“Your mindset is worth more than your body.”

Well, at least it is according to Heather Watson, Great Britain’s No.2 and one of the most consistent British women’s tennis players.

Earlier in the season, Watson sat down with Women’s Health UK as a part of New Balance’s Toughest Opponent series, which discusses the inner battles that athletes have to fight within themselves. She shared her personal tips for how to ace the most important aspects of training and unlocking a positive mentality.

“Tennis, like running, is one of those sports where there’s so many factors you can’t control,” she said. “You need to be prepared for anything that hits you.”

Read on to hear what she had to say on how to improve your speed, stamina, and much more.