Mecanim RigidBody JUMP

Hi

I want to make a character jump, with animation. This is the code:

 ........
 private Animator anim;
 ........
 
 if (Input.GetButtonDown ("Vertical"))
  {
     if (Input.GetAxis("Vertical")>0){
            rigidbody.AddForce(jumpVelocity, ForceMode.VelocityChange);
            anim.SetBool("Jumping",true);
         }
     else{
            anim.SetBool ("Duck", true);
         }
 }

The "Duck" parameter works 100% of the times and the "Jump" function works 100% as a rigidbody with Force, but only 70-80% with the "Jump" animation.

The transition setting in Animator are the same for Duck and Jump. Even if I remove the "Add Force" line, the jump animation still works 70-80% of the times the button is pressed.

I'm using unity 4.3.x.

Any ideea of what I'm doing wrong??

Thank you