Berlin - Rafael Nadal believes the modern game is too fast, increasing the risk of injuries at elite level, and advocates the use of balls which bounce less to slow things down.
The 30-year-old Spaniard, who has won 14 Grand Slam titles in his career, has been blighted by injury and believes the game should be slowed down to extend players' careers at the top level.
"Today, we play with much more strength. Almost any player can hit a winning point from any position," the current world number 5 told Saturday's edition of German magazine Der Spiegel.
Nadal says the fast pace of modern tennis often requires a violent change of pace and direction which increases the risk of injury.
"The balls travel faster and when you want to return one, you may have to suddenly stop, while playing at a high tempo, or suddenly change direction," he said.
"It's times like these that you can hurt yourself, it's causing us injuries."
The former world number one has not reached a final since winning the ATP tournament in Barcelona in April, his second title of the year.
On Thursday, Nadal suggested he may call an early halt to his season, and hit the practice courts to try to halt a slide in form after his first-round defeat at the Shanghai Masters.