Answer: Your son is very
young, far too young for you to be overly concerned about starting his
physical fitness training.
Another word of caution. You say that you
don't want to force him to play any particular sport but then you say that
your dream is to have him represent his country in the Olympic Games. If
it is your dream but not his dream, you are both probably heading for
difficult and troublesome times as he gets older.
My advice is to expose him (don't push or
pressure him) to a variety of games when he is young (starting now). Games
that involve hand/eye coordination, foot/eye coordination. Play catch with
him with all shapes and sizes of balls. Have him kick soccer balls and
footballs. Have him swing plastic bats/racquets/clubs at plastic whiffle
balls. When he is ready, take him skating or skiing. Have him shoot
mini-basketballs at mini-baskets.
These games should be fun for him. He will
show you the things he enjoys most by his enthusiasm and delight.
Gradually expand those games into learning situations to improve his
technique, but be careful not to take the fun out of the play. Avoid
frustrating situations, i.e. situations that may require far more skill
than his current level. Remember that his attention span is not very long,
so understand when he gives up or moves to a new activity quickly.
Don't get too hung up on making him into a
superstar so early. He may or may not fulfill your dream. Instead focus on
making sure he enjoys his youth, his development and his play time. If it
is to be, his development into a skilled athlete will occur naturally, not
because you forced it. In any case, you should be there to help, support
and love him whatever his athletic abilities may be.