A multi-year injury epidemiology analysis of an elite national junior tennis program

Objectives

To profile multi-year injury incidence and severity trends in elite junior tennis players from a national program.

Shoulder functional ratio in elite junior tennis players

ObjectiveTo evaluate shoulder rotation strength and compare the functional ratio between shoulders of elite junior tennis players.DesignThis cross-sectional study evaluated muscular rotation performance of 40 junior tennis players (26 male and 14 female) with an isokinetic dynamometer.Main outcome measuresStrength variables of external (ER) and internal rotators (IR) in concentric and eccentric modes were considered. For the peak torque functional ratio, the eccentric strength of the ER and the concentric strength of the IR were calculated.ResultsAll variables related to IR were significantly higher on the dominant compared to the non-dominant side in males and females (p < 0.05), but only boys exhibited this dominance effect in ER (p < 0.05 and p < 0.001). Regarding functional ratios, they were significantly lower for the dominant shoulder (p < 0.001) and below 1.00 for both groups, indicating that the eccentric strength of the ER was not greater than the concentric strength of the IR.ConclusionElite junior tennis players without shoulder injury have shoulder rotation muscle strength imbalances that alter the normal functional ratio between rotator cuff muscles. Although these differences do not seem to affect the athletic performance, detection and prevention with exercise programs at an early age are recommended.     

Fitness evaluations and fitness findings in competitive junior tennis players

Elite tennis players, as well as a large number of active recreational players, are involved in a sport that applies high repetitive loads that can create tension overload situations in certain key anatomic areas of the body and add to possible overload situations in other areas of the body. This results in patterns of inflexibility and weakness that can be demonstrated on a tennis-specific musculoskeletal exam, and that can be correlated with areas of increased injury occurrence. These players report conditioning programs that are, for the most part, inadequate to confer total conditioning of all the muscular parameters important in playing tennis. All of these factors, in addition to the frequency and type of playing, contribute to the occurrence of the overload injuries noted. These aspects need to be addressed in a preventative program for injury reduction. We do not believe that major changes in the way that tennis is played should be implemented until the effects of a proper preventative conditioning program are evaluated. The "ideal" conditioning program has not yet been found. While the exact composition of the program is in doubt, our studies allow us to recommend flexibility, strength, and endurance training for all athletes playing tennis at frequent intervals. This program should be guided by the findings on the preparticipation exam.     

Flexibility comparisons of junior elite tennis players to other athletes

Flexibility measurements were obtained in 86 junior elite tennis players and compared to the flexibility measurements of 139 athletes involved in other sports. The measurements obtained included sit and reach flexibility, quadricep flexibility, hamstring flexibility, gastrocnemius flexibility, shoulder internal rotation, and shoulder external rotation. All measurements except sit and reach flexibility were obtained goniometrically. Tennis players were significantly tighter in sit and reach flexibility, dominant shoulder internal rotation, and nondominant shoulder internal rotation. They were significantly more flexible in dominant shoulder external rotation and nondominant shoulder external rotation. The flexibility differences found in tennis players suggest adaptations to the musculoskeletal demands of their sport. These results suggest that a sport-specific flexibility program may be necessary for junior elite tennis players in order to promote maximum performance and help prevent flexibility-related injuries.     

Injury risk factors in junior tennis players: a prospective 2‐year study

The aim was to investigate injury risk factors in junior tennis players. Fifty‐five players, 35 boys and 20 girls, answered a questionnaire about training habits, time of exposure, previous injuries and equipment factors. A battery of clinical tests and functional performance tests were also carried out. All tennis‐related injuries that occurred during a 2‐year period were identified and recorded. An injury was defined as an injury if it was impossible to participate in regular tennis training or playing matches during at least one occasion, a time loss injury. Potential injury risk factors were tested in a forward stepwise logistic regression model for injury. Thirty‐nine players sustained totally 100 new and recurrent injuries. Injuries to the lower extremity were the most common ones (51%) followed by the upper extremity (24%) and the trunk (24%). Injured players performed more singles per week (P<0.0001) and played more tennis hours per year (P=0.016) than the uninjured players. Playing tennis more than 6 h/week was found to be a risk factor for back pain. A previous injury regardless of location was identified as an injury risk factor, and a previous injury to the back was a risk factor for back pain.     

MRI findings in the lumbar spines of asymptomatic elite junior tennis players

Objective

To evaluate the MRI findings in the lumbar spines of asymptomatic elite junior tennis players.

