Alberto Contador
Contador became a professional in 2003. In 2004 he started to have headaches. A few days later, while he was racing, he crashed and went to hospital. There, doctors found a problem with a blood vessel in his brain. He needed some dangerous surgery, and needed many months to recover (get better). In 2005 he was healthy, and rode in his first Tour de France. He finished in 31st place.