Sean Fyfe reviews the research and offers practical advice.
Tennis is a sport that places extremely high demands on the structural integrity of the body’s joints. Athletes have to perform repetitive, asymmetrical and technically challenging movements at high speed in dynamic settings, often at the limits of their physical and mental endurance. It can become a daily battle against chronic injuries, which too often results in premature departure from the sport.
In terms of sports medicine knowledge, the days of just treating tennis injuries are well behind us.
Among sports support professionals prevention and education at a young age are now seen as the key to decreasing injury rates. To entrench appropriate strategies within tennis organisations and educate players and parents is challenging, to say the least; yet it is not until we can do this effectively that we will see the results of our better understanding of injury patterns and causes. It is my opinion that if players are screened, educated and perform specific injury prevention exercises regularly from a young age, they will see a substantial decrease in injury over their careers.
We don’t have any definitive source to quantify prevalence or type of tennis injuries. The available studies differ significantly, depending on what variables are used. A 1989 Danish study (1) suggested that elite male tennis players suffered 2.3 injuries per player per 1,000 playing hours. Of these, 45% were upper limb injuries, 17% shoulder, 67% the result of overuse, 14% strains, 17% sprains, 2% fractures and 5% blisters.
By contrast, ATP sports medicine officials conducted a study of the injuries for which professional players seek treatment from officials (2). They found that 35-50% of all injuries were to the lower extremities, 20% to the upper limb, and 20% to the lower back. Players sought treatment for massage and stretching in 15-30% of cases. There are obvious limitations to this study: many players would not seek treatment from officials for chronic overuse conditions (which are more likely to occur in the upper body), whereas acute injuries are more likely to occur in the lower limbs.
If we then consider elite versus social players, the statistics vary again. In my experience, social players are less likely to suffer from overuse injures because they play less tennis than pros, but are more prone to acute lower limb injuries because of their decreased conditioning. This has been supported in some studies but not in others.
A US study (3) of 14 to 16 year olds in the US Nationals between 1996 and 1999 found some interesting gender differences. While the rate of injury was almost identical between girls (19 injuries per 100 athletes) and boys (18.4), the types of injuries differed markedly. Boys suffered more acute injuries, which was linked to their more aggressive and explosive style of play, eg much more serve and volley. Girls suffered more overuse injuries to the lower limbs, thought to be because of the increased time spent rallying from the baseline, placing more chronic stress on lower limb structures. The study called for further research on gender injury differences, as there is little data available.
It was also noted that most injuries, boys’ and girls’, were related to overuse; and that a significant number of those who got injured had sustained a serious injury in the previous year but had continued to train and compete. This confirms the need for better injury management and education, especially for young players.
There has been a lot of media coverage recently reporting alarming increases in injury rates among the professional tennis circuit. Players have also been quite outspoken about the scheduling of their professional calendar and the lack of an off-season, claiming that they are struggling to meet the demands of the tour. Lleyton Hewitt is a prime example of someone who has significantly cut back his schedule to focus on longevity in the game. Other reasons offered for increased injury incidence include the speed of the game and the power that can be delivered from modern racquets.
However, a study conducted by the ATP sports medicine trainer Doug Spreen (4), does not exactly confirm this supposed injury trend. Spreen found only incremental increases in injury rates among players between 1995 and 2000, measured in terms of withdrawals from tournaments before the start and retirements from matches. In the players’ defence, it would be reasonable to query how far this study would have reflected the incidence of chronic injuries, as they are less likely to have come to the attention of the ATP’s trainers. Regardless, we need more elite level research, during both tournaments and training, to determine whether or not the overall injury rate (both chronic and acute) is in fact increasing, as suggested by the media and the players.
It is inevitable that in a sport where players are accelerating, stopping, turning and lunging for anything from one to five hours, acute injuries occur. Most acute lower-limb joint injuries are minor compared to what is seen in contact sports such as football. Acute ankle sprains, low grade knee ligament sprains and meniscal injuries to the knee are common. Although muscle strains are seen, they are also far less common than in sports such as Australian Rules Football or rugby, as players rarely run more then 10 steps in one direction and therefore never really use the full sprinting stride that puts the hamstring and rectus femoris muscles under high load. Nor are athletes required to kick, which we all know is a predisposing factor for muscle strains.
Calf muscle strains are common among older social athletes. Among adolescents, it is essential during assessments (as in any sport demanding dynamic and powerful movements) to consider the possibility of avulsion injuries at muscle insertion sites.
The most common acute injury site in the upper limb is the wrist. A perfect example of how wrist injuries happen was Boris Becker at Wimbledon in 1996, stretching for a wide forehand return which he mistimed, forcing his wrist into hyperextension with rotation and leading to his subsequent withdrawal from the tournament. Although acute injuries are hard to predict and prevent, measures can still be taken to reduce the risk, such as proprioceptive and strength training for susceptible joints, advice on bracing and taping, and ensuring the player is using the right equipment.
