Sit-ups and crunches are mainstays of a classic core workout, but they're not doing your abs as many favors as you might think.
In fact, planks can actually engage more of your midsection — and help you improve your posture, balance and muscular endurance in the process, says Elise Joan, yoga teacher and creator of Barre Blend.
For Week 3 of the 4-Week Plank Challenge, Joan upped the intensity with a set of more challenging plank variations to push your core strength and incorporate more work from your glutes.
Remember, each day you'll do 2 sets of a different plank variation. Hold each plank for 30 seconds, or if you're ready to progress, this week you can aim for 60 seconds. The longer you hold, the stronger you'll get. Just make sure you're able to maintain proper form the entire time.
Joan breaks down this week's moves in the video above. And keep scrolling for step-by-step instructions for each plank variation.
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Challenge Day 15: Classic Plank With Leg Lift
- Start in a straight-arm plank, making sure your body forms a line from head to hips to heels.
- Lift one foot a few inches and hold for 15 seconds.
- Set that foot down.
- Lift the other foot and hold for 15 seconds.
Challenge Day 16: Plank With Hamstring Lift
- Begin in a straight-arm plank.
- Bend one leg at the knee and pulse your foot up toward the ceiling 10 times.
- Lower that leg to the ground and repeat on the other side.
Challenge Day 17: Side Forearm Plank
- Start in a forearm plank.
- Roll to one side, balancing on one forearm and the outer edge of your bottom foot.
- Press into your forearm to keep your hips lifted. Raise your top arm overhead.
- Hold for 30 seconds. When you do this variation again later today, roll to the opposite side.
To modify, bend your top leg and plant that foot a bit in front of you for added support. You can also lower your bottom knee (or both knees) to the ground.
Challenge Day 18: Side Forearm Plank Curl
- Start in a forearm side plank with your top hand behind your head.
- Twist so that your top elbow reaches down toward your bottom elbow.
- Lift back up.
- Keep twisting for 30 seconds. When you do this variation again later today, switch sides.
You can keep both legs straight or modify by bending your top leg and bringing that foot to the ground slightly in front of you for support.
Challenge Day 19: Reverse Plank
- Sit with your legs extended in front of you.
- Place your hands a few inches behind you, fingers pointing toward your feet. Lift your hips off the floor with your weight in your hands and heels. Your body should still be in a straight line from head to hips to heels.
- Hold for 30 seconds.
Challenge Day 20: Lateral Leg Tap Plank
- Begin in a high plank.
- Tap one foot out to the side 3 times. Extend your leg farther on each tap.
- Return to the starting position.
- Repeat on the other side for 3 taps.
- Continue alternating legs for 30 seconds.
Challenge Day 21: Single-Leg Side Plank
- Start in a forearm side plank.
- Lift your top leg several inches.
- Hold for 30 seconds. Switch sides when you do this variation again later today.
To modify, bend your top leg and bring that foot to the ground in front of you or lower your bottom knee.
Ready for More?
Get the final (and toughest!) seven plank variations in Week 4 of the 4-Week Plank Challenge.