Muscle twitches fall into two main types. There’s myoclonus, where a whole muscle or group of muscles twitch or spasm. Then ...

Plus, exactly how to train to sculpt your muscles.

If you have ever lifted a weight, you know the routine: challenge the muscle, give it rest, feed it and repeat. Over time, it ...

Understanding how muscles grow is the key difference between training hard and training effectively. Muscle hypertrophy is ...

Global growth is projected at –4.9 percent in 2020, 1.9 percentage points below the April 2020 World Economic Outlook (WEO) forecast. The COVID-19 pandemic has had a more negative impact on activity ...

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 ...

Dr. Valerie Cholet is a Professor of Kinesiology. She earned her doctorate at Penn State University and has taught in higher education for over 20 years. Her areas of specialization include Exercise ...

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 12, 2026 Add ...

Oluseun Olufade, MD, is an Orthopedic Surgeon and Assistant Professor of Orthopedics at the Emory School of Medicine. Rest and changes in activity can help treat back spasms that cause lower back pain ...