Tuesday 10 July 2018
Tennis fans could be forgiven for feeling a sense of deja vu. For the first time since 2012, Rafael Nadal and Roger Federer sit atop the world rankings, confounding their critics and continuing to defy age and injury.
Anyone who has watched these two careers down the years will know that Nadal is king of clay, and Federer is a titan on the turf. But how many know exactly why? And how is it that these particular players can so outclass their opposition when playing on their favourite surfaces?
It is extremely difficult for one player to dominate across all the courts, and thus, all the slams. Each surface presents different challenges, and on the professional tour, players have limited time to adapt their movement and playing style for different parts of the programme. A tennis season begins with acrylic hard courts, transfers to clay, has a brief encounter with grass, and then goes back to hard to see out the year. There are just four weeks between the clay court season ending and the start of Wimbledon.
Tennis courts are deceptively complex structures. Formed of multiple layers of material that determine the qualities of the court, a surface can determine a player’s performance as well as their injury risk. Different surfaces elicit different reactions from the ball – bounce, spin, speed and direction – and from the player, so professionals have to adapt their play effectively.
Grass courts are now the least utilised surface, but Wimbledon will always lend “lawn tennis” a certain prestige. While clay courts are classified as “slow” by the International Tennis Federation (ITF), grass courts produce very little friction with the ball, meaning that shots shoot off the turf with high speed and low bounce. This means that players have less time to return the ball than they might on clay or hard, resulting in shorter rallies, and the possibility of ending a point quickly from the net. Federer’s finesse and ability to use the speed of the ball against his opponent, makes him ideally suited to quick, technical grass court play.
A recent study found that players had significantly faster first and second serves at Wimbledon compared with the other grand slams. This has made the Wimbledon grass a natural home for the “serve and volley” tactic – a favourite of past greats such as John McEnroe, Pete Sampras and Goren Ivanesevic. At other grand slams, players vary their serves, using slower, spin serves to try to make it difficult for their opponents to prepare. At Wimbledon, most opt for power.
It’s not just the faster courts that favour certain types of player. On clay, balls travel slower and bounce higher, eliciting longer rallies, more points played from the baseline, and a great deal more running. Heavy topspin can give the already high bounce an extra kick, pushing a returning player back in the court and making it hard for them to attack.
Nadal’s topsin forehand is revered and reviled by his fellow players, while his athleticism and staying power help him dominate a surface that puts a premium on fitness. Players must spend more energy on the clay court to achieve the same distance they would on grass or hard, mostly through the prominence of sliding.
When stretching for shots or changing direction on low friction clay, sliding is an essential weapon in the arsenal. Sliding when slowing down reduces the time taken to turn on the slippery clay surface. The loading distribution required to ensure a successful slide, though, increases pressure on the knee and requires intense muscular control that can be extremely fatiguing. Nadal doesn’t just have better ball-striking than many of his rivals, his game has vastly superior physicality.
Hard courts – the newest but perhaps most popular to play on – are in many ways the middle child of the tennis court world. Rated as medium pace, the US and Australian Opens see similar serve speeds to the French. Rally length and percentage baseline play clock in somewhere between grass and clay, and although Novak Djokovic slides on hard surfaces, the high friction levels make this rare and extremely difficult. Many sorts of players can succeed on hard courts – naturally including Federer and Nadal.
Recent research suggests that your chances of injury are similar across the surfaces. But regularly playing on different surfaces and transitioning between them can increase a player’s injury risk substantially, particularly if there is not sufficient time to fully adapt.
Different ball speed, bounce height and sliding characteristics are large disparities in a game as technical and precise as professional tennis, so players must carefully manage their training and playing schedules if they are to perform at the highest level. This is extremely physically demanding, and is probably why so few players have been able to dominate across the different courts.
Meanwhile, despite being the wrong side of 30, the king of clay and the greatest on grass just keep on winning.
Chelsea Starbuck, Research Fellow in Health Sciences,