Biophysics Problem 44

In a high dive, why does the human body in a tucked position rotate so much faster than in an extended position?

First Step

Remember that the angular momentum is conserved.  Angular momentum is the produce $I \;\omega,$ where $I$ is the moment of inertia, and $\omega$ is the angular frequency.

This question boils down to whether your moment of inertia $I$ is more more or less when your body is tucked than when it is extended.

From your readings, you should realize that $I$ gets less when your body larger when your body is tucked.  Because of Conservation of Angular Momentum, the angular frequency $\omega$ must increase if $I$ decreases.

Thus, your body rotates faster (i.e. it has a larger $\omega$ when it is in a tucked position.