Why does skin get thicker when stretched? It's a "natural" reaction. First it follows the weight and becomes longer. If the weight is applied regularly and for a long time, the skin would become thinner and thinner. The skin reacts with a kind of reinforcement to hold the weight for a long time without damage. I noticed it when I could no longer put the weights on without jamming the house. I always use split weights so that I can quickly free the eggs in an emergency.