If the idea of fancy machines and heavy weights is intimidating, you may want to consider total body resistance exercises, or TRX. The latest fitness craze relies on suspension training techniques and resistance for a full-body workout. All you need is a set of straps. “The principals are simple: Use your own body weight to increase strength, tone, and definition without adding bulk,” says Claire Finlay, founder of Transition Zone. Here, she shares four essential TRX exercises: suspension-band rows, single leg squats, lateral jump squats, and mountain climbers. You can step toward the bands for more challenge or away for less — you decide how hard you work. Either way, though, expect a full-body burn.