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Exercises

Exercises for a flat stomach: crunches, leg raises and planks

Published October 29, 2026

The best exercises for a flat stomach are crunches and cable crunches for the upper abs, lying and hanging knee raises for the lower abs, and the long lever plank and walkout to train your stomach to stay tight. Pair them with full-body moves such as the dumbbell swing and burpee. A flat stomach needs both stronger abs and less fat over them, and that fat comes off with overall fat loss, not from ab work alone. Do 15 to 25 hard ab sets a week over 2 or 3 sessions, 10 to 20 reps each.

  1. Crunch Abs
  2. Cable Crunch Abs
  3. Lying Knee Raise Abs
  4. Hanging Knee Raise Abs
  5. Long Lever Plank Abs
  6. Walkout Abs, Shoulders, Chest
  7. Dumbbell Swing Glutes, Hamstrings

Crunches for the upper abs

Crunches curl your ribs toward your hips, which works the six-pack muscle hardest at its upper end. Start with the floor crunch and toe touch at home, then load the movement with a cable or a decline bench so you can keep adding resistance.

Upper abs, floor crunch

Crunch

Abs

The basic crunch is the simplest way to work the abs through their main job, curling the trunk. It is where beginners should start and a good high-rep finisher later.

How to do it

  1. Lie on your back with your knees bent, feet flat, and your arms reaching straight forward at shoulder height.
  2. Breathe out and curl your head and shoulders up until the shoulder blades clear the mat, sliding your hands toward your knees as your ribs move toward your hips.
  3. Pause for a second when your shoulder blades are just off the floor.
  4. Uncurl slowly until your shoulders touch down, then start the next rep.

Cues

  • Ribs to hips
  • Reach, don't pull
  • Exhale up

Common mistakes

  • Jerking your arms forward to get up: the reach follows the curl, your abs start it.
  • Bouncing off the floor: lower under control so every rep starts from rest.

Swap for: Decline Crunch, Cable Crunch

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Upper abs, legs-up crunch

Toe Touch Crunch

Abs

With your legs straight up, the reach toward your toes keeps the work in your abs instead of your hip flexors. Hold a light ball as in the demo, or do it with empty hands.

How to do it

  1. Lie back with your legs straight up and a light ball or nothing in your hands.
  2. Reach your hands up toward your toes by lifting the shoulder blades.
  3. Lower your shoulders with control.

Cues

  • Reach up, not forward
  • Legs still

Common mistakes

  • Swinging the arms to get up: slow the reach.

Swap for: Crunch, Reverse Crunch, Cable Crunch

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Abs, weighted crunch

Cable Crunch

Abs

Standing with your back to a high cable lets you load the crunch like any other muscle and add weight in small steps. It is the best gym option for building ab muscle that shows when body fat is low enough.

How to do it

  1. Attach a rope to a high pulley, turn your back to the stack and hold the ends behind your head.
  2. Step forward so the weight lifts, then brace your hips in place and curl your ribs down toward your pelvis.
  3. Pause when your trunk is fully curled, then let the rope pull you back up slowly.

Cues

  • Ribs to pelvis
  • Hips still
  • Round, don't hinge

Common mistakes

  • Hinging at the hips so the body weight pulls the stack down.
  • Pulling the rope with the arms instead of keeping the hands at the head.

Swap for: Machine Crunch, Decline Crunch

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Abs, decline sit-up

Decline Crunch

Abs

The decline bench makes the curl harder by putting your torso below your hips, and holding a plate on your chest makes it harder still.

How to do it

  1. Hook your feet under the pads of a decline bench and lie back with your fingertips lightly behind your head.
  2. Curl up, chin tucked, until your trunk is upright.
  3. Lower slowly, one segment of the back at a time.

Cues

  • Curl up
  • Slow down
  • Plate at chest when easy

Common mistakes

  • Throwing the arms forward to sit up.
  • Dropping back fast and bouncing off the bench.

Swap for: Plate Sit-Up, Cable Crunch

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Knee and leg raises for the lower abs

Lifting your legs makes the lower abs curl your pelvis up, the part of the stomach that sits below the belly button. Begin lying down, then move to hanging when you can control the swing.

Lower abs, knee raise on the floor

Lying Knee Raise

Abs

Drawing your knees in while your lower back stays on the mat trains the lower abs with no equipment. It is the first lower-ab move for beginners.

How to do it

  1. Lie face up on a mat with your knees bent, feet flat and fingertips resting lightly behind your head.
  2. Press your lower back into the floor and lift your feet.
  3. Draw your knees in toward your chest, keeping them bent.
  4. Lower your feet back out until your heels hover just above the floor, then repeat.

Cues

  • Low back down
  • Knees in
  • Heels hover

Common mistakes

  • Arching your lower back as the legs go out: shorten the range until you can keep it flat.
  • Dropping your heels to rest between reps: keep them hovering so the next rep starts under load.
  • Pulling on your head: your hands only rest there.