Materials and Methods

The lumbar spine MRI studies of 98 asymptomatic junior elite tennis players (51 male, 47 female) with a mean age of 18 years (age range 11.2–26.3 years; standard deviation 3.1) was reviewed by two consultant musculoskeletal radiologists using consensus opinion. Images were assessed using accepted classification systems.

Results

Four players (4 %) had no abnormality. Facet joint arthropathy occurred in 89.7 % of the players, being mild in 84.5 % of cases. There were 41 synovial cysts in 22.4 % of the cohort all occurring in the presence of facet arthropathy. Disc degeneration was noted in 62.2 % of players, being mild in 76.2 % of those affected. Disc herniation was noted in 30.6 % of players, with 86.1 % of these being broad based and 13.9 % being focal. There was nerve root compression in 2 %. There were 41 pars interarticularis abnormalities in 29.6 % of patients, 63.4 % of these being grades 1–3. There was grade 1 spondylolisthesis in 5.1 % of players. The prevalence of facet joint arthropathy, disc degeneration, disc herniation and pars interarticularis fracture was lower in female players than in male and lower in the under 16-year-olds compared with the over 20-year-olds.

Conclusion

There is a significant amount of underlying pathology that would normally go undetected in this group of asymptomatic elite athletes. Whilst these findings cannot be detected clinically, their relevance is in facilitating appropriate prehabilitation to prevent loss of playing time and potentially career-ending injuries.     

Injury profile in junior tennis players: a prospective two year study

The aim of this study was to prospectively make a survey of injuries in junior players from a Swedish local tennis club during a 2-year period in relation to gender, anatomic location, month of the year when injured, injury type and injury severity. All 12–18 years old members in a tennis club playing more than twice weekly were asked to participate. Fifty-five junior tennis players, 35 boys and 20 girls accepted to participate. All tennis-related injuries were prospectively registered and evaluated. Time of exposure for playing tennis was recorded. Thirty-nine players sustained 100 injuries, 73 in boys and 27 in girls. Injury incidence for boys was 1.7 injuries/1000 h of tennis playing time and for girls 0.6 injuries/1000 h. Ankle sprains, low back pain and knee injuries were the most common ones. Sixty-five percent were new injuries, and the majority of these injuries were located at the knee joint followed by the ankle joint, while most of the recurrent injuries were found in the lumbar spine. Boys suffered mainly from low back pain and ankle injuries and girls from low back pain and knee injuries. Forty-three percent of the injuries caused absence from tennis for more than 4 weeks and 31% more than 1 week.     

Physiological upper limits of left ventricular dimensions in highly trained junior tennis players

Background

The differentiation between physiological cardiac enlargement and cardiomyopathy is crucial, considering that most young non‐traumatic deaths in sport are due to cardiomyopathy. Currently, there are few data relating to cardiac dimensions in junior elite tennis players. The aim of this study was to define the upper limits of left ventricular dimensions in a large cohort of national adolescent tennis players.

Methods

Between 1996 and 2003, 259 adolescent tennis players (152 males), mean (SD) age 14.8 (1.4) years (range 13–19) and 86 healthy age, gender and body surface matched sedentary controls underwent 12‐lead ECG and 2D‐transthoracic echocardiography.

Results

Inter‐ventricular septal end diastolic dimension (IVSd), left ventricular end diastolic dimension (LVEDd) and left ventricular end diastolic posterior wall dimension (LVPWd) in tennis players were significantly higher than in controls (8.9 mm vs 8.3 mm p<0.001, 48.9 mm vs 47.9 mm p<0.05 and 9 mm vs 8.3 mm p<0.001 respectively), however in absolute terms, the difference did not exceed 7%. None of the tennis players had a wall thickness exceeding 12 mm or a left ventricular cavity size exceeding 60 mm.

Conclusions

Tennis players exhibit modest increases in cardiac dimensions, which do not resemble those seen in individuals with cardiomyopathy affecting the left ventricle.The differentiation between physiological cardiac adaptation (athlete''s heart) and cardiomyopathy is crucial, as up to 40% of all non‐traumatic sudden cardiac deaths in young athletes are either due to hypertrophic or dilated cardiomyopathy.^1,2 The vast majority of echocardiographic studies have evaluated only adult athletes, however, there are few data assessing physiological adaptation in adolescent athletes in whom sudden death from cardiomyopathy is most prevalent.³ The steady trickle of sudden cardiac deaths in high profile athletes including tennis players^4,5 has prompted some sporting bodies to implement compulsory cardiovascular evaluation of all junior recruits specifically aimed at excluding cardiomyopathy prior to acceptance for competition.Tennis is a popular sport attracting millions of players and fans worldwide.⁶ The British Lawn Tennis association was the first elite sporting organisation in the UK to adopt cardiovascular screening of all their national junior athletes for conditions predisposing to sudden cardiac death. Our group has been responsible for performing cardiovascular evaluation on all junior national tennis players since 1996. The aim of this study was to identify physiological upper limits of cardiac enlargement in junior tennis players to help facilitate the differentiation between physiological and pathological cardiac enlargement should other countries decide to follow suit.     

