What is Strength?

Strong Man is Strong

Everyone seems to agree that strength is a good thing.

Sports trainers claim that increasing your strength will allow you to run faster, jump higher, hit harder. Physical therapists will tell you that increasing strength in a certain muscle will cure back pain, knee pain, and hip pain.

Regardless of whether or not these claims have any merit, one thing I find interesting is that hardly anyone ever defines what they mean by strength. And that’s probably because it can be a very elusive concept to pin down.

For example, one of the dictionary definitions for strength is: “the state or quality or property of being strong.” Fair enough, but that is a circular definition that doesn’t tell us very much. Many strength coaches will provide similarly muddy definitions, usually implicitly.

So what is a good definition of strength?

How about this: strength is the ability to create muscular tension. That’s not a bad start, strength definitely seems to have something to do with muscular work. But this definition doesn’t say anything about whether the tension can create useful real world movements that we would consider to be an impressive display of strength. For example, someone might be able to create a huge amount of tension in their body while remaining completely still and not doing anything. Is that strong? Not in any practical sense.

Let’s consider some real world examples of feats that are commonly considered to require strength.

Check out Benedikt Magnusson. I love this guy’s style:


Very impressive. But is he as strong as this guy?


And as long as I’m inviting bar room debates along the lines of whether a tiger could beat up a lion, let’s also ask: who is stronger, someone who can clean and jerk 1.5 times his bodyweight, or someone who can bale hay all day long and come back and do it the next day? Who has stronger legs, Lance Armstrong or David Beckham? And how do we measure the leg strength of Haile Gebreselassie, a guy who is only 5' 3 and 123 pounds soaking wet, but can run 26 miles in a row well under a five minute pace?

Of course these are all silly questions. (But strangely compelling!) One way to answer them might be to start defining different kinds of strength. So one guy has absolute strength, the other guy has power, one guy has strength endurance, etc. Experts have created many different categories of strength along these lines, distinguishing maximal strength from strength speed, from speed strength, from strength endurance from reactive strength. And then of course there’s eccentric, isometric and concentric strength.

But there are further complications to consider. Even within any one of these categories of strength, it’s real world application depends on many other variables, such as the angle of the joint, accurate direction of the resultant force, the positioning and movement of the other joints, postural control and balance, the ability to relax the antagonist muscles and recruit stabilizer muscles, maintenance of a focused mental state, the absence of pain, etc.

In fact, if we were to extend all the categories of strength to their logical conclusion and respect the true specificity of strength, we could simply say that great deadlifters have great lifting strength, that marathoners have long distance running strength, and that Tiger Woods has great golf ball hitting strength. But now we are right back to our circular definition, where we just say that strength is the quality of being able to do stuff that takes strength.

So what is strength?

I’m still not sure how to define it, but I know I like this quote that I found while doing some google searches on this subject. Here's an excerpt from an excellent article by Chip Conrad:

If we define strength in the physical world as “force development” and acknowledge all the different degrees of force development, then we have a giant spectrum of strength, from the archetypical absolute maximal force development . . . to extreme endurance events ... It is all force development, from the body generating as much force as possible at once (powerlifting, Olympic lifting, throwing cars off pinned loved ones, etc.) to low-level force development over a long duration (what is called “endurance,” and often treated as something different from “strength.”).

With such a spectrum of possibility, why is it that the average weight trainer works within the very limited prison of 6–10 or 8–12 reps with moderate speed and weight? . . .What about speed? Duration? Distance? The weight room isn’t just for the limited ideals of a bodybuilder.

Beyond physical strength, we hear of strength of spirit, strength of character, and strong morale, all of which should have definitions of their own since they are often talked about as vague but determined, admirable traits. Perhaps these are simply ways of overcoming obstacles, showing a “strength” that has little to do with mere physiology or muscle.

How about a small, simple definition for strength? Ability. To be strong is to have ability. In life, in the gym, and in relationships. The ability to overcome the physical, emotional, or subjective obstacles that hinder our progress as human beings. That is strength.

I like it!

What do you think? Let me know in the comments below.