5 Reasons why Roger Federer, even at the age of 35, is able to play like he's 25

#2 Strong lower body

Continuing with the body structures, another important element of a tennis player is his leg muscles. The quads, hamstring and calves form the source of power for a tennis player, who has to constantly run, jump and bend throughout his matches.

Federer’s strong leg muscles and light upper body give him extra ammunition to run around the court in this age of baseline play, without exhausting his energy reserves significantly.

Mammoth five-setters at Wimbledon last year, and the Australian Open this year (2017), prove that Federer is able to remain aggressive even in a four-hour plus match. And that wouldn’t be possible if the Swiss didn’t have incredible strength in his lower body to do all the heavy lifting.