I’m a short skinny lightweight, so fo rme I have to blast rip or shred holes in the ground.
Unfortunately, being light means I have no bulk to toss behind a shovel.
Actually, what it means is that you have to do things scientifically. Keep your shovel sharp, and use it to divide the material to be shoveled.
Once the ground is softened up, leverage comes into play. As with heavy shovels of snow, drag the shovel back with its load instead of lifting it. When ready to lift, use a minimum arc to get the load where it needs to be. Use one arm, or even a knee, as a fulcrum for this motion.
Take smaller amounts, and set a steady pace.
My only problem with shoveling is that I was twice your age, five years ago. My shovel is getting old.
If you'd like, we can invent a shovel for old men. I know how to do it, but we'll need to make prototypes.