Tennis is played in more than 200 countries and, given the nature of the game, carries many common injuries, regardless of what level you are playing at. Recently, researchers based in the Netherlands trawled through more than 70 published reports dating back to the 1960s (‘Tennis injuries: occurrence, aetiology, and prevention’, British Journal of Sports Medicine 2006; 40:415-423), to try and answer three important questions:
*What are the most common tennis injuries?
*What associated risk factors and mechanisms cause tennis injuries?
*What preventive measures can be taken to reduce the occurrence of injuries?
The majority of injuries occur in the legs and feet, followed by the arms and shoulders, and then the trunk. Typical injuries are tendon ruptures, plantar fascia tears, muscle tears, stress fractures and intra-articular knee injuries. The study indicated that the majority of injuries sustained were acute rather than chronic; most acute injuries occurred in the lower limbs, and chronic injuries were located in the upper body.
Injury risk in tennis has been shown gradually to increase with age, from 0.01 injuries per player per year in the 6-year to 12-year age group, to 0.5 injuries per player per year in those aged 75 and above. In particular, older players were at increased risk of tennis elbow. As you get older you will pick up more injuries. Higher training volumes also increased the risk of injury, while injuries picked up during indoor play were more severe than those sustained outdoors.
Injury rates between male and female players were compared in four studies, three of which concluded that the difference was not significant. However, one study comparing older elite level players (male 28 years, female 22 years) did report a higher incidence in men (2.7 injuries per 1,000 hours) compared to women (1.1 injuries per 1,000 hours). We have already noted that injury risk increases with age but one outstanding question raised by this study is why are men at greater risk compared to women as they get older?
The research team concluded they had insufficient evidence from the studies to be able to identify proven measures for preventing tennis injuries. However, based on clinical experience and the results of successful preventive measures used in other sports, they went on to suggest that physical preparation targeting injuryprone movement patterns may be beneficial. Other potentially useful interventions include education of players, parents and coaches about tennis injuries, regular musculoskeletal screening and adjustment of equipment (shoes, racquets, strings and balls as well as court surfaces).
One upper-limb chronic injury afflicting tennis players is osteoarthritis. If you repeatedly hit a ball overhead you are going to generate high forces across large ranges of movement that will inevitably place the shoulder under a large amount of stress. Osteoarthritis is the progressive loss of articular cartilage, which begins with fraying, or fibrillation, of the articular surface and progresses to exposure of the subchondral bone. Researchers based in Argentina studied 18 asymptomatic senior tennis players and 18 matched controls to determine the prevalence of primary glenohumeral osteoarthritis in senior tennis players (‘Is tennis a predisposing factor for degenerative shoulder disease? A controlled study in former elite players’, British Journal of Sports Medicine 2006; 40:447-450).
Radiographic images were obtained of both shoulders and the results showed that 33% of the players had osteoarthritic changes in their dominant shoulder (five had minimal changes, one had moderate changes), compared to 11% of the controls (two had minimal changes). The classification of glenohumeral arthritis was established according to work by Koss et al (Am J Sports Med, 1997; 25:809-812): minimal changes were defined as less than 1mm narrowing of the joint space, no osteophytes, slight sclerosis and no cysts; moderate changes were defined as narrowing less than or equal to 2mm, mild to moderate osteophytes, moderate sclerosis and no cysts.
Degeneration of the dominant shoulder acromioclavicular joint was greater in the study group (55.5%) than in the control group (27.7%). The glenoid articular surface was more often affected than the humeral side. The research team concluded that prolonged intensive tennis practice might be a predisposing factor for the development of mild degenerative articular changes in the dominant shoulder.
ACL injury lowers your game
One of the most severe lower limb injuries that a tennis player can pick up is a rupture of the anterior cruciate ligament (ACL). Of all the ligaments of the knee, the ACL is the one that most commonly suffers complete disruption. Surgical reconstruction of the knee can allow players to return to tennis after an appropriate period of rehab, but little information exists about the limitations players face when they return to the court without having had surgical reconstruction.
Researchers have recently tried to identify the specific subjective limitations among tennis players with unilateral ACL deficiency (‘Tennis specific limitations in players with an ACL deficient knee’, British Journal of Sports Medicine 2006; 40:451-453). Sixteen tennis players with a chronic ACL deficient knee (confirmed clinically and by MRI scan) and 16 healthy players took part in the study. Both groups completed a questionnaire on tennis-specific abilities.
The results of the study showed that the players with an ACL deficient knee evaluated their tennis performance at an average 66.9% of their pre-injury level. Most strokes showed no significant impairment. However, one of their major limitations was landing after hitting a smash, with some players avoiding the smash altogether. And while forward running movements were not troublesome, the ACL-deficient players recognised their limitations when trying rapidly to decelerate and change direction.
It’s not surprising that the players with an ACL deficiency felt their performance was impaired when you consider that research has shown that 86% of shear forces are considered to be restrained by the ACL. When you take to the court with an ACL-deficient knee these loads must be restrained by the articulating surfaces and surrounding soft tissues (tissues and surfaces that are not designed to perform this task!).
In summary, the research team concluded that complete ACL ruptures cause significant alteration of knee joint kinematics and, left untreated, there will be specific limitations on subjective tennis performance associated with ACL injuries (instability, chronic articular degeneration and knee dysfunction).