The technology behind tennis and the equipment used is continually evolving and support professionals must be aware of the impact it can have on a presenting injury. It is always hard for non-players of a sport to appreciate how subtle variations in equipment can change the load on a player’s body, so when searching for underlying causes, be sure to question the player about any recent changes in equipment.
Racquet type can be critical, particularly with juniors, who make frequent changes as they grow out of their racquets and are influenced by new trends. The stiffness of the racquet is paramount: if it is too stiff for the particular player, it can cause upper-limb injuries. Often juniors select racquets that are too stiff for their physical development. Professionals usually aim for a stiff racquet because it provides them with more feel; but juniors need flexibility in the racquet so that the shock on impact is dispersed.
String tension has the same effect. As players get older, their increased physical strength means they need less assistance from the racquet to produce power at contact and they generally increase their string tension in their quest for more control. Juniors should make these increases in small increments, but they often do it in big jumps, to the detriment of their wrists, elbows or shoulders. I would advise that tension should not be increased by any more than 2lb at a time.
You should also consider the type of string being used. In the past 10 years some very stiff string types have come into use, which are very popular for the power and durability they deliver. But they do increase shock through the upper limb on contact.
Finally, in terms of racquet set-up, is the grip size. In tennis, you should play with a relaxed feel on the racquet. A grip too big or small will increase grip tension and the likelihood of elbow and wrist injuries, as well as impeding a fluent swing.
For anyone who presents with lateral epicondylitis (tennis elbow, see below), you must take an in-depth look at their racquet set-up. This is particularly important for middle-aged women, where the prevalence is high. The correct grip size, a flexible racquet and string type and quite loose string tension are essential for this group.
The ATP study(2) also analysed the impact on injuries of the court surface, finding clay far more forgiving than grass or hard court, with 0.2 treatments per match on clay compared with 0.37 and 0.42 on hard court and grass respectively. Clay is a slower, softer surface, encouraging a less explosive style of tennis, and this was seen as the reason behind the lesser injury rate. Artificial grass, commonly seen at local tennis clubs, has similar qualities to clay.
Support professionals should take note of this in their advice, especially to older players, who are often in a position to be able to choose their training and playing surfaces, and who usually need a surface that helps to offload lower limb joints.
The prevention of overuse injuries is where we as sports medicine practitioners can have a profound effect on the careers of promising young players. Succumbing to injury can blight a career in its early stages: because tennis depends on the cumulative effect of training specific neural patterns, prolonged periods of rest can interrupt this process to the long-term detriment of the athlete’s technical competence. A 14 year old suffering from chronic shoulder tendinitis with underlying instability and changes in joint range of movement may have to limit his or her serving for three to six months while making the necessary changes to the joint in rehabilitation. This comes at a point when physical development is usually peaking and when the young athlete’s serve will be undergoing critical changes.
I have already mentioned the need for screening and preventive programmes within the weekly training regimes of younger athletes. But equally important is the education of coaches. Most coaches don’t understand injury presentations and the progressive nature of overuse injuries with continual overload and subsequent loss of joint integrity. It is our job when managing the injury of a young player to ensure that coaches are aiming at quality, not quantity, in their training programmes, particularly with serving practice. The notion of a youngster serving basket after basket of balls, or a coach training a youngster on court until he or she drops, is no longer acceptable. The risk of injury is too great and in a sport as technical as tennis, heightened fatigue just leads to the training of incorrect neural pathways (ie, bad habits), which will further compromise joints.
The emphasis needs to be on replicating the correct technique during training for each stroke, and this is only possible by ensuring the athlete has a sufficient recovery period between training drills, especially for athletes with a particular injury concern.
For older players, the chronic injury concerns are somewhat different. A prime example is tennis elbow or lateral epicondylitis – far more common among older players than the young, in my experience. The typical presentation is an elderly female with a single-handed backhand who leads with the elbow and straightens the elbow and extends the wrist on contact, placing the wrist extensors under excessive tension (rather than swinging from the shoulder with a straight arm and using the entire body to execute the stroke). With tennis elbow, you will need to look at the cervical and thoracic spine, as there is usually some associated dysfunction in this area.
Not surprisingly, injuries to the lumbar spine, shoulder and knees are generally more down to degeneration and stiffness in older people.
Among serious tennis players there are five key areas of susceptibility for overuse injuries: shoulder, medial elbow, wrist, lumbar spine and anterior knee complex. Injury prevention programmes for young athletes should target key areas of flexibility and strength at these joints and should, for any serious young player, be started by the age of 12. I have already written in-depth about management of the elbow (see SIB 35), and will in upcoming issues focus on other key sites.
Sean Fyfe is a physiotherapist working with Metis Physio Centres in London, a multi-disciplinary clinic. He works with elite dancers and theatre performers