Ground Reaction Forces -GRF-

So what does it man when you hear someone refer to Ground Reaction Forces (GRF)!  Generally speaking it means that the ground is responding to (reacting to) the forces that the body has exerted into the ground. The amount of forces the body drives into the ground equals the amount of forces the ground then reacts to and provides these forces back thru the rest of the body, particularly upper or lower body segments, for a particular movement/action.

And of course the Legs and Hips (L/H) is where this force originates from...Right?  Nope, not in my opinion.  Forces get transferred to the L/H and ultimately into the ground, but it's not the L/H from where forces are originated.  Forces originate from within the CORE. (see blog May 5, 2013 "Core Stability-an absolute must!")

Need more information. I came across an article from the January 2011 issue of The Journal of Strength & Conditioning Research. It stated the following-  "Core stability is achieved through stabilization of one's torso, thus allowing optimal production, transfer, and control of force and motion to the terminal segment during a kinetic chain activity".  And in baseball, this activity is rotation

To further clarify, research performed by Hodges and Richardson, two renowned Physical Therapists,  examined the sequence of muscle activation during whole body movements (kinetic chain activity) and found that some of the core stablizers (TVA, Multifidus, abdominals, and obliques) were activated (core stiffening) before limb movements (terminal segment). All in all, the body transfers forces from CORE to LIMB(s), and the forces we are generating pass thru the entire body (the entire kinetic chain).

Why is this so important? It's because many core exercises are STILL being performed on our butts. And core exercises from the seated/lying down positions do very little in creating the core stiffness necessary for establishing rotational power. In other words they dont transfer very well to on-field baseball performance. I advocate the importance of core stiffness (anti-rotation, anti-flexion, anti-extension, anti-lateral flexion) exercises for all my clients but especially for my baseball players across all levels. Core stiffness/stabilization plays a tremendous role in maximizing ground reaction forces necessary for baseball's rotational power as seen in throwing, hitting & running. 

The Paralell Stance 1-Arm Cable Press is just one example of a core stiffening drill that has positive implication for baseball rotational demands:

Out train the game...and get off the floor to train the core.

-Adam-