Strength vs. Stability

Hi everyone, it’s Erienne from Peak Endurance PT here. Today I want to talk to you guys about the difference between the strength of a muscle and stability. So I talk about this a decent amount with my clients. And I just think it’s important to know and understand the difference.

The strength of a muscle is the amount of force it can produce. Stability is a muscle’s ability to control and coordinate and to hold an area steady. So you can have a muscle that’s really strong. But that muscle might not necessarily be coordinated enough to do its job when it is required to stabilize a joint for instance.

Here are some examples of this. At the shoulder, if I muscle test, if I do a strength strength, I could get all really strong results. No pain, five or five strength, good to go. But if we take that same shoulder and put it overhead in a more difficult position and a do a strength test there I could get a couple different results. It could be weaker or cause pain, because it is a less stable position. And the muscles don’t work as well.

Another example of that is if I put you in an overhead squat position, and your shoulder is rotating in and out and can’t quite get that coordination of that stabilization. That could start to cause issues as well.

So it’s not that my shoulder isn’t strong. My muscles can produce a good amount of force. But it’s that more challenging position that is hard for those muscles to coordinate and stabilize.

Another example is at the ankle. If I do a strength test for your ankle, and I tried to move you from a toe up position to a toe down position or toe into a toe out position and I can’t even budge you, your ankle is really strong. It can produce a lot of force. But if I get you in a single leg balance exercise, and that foot is doing nothing but wobbling side to side, it doesn’t quite have that coordination or that stability.

What that looks like, exercise-wise depends. If we’re going after pure strength, if your muscle is weak, we are trying to fatigue that muscle. So you’re gonna get that classic muscle burn.

But if we are working on a stability exercise, you won’t necessarily feel that same sensation. It might be an overhead kettlebell hold. I’m not getting a muscle burn. But this arm is really wobbly compared to this nice stable arm. Or I can balance perfectly on my left foot, but on my right foot, I’m falling all over the place because my ankle is nice and wobbly.

So with a strength exercise, you can tell it’s getting better, because you can do more reps or more weight. With a stability exercise it might not feel like that. It might just be the fact that you’re not as wobbly anymore. Or you can balance better. You can hold a weight over your head without as much movement.

So there is a difference between strength and stability. That’s important to know. And it’s important to target the exercises to where the deficit is. Hammering strength on a muscle that’s already strong, but not stable isn’t necessarily going to improve that stability.