Plank jack push-ups work several muscle groups at once, Kenzie said, "including your core and upper body, which makes it a great addition to quick workout routines for those short on time."
- Begin in plank position, with your shoulders over your wrists, your body in one straight line, and your feet together.
- Like the motion of a jumping jack, jump your legs wide, bring your legs back together, then complete a push-up. Jump as quickly as you want, but keep your pelvis steady and don't let your booty rise toward the ceiling.
- This counts as one rep. Kenzie said to start with three sets of 10 reps, then increase to 15 and 20 reps. (Find more footage of this exercise here.) A modified version of this would be plank jacks without the push-ups, seen above.
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