Building muscles: Muscle stem cells (their nuclei marked in blue) gradually alter their structure and function, becoming adult muscle cells (whose nuclei turn red). Those cells will eventually fuse ...

This discovery changes the way scientists think about aging. It suggests that part of what we call age-related weakness may actually be a communication problem between the brain and the muscles. As ...

If you have ever lifted a weight, you know the routine: challenge the muscle, give it rest, feed it and repeat. Over time, it grows stronger. Of course, muscles only grow when the challenge increases ...