Isokinetic profile of wrist and forearm strength in elite female junior tennis players

Background

In tennis, injuries to the elbow and wrist occur secondary to the repetitive nature of play and are seen at increasingly young ages. Isokinetic testing can be used to determine muscular strength levels, but dominant/non‐dominant and agonist/antagonist relations are needed for meaningful interpretation of the results.

Objectives

To determine whether there are laterality differences in wrist extension/flexion (E/F) and forearm supination/pronation (S/P) strength in elite female tennis players.

Methods

32 elite female tennis players (age 12 to 16 years) with no history of upper extremity injury underwent bilateral isokinetic testing using a Cybex 6000 dynamometer. Peak torque and single repetition work values for wrist E/F and forearm S/P were measured at speeds of 90°/s and 210°/s, with random determination of the starting extremity. Repeated measures analysis of variance was used to determine differences between extremities for peak torque and single repetition work values.

Results

Significantly greater (p<0.01) dominant arm wrist E/F and forearm pronation strength was measured at both testing speeds. Significantly less (p<0.01) dominant side forearm supination strength was measured at both testing speeds.

Conclusions

Greater dominant arm wrist E/F and forearm pronation strength is common and normal in young elite level female tennis players. These strength relations indicate sport specific muscular adaptations in the dominant tennis playing extremity. The results of this study can guide clinicians who work with young athletes from this population. Restoring greater dominant side wrist and forearm strength is indicated after an injury to the dominant upper extremity in such players.     

Anthropometric characteristics, body composition and somatotype of elite junior tennis players

Objectives

The aims of this study were to describe the anthropometric characteristics, body composition and somatotype of elite male and female junior tennis players, to compare the anthropometric data, body composition and somatotype of the first 12 elite junior tennis players on the ranking with the lower ranked players, and to establish an anthropometric profile chart for elite junior tennis players.

Methods

A total of 123 (57 males and 66 females) elite junior tennis players participated in this study. The athletes were divided into two groups, the first 12 and the lower ranked players, according to gender. A total of 17 anthropometric variables were recorded of each subject.

Results

There were no significant differences in height and weight between the first 12 and the lower ranked boys, while the first 12 girls were significantly taller than the lower ranked girls (p = 0.009). Significant differences were found for humeral and femoral breadths between the first 12 and the lower ranked girls (p = 0.000; p = 0.004, respectively). The mean (SD) somatotype of elite male junior tennis players could be defined as ectomesomorphic (2.4 (0.7), 5.2 (0.8), 2.9 (0.7)) and the mean (SD) somatotype of elite female junior tennis players evaluated could be defined as endomesomorphic (3.8 (0.9), 4.6 (1.0), 2.4 (1.0)). No significant differences were found in somatotype components between the first 12 and the lower ranked players of both genders.

Conclusions

When comparing the first 12 and the lower ranked elite junior tennis players of both genders, no significant differences were observed in any measured item for the boys. By contrast, significant differences were observed in height and humeral and femoral breadths between the first 12 and the lower ranked girls, whereby the first 12 were taller and had wider humeral and femoral breadths than the lower ranked players. These differences could influence the playing style of junior female players.The interest in anthropometric characteristics, body composition and somatotype from different competitive sports has increased over the last decades. It has been well described that there are specific physical characteristics in many sports, such as the anthropometric profile, that indicate whether the player would be suitable to compete at the highest level in a specific sport.^{1,2,3,4,5,6,7,8} The quantification of morphological characteristics of elite athletes can be a key point in relating body structure to sports performance.During the past two decades, great changes have taken place in tennis with respect to technique and tactics, and even more so with respect to the physical performance of the players. Nowadays, tennis is one of the most popular sports in the world and is extensively studied. Most of the scientific literature has focused on physiological^{9,10,11,12,13,14,15,16,17} and biomechanical variables,^{18,19,20,21,22,23,24,25,26,27,28,29} physical performance,^30,31,32,33 and prevention and treatment of injuries.^{34,35,36,37,38,39,40} At present, there is little data on the physical characteristics of young^41,42,43,44 and adult⁴⁵ tennis players.Therefore, the purpose of this study was to determine the anthropometric characteristics, body composition and somatotype of elite junior tennis players, in order to use this for training and for the detection and identification of talented players.     

