How to Do Your Own Core Assessment

The core test turns four plank holds into two comparisons: your left side against your right, and your reverse plank against your front plank. All you need is a floor, a timer, and something to write on. This page covers what the test measures, how to take it on your own, and how to read your numbers.

For why these comparisons matter, read What Your Core Really Is.

Who This Test Is For

This test is for anyone who can answer no to all three questions under Before You Test.

Coach's Note: Cannot hold a full plank yet? Do it from your knees. If that is too much, do it on an incline on a bench. If that is still too much, lean against a wall.

Coach Max

What It Tests

Your core is more than your abs. Think of it as a cylinder: a front wall, side walls and a back wall. Each plank loads one part of it.

• Front plank: the front wall. It is what keeps your low back from sagging when you stand, carry and lift all day.
• Side plank: the side walls. Your obliques, plus the hip muscles that stop your pelvis dropping every time you take a step.
• Reverse plank: the back wall. It loads the muscles either side of your spine along with your glutes.

The times matter, but the comparisons matter more. Your left side against your right shows whether one side gives out sooner. Your reverse plank against your front plank shows whether the back of your core keeps up with the front.

The idea comes from spine researcher Stuart McGill's core endurance tests, which compare holds against each other.

What You Need

• A clear stretch of floor, long enough to lie out flat.
• A timer. The stopwatch on your phone works.
• A way to count one minute of rest between holds.
• Something to write on: a pen and paper.
• A partner or a camera, if you have one, to count you in and watch your hips.

Before You Test

Every hold in this test is a maximal effort, so answer these three questions first:

1. Has a doctor ever told you to avoid intense exercise?
2. Do you get chest pain or unusual dizziness during activity?
3. Any current injury this test could make worse?

Yes to any? Sit this one out for now and check with your doctor. This test will be here when you are cleared.

How to Take the Test

Four holds, always in this order: a front plank, a side plank on each side, and a reverse plank. Rest one minute between holds.

1. Front plank. Forearms down, elbows under your shoulders. One line from heel to head, chin tucked. Squeeze your glutes, pull your ribs down and brace like you are about to take a punch. Eyes on the floor just ahead, not up. Belly button to spine. Write down your time.

   

2. Side plank, on both sides, left then right. Forearm down, elbow under your shoulder, feet stacked. Head in a straight line, chin tucked. Build the tension first, then lift the hips. Push the down shoulder away from your ear. Keep one line from ear to ankle. Belly button to spine. Write down both times.

   

3. Reverse plank. Face up, legs straight, heels down. Hands under your shoulders. Point your fingers toward your feet or away from them, whichever feels better on your wrists and shoulders. Drive your hips to the ceiling and hold them there. Squeeze the glutes hard, open the chest, and do not let the hips sink. Belly button to spine. Write down your time.

   

4. Check your two comparisons with the calculator below.

The rules for every hold

• Get set, then start the clock. Get into position first. With a partner, have them count 3, 2, 1, Go, and start the clock on Go.
• Stop the clock when your hips drop, or when you come down.
• One minute of rest between holds, your two sides included. When the minute is up, get set for the next hold. There is no rest after the reverse plank: the test is done.
• All four, every time. Your two sides make one comparison, your front and reverse make the other, so you need all four numbers.

This test is coming to Built & Balanced as one of its self-checks. If you let its camera time you, you get three seconds to fix each break, which timing yourself does not give you, so compare self-timed results with self-timed results.

Your Calculator

Your two sides, step by step.

1. Subtract the shorter side from the longer side. That is your gap, in seconds.
2. Divide the gap by the longer side, then multiply by 100. That is your gap as a percent.
3. Keep the decimals. 5.0 percent or under counts as even. Anything over 5.0 is a gap, even one that rounds down to 5.

For example, left 62 seconds and right 71 seconds is a 9-second gap. 9 divided by 71, times 100, is 12.7 percent: a gap.

Your front and back. Just shoot for your reverse plank to at least match your front plank, then beat it.

How to Read Your Result

Your two sides. Do not overcomplicate it. Just shoot for balance.

Your front and back

Our coaching target is a reverse plank that at least matches your front plank, and then outlasts it. Long term, shoot for 1.5 times as long. It is a coaching target, not a medical standard.

• They matched. Your reverse plank matched your front plank. That meets the target. Next step: outlast it.
• Your reverse plank lasted longer. Your reverse plank outlasted your front plank by (the difference). That is the direction we train toward.
• Your front plank lasted longer. Your front plank outlasted your reverse plank by (the difference). That gap is your target to close.

Those two comparisons show you where to start: your weaker side, or the back of your core.

Your numbers are where you start, not a judgment about who you are.

Retest after 4 weeks of consistent effort. Time it the same way and in the same order, so your next test compares to this one.

Spencer Maxwell Shilstone

Performance Systems Builder · Founder, MaxWell Nutrition

Founder of MaxWell Nutrition and Shilstone Performance Systems. Spencer works with teams and individuals to help them reach their performance goals. He has the honor and privilege of working with and building integrative performance programs for members of U.S. Army Special Operations Command. Optimum Performance is his column at MaxWell Nutrition.