I want to make the bike kid ride his bike.

I know that I could make this look good if I could use a function for time as a velocity for certain parts of his body. Basically what I want to do is have his left foot move forward at a speed of f(x) and upward at a speed of g(x). I want to use formulas for harmonic motion to do this. Any ideas?

[ottosparks]

Here's an example Hope it helps!