Planks begin with hands under shoulders and feet hip-width apart with heels pressing back. On your toes. Pull your core inside and align your hips and shoulders. Hold the plank for 30 seconds, breathing into your ribcage and out through your lips to engage your core.
Mountaineers follow. In a straight-arm plank posture, bring one knee up to your chest, then back, and repeat with the other side. Smith calls this "running" motion. She says, "This is also an effective way to add cardio to your workout routine and shred your abs at the same time."
Start in a plank with feet slightly wider than hip-width apart. Push your hips up to form a downward-facing dog. As you pull your belly button inward and up, touch your right ankle with your left hand. Plank again. Tap your right hand on your left ankle in downward dog again. Maintain arm-ankle alternation.
Leg lifts require lying on your back with both hands beneath your buttocks. Fully raise your legs above your hips. Take a deep breath and slowly drop your legs to one inch above the mat. Maintain straight legs. Exhale and lift your legs over your hips.
The alternate jack knife is Smith's final women's ab workout. Start by lying on your back with your hands over your head and your legs fully extended in front of you. Next, raise your right hand and left leg simultaneously. Use your abs. Your right hand should reach the outside of your left ankle. After a time, slowly lower your arm and leg to the starting position. Repeat with your right leg and left hand.