How can a ten year old child learn this?

A ten year old child should not train in this method, as they are still growing and it could cause difficulties later in life in the hand and wrist. Additionally, their forearm bones are at risk if the technique is poor, which can happen as a result when they attempt to substitute with strength. Generally, children are not permitted to break boards with their knuckles or fingers, let alone perform pushups on their knuckles. However, if desired, you could take these steps about three times slower to allow the child's body to adapt to the new environmental challenge it is experiencing. Also, don't flex fingers fully straight. Use a slight, strong bend.