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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