Is there a piece of equipment that protects against vibration?
I believe you are using the tool wrong. With a sawsall I have seen many people try and hold the saw in place, I am a big guy 6'5" and close to 300lbs and I could do this for a few minutes but prefer to use the guard to stop the tool from pulling my arms around. Push the guard up to the work and don't try to feed two fast or it will push back. When properly cutting it takes very little effort to hold the tool in place and let it do the cutting. If you do not use the guard to keep the tool from moving the sawsall is putting your arms through what it would take to cut using a hack saw. Keep the saw tight to the work and let it do the work.