ground reaction forces in golf: a response

if you try to create a rotational movement like a med ball pass standing on a slippery surface, why do your feet move in the opposite direction of the intended rotation??

you use ground reaction force to produce a force-couple/torque which is translated from the feet-ground through the legs to the pelvis to initiate the rotational motion which in turn produces the subsequent coordination to toss the med ball

ground reaction force is the force that is equal and OPPOSITE of the force applied by you into the ground through your feet

when you stand on "sliders" you aren't able to create friction, so the ground is not able to "push back" ... the legs twist in the direction you are applying force

this video/response is in response to a nice video post last week by James Hong to Michael Beaumont regarding the lower body action or mechanism in the golf swing

Some papers on the topic... use the references in each paper as additional resources and/or pubmed or google educational searches on ground reaction forces in swing patterns or in sport biomechanics - also try to google "cavanagh ground reaction forces":

Lower Body Mechanics During the Baseball Swing
 
Ground Reaction Forces and Torques of Professional and Amateur Golfers

A comparison of golf shoe designs highlights greater ground reaction forces with shorter irons

Messier, 1985

Williams and Cavanagh, 1983