I found FMQing on my domestic machine pretty hard on my entire upper body. If you are FMQing on a domestic machine, I would recommend investing (or making) a suspender system for the quilt while you are working on it. This takes a *lot* of the weight off your body. Here is a link to a commercial system, although some people make their own out of PVC:
http://www.jennoop.com/suspenders.html
And here is a short Youtube video:
https://www.youtube.com/watch?v=gJGph8am6BE