Carlos Alcaraz is back at training, and the Murcian player has posted a video showing himself training... with his left hand. Alcaraz is right-handed, and suffered an injury in his wrist that kept him out for most of the clay season, and will also cause him to miss Wimbledon later this month, eyeing an (optimistic) return for the US Open and the American tour in August.
If he is right-handed, why train with his left hand? The obvious reason is that, even if he cannot use his right hand yet, he needs to stay fit, but there's more than that. In his training session, he actually swings the right arm to practice the movement, even if he cannot hold the racket with that hand and returns the ball with the racket in his left hand.
According to Punto de Break, Alcaraz is using the technique called "cross-education", a neuromuscular phenomenon whereby training one limb can help maintain or improve some of the strength, coordination, or activation of the opposite limb, even if it is not being directly trained, by stimulating the nervous system.