Plus, you forget the force of gravity has little to do with mass! This is simple physics. Any object will fall at 9.62 m/s^2 (if i remember correctly). Thus, 100lbs and 10lbs are under being pulled via the same force. Assuming each fiber is equal in strength, then mass has nothing to do with it.
Finally, you also forget that each muscle fiber, bundle of fibers, and muscle belly is held in place by muscle fascia. This fascia is very strong, strand for strand stronger than steel.
I think you need to re-evaluate and formulate a new hypothesis.