This one I got out of a church sermon recently.
It's very easy to massage incorrectly. The most natural way to go about it is to use your hand muscles for everything. You have the most nerves in your fingers, so you can feel the muscles, the knots, the bones, and where pressure is needed. Your elbow? Notsomuch. Also, it's easier to bend over than it is to widen your stance and lower your body so that bending doesn't happen.
But when you use your elbow, you're using your upper arm and back muscles (think about it: MUCH bigger and stronger than the ones in your hand!) to do the work. And when you bend over all the time, well, duh, you're going to throw your back out of whack. More than that, when you have your feet wide apart, your power comes all the way from your back foot out your fingers, rather than from just your shoulders or wrists. The way the teacher described it is that ideally... [okay, this is complicated. Imagine the person is laying face up on the table. If I am working on their left side, I should have my right foot more towards the head of the table and my left more towards the foot of the table, with my torso turned to my right, right leg bent.] ... for my long strokes along the arm or leg, all of my weight should be in my left leg - I should be able to lift the right foot fully off the ground. Using my whole body to do the work.
Life is like that. When we don't depend on God's power to run our lives, it's like we're trying to give a massage from our fingertips and not from our weight-bearing foot. We have so little strength within ourselves. We need Him or else we just end up sore and broken... and forced to depend on Him to keep going whether we want to or not!