How to do mountain climbers: Get into a high-plank position with your wrists directly under your shoulders. Keep your core tight, drawing your belly button in toward your spine. Drive your right knee ...
These low-resistance exercises use your body weight rather than other equipment. You do many repetitions of each move to help build muscle while improving how long you can keep the exercise going.
Hold a dumbbell in each hand at shoulder height, palms facing in. Lower into a squat, keeping your chest up and knees tracking over your toes. Push through your heels to stand up explosively, pressing ...