Muscle fatigue is a decreased ability to create force with your muscles. Electrolyte imbalance and overuse are some of the most common causes of muscle fatigue. Rest and massage are the best ways to ...

Beth Skwarecki is Lifehacker’s Senior Health Editor, and holds certifications as a personal trainer and weightlifting coach. She has been writing about health for over 10 years. January 26, 2023 Add ...

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.