What muscles does a high plank work?

Your abs are the target, holding your middle up so the line does not break. Your shoulders carry you on straight arms, your glutes hold the hips level, and your triceps keep the elbows from folding. Nothing shortens, because nothing moves.

Is a high plank the same as a forearm plank?

No. The line of the body is the same and the contact point is not, which changes what your arms and wrists are doing rather than what your trunk is doing. The popular claim that the forearm version works the abs harder rests on one unpublished thesis, so treat it as a lead rather than a finding.

Should I do planks on my hands or my elbows?

Elbows if your wrists are the thing that ends the set, which for most people they are. Hands if you want the shoulder support that comes with straight arms, or if you are building toward push-ups. Neither one is the correct answer to a question about your trunk.

Why do my wrists hurt in a high plank?

Because a large share of you is going through them while they are bent back near the end of their range. Raise your hands on parallel bars or dumbbell handles so the wrist sits straighter, or hold the position on your fists. If something hurts and keeps hurting, that is a question for a physiotherapist.

How do you make a plank harder without adding time?

Move your hands further forward than your shoulders. Measured against an ordinary hold, the long-lever version raised activity in the upper abdominals and at the sides of the trunk, and the reaching was doing more of that than any pelvic tucking. Lifting one foot works too.

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Bodyweight · beginner · waist

Plank

Also called High plank, Straight-arm plank, Plank on hands, Front support, Plank pose, Push-up position hold.

The short answer

The hold demonstrated here is the straight-arm version: palms flat beneath your shoulders, elbows locked out, body held as one line from head to heels while nothing travels anywhere. Most people who say plank mean the elbow version instead, and the difference is not decoration, because straight arms are the top of a push-up and that position has been measured at close to 69 percent of your body mass passing through your hands. Your abs still do the holding, refusing to let your middle drop toward the floor, and your shoulders and glutes own the two ends of the line.

How to do it

Step oneBegin face down on the floor and press yourself up onto straight arms with your palms flat beneath your shoulders.
Step twoLift your hips off the floor so your body forms a straight line from head to heels.
Step threeEngage your core, squeeze your glutes, and keep your hips level throughout.
Step fourHold the position while breathing steadily for the desired duration.
Step fiveLower your knees to the floor to release.

What usually goes wrong

Each starts with what you would notice.

Your wrists give out well before anything in your middle does.

WhyStraight arms stack you over two bent-back wrists, and the load going through them is not small. Held on the toes with the hands under the shoulders, close to 69 percent of a person has been recorded passing into the floor through the hands.

FixPut something under your hands that lets the wrist stay straighter: a pair of dumbbell handles, push-up bars, or your fists on a mat. Dropping to your elbows also solves it, and that is a different exercise rather than an easier one.

Your lower back is the part that aches and your stomach never joins in.

WhyThe middle of you has settled downward, so your back is arching and the front of your trunk has stopped being what keeps you off the floor.

FixSqueeze your backside, tilt your pelvis a fraction toward your ribs, and end the hold the moment the arch comes back. The line going is the set finishing, whatever the clock says.

Your backside is riding high and you could stay there all afternoon.

WhyOn straight arms the hips lift very easily, and once they do you are drifting toward a dog shape, propped between two ends with a good deal less trying to bend you.

FixBring the hips down until your shoulders, hips and heels would all touch one straight edge. Film yourself from the side for a few seconds, because this drift is close to invisible from the inside.

You keep beating your own time and the exercise never gets harder.

WhyMore seconds at a load that stopped challenging you buys more of a quality you already had, rather than raising the demand.

FixLengthen the lever instead. Walking the hands further forward than your shoulders has been measured to raise activity in the upper abdominals and the muscles at the sides of the trunk, and it was the reach rather than the pelvic tuck doing most of that work.

You put your hands on something wobbly and assume that is a free upgrade.

WhyIt does raise the challenge, and it raises something else at the same time. When straight-arm holds were done with the hands suspended rather than on the floor, abdominal and lat activity went up significantly, and so did both average and peak compressive force at the lumbar joints.

FixTreat instability as a real progression with a real cost rather than as a novelty. If your lower back is the reason you picked this exercise, reach the hands further forward on solid ground instead, which raises the demand without raising the compression.

