The most important thing for any athlete is to know his ability. If you know your ability and have even a little bit of a strong mindset, you can get success, because your ability takes you to success.

This quote means that it is very important for an athlete to understand their own physical and mental capabilities. If an athlete can have an idea of what they can achieve combined with a strong mental attitude, then that athlete is likely to be successful. Knowing their own ability allows the athlete to recognize how much they can achieve and this can help them reach their goals.