The TRX (total body resistance exercise) Suspension Trainer [1] is one of the most overlooked pieces of equipment in the gym. Whether you want to target your abs [2], work your arms [3], or get in a killer total-body workout [4], the TRX has got you covered. If you're new to suspension training, the TRX mountain climber is a great introductory move. It'll work your core like never before, and as a bonus, you'll work your arms as well.

Here's how to do it:

• With the straps at mid-calf length, place your feet into each of the foot cradles.
• Lift your knees off the ground, coming into a plank position with your hands directly underneath your shoulders. Your back should be flat, and your core should be engaged (there should be no arch or dip of the torso visible).
• Bring your left knee to your left elbow, then return to your starting position. Bring the right knee to your right elbow. This completes one rep. As you become familiar with the movement, begin to pick up the pace.
• Be sure to avoid sawing (the handles move up and down) the TRX, by putting even weight into the foot cradles.
• Repeat for a total of 15 reps.