Posted by: Jack Mankin (MrBatspeed@aol.com) on Thu Jul 1 13:35:55 2010

Hi All

I am starting this month's discussions by outlining the bio-mechanical principles that are reinforced with a new rotational training aid we will soon offer on the site. Over the past few months, other coaches and myself have tested the aid on our students. We find it does a great job in helping the student overcome many of the problems they have in acquiring sound rotational mechanics.

One of the main problems we find in our students is they rely to much on the back-side (Back-Hand Dominate) and make inefficient use of the lead-side. Video analysis of these hitters shows that relying too much on the back-side causes the trajectory of their back-elbow to accelerate much faster than the lead-elbow. This results in their back-elbow trajectory swinging under their armpit and in many cases catching up to the advancement of the lead-elbow (back-elbow under the lead-elbow).

Video analysis of high-level mechanics shows that their lead-elbow accelerates at the same rate as their back-elbow. This means that the distance between their elbows remains relatively constant from initiation to contact. This also means their forearms are accelerating at the same rate (however, in opposing directions).

Below is one of our video clips that discuss the trajectory of the back-elbow of four good hitters. Note, (1) that the distance between their elbows remains fairly constant and (2) approaching contact, their elbows and forearms are applying force from 'opposing' directions -- back-side driving the back-forearm forward as the lead-side pulls the lead- forearm rearward. This result is applying torque (BHT) that really accelerates the meat of the bat to contact.

Four Good Hitters - Back Elbow

Back-side dominate mechanics that cause the back-elbow to accelerate much faster than the lead-elbow results in both forearms moving forward at contact. Both hands applying a forward force induces little torque which results in the bat-head dragging 30+ degrees behind the hands in the contact zone. -- This is what our new training aid is designed to correct. It promotes balanced mechanics where both elbows and forearm accelerate at the same (although opposing) rate.

Jack Mankin