Muscular strength, functional performances and injury risk in professional and junior elite soccer players

Muscle strength and anaerobic power of the lower extremities are neuromuscular variables that influence performance in many sports activities, including soccer. Despite frequent contradictions in the literature, it may be assumed that muscle strength and balance play a key role in targeted acute muscle injuries. The purpose of the present study was to provide and compare pre-season muscular strength and power profiles in professional and junior elite soccer players throughout the developmental years of 15-21. One original aspect of our study was that isokinetic data were considered alongside the past history of injury in these players. Fifty-seven elite and junior elite male soccer players were assigned to three groups: PRO, n=19; U-21, n=20 and U-17, n=18. Players benefited from knee flexor and extensor isokinetic testing consisting of concentric and eccentric exercises. A context of lingering muscle disorder was defined using statistically selected cut-offs. Functional performance was evaluated throughout a squat jump and 10 m sprint. The PRO group ran faster and jumped higher than the U-17 group (P<0.05). No significant difference in isokinetic muscle strength performance was observed between the three groups when considering normalized body mass parameters. Individual isokinetic profiles enabled the identification of 32/57 (56%) subjects presenting lower limb muscular imbalance. Thirty-six out of 57 players were identified as having sustained a previous major lower limb injury. Of these 36 players, 23 still showed significant muscular imbalance (64%). New trends in rational training could focus more on the risk of imbalance and implement antagonist strengthening aimed at injury prevention. Such an intervention would benefit not only athletes recovering from injury, but also uninjured players. An interdisciplinary approach involving trainers, a physical coach, and medical staff would be of interest to consider in implementing a prevention programme.     

Incidence of injury in junior and senior rugby league players

Rugby league is an international collision sport played at junior, amateur, semi-professional and professional levels. Due to the high numbers of physical collisions and tackles, musculoskeletal injuries are common. A large percentage of injuries result in long-term employment and study limitations, medical costs and loss of income. Review articles addressing the applied physiology of rugby league and common rugby league injuries have been published. However, both of these review articles have focused on the professional rugby league player. This review addresses the extent of the injury problem in rugby league in all levels of competition (i.e. junior, amateur, semi-professional and professional). The incidence of rugby league injuries typically increases as the playing level is increased. The majority of studies have shown that the head and neck is the most common site of match injuries in senior rugby league players, while knee injuries are the most common site of injury in junior rugby league players. Muscular injuries are the most common type of injury sustained by senior rugby league players, while junior rugby league players more commonly sustain fractures. Injuries are most commonly sustained in tackles, by the tackled player. Thigh and calf strains are the most common injuries sustained during rugby league training, while overexertion is the most common cause of training injuries. Player fatigue may influence the incidence of injury, with most sub-elite (amateur and semi-professional) rugby league injuries occurring in the second half of matches or the latter stages of training sessions. The majority of training injuries occur in the early stages of the season, while match injuries occur in the latter stages of the season, suggesting that changes in training and playing intensity may influence the incidence of injury in rugby league. Injury prevention studies are required to reduce the incidence, severity and cost of rugby league injuries. These injury prevention strategies could include coaching on defensive skills, correct tackling technique, correct falling technique and methods to minimise the absorption of impact forces in tackles. Game-specific attacking and defensive drills practised before and during fatigue may also encourage players to make appropriate decisions under fatigued conditions and apply learnt skills during the pressure of competitive matches. Further studies investigating risk factors for injury in junior and senior rugby league players, injuries sustained by specific playing positions and the influence of injuries on playing performance are warranted.     

Shoulder strength profile in elite junior tennis players: horizontal adduction and abduction isokinetic evaluation

Objective

To establish normative data for muscle performance during isokinetic horizontal abduction and adduction of the shoulder in elite junior tennis players.

Methods

Thirty six tennis players were evaluated (23 male, 13 female; mean age 14 years (range 12–18)). An isokinetic dynamometer was used to test the shoulder horizontal abductors and adductors at 60 and 180°/s. Absolute and relative peak torque (PT and PT/BW), total work (TW), endurance ratio (ER), and the ratio of the peak torque between horizontal abductors and adductors (HAB/HAD ratio) were recorded. Data were compared for the dominant and non‐dominant shoulders, horizontal abductor and adductor muscles, and between players grouped according to age.

