how to teach a child to ride a bike?

[gingerlou]

i recently bought my son a bike for his 5th birthday. it has training wheels on it. he gets on it fine and attempts to use the pedals. the problem he has is that he pedals in the right direction with his right foot, but when that foot reaches the ground, rather than bringing his left foot up and around he pushes it backwards, stopping the bike. i have tried everything i can think of to get him to use both feet in the same direction but it just isnt working. if i try and use my hand to pedal with his foot he fights against it and pushes the other way. any suggestions would be really appreciated. thanks