The BEST Core Exercise

Okay, technically they are the two best core exercises, but the Roll-out

and the Stability Ball Pike/Knee-In

are, in my opinion, the most complete core exercise combination. Period.

Here’s why

  1. They address the two primary functions of the core musculature unlike any other movement.
  2. They are infinitely scalable. Beginners can modify the movements to protect their lower backs while advanced athletes can perform variations that completely tax their strength, balance and co-ordination.

This is the part of the post where I discuss the science behind the exercise, so if that is not your thing, please skip ahead to the videos.

Core Function and the Roll-Out

The two main functions of the core are:

  1. The stabilization of the spine via abdominal compression
  2. Movement – spinal flexion, extension, rotation, tilting the pelvis

Spinal Stabilization

Physiologists often use the analogy of the human spine being like the mast of a sailing ship.

The core muscles – Transverse abdominus, Rectus abdominus, External and Internal obliques, Multifidus, Quadratus lumborum, Iliopsoas, and the Erector spinae all work together as a group to support your spine from your pelvis to your rib cage. While they all work as a team, the Transverse abdominus is the key player.

While there is great debate about the best way to train the Transverse Abdominis (T.A.), there is a general consensus that any movement where you are forced to tighten you core against the demands of gravity or an outside source WILL be effective to develop the T.A.

One of the most popular T.A. dominant exercises is the bridge or plank.

The Roll-out and the Stability Ball Pike/Knee-In provide the same benefit as the bridge, but with the added benefit of being a dynamic, rather than static movement.

Core/Spinal Movement

Spinal Flexion is controlled mainly by the Rectus abdominus and the Iliopsoas. The most popular Spinal Flexion exercises are the crunch and reverse crunch.

The Roll-out produces the same movement as the crunch with the added benefit of spinal stabilization.

The Stability Ball Pike/Knee-In gives you the same benefits as the reverse crunch with the added stabilization.

Spinal Extension is controlled mainly by the Erector spinae and the Multifidus muscles. Spinal extension training is generally addressed by posterior chain movements like deadlifts, good mornings and bodyweight hip extension movements. As such, this section of the “core” will be omitted from this post.

Lateral Flexion is controlled mainly by the External and Internal obliques. Lateral flexion is usually trained by some form of side bends.

Rotation is controlled mainly by the Obliques, Multifidus and the Erector spinae. Spinal rotation exercises have been the flavor of the month for a little while now. One of the most popular is the wood chop.

You will have to forgive my lack of video (my digital recorder was stolen, hence the youtube videos), but if you can imagine, performing the Roll-out moving at various angles will give you an intense lateral flexion movement combined with forward flexion and stabilization.

With the Stability Ball Pike/Knee-In, you can combine spinal flexion and stabilization with lateral flexion and rotation by rotating and twisting the hips as you move the stability ball back and forth.


As you have seen in the accompanying videos, there are various ways to perform the Roll-out and the Stability Ball Pike/Knee-In.

With the Roll-outs:

  • beginners could start on their knees with a stability balls,
  • increasing the difficulty by moving their arms further away from their body.
  • graduating to the ab wheel,
  • then a loaded barbell.

The variations are as endless as your imagination. For example, stretch tubing can be attached to the ab wheel in order to increase or decrease exercise intensity.


As I said at the outset, the Roll-out and the Stability Ball Pike/Knee-In are the best core exercises. I hope that I may have converted a few of the ab crunchers out there.

Give them a try. And if you don’t own an ab wheel, Amazon sells them at a great price.

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  1. The squat is fantastic for improving the core’s ability to stabilize the spine. In my attempt to pick one movement, I wanted to address stability and movement.

    Thanks for the feedback

    Re: your site – Do you ship to Canada? If so, how do you deal with supps coming across the border – customs often equate supplements with steroids

  2. Hey, great post on core exercises! This is an unrelated question, what’s a good exercise for wrist strenth/forearms? I keep getting wrist pain from exercises like the flat bench press. I’ve tried hammer curls which someone recommended, but intuitively, they work more on the elbow joint.

  3. Grip / forearm strength involves a few different components.

    Forearm strength is best handled indirectly through grip training, bicep training and through grip and hold exercises like deadlifts, shrugs and farmers walks.

    Grip strength can be broken down into:

    Grip strength/power – use a hand gripper to work this aspect –

    Grip and hold strength – gripper/deadlifts/farmers walks

    Pinch strength – plate pinch – squeeze two 5 lb weight plates together with your fingers & hold as long as possible

    Hand extensor strength – wrap rubber bands around you closed fingers & open

    Wrist strength – Flexion/Extension with a wrist roller –

    Jarret, I would also look at how you are holding your hands/wrists during bench presses. Do you let your wrists bend back & hold the bar on your palm OR do you hold your wrist straight?

    Picture the forearm/wrist flexor muscles held in a stretched position under load – Given time and increasing bench press loads, and you will get wrist pain.

    You might want to look at an elastic wrist brace to help you keep your wrist straight. It will take a little practice to get used to benching this way

    Hope this helps

  4. Hey that’s good stuff.. You should do a post on wrist strength/grip position.

    I read once that while doing any exercise where you grip something, you should concentrate on holding the grip lightly, not squeezing it. It helps you focus on the muscle(s) you’re intending to workout, rather than flexing a lot of unnecessary muscles. On the butterfly or overhead press, I often don’t even curl my fingers around the bar/grips.