Results

The dominant shoulder was significantly (p<0.05) stronger than the non‐dominant shoulder in all variables except ER and HAB/HAD ratio. The abductors were significantly (p<0.05) weaker than the adductors in all subjects. The type of backhand (one handed or two handed) did not influence the strength of the shoulder horizontal abductors on the dominant side. The number of years of tennis practice had an effect on muscle strength as evaluated by absolute data (PT and TW) but not relative measurements (PT/BW and TW/BW).

Conclusion

The findings confirm that horizontal abduction and adduction are stronger in the dominant shoulder of junior tennis players. The clinical relevance of these findings is not established, and more studies are needed to compare tennis players with athletes from other sports and non‐athletes.     

Hip and shoulder internal rotation range of motion deficits in professional tennis players

One hundred tennis players were recruited from the professional men's tennis tour to investigate the correlation between hip internal rotation deficits and low back pain (LBP), as well as shoulder internal rotation deficits and shoulder pain. A statistically significant correlation was observed between dominant shoulder internal rotation deficits and shoulder pain. Also observed was a statistically significant correlation between lead hip internal rotation deficits and lumbar extension deficits with LBP. We conclude that due to repetitive demands on the dominant shoulder and repetitive pivoting at the lead hip, the cycle of microtrauma and scar formation leads to capsular contracture and subsequent reduction in internal range of motion. It is likely that the limitation in lumbar extension in the symptomatic group is not only due to decreased flexibility from an increased load on the spine, but also due to a protective mechanism to prevent further exacerbation of the LBP. Physical conditioning that includes shoulder as well as hip internal rotation stretching programs should therefore be essential aspects in the treatment of tennis players with shoulder pain and LBP respectively.     

Asymmetry during Functional Movement Screening and injury risk in junior football players: A replication study

An indicator of movement quality and potential injury risk during Functional Movement Screen (FMS ) testing is the presence of asymmetry when comparing the left and right sides of the body. The aim of the study was to investigate the reproducibility of the injury risk model proposed in our previous research (Chalmers et al. 2017; derivation study) that showed an increased injury risk for elite junior Australian football players demonstrating ≥2 asymmetrical FMS subtests. We used a direct replication design. Players underwent pre‐season FMS testing, and an injury surveillance system monitored 277 male participants during the subsequent regular season competition. Designated club officials monitored the weekly competition participation of players. The definition of an injury was “a trauma or medical condition which caused a player to miss a competitive game”. Cox proportional hazards regression models were used to investigate the relationship between asymmetry and number of games played before first injury (ie, survival time). The level of reproducibility was determined according to statistical significance, effect size, and subjective assessment. Demonstrating asymmetry during FMS testing was not associated with a significant increase in prospective injury risk in the replication study (P  >  .05). Moreover, effect sizes (hazard ratios) from the derivation dataset were not within the 95% confidence intervals of the respective asymmetry predictor in the replication dataset. Subjectively, researchers were in agreement that the findings from the derivation data were not successfully reproduced. Clinicians and researchers should be cautious about using FMS asymmetry findings to derive injury risk for junior football players.     

Shoulder injuries in tennis players

The mechanism of the overhead action in throwing sports has been studied extensively. This motion is unnatural and highly dynamic, often exceeding the physiological limits of the joint. Owing to overload of various anatomical structures, the shoulder is susceptible to injury. Optimal shoulder function requires good kinetic chain function, optimal stability, and coordination of the scapula in the overhead action. A well balanced action of the rotator cuff muscles and capsular structures is necessary to obtain a stable centre of rotation during the overhead action. This review concerns shoulder injuries, related to the overhead motion in tennis players, which can be explained by the same mechanism as thrower's shoulder.     

Spondylolysis in young tennis players

The general aetiology, diagnosis, and treatment of spondylolysis, a bone defect in the pars interarticularis of the vertebra, are reviewed. A retrospective study of young tennis players diagnosed between 2000 and 2004 with spondylolysis with or without spondylolisthesis, assessed by radiography and planar bone scintigraphy, is described. If the radiographic results were negative, computed tomography was performed. Sixty six cases were evaluated: 53 L5 lesions, eight L4 lesions, two L3 lesions, and one bilateral lesion at the L2 level. Two more lesions at two levels were found (bilateral L5 and unilateral L4 and L3 on the right side). Classification, treatment, and outcome of the cases are reported. A combination of radiography, planar bone scintigraphy, and SPECT is useful for evaluating spondylolysis in tennis players and recommending treatment. Use of a brace did not appear to achieve significant results.