Re: Jack: When does BHT take place?
>>> When does BHT start? Right from initiation or at the last minute? I know THT starts right from initiaton by bringing a high back elbow down to your backside, but does BHT start at the same time or right after THT, or just at the very end right when you make contact? Thanks, doug. <<<
For torque to accelerate the bat-head requires the top and bottom hand is applying force from opposing directions. During the initiation of the swing, the rotation of the shoulders is causing the bottom-hand to exert a strong force on the handle around toward the pitcher while the top-hand is being pulled rearward as the back forearm and elbow lowers.
Although the forces from both hands are involved, I refer to torque applied during initiation as THT mainly to distinguish the difference of how the top-hand is uses in rotational transfer mechanics as compared to linear mechanics. With linear mechanics, the top-hand is pushing forward with the palm. With rotational mechanics, the top-hand is pulling rearward with the fingers.
With both linear and rotational mechanics, the forces of the bottom-hand are being directed around toward the pitcher. The problem with linear mechanics is that little torque is applied during initiation because the force of the top-hand is also directed forward (not opposing). This accelerates the knob but leaves the bat-head just trailing behind the hands well into the swing.
Just because I refer to torque applied during initiation as THT does not mean we should not place equal importance on the bottom-hand. I have my students focus on both during their workout. For the bottom-hand to exert a strong force during initiation, I have them focus on getting the lead-shoulder to be pulling rearward (105 degree position) at contact. For the top-hand, I have them focus on accelerating the bat-head rearward to, and through, the lag position as the shoulders start to rotate. Then focus on both – the role of the bottom and top hands working together – but always applying opposing forces.
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