While many arms exercises are biceps-focused, this simple isolation exercise dials in on the triceps, or the backs of your arms. (If you do find your biceps working overtime, this is a great way to make sure you're building balanced upper-body strength.) "By hugging your elbows in toward your body and using your own bodyweight, this area is majorly targeted," says Speir. And it's really easy to do anywhere. "The great thing about this move is it takes up the smallest amount of space," she adds.
HOW TO DO IT: Start in a bent-knee push-up position with your palms underneath your shoulders and knees bent at 90-degrees. Kick your right leg in front of you and assume a one-arm, one-leg hip bridge. Hold for one count, then reverse the movement and repeat on the other side. Move at a slower, more-controlled pace if it’s difficult, or even try a modified version called “sit-throughs,” where you sit on the outside of your hip as you move to each side.
In a high plank position—palms flat on the floor beneath your shoulders, arms straight. Ease down on to your left forearm. Then, ease down your right arm until you’re in a forearm plank. Now push up with your right hand and then your left to return to a high plank. Repeat, alternating which side you lower first with each rep.” Lagree recommends doing two sets of ten reps. Another workout worth trying: these 9 resistance band exercises that will work your entire body.