When it comes to building a strong, stable core, doing endless crunches isn’t the most effective approach. In fact, you can achieve better results with just three powerful core exercises that engage your entire midsection, as well as your arms, legs, and heart.
These core exercises offer more than just a focus on the abdominal muscles — they engage the entire body, improve posture, enhance stability, and even increase heart rate. Instead of grinding through 100 crunches, try this smarter, more efficient routine.
3 Core Exercises to Flat Belly That Beat 100 Crunches
1. Plank
Muscles Targeted: Transverse abdominis (deep core corset), rectus abdominis (front abs), obliques (sides), shoulders (deltoids and stabilizers), glutes, quads, and lower back (erectors).
How to do it (step-by-step):
- Start by lying face down with your forearms on the floor, your elbows directly under your shoulders and your forearms either parallel or with your hands clasped together.
- Extend your legs backwards with your toes curled under and your feet hip-width apart.
- Lift your entire body into a straight line from head to heels, ensuring that your hips do not sag and your butt does not pike.
- Engage your core — pull your navel towards your spine and squeeze your glutes and quads.
- Keep your neck in a neutral position, gazing slightly forward of your hands (not up or down).
- Keep your shoulders pulled away from your ears to maintain a long neck.
- Maintain this perfect position and breathe steadily at a normal rhythm (do not hold your breath).
- Perform 3 sets of 30–90 seconds (start at 20–30 seconds and build up).
Tip: If you start to shake, then drop to your knees for a moment, then stand back up and carry on.
Why it works:
The plank is the gold standard of isometric core exercises. It builds deep core endurance, activates all layers of the abdominal wall — especially the transverse abdominis, which pulls in the belly — strengthens posture muscles, and creates metabolic demand, or calorie burn, even when you’re not moving. Unlike crunches, the plank trains anti-extension strength, which is the ability that flattens the stomach and protects the lower back in real life.
2. Mountain Climbers
Targeted Muscles: Core (rectus abdominis, obliques, and transverse abdominis), hip flexors, shoulders and arms (stabilization), quads, and cardiovascular system.
How to do it (step-by-step):
- Start in a high plank position with your hands directly under your shoulders and your body in a straight line from head to heels. Engage your core and glutes.
- Quickly drive your right knee forward towards your chest, so that your foot hovers or lightly taps the floor.
- Immediately switch — drive your left knee towards your chest while extending your right leg straight back.
- Alternate legs rapidly, as if running in place while holding a perfect plank.
- Keep your hips low and stable — do not rock, bounce or pike.
- Maintain plank alignment with your shoulders over your hands and your back flat.
- Duration/reps: three sets of 30–60 seconds (or 20–30 reps per leg).
Tip: Prioritise core stability — ‘plank first, knees second’. Speed is good, but good form is better.
Why it works:
Mountain climbers transform the plank into a dynamic, high-intensity exercise for the core and cardio system. They maintain constant tension throughout their core, significantly increasing their heart rate and burning fat. This strengthens their abs, especially their lower abs, improves their endurance and trains their hip flexor power and coordination. The rapid knee drives also engage anti-extension strength, helping to flatten the belly more effectively than static holds alone.
3. Chair Dip
Muscles Targeted: Triceps (back of arms — main flab area), chest (pectorals), shoulders (anterior deltoids), and core (stabilization and anti-extension).
How to do it (step-by-step):
- Sit on the edge of a sturdy chair, bench or sofa with your hands gripping the edge beside your hips and your fingers pointing forwards.
- Slide your hips forward off the seat with your legs extended straight in front (or with your knees bent at 90° for an easier version).
- Keep your shoulders down and away from your ears — don’t shrug.
- Bend your elbows and inhale as you lower your body straight down until your upper arms are parallel to the seat (or lower if you are flexible).
- Keep your torso upright or slightly forward; don’t let your hips sag backwards or lean too far forwards.
- Exhale and push through your palms to straighten your arms, squeezing your triceps hard at the top.
- Repeat in a controlled manner — no bouncing or swinging.
- Repeat for 3 sets of 10–15 repetitions.
Tip: To maximise triceps activation, keep your elbows pointing straight back (not flaring out).
Why it works: Chair dips put intense pressure on the triceps, which are the primary muscles responsible for “flabby” or “batwing” upper arms. They also engage the chest and shoulders, improve posture by pulling the shoulders back, and force the core to stabilize the torso, making them a true compound upper body and core exercise. When performed correctly, chair dips can help tighten the underarm area and reduce the appearance of sagging.
Try doing all three core exercises in a row as a finisher to your workout, or as a quick, stand-alone routine. Your body will thank you, and you’ll see faster results than with basic crunches.