Swap for: Reverse Crunch, Captain's Chair Knee Raise

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Lower abs, alternating leg lift

Alternating Leg Raise

Abs

Lifting one straight leg at a time is harder than a knee raise but easier than raising both. It bridges the floor and hanging versions.

How to do it

  1. Lie on your back, legs straight, fingertips resting lightly behind your head.
  2. Press your lower back into the floor and lift both heels a few inches.
  3. Lift one straight leg toward the ceiling while the other stays just off the floor.
  4. Lower it as the other one comes up, switching legs in a smooth scissor.

Cues

  • Back stays flat
  • Long legs
  • Slow switch

Common mistakes

  • Letting the lower back lift off the mat: keep the bottom leg higher until it stays down.
  • Rushing the switch so the legs swing rather than lift: count two seconds up and two down.
  • Pulling on your head: your hands only rest there, elbows wide.

Swap for: Lying Knee Raise, Hanging Leg Raise

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Lower abs, hanging

Hanging Knee Raise

Abs

Hanging from a bar and curling your knees up makes your lower abs lift your whole lower body. It is the hardest lower-ab move on this page and the one to work toward.

How to do it

  1. Hang from the bar with straight arms and your legs together.
  2. Draw your knees up toward your chest and curl your pelvis up at the top.
  3. Lower your legs slowly until they hang straight and still.

Cues

  • Curl the pelvis
  • Stop the swing
  • Slow down

Common mistakes

  • Swinging into each rep: pause at the bottom until you are still.
  • Lifting the knees only to hip height, which works the hip flexors more than the abs.

Swap for: Captain's Chair Knee Raise, Reverse Crunch

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Planks that train your stomach to stay tight

Holding a long plank teaches your abs to keep your belly drawn in while the rest of your body works. The walkout adds movement to the same idea and doubles as a warm-up.

Abs, hard plank

Long Lever Plank

Abs

Moving your elbows forward of your shoulders makes a plank much harder in seconds instead of minutes. Short hard holds train the stomach to stay tight better than long easy ones.

How to do it

  1. Get into a forearm plank, then shift your elbows forward until they sit a few inches in front of your eyes.
  2. Squeeze your glutes and tuck your tailbone slightly so your lower back flattens.
  3. Hold your body in a single line, head to heels.
  4. End the hold when your hips begin to sag, rest, and go again.

Cues

  • Glutes tight, ribs down
  • Elbows forward, not wide
  • Short, hard holds

Common mistakes

  • Raising your hips to take the strain off: keep the line and hold for less time.
  • Holding your breath: breathe short and steady through the hold.

Swap for: Plank, Ab Wheel Rollout, Stability Ball Body Saw

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Abs and shoulders, hand walk

Walkout

Abs, Shoulders, Chest

Walking your hands out to a plank and back works your abs, shoulders and hamstrings in one move. It is a good first exercise of the session.

How to do it

  1. Stand with feet hip-width, hinge at the hips and put your palms on the floor, bending the knees as much as you need.
  2. Crawl your hands out one at a time into a high plank.
  3. Hold a beat, then crawl the hands back toward your feet and roll up to standing.

Cues

  • Brace your stomach in the plank so your hips do not sag.
  • Keep the legs as straight as you comfortably can on the way down.

Common mistakes

  • Letting the hips drop in the plank.

Swap for: Bear Crawl, Spider Plank

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Full-body moves for fat loss

Swings and burpees use your legs, back and core together and push your heart rate up, so they burn far more than any crunch. Put them first in a session when fat loss is part of the goal.

Glutes and hamstrings, conditioning swing

Dumbbell Swing

Glutes, Hamstrings

Swinging one dumbbell from the hips trains the back of your body and keeps your heart rate high. Sets of 15 to 20 make it a fat-loss tool that also builds muscle.

How to do it

  1. Hold one dumbbell by one end with both hands, feet a little wider than your hips.
  2. Hike the dumbbell back between your legs by hinging at the hips.
  3. Snap your hips forward so the dumbbell floats up to chest height on its own.
  4. Let it fall back between your legs and hinge into the next rep.

Cues

  • Hinge, do not squat
  • Hips drive, arms just hold
  • Stand fully tall at the top

Common mistakes

  • Lifting the dumbbell with your shoulders instead of driving it with your hips.
  • Letting the dumbbell drop toward your knees on the backswing; keep it high between your thighs.

Swap for: Kettlebell Swing, Dumbbell Romanian Deadlift, One-Arm Dumbbell Snatch

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Full body, conditioning

Burpee

Quads, Glutes, Chest, Shoulders

The burpee drops you to the floor and back up, working legs, chest and core in every rep. Use it in short rounds; quality drops fast when you are tired.

How to do it

  1. Stand tall, then squat down and plant your palms.
  2. Kick your feet back into a plank.
  3. Jump your feet back under you.
  4. Stand up and jump, reaching your arms overhead.

Cues

  • Fast down, fast up
  • Solid plank
  • Land soft

Common mistakes

  • Sagging hips in the plank: brace on every rep.
  • Slowing to a walk-out: keep it crisp or rest.

