TRX

Invented by a former U.S. Navy SEAL, the TRX (short for total-body resistance exercise) turns every exercise into a challenge for your core by using two simple resources: gravity and your body weight.

All you have to do is anchor the TRX straps to a secure spot — think a weight machine, a door frame, or monkey bars if you’re getting creative. Depending on the exercise, you’ll use your feet or hands to hold onto the straps.

In general, a part of your body will be suspended above the floor. You may also be leaning into or away from the straps to create resistance and destabilization.

Knocking your balance out of whack gives you no other option but to adjust, which means engaging your midsection and back and firing up your shoulders and hips to maintain control throughout the movement.