to establish definitions, methods and reporting procedures that are applicable to the specific requirements of tennis. Design: The International Tennis Federation facilitated a meeting of 11 experts from seven countries representing a range of tennis stakeholders. Using a mixed methods consensus approach, key issues related to definitions, methodology and implementation were discussed and voted on by the group during a structured 1-day meeting. Following this meeting, two members of the group collaborated to produce a draft statement, based on the group discussions and voting outcomes. Three revisions were prepared and circulated for comment before the final consensus statement was produced. Results: A definition of medical conditions (injuries and illnesses) that should be recorded in tennis epidemiological studies and criteria for recording the severity and nature of these conditions are proposed. Suggestions are made for recording players’ baseline information together with recommendations on how medical conditions sustained during match play and training should be reported. Conclusions: The definitions and methodology proposed for recording injuries and illnesses sustained during tennis activities will lead to more consistent and comparable data being collected. The surveillance procedures presented here may also be applicable to other racket sports.

Health Benefits of Tennis

The aim of the study was to explore the role of tennis in the promotion of health and prevention of disease. The focus was on risk factors and diseases related to a sedentary lifestyle, including low fitness levels, obesity, hyperlipidaemia, hypertension, diabetes mellitus, cardiovascular disease, and osteoporosis. A literature search was undertaken to retrieve relevant articles. Structured computer searches of PubMed, Embase, and CINAHL were undertaken, along with hand searching of key journals and reference lists to locate relevant studies published up to March 2007. These had to be cohort studies (of either cross sectional or longitudinal design), case–control studies, or experimental studies. Twenty four studies were identified that dealt with physical fitness of tennis players, including 17 on intensity of play and 16 on maximum oxygen uptake; 17 investigated the relation between tennis and (risk factors for) cardiovascular disease; and 22 examined the effect of tennis on bone health. People who choose to play tennis appear to have significant health benefits, including improved aerobic fitness, a lower body fat percentage, a more favourable lipid profile, reduced risk for developing cardiovascular disease, and improved bone health.

Hyperthermic-related challenges in aquatics, athletics, football, tennis and triathlon

Although many elite sporting events occur in climate-controlled venues, some athletes train and compete in environments that can potentially pose a risk to the athletes health. In particular, athletes in aquatics, track and field, tennis, football and triathlon can be exposed to extreme heat during competition or while training. The International Federations responsible for these sports are aware of these health risks and have implemented measures to help protect the health of their athletes. This review paper outlines the sport-specific environmental health risks and the safety standards implemented to safeguard athlete health.

The influence of tennis court surfaces on player perceptions and biomechanical response

ABSTRACT This study aimed to examine player perceptions and biomechanical responses to tennis surfaces and to evaluate the influence of prior clay court experience. Two groups with different clay experiences (experience group, n = 5 and low-experience group, n = 5) performed a 180° turning movement. Three-dimensional ankle and knee movements (50 Hz), plantar pressure of the turning step (100 Hz) and perception data (visual analogue scale questionnaire) were collected for two tennis courts (acrylic and clay). Greater initial knee flexion (acrylic 20. 8 ± 11.2° and clay 32.5 ± 9.4°) and a more upright position were reported on the clay compared to the acrylic court (P < 0.05). This suggests adaptations to increase player stability on clay. Greater hallux pressures and lower midfoot pressures were observed on the clay court, allowing for sliding whilst providing grip at the forefoot. Players with prior clay court experience exhibited later peak knee flexion compared to those with low experience. All participants perceived the differences in surface properties between courts and thus responded appropriately to these differences. The level of previous clay court experience did not influence players’ perceptions of the surfaces; however, those with greater clay court experience may reduce injury risk as a result of reduced loading through later peak knee flexion.

Estimation of Errors in Force Platform Data.

Force platforms (FPs) are regularly used in the biomechanical analysis of sport and exercise techniques, often in combination with image-based motion analysis (e.g., Begg & Kamruzzaman, 2005; Kuitunen, Komi, & Kyrolainen, 2002; Rahmani, Dalleau, Viale, Hautier, & Lacour, 2000; Rodano & Squadrone, 2002). Force time data, particularly when combined with joint positions and segmental inertia parameters, can be used to evaluate the effectiveness of a wide range of movement patterns in sport and exercise (Bartlett, Messenger, & Lindsay, 1997). According to Dainty and Norman (1987) and Bartlett et al. (1997), valid and reliable force measures depend on low threshold, hysteresis and cross-talk, high linearity, adequate sensitivity and the elimination of cable interference, electrical inductance, and temperature and humidity variations. Moreover, a platform must possess high stiffness and high natural frequency and be located such that extraneous vibrations are excluded. Given that FPs are regularly used in sport and exercise research not only for data collection but also for evaluating other biomechanical equipment (e.g., Rahmani et al., 2000), the lack of attention paid to the likelihood of errors in their measurements is somewhat surprising. Although the scientific literature for kinematic data has established and consistently reported the estimation and propagation of errors, FP data are often taken as error-free. For example, Johnson and Buckley (2001) used a FP to measure ground reaction forces during sprinting, without calculating or reporting possible errors in FP data. Reporting FP data to an unjustifiably high precision and assuming they are acceptably accurate is potentially problematic. For example, when the force data are used for further calculations, such as estimating joint moments from external forces, the error in the force measures will propagate through the calculation--especially in the absence of postprocessing techniques--and directly affect the final result. Some investigators, however, have tried to assess the accuracy and reliability of their measurements. Bobbert and Schamhardt (1990) and Mita et al. (1993) found inaccuracies in estimates of the center of pressure position, especially toward the platform edges, and identified poor calibration and differences in the individual characteristics among the load cell amplifiers as possible causes. Although FP calibration data are usually available from manufacturers, researchers should not assume the manufacturer-quoted values are retained following installation and over time. Experimental error is inevitable in a study that uses FP as a data collection tool and can arise from a variety of sources, which may influence the reliability of the findings and the studys validity. Despite this, neither calibration of FP nor estimation of potential errors in FP measurements is reported in most investigations. Furthermore, because the existing methods reported in studies for FP error calculation require sophisticated equipment and are time-consuming, their application in other FP studies would be rather complicated and, in many laboratories, not possible. Therefore, the purpose of the present study was to establish the magnitude of possible measurement errors from a FP typically used in sport and exercise biomechanics, by applying an easy-to-use, rime-efficient method.

