Let's just address the elephant in the room: after looking through her Instagram story [1], how does Kendall Jenner have such a toned core? While we see her napping, lounging and doing her thing, she also trains hard and makes every ab exercise count. Even though a lot of compound exercises engage your core [2], you still need direct core work to tighten up your midsection. We have the workout to make to make your core tone up fast.

This workout kicks off with a bang to tone, tighten, and strengthen your abs all at once. Every move matters and makes an impact. You're sure to feel and see the results for the next couple days.

We sought out this workout from Raphael Konforti, Youfit's [3] national director of fitness. According to Konforti, to maximize results, be sure to rest between each set and move so you can give every rep your best effort. "These four exercises can either be done one at a time or in delayed circuit so you do a different exercise set but still rest about 30 seconds for full effort" Konforti told us.

Ball Pike to Plank

You might need a few practice reps on this move before your first set but it won't take many reps to reap the benefits of this exercise. Start strong and stay strong.

• Start in a plank position with your hands directly under your shoulders and your shins on the ball.
• Keep your feet, hips, and shoulders in one long line.
• As you exhale pull your hips up to fold your body in half, pulling the ball forward toward your hands.
• Your toes will move onto the top of ball and your back will become perpendicular to the floor. Allow your head to fall between your arms, keeping your neck long and in line with your spine.
• Reverse yourself back into a plank position and keeping your hips above your shoulders.
• Do three sets of 8 reps.

Knee Hug Sit-Up

Show yourself and especially your core some love with this exercise. Keeping your feet and back off the ground will keep your core under tension for the entire set.

• Begin sitting, balanced just behind your hip bones, and lean back slightly to lift your feet off the floor; gently pull your knees to your chest.
• Exhale, pull your belly button to your spine, and lean back slightly as you open your arms to the sides and straighten your legs.
• Inhale and return to the starting position to complete one rep.
  Do three sets of 12 reps.

Toe Touch Crunch

Reach for the stars as you reach your toes. Don't be fooled by the name, keeping your legs up puts your lower abs on full notice.

• Lie on your back, and lift your legs and arms up so they are extended toward the ceiling. Lift your upper back off the floor, reaching your hands toward your feet.
• Lower your legs toward the floor while reaching your arms overhead, keeping your shoulders off the mat.
• Repeat the crunch motion to complete one rep.
• Do three sets of 12 reps

Single Leg Lift Crunch

Taking on this move back-to-back with the toe touch crunch is no joke. You'll be training the same movement and muscles from a slightly different angle to make sure you don't miss an inch of abs.

• Start lying on your back with your arms reaching toward the ceiling.
• Exhale and roll up toward sitting while lifting your left leg up. Pause at the top and reach for your toes before rolling down slowly back to the mat. This completes one rep.
• Repeat, all reps on the left leg before switching to the right.
• Complete 12 reps on each side.