They started early, per the Orange County Register:
"Since he was 3 years old he's been training Karate and wanting to be a fighter. It's not just any Karate, it's Machida Karate. He incorporates a lot of things that the sport of Karate has taken out. He utilize elbows and knees, which in the sport of Karate they don't do. It goes back to the training and being Machida Karate."
Machida said his father never forced him to train. It was just something that came natural to him and he wanted to be around it all the time.
"It wasn't the same kind of training that you would do like a pro athlete," Machida said. "It's not like I was there and my father was forcing me to train. Even if I wasn't training I was there at the academy every day running around. I would go train for 20 minutes and watching you learn a lot. I was just in that environment. My son is 1 year old and he's already copying my punches."
Machida had a black belt in Karate by the time he reached his 13th birthday. He also began training in Sumo at 12 and Brazilian Jiu-Jitsu at 15. But Karate, specifically, Machida Karate has always been his first love.
And they ran a tight ship at Casa Machida, per MMA Weekly:
Lyoto grew up in his dad's dojo and began learning the art at age three between the usual stuff of a kid's life. Until the age of 10, dad was a stern disciplinarian.
When Lyoto or his brothers Chinzo and Take got into trouble, Yoshizo would make them sit on their ankles for an hour or more, eyes closed, facing a wall.
With all the fights, Lyoto learned to sit and be still from an early age.
"Up until 10 years old, that's when you can instill discipline," said Yoshizo. "I did everything I could the first 10 years, and then they're on their own. Every day I was telling them what they can and can't do."
Even with tens of thousands of budding MMA fighters beginning to train seriously at very young ages in America, very very few will have the kind of upbringing that have made Lyoto Machida such an effective MMA fighter.
But somewhere out there, probably in the USA but possibly in Brazil, Japan, Russia, Canada or the European Union, maybe even in China, there is an Earl Woods (father of Tiger) or Richard Williams (father of Venus and Serena) who's training their little wunderkind right now.