10 Commandos (5 per side). Start in a high plank. Keeping your core tight and hips steady, walk down to your right forearm, then left forearm (so you’re now in a forearm plank). Then step up onto your right hand, then left hand so you’re in a high plank. That’s one rep! Repeat 5x with the right arm leading, then switch to left.
The One Hundred. Lay on your back, with your legs in tabletop. Lift your head, neck, shoulders off the floor and straighten your legs (your core should immediately engage, deeply). Your arms should be straight and lifted a few inches off the ground. Quickly pump your arms up and down, inhaling for 5 pumps and exhaling for 5 pumps. Do 100 pumps total. You should be flattening your waist towards the ground the entire time.
5 Side-to-Side Plank. Start in a high plank. Reach your right arm to the ceiling, so that the front of your body faces the right. Then, pivot back through center, immediately repeating on the left (that’s one rep).
10 Double Leg Stretch. Lie on your back. With your head and shoulders lifted off the ground, bend both legs into your chest and gently use both hands to hug your shins (so you’re curled into a ball). Then, extend both legs out straight in front of you as you reach both of your arms overhead (so your body is now one long line). Keep your low back glued to the ground. Circle your arms out and around back to your shins as move into the starting position (curled into a ball again).
(Immediately transition between these two moves so your core doesn’t get a break).
10 Scissor Kicks. Lie on your back. Extend your right leg up so that it’s perpendicular to the floor. Bring both hands behind your right calf, pulling it in toward your face, and curl your head up. Lift your left leg of the floor a few inches. Swiftly switch legs, grabbing behind your left calf and letting your right leg hover above the floor. Continue switching your legs at a moderate pace, repeating 10 reps per side.
15 Triceps Dips. Sit on the floor with your knees bent and feet flexed in front of you. Place your palms on the floor underneath your shoulders, fingers facing toward your body. With straight arms, lift your butt off the ground. Bend your elbows to lower yourself (keeping butt lifted), then straighten arms again. Repeat 15x.