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. Sprint interval ...

HIIT, or high-intensity interval training, is increasingly popular, and it provides plenty of benefits, from torching calories to increasing your VO2 max and overall athletic performance. SIT, or ...

Isometrics are strength training exercises that focus on building strength through muscle contractions instead of movement.

The sit-up has dominated workout routines for decades, but fitness professionals increasingly question whether this familiar movement deserves its place in modern training programs. The issue isn’t ...