20-Min Core & Abs Workout

Overview

Your core does a lot more than crunch. It resists extension, resists rotation, resists lateral flexion, and produces controlled movement. This workout trains all four functions. No sit-ups in weeks 1-2 — on purpose. You'll build a stronger core without wrecking your hip flexors.

Do this workout 3 times per week. It works as a standalone session or tacked onto the end of any other workout.

The Workout

Three blocks plus a finisher. Rest 30 seconds between exercises, 45 seconds between blocks.

Block 1: Anti-Extension (5 min)

These exercises train your core to resist your lower back from arching.

• •Dead Bug: 3x8 per side
• •Lie on your back, arms straight up, knees at 90 degrees. Lower opposite arm and leg toward the floor without letting your lower back lift off the ground. If your back arches, you've gone too far.
• •Plank: 3x30s (work up to 45s)
• •Forearms on the ground, body in a straight line from head to heels. Squeeze your glutes and brace like someone's about to poke your stomach. If your hips sag, you're done with that set.

Block 2: Anti-Rotation & Anti-Lateral Flexion (6 min)

These exercises train your core to resist twisting and side-bending forces.

• •Bird Dog: 3x8 per side
• •On all fours. Extend opposite arm and leg. Hold for 2 seconds at the top. Don't let your hips rotate — imagine balancing a cup of water on your lower back.
• •Side Plank: 2x20s per side (work up to 30s)
• •Stack your feet or stagger them. Hips off the ground, body in a straight line. If 20 seconds is too hard, do it from your knees.
• •Pallof Press (Bodyweight Version): 2x8 per side
• •Get in a half-kneeling position. Clasp hands together, press them straight out from your chest, hold for 2 seconds, then pull back. Your body will want to rotate — don't let it. If you have a band, anchor it at chest height for added resistance.

Block 3: Controlled Dynamic Movement (5 min)

Now we add movement, but slowly and with control.

• •Reverse Crunch: 3x10
• •Lie on your back, knees bent. Slowly curl your hips off the floor, bringing knees toward your chest. Lower with control over 3 seconds. This is not a leg swing — your lower abs do the work.
• •Slow Mountain Climber: 3x8 per side
• •From a push-up position, bring one knee toward your chest over 2 seconds, then return over 2 seconds. No bouncing, no rushing. Keep your hips level.

Finisher: Hollow Body Hold (4 min)

• •Hollow Body Hold: 3x20s (work up to 30s)
• •Lie on your back. Press your lower back into the floor. Lift your shoulders and legs a few inches off the ground. Arms by your sides or overhead for more challenge. If your lower back comes off the floor, bend your knees more.

4-Week Progression

Common Mistakes

• •Rushing through reps. Core work is about control. If you're flying through dead bugs, you're not doing them right.
• •Holding your breath. Breathe out on the effort. Exhale as you press out on the Pallof press, exhale as you lift on the reverse crunch.
• •Letting your lower back arch. This is the number one sign your core has given out. Stop the set when this happens.
• •Only training flexion. Sit-ups and crunches are fine eventually, but they're one of four core functions. Most people are weak in anti-rotation and anti-extension.

What's Next

After 4 weeks, add this workout as a finisher to any strength program, or progress to weighted core work: cable Pallof presses, hanging knee raises, and ab wheel rollouts.