This is an intermediate exercise that targets the hips, abdominals, and lower back, while simultaneously increasing shoulder mobility and flexion.
Start in plank position, with your elbows directly beneath your shoulders and your feet hip-width apart. Make sure that your body forms a straight line from your shoulders to your ankles.
Lift your hips so they're higher than your shoulders. Then, lift one foot off the ground and tap it next to your other foot. Return the foot to the starting position, and drop your hips back into the plank position. Repeat with the opposite leg. That's one rep.
Don't allow your hips to sag and drop low at any point.
Press your elbows forcefully into the floor to create more stability.