    What do you think?

  5. Hi Peggy,

    Start here

    For Lordosis / Sway Back

    The short answer is that you need to stretch some muscles:

    * Psoas
    * Iliacus
    * Rectus Femoris
    * Tensor Fascia Latae
    * Spinal Erectors (special care here)

    and strengthen other muscles:

    * Rectus Abdominis
    * External Obliques
    * Glutes
    * Hamstrings

    Thanks to your question, I will be putting an article together to help correct this postural problem

    It will take me a few days, but it’s on the way

  6. I think one of the hardest things for me is getting too caught up in reps and sets. Lets say I plan on doing 4 sets of 12 reps sometimes I make it so I have to hit those exactly when maybe 3 sets was enough and on my last set I only got 10 reps but I quickly lower the weight and bust out 2 more reps.

  7. I am wary to recommend “instinctive” training because most people have little idea of what their body is capable (or incapable) of from day to day, BUT blindly sticking to a predetermined rep/set scheme is just as foolish.

    Some days you are going to be stronger/faster than other days.

    When I work one on one with clients, I am constantly analyzing their form/breathing/posture/facial contortions/etc to judge how close to failure they are.

    Depending on the goal of the workout, I might stop a set as soon as their form slips below “perfect”. Other times, speed of movement is most important. Other times, I will push for absolute failure and I will help keep the reps in good form. Other times, I want 1 rep even if they could get 3. and so on and so on….

    If you want to break away from reps/sets, you can try using time as a measurement (see EDT – escalating density training) …or intensity or form..

  8. I love doing core exercises. I just recently really started enjoying them. Thanks for all the illustrations on the page. Very good stuff.

  9. Good post. Have a bit of a problem with the reverse crunch exercise. The form is terrible. Pulling on the neck not only is improper form, but it promotes bad posture and creates a stress on the cervical spine. A proper crunch of any kind should maintain the head in a neutral position. Pulling on the neck does not increase the abdominal contraction. Just my two cents.

    In response to the strong forearms question…Try rock climbing. Four times up and my forearms were on fire for two days. The exercises are great, but you can strengthen the forearms in a more functional way by utilizing them in activities such as these.


  10. I agree about the reverse crunch – I really need to film my own videos.

    I included the video only as a means to demonstrate spinal flexion. Since a conversation I had with Dr. Stuart McGill about 8 yrs ago, I haven’t had a client do any form of crunches. They’re spine crushers…literally.

  11. Great article, very good descriptions of the exercises, however I feel an observation is needed in regards to the Reverse Crunch Technique, holding the head with the hands places the lower cervical spine towards flexion ( forward bending in sagital plane ) and therefore increases the amount of stress in the intervertebral discs, by augmenting posterior displacement. This is a source of neck pain and abnormal mechanics of the cervical spine. Instead I proposed supporting the neck by using a towel roll and holding with both hands overhead to the legs of a partner or a chair or any other suitable piece of equipment.
    I do enjoy reading your blog, thanks for all your postings.


  12. Another for Transverse Abs:

    Kneel and place your body on all fours (hands and knees) in a place where your able to see yourself sideways in a mirror (in order to correct posture).

    Get a friend to balance a medicine ball on your back but do not curve your lower spine to allow it to settle, keep your back straight.

    Next practice holding in your belly until it looks as thin as possible, basicly your sucking your navel to the spine. Make sure you do not do this by sucking in your breath, the aim is to keep breathing as normally as possible, make sure the medicine ball does not move off your back, make sure your thighs and bottom do not also tighten to take the load, you want your TV do be doing all the work.

    Hold for anywhere from 5 seconds upwards before letting go for 5 or so seconds and then repeating.

  13. Both exercises are excellent. Only comments are they might not be appropriate for beginners and they require equipment (though they can be modified). And any exercise gets stale quickly. Things need to be changed all the time for both physical and mental reasons.

  14. I agree 100% Ron – no exercise is perfect for all people all of the time

  15. Great article with detailed information. This is something I preach to my patients day in and day out in the clinic, when it comes to core musculature being one of the cornerstones of spinal stability and spinal health.

  16. The poor version is with paper plates on carpet or towels on hardwood. So equiptment isnt exactly necessary 🙂  just more convenient 

  17. […] Now that you’ve watched the video and have come to the conclusion that BW Skullcrushers are the best possible arm exercise for men and women…feel free to check out some of my other videos and/or  head over to Health Habits to discover the best core exercise of all time. […]

  18. I agree on the plank.
    One can make it harder by elevating the feet.Or do the ‘stir the pot’ exercise.

    The ab wheel works the illiopsoas too much in my opinion.It’s like doing a reverse roman chair sit up.
    It can give a hollow lower back due to tightening of the illiopsoas.
    stretching doesn’t always solve the problem.

  19. I have to comment on my own comment.
    Having worked with the ab wheel for quite a while now, I have to say that when stretching the iliopsoas in a very effective manner(knee on bench and a little force keeping the leg behind the body). I do it every time I have used the ab wheel for around 30 seconds each leg.
    The hollow back ,tight feeling isn’t an issue anymore. Now I find the ab wheel my most effective ab exercise.
    In fact I use this one in combination with side planks.
    Nothing more. And the results are great.

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