When you lift weights, your muscles grow because of the physical pulling and stretching forces they feel—this is thought to be the main reason they get bigger.

We’re not sure if the soreness and tiny tears in your muscles after a tough workout actually help your muscles grow bigger—or if they’re just a side effect.

When you lift weights, your muscles grow bigger mainly because of the physical tugging and stretching they feel — and scientists think a special protein team (filamin-C and BAG3) might be the muscle’s internal detector that tells the cell to start growing, but we still don’t fully understand how it works.

When healthy young men lift weights until they're too tired to continue, their muscles grow about the same amount in both their arms and legs, no matter how heavy the weights are.

Performing resistance exercises to momentary muscular failure with maximal concentric velocity and controlled eccentric phase induces skeletal muscle hypertrophy.

Doing slow, gentle weight training can build muscle and make you just as strong as lifting heavy weights quickly.