How to make both hands of the player grip the axe handle durring swing animation?

I created a player model using makehuman and do not know how to make both the player's hands grip the axe while using it. Can someone please help me?

 

Update:
I found out about inverse kinematics. But now I face a new problem, when I press the play button the player's legs bend as if he is crouching. How do I fix this?