Ready to step outside your comfort zone... and up onto a plyo box? This super spicy power-building workout is tough and will challenge you in ways the most grueling long run can’t—and that’s on ...

Gains are just around the corner.

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. While plenty of ...