Using Ground Reaction Force (GRF)

Most of us know about gravity’s effect, bearing down upon our body keeping us on the earth. The concept of gravity is a downward force, sometimes an oppressive one, which we are left alone to stand up against. There is, however, another force to consider called Ground Reaction Force (GRF). GRF is the push off that opposes gravity! GRF is a physics term I learned in college. It stems from Newton’s concept that for every action there is an opposite and equal reaction. Gravity and GRF are forces of nature that are always affecting us. No matter the direction or angle, gravity and GRF are working together to stabilize you.

In Physical Therapy, I think of these opposing forces acting along the bone segments. In order to harness the possibility of GRF we must understand that GRF and Gravity aren’t just effecting us from top and bottom. As 3 dimensional creatures, we exist up and down, side to side, and front to back in both motion and stillness. The opposing actions of physics are a sum of all these motions. This paradigm shift changed my world.  We talked about 3 dimensions and dynamic motion in PT school, but everything was simplified down to measuring angles, width, length, etc. We collected information in 2 dimensions or less but rarely integrated these observations into the 3 dimension that we feel. I would go so far as to say that as physical therapist we hardly even address the 4^th dimension of time in which we live. Using Aston Patterning in my physical therapy practice, I now integrate all of these observations into a dynamic vision of  the body within both time and space.

Judith Aston has developed the play between gravity and GRF in her work – creating sophisticated technology for keeping your body healthy. We can use our awareness of GRF to un-weight our segments and unload our joints, creating hydration in our tissues.

Try this simple experiment: Rock side-to-side and forward and back. Now push into the floor feeling motion up to down.  You have just experienced GRF in all the planes. Find a comfortable position within these planes. There should be a range of motion in your optimal posture. As you breathe for example, you should notice slight bending and straightening of your spine.  As you inhale the breath straightens you, as you exhale your spine bends.  Your ribs expand side to side and front to back. There is a change in motion up-to-down, side-to-side, and front-to-back throughout each section of your body. None of these motions exist in one plane. You should feel supported from all angles. Now that you have noticed this 3 dimensional wave of motion, try and hold onto the awareness in other daily practices like walking, doing the dishes, or even brushing your teeth. Use GRF and Gravity to support you not just weigh you down. I talked about this concept in my previous post about Good Posture From The Bottom Up.

Judith takes this concept of using the Earth to support our movement even further by suggesting that we also support the Earth’s movements.  I wanted to include a clip of Judith talking on the subject:

If video doesn’t show below click here: Judith Aston Video on Supporting the Earth