Hands or elbows

This is the question the page exists to answer, and the honest reply starts with what has not been settled. The comparison everyone quotes, that the elbow version works the abs harder, traces to a single unpublished masters thesis on 19 people. Its abdominal readings do favor the elbow version, and the spread around those readings is wide enough to swallow the gap. No peer-reviewed journal has run the same test.

What is not in doubt is where your weight lands. Straight arms put it through two wrists held near the end of their range. Elbows spread the same load down two forearms and take the wrist out of the picture, which is why people who plank for minutes at a time almost all end up on their elbows.

The other difference is your shoulder. Straight-arm support asks the muscle that holds your shoulder blade flat to your ribs to keep doing it under load, which the elbow version largely takes away. That is a reason to own both positions rather than a reason to rank them.

If it is the elbow position you came to look at, the closest demonstration on this site is the weighted plank, which is that exact setup with a plate laid on the back. Read the plate as extra and the position underneath it as the thing you wanted.

This is the top of a push-up

They are the same position. A push-up starts here, travels down and comes back, and this exercise is what is left when you delete the traveling.

That is worth knowing because it tells you what the hold actually costs your arms. With the hands on a force plate, the up position of a traditional push-up came out at 69.16 percent of body mass going through the hands, rising to 75.04 percent at the bottom. Those were 28 strength-trained men, so read it as the shape of the thing rather than as your number.

It also gives you a use for the position that has nothing to do with your abs. If a full push-up is not there yet, holding the top of one is a way to get familiar with carrying that much of yourself on your hands before you ask the arms to move as well.

The compression figure that has nothing under it

The standard argument for planking rather than doing sit-ups comes with a number attached: a plank is said to work the trunk at around 1400 to 1600 newtons of spinal compression, well below what repeated loaded bending produces. The figure appears everywhere, this site included until now. Followed back, there is nothing at the end of it.

The paper it is usually hung on, a 1997 comparison of abdominal exercises from Stuart McGill and Craig Axler, measured 11 exercises and none of them was a plank. Sit-ups, curl-ups, leg raises, hanging raises and a side support are the whole list. A 2004 set of stabilization exercises from the same laboratory has no plank in it either. Whoever first attached newtons to a plank did not get them from those studies, and no later study appears to have measured it.

The sit-up number, by contrast, is real and was modeled directly: above 3000 newtons for both bent-knee and straight-leg versions. So the comparison people make is between a measured figure and a borrowed one.

None of that damages the case for the exercise. Holding a position while your spine stays where it is remains structurally different from bending it repeatedly under load, and that argument never needed a number. It just should not be dressed up as one. What the position will not do is change what covers your abdominal muscles, which no exercise decides.

What it is for

The plank is a bodyweight isometric exercise targeting the abs, maintaining a rigid straight-body position on the hands, with the arms straight and the palms beneath the shoulders, to build core endurance, spinal stability and full-body tension.

Questions people ask

What muscles does a high plank work?: Your abs are the target, holding your middle up so the line does not break. Your shoulders carry you on straight arms, your glutes hold the hips level, and your triceps keep the elbows from folding. Nothing shortens, because nothing moves.
Is a high plank the same as a forearm plank?: No. The line of the body is the same and the contact point is not, which changes what your arms and wrists are doing rather than what your trunk is doing. The popular claim that the forearm version works the abs harder rests on one unpublished thesis, so treat it as a lead rather than a finding.
Should I do planks on my hands or my elbows?: Elbows if your wrists are the thing that ends the set, which for most people they are. Hands if you want the shoulder support that comes with straight arms, or if you are building toward push-ups. Neither one is the correct answer to a question about your trunk.
Why do my wrists hurt in a high plank?: Because a large share of you is going through them while they are bent back near the end of their range. Raise your hands on parallel bars or dumbbell handles so the wrist sits straighter, or hold the position on your fists. If something hurts and keeps hurting, that is a question for a physiotherapist.
How do you make a plank harder without adding time?: Move your hands further forward than your shoulders. Measured against an ordinary hold, the long-lever version raised activity in the upper abdominals and at the sides of the trunk, and the reaching was doing more of that than any pelvic tucking. Lifting one foot works too.
How much of your bodyweight is a high plank?: Around two thirds through the hands. On a force plate the top of a traditional push-up came out at 69.16 percent of body mass, in a group of 28 strength-trained men. The rest of you is on your toes.