Ball and Racket Movements Recorded at the 2006 Wimbledon Qualifying Tournament (P109)

This paper contains the recorded shot movements of 13 players in practice conditions at the Wimbledon 2006 Qualifying Tournament. A 2-camera 3D system was used to track the racket and ball for a period of 0.02 seconds for each recorded shot. Custom-written analysis software was used to extract the required co-ordinates from the ball and racket positions and transform them into 3D. From this information the following things were obtained; ball velocity before and after impact; racket linear and angular velocity before impact; ball spin and impact position. It was found that although ball velocity was very similar for all players before impact, male players were able to generate higher ball velocities after impact. This was found to be due to a higher racket COM velocity. Impact position and angular velocities were very similar for both sexes.

Measuring Ball Spin Off a Tennis Racket

A series of experiments were carried out in which a spinning tennis ball was projected obliquely at a head clamped racket. In each experiment a different string was used in the racket frame. An automated image analysis algorithm was used to measure the velocity and spin of the ball. It has been found that, for the majority of impacts, the magnitude of the ball rebound spin was dependent on string stiffness. It has been concluded that the string stiffness influences the magnitude of stringbed lateral movement during impact. This differing magnitude of lateral string movement, in turn, influences the amount of ball rebound spin.

Health promotion through sport: international sport federations’ priorities, actions and opportunities

Objective To identify areas of priority and activity for international sportsfederations (IFs) with respect to athlete health and safety, and global health. Results serve to direct the work of the Association of Summer Olympic IF Medical and Scientific Consultative Group, the International Olympic Committee and to influence IFs’ planning and priorities. Methods The 28 IFs participating in the Summer Olympic Games (2016) were asked to rank the relative importance of 11 health-related topics and to report their activities or research initiatives on 27 identified topics using an electronic survey. A comparison with a similar survey (2012) was made. Results The response rate was 100%. In general, the ‘fight against doping’ had the highest priority followed by ‘image as a safe sport’. The topics with the lowest importance ratings were ‘increasing the number of elite athletes’, and ‘health of the general population’. Despite ranking ‘health of your athletes,’ as a top priority, IFs are not addressing all aspects of athlete health. In comparison with 2012, there was a significant decrease in priority for IFs is ‘health of the general population’. Conclusion Despite the widespread knowledge of the importance of the promotion of physical activity (sport) on global health, the decreasing priority and programming of the IFs on physical activity promotion is concerning. Although IFs have prioritised the protection of the health of elite athletes, there are gaps in programming demonstrating that IFs are missing important areas of athlete health. Improving recreational athlete health programming could also benefit population health as well as improve IF fan base and sport participation.

Tennis footwear: An investigation of impact characteristics

Tennis is promoted as an excellent source of physical activity for individuals of all ages and abilities due to the fitness and psychosocial benefits associated with play. For elite players achieving world class status is the ultimate performance goal. The pursuit of excellence and mass participation in tennis has lead to great investment in equipment from both a performance enhancement and an injury prevention perspective. Rapid, multi-directional movement will typically increase both the load and the rate of loading experienced by an athlete. The consequence of this on the musculoskeletal system is to increase the likelihood of sustaining an injury depicted by an acute or chronic mechanism (Luethi et al. 1986). Footwear is considered a sensible strategy in injury prevention specifically for the lower limbs due to its potential ability to attenuate impact forces via cushioning. Confounding the potential of injury further is the hardness of the playing surfaces which is associated with an increase in injury risk (Strauss 2003). These considerations are particularly applicable for tennis as the game is played on difference court surfaces with varying degrees of hardness, ranging from the acrylic ‘hard’ to the grass ‘soft’ courts. Currently there is limited understanding of the interaction between the player, the surface and the role footwear has in injury prevention. The aims of this study are two-fold: (1) to measure the impact properties of a variety of tennis footwear independently of human interaction; and (2) to evaluate the impact characteristics of the shoe-surface interface.