Why Can’t I Just Do Free Weight Extension Exercises?
If you do not have Carpal Tunnel Syndrome (CTS) than you certainly can. BUT, if you have CTS, turning the hand/wrist into a palm-down position causes the radius and ulna to cross over each other like an “X”, twisting the muscles in the forearm and impinging the carpal tunnel even further. (Like rolling up an egg in a dish towel and then twisting it tighter and tighter. It’s going to crush and break the egg.) This is what happens in the small confines of the carpal tunnel.
In addition to the increased pressure on the carpal tunnel as you hold the weights in the palm down position, you are enhancing the pressure even more by gripping/squeezing with the wrist / finger flexor muscles and finger adductor muscles. And then on top of that, you extend the wrist backwards, stretching the flexor muscles while they are in a contracted position. This causes a massive increase of pressure within the carpal tunnel as well as a narrowing of the carpal tunnel. And as you flex and extend the wrist against resistance, the flexor tendons are dragging back and forth in a space that has no room, causing friction of the flexor tendons and median nerve, resulting the the swelling of the tendons and median nerve.
Pure extension in a palm-up or neutral position is the key to recovery for those who are suffering from CTS caused by a muscle imbalance.