Adding perturbations to an exercise basically means to manually disturb the stability of a given exercise.  The goal is to make the environment more unpredictable and increase the stability challenge of the exercise, movement pattern or muscle groups used.  I’ve been introduced to this concept a couple years ago at the Optimal Shoulder Performance seminar.  This is a concept that Mike Reinold was (and still is to this day) using for rotator cuff exercises with his baseball pitchers.

A typical exercise would put the athlete in a given position and the coach or trainer would give manual perturbations to the arm to challenge the stability of the humeral head in the shoulder joint, and improve the stabilization ability of the rotator cuff muscles for injury prevention purposes.

I immediately embraced the concept as I thought it was a genius idea, and I’ve been using rhythmic stabilization exercises for the rotator cuff ever since.

The concept can also be applied with other types of exercises…

Any exercise with the purpose of improving stability could be a candidate for a progression using perturbations.

When you’re trying to improve stability, your body and your brain need to be challenged.  This is why so many people use the stability ball; it increases the challenge of stability and makes you work harder.  The thing with stability balls is that they’re not always used smartly, and not always by smart people.  But I digress.

Hint: NOT the smart kind.

A lot of core exercises designed to improve stability can be progressed to manual perturbation.  As I’ve mentioned above, the perturbation will help improve control and stability.  When training stability, the important thing to remember is that motor control (which is the brain-to-muscle connection that works to improve stability) can not be improved unless it fails to succeed doing certain tasks.  Your brain needs to be challenged beyond its own stability limitations.  If you always work within your strengths, or your current level of stability, you’re not going to improve.  This is a great point that Mike Reinold highlighted in Functional Stability for the Core.

How do you actually apply this?

It could be something as simple as adding manual perturbations to a front plank.  A mastery of the front plank is in order before attempting any type of manual perturbation to your clients or athletes.  The same concept can also be applied to other core exercises like dead bugs, belly press, glute bridges, bird dogs, etc.

Again the important thing is to follow the progression; make sure your client or athlete is efficient at the basic exercises and doesn’t compensate in any way.  The logical progression for any exercise would be:

1. Stable
2. Stable with perturbation
3. Unstable
4. Unstable with perturbation

Using this progression with a front plank, the progression might look something like this:

1. Front plank
2. Front plank with perturbation
3. Stability ball front plank
4. Stability ball front plank with perturbation

The idea with the manual perturbations is to make it challenging and push it just beyond the point where the athlete or client maintains perfect form, but it shouldn’t be unbearable- if that makes any sense.

If you want more ideas on how to incorporate perturbations/rhythmic stabilization you should definitely check out Eric Cressey and Mike Reinold’s Functional Stability for the Core.

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Functional training is a term used quite a bit these days. Functional training might have totally different meanings depending on who you talk to. It can also be used for a variety of training methods and exercises. One that is refered to a lot as “functional training”, and in my own opinion is just a load of crap is unstable training surface.

This is probably the stupidest thing I have ever seen:

And don’t get me wrong, this is not just because I dislike it; unstable surface training is totally useless and counterproductive from a performance training standpoint. Before I get too much hate mail about this, I am just going to prove my point.

- First of all, I don’t know of any sports that are played on a surface that is unstable and/or moving under you (with the exception of alpine and water skying).  As far as I know, sports are played on floors, grass and ice which are all really stable surfaces. 

- From a safety standoint, I am not sure how safe it is to perform this kind of exercise in training.  There is a significant risk of falling off the stability ball, Bosu or whatever implement you’re using.  Keeping in perspective that my first two goals as a strength and conditioning coach are to avoid hurting my athletes during training and preventing their risk of injuries, I want to stay away from anything that ressembles loading my athletes with weights on a very unstable surface.

- Performing exercises on unstable surfaces require extra stabilization at the joints involved (mainly the hips, knees and ankles for lower body training).  At first, more stabilization might sounds interesting, but consider this: while performing an exercise on an unstable surface, your antagonist muscles are required to activate to take care of the unstable demand placed on the joint(s).  On the other side, if you’re trying to improve strength and power in your athletes’ program you need the exact opposite; you need the antagonist to relax as much as possible if you want to improve the force expression at the involved joint.  So right here, we have two totally conflicting situations and different goals.  Why not improve both at the same? Well, the bad news is that studies have showed that incoporating as little as 5% of your total training volume in unstable surface training decreases maximum force output in trained athletes. Doesn’t sound too good to me.

I don’t think I need to go much further; if you’re looking to improve speed, power, strength and overall performance you might want to reconsider using unstable surface training if it is unsafe, totally non-sport specific and decreases force production.

The only valuable use unstable surfaces might have is to reestablish proprioception in people who had ankle sprains, as there is sufficient proof in the litterature to support that, but that is pretty much all it is good for. 

As for as training for improved stability, I am all for it; but I think it should be done in a more sport-specific context.  For example, single leg exercises might have tremendous value in a training program as almost everything in sports happen on one leg at the time, for example running and skating.  Using single leg exercises like the reverse lunge will take care of all the stability you need.

But I won’t go into more details about this, as it could be the topic for a whole other blog post.

If you want to learn more about the use of unstable surface training, you need to pick up The Truth About Unstable Surface Training by Eric Cressey.  Eric goes into great details on everything that touches unstable surface training.