Muscle contraction is the tightening, shortening, or lengthening of muscles when you do some activity. It can happen when you hold or pick up something, or when you stretch or exercise with weights.

Muscle weakness may be due to a chronic condition or an infection. Conditions that can weaken muscles include Addison’s disease, anemia, diabetes, fibromyalgia, and more. Muscle weakness is a lack of ...

It might be more than you think.

The core components of health-related fitness include cardiovascular and muscular endurance, flexibility, and your body’s ratio of fat compared to muscle and bone. It’s well known that being ...

If you're looking to build muscle, it's essential to be realistic about how long it will take (and that it may take you longer than your workout buddies), what it requires and the various factors that ...