Roger Federer recently shed a light on his sons’ demanding tennis schedule, highlighting the evolving and increasingly challenging nature of the sport in recent years.

Federer and his wife Mirka share four children, twin daughters Myla Rose and Charlene, and twin sons Leo and Lenny. Last month, the 20-time Grand Slam disclosed that all four of his children have developed an interest in tennis, with his daughters visiting John McEnroe’s academy in East Hampton, and his twin sons attending a training camp at Rafael Nadal’s academy in Mallorca.

In a featured interview, the 42-year-old discussed the increasingly demanding nature of professional tennis. He mentioned that that he had noticed this change in his own children, sharing that his nine-year-old sons now follow a rigorous training regimen, practicing four times a week.

The former World No. 1 expressed concerns about the intensity of his sons’ schedule, pointing out that it left them with limited time for other activities.

“I think everything has moved forward. I’m seeing this with my children right now. My nine-year-old sons are now scheduled to play tennis four times a week. I think that’s too much. When is there still time for the other things?” Federer said.

“You always intervene earlier in order to ideally prepare the characters for what is to come. That can be positive and negative, but I’m more cautious,” he added.