Need another option? Go old school. Take an old tire, put on a belt, and attach it to the tire with a 10 to 15-yard cord. You're having to work so much harder than simply running alone, and it'll help increase your stride. You could also run with a parachute - or even in the wind - for added resistance.
- 8 Holiday Cocktails Made with MoonshineMust-try recipes from America's most visited distillery.
- Form CheckThe easy reminders for five basic lifts.
- Recover Like a ProCheck out these 12 game-changing workout recovery tools.
- Best Health and Fitness Breakthroughs of 2014The year's best health and fitness research.