We don’t really know how much force can be applied to normal tendons much less healing soft tissues. Animal and cadaver studies have given surgeons a general idea. The amount of acceptable force will increase over time as the tissues interface with the bone.
You’re best off to follow your surgeon’s advice carefully. The healing tissue is very weak and can’t hold together with stress or pull. Even the simplest of movements can put a greater load on the surgical site than it can handle.
Most surgeons give their patients specific guidelines to follow. There are some general guidelines for everyone having the surgery you had. There are some just for you based on your age, the condition of your soft tissues and bones, and the type of surgery done. Be sure and ask if you don’t know what are the limits in your case. You wouldn’t want to undo what the surgeon just spent hours (and your money) fixing.