When young men lift weights to build muscle, their muscle-building process speeds up at first but slows down after 10 weeks, even if they keep increasing the difficulty.

Your muscles make more protein at first when you start lifting weights, but after a few weeks, that boost fades—even if you keep lifting harder.

Your muscles make more protein at first when you start lifting weights, but after a few weeks, that boost fades—even if you keep lifting harder.

Your muscles make more protein when you start lifting weights, but after a few weeks, that boost fades — even if you keep lifting harder — no matter if you use heavy or light weights.

When you start lifting weights, your muscles build new protein faster in the first week than they do after 10 weeks, even if you keep training.

After 10 weeks of working out, men who are already somewhat active don't build muscle as efficiently as before, and their bodies don't respond as strongly to exercise—this happens whether they're doing cardio or weight training.