Nadal hits out again at hard courts, says 20-second rule is too short

Former world number one Rafa Nadal has renewed his attack on hard courts as he prepares for the second tournament on his comeback trail at the Brazil Open.

The 26-year-old Spaniard, who returned to competitive action at the Chile Open last week after a left knee condition sidelined him for seven months, said the number of tournaments played on hard surfaces would limit players' careers. He also criticised a move to speed up matches by strictly enforcing the 20-second rule between points at grand slams.

"Hard courts are aggressive on the knees, back and ankles," the 11-times grand slam champion said. "That is a theme among the players and doctors. To make a change like that [reduce the amount of hard court events] it won't be possible in this generation but I think that the ATP has to work to think of how to lengthen tennis players' careers.

"Can you imagine football players playing on cement?"

Nadal has often been criticised for the length of time he takes between points but warn ings for slow play have been few and far between.

"I don't think the players are happy with the new rule and we'd like it to be modified and that the referee interpret when you can take longer rather than it be something mathematical," Nadal said. "People want to see long rallies and hard-fought points. Twenty five seconds is not enough."