Swap for: Half Burpee, Mountain Climber, Dumbbell Burpee

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Put them together: example sessions

Each session below picks from the exercises above for one situation, with the sets, reps, rest and RIR filled in.

Session 1

Starting at home with no equipment

Open in the session builder
  • Workouts3× a week
  • Working sets24 a week
  • Per workout~15 min
  • EquipmentBodyweight

You are new to ab training, you have a mat and 15 minutes, and you want to start three times a week at home.

Each session is 8 sets: one upper-ab move, one lower-ab move and one hold or walkout, about 24 hard sets a week. Abs recover quickly, so three short sessions build the habit faster than one long one.

Abs A
ExerciseSets × repsRIRRest
Crunch 3 × 10–20 2 1 min
Lying Knee Raise 3 × 8–15 2 1 min
Long Lever PlankSeconds per hold. 2 × 15–30 2 1 min

Open Abs A in the session builder

Abs B
ExerciseSets × repsRIRRest
Walkout 2 × 5–8 3 1 min
Toe Touch Crunch 3 × 10–15 2 1 min
Alternating Leg RaisePer leg. 3 × 8–12 2 1 min

Open Abs B in the session builder

How to run it
Spread Abs A and Abs B over three days with a gap between each, e.g. Tuesday, Thursday and Saturday.
How to progress
Each week, aim for 2 more reps or 5 more seconds on every set. When a move passes the top of its range at the target reps in reserve, move to the next version: toe-touch crunch to cable crunch, lying knee raise to alternating leg raise.
Open in the session builder

Session 2

In the gym, building visible abs

Open in the session builder
  • Workouts2× a week
  • Working sets18 a week
  • Per workout~20 min
  • EquipmentDumbbells, Adjustable Cable, Pull-Up Bar, Decline Bench

You lift in a gym already and want to build ab muscle that shows, with weighted work you can progress like any other lift.

Two sessions of 9 sets give 15 ab sets a week, mostly weighted, plus 3 sets of swings to open one session. Abs grow like other muscles, so loaded sets of 10 to 15 close to failure build more than endless bodyweight reps.

Session A
ExerciseSets × repsRIRRest
Dumbbell Swing1 warm-up set first 3 × 12–15 2 90 s
Cable Crunch 3 × 10–15 1 1 min
Hanging Knee Raise 3 × 8–12 1 75 s

Open Session A in the session builder

Session B
ExerciseSets × repsRIRRest
Decline CrunchPlate on the chest when easy. 3 × 10–15 1 75 s
Hanging Knee Raise 3 × 8–12 1 75 s
Long Lever PlankSeconds per hold. 3 × 20–30 1 1 min

Open Session B in the session builder

How to run it
Bolt Session A and Session B onto two existing gym days, after your main lifts, with a rest day between them.
How to progress
Once all sets reach the top of the range at the planned reps in reserve, make it harder: a plate more on the cable crunch, a heavier plate on decline crunches, or a slower lowering on hanging knee raises.
Open in the session builder

Session 3

Losing fat at home in 20 minutes

Open in the session builder
  • Workouts3× a week
  • Working sets39 a week
  • Per workout~25 min
  • EquipmentDumbbells

You are losing weight, you train at home with one dumbbell, and you want sessions that burn more than a floor routine while still working your abs.

Two full-body moves open each session for 7 sets, then two ab moves add 6 more, 13 sets in about 20 minutes. Three sessions a week give the abs 18 sets and add hard conditioning on top.

Circuit
ExerciseSets × repsRIRRest
Dumbbell Swing1 warm-up set first 4 × 15–20 2 1 min
Burpee 3 × 6–12 3 1 min
Crunch 3 × 15–25 1 45 s
Lying Knee Raise 3 × 10–15 1 45 s
How to run it
Do the circuit on three non-consecutive days and walk on the others. Move between exercises with the listed rest only.
How to progress
Add reps across the set range first. Then use a heavier dumbbell on the swing, and move from lying knee raises to alternating leg raises once 15 reps feel easy.
Open in the session builder

Make it fit you

Questions

How can I flatten my tummy?

Lose body fat by eating a little less than you burn, walk most days, and train your abs 2 or 3 times a week with crunches, knee raises and planks. Lifting weights for the rest of your body helps by keeping your muscle while the fat comes off.

Can walking for 30 minutes reduce belly fat?

Walking 30 minutes a day burns extra energy every day, which adds up to fat loss over weeks, including from your belly. It works best combined with a small calorie deficit and strength training.

Do crunches flatten your stomach?

Crunches build the abdominal muscle, which makes your stomach firmer. They do not burn the fat on top of it. You need both: stronger abs and lower body fat.

What is the best time to exercise for a flat stomach?

The time you can stick to. Morning, lunch and evening sessions give similar results when the training and eating are the same, so pick the slot you will keep for months.

How long does it take to get a flat stomach?

It depends on how much fat you have to lose. Your abs get stronger within a few weeks; a change you can see takes months rather than weeks, and longer the more fat there is to lose.