Wimbledon 2013: Is sugar in the grass causing slip-ups? Unusual explanations for spate of injuries among tournament's top players This week at Wimbledon, a succession of highly fancied contenders who crashed out of the tournament complained that "dangerous" court conditions caused them to slip and, in some cases, injure themselves. An extraordinary number of players have retired hurt this year, many of them after taking a tumble. On Wednesday alone, seven withdrew - an all-time record for a single day. Women's number two seed Victoria Azarenka and former champion Maria Sharapova - both of whom had falls - were among many who blamed the grass surface, suggesting it is unusually slippery this year. So are they right? Or is it just a case of bad workmen blaming their tools? Here, Guy Adams looks at possible explanations for so many Wimbledon slip-ups . . . Slippy: Maria Sharapova of Russia slips during her women's singles tennis match against Michelle Larcher De Brito as she crashes out of Wimbledon Too much sugar in the grass In the late Nineties, the All-England Club replaced its traditional "bowling green" grass strains with harder-wearing ryegrass varieties. But the new tough surface also helped the ball sit up higher, resulting in more of the gruelling baseline rallies most likely to cause injury. This year, after a wet winter and late spring, horticulturalists say Britain's lawns and meadows are at the stage they would usually reach in May, when grass is full of sucrose, or sugar. But the club insists its grass is "almost identical" to 2012. Pain: The Russian was heard describing the court as 'dangerous' during her match A new groundsman Neil Stubley recently became head groundsman and this is the first year he has been in sole charge. And several players have complained about his performance. Caroline Wozniacki, for example, wondered if the grass was "a little longer" than usual. But tests show Wimbledon's grass to be exactly the same length - 8mm - as usual. Olympic legacy The Olympic Games were contested on SW19"s hallowed grass in early August last year, dramatically reducing the time available for the club's 16 full-time groundsmen to tear up one set of show courts and lay down the next. Neil Stubley's long-standing predecessor as head groundsman, Eddie Seaward, warned: "My successor will have a month's less time to prepare the grass for the 2013 Championships, and to do the renovation programme." Fashionable footwear Former women's number one Kim Clijsters reportedly said this week that a "new rule" relating to the number of pimples allowed on the soles of players" shoes is causing mishaps. However the Association of Tennis Professionals (ATP) responded, rightly, that there has been no such rule-change. Yet several of this year's leading contenders have tinkered with their shoes at the behest of sponsors. Take Roger Federer, who attempted to use the tournament to launch a new Nike tennis trainer. He was forced to change plans when its orange soles fell foul of the dress code. Two days later, he was out of the tournament. Injured: Russia's Maria Sharapova is treated for an injury after falling over during her match at Wimbledon Beefing up with age When Boris Becker won Wimbledon in 1985, he was a gangly 17-year-old. When Martina Hingis first lifted a trophy on Centre Court in the mid-Nineties, she was just 15. Today's players are a different age, and shape. Federer was a stocky 30 when he won Wimbledon last year. The powerful Serena Williams is 31. Murray and Djokovic are 26, and buff. Nadal is 27, and has famous biceps. Tennis has in recent years been tougher and more physical than at any time in its history. To win, you must be stronger, taller and leaner. As a result, players are pushed more than ever to their physical limits, and this can trigger injuries - especially among older players. The way they run Andy Murray accused his peers of failing to adjust to the demands of grass courts, where the ball comes at them fast and low, placing pressure on knees and ankles. "The way the guys throw their bodies around the court now, they seem to slip down more than they used to," he said. You can't move like that on a grass court; you need to be very particular with your foot placement. Unlucky number seven: Jo-Wilfried Tsonga has became another casualty at Wimbledon Sports scientists agree, saying that the speed and irregularity of the surface means players often hit from an imperfect position, irritating sore joints. That problem is exacerbated by the fact that they play much less on grass than in the past, and have little time to familiarise themselves with the surface. Just a fortnight separates the French Open, which is played on slower, stickier clay, and Wimbledon. "The transition from clay to grass is a flashpoint for injuries," says Karl Cooke, the LTA's sports science manager. All of a sudden the ball is coming through lower, and players have less time to react. An English summer Wimbledon wouldn't be Wimbledon without a moan about the weather. Although the 2013 Championships hasn't suffered any completely rained-off days so far, the weather in SW19 has been peculiarly muggy, with mostly cloudy skies and temperatures in the 20s. A spokesman for the All-England club believes extra humidity is moistening the surface - at a stage of the tournament when virgin grass usually tends to be at its least worn and most slippery.