Why do healthy people get stronger with exercise but people with DMD don’t?

Explanation:

DMD ,Duchenne Muscular dystrophy .

it's an inherited disorder of progressive muscular weakness .

when you do exercise it it strengthens your mascular strength .but a person with DMD which cannot cannot progress its muscular growth because of muscular weakness . they does not get benefit with exercise .

DMD is nothing but it's the stop of the muscular growth .DMD create an obstacle when you do exercise and tries to improve the strength of your muscles as because the growth has already stopped . there will be no change with exercise .

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!