The best upper body workout I get is a byproduct of preparing rough lumber by hand. When my arms feel achy the next day it is a reminder that I should hand plane timber more often.
I’ve been preparing stock for the dulcimers I will build this Winter. I start out by digging through the wood that has been aging in the attic, cutting it to length and then squaring it up in preparation for resawing.
A wooden jack plane gets things roughly flat and I follow up with a #7 and a #5 that have been sharpened with back bevels so the edge is at about 55 degrees.
The higher the angle the smoother the surface and the less tear-out of tricky grain. Since the old Stanley planes have frogs that hold the blade at 45 degrees the back of the blade can be slightly beveled to effectively increase the angle of the edge.
I hone the back bevel by about 10 degrees. The high angle of the cutting edge leaves a surface free of tear-out. The higher the blade angle or bevel the more muscle it takes to push the plane. I find the benefits to be well worth the effort.