I often write about the importance of strength training, and highlight it in my speaking engagements, as well. But then, it’s come to my attention, when someone in my Facebook group (have you joined, by the way? If not, here’s the link) asked:
Why are classes like Group Power or Body Pump considered endurance and not strength training? I mean, participants are lifting substantial weights, and doing multiple sets on each muscle group, just faster than you would in a typical strength training setting. So why does it not ‘count’ towards increased muscular strength?
Original source: here.
And then I realized – most people either don’t know what strength training is, or have a completely false perspective of what it is.
It’s so basic that I thought everyone had a clear understanding of what strength training is – but I was wrong. Today, we’ll make it right, and give a clear, official (Igor-official, that is) definition of strength training.
So what’s the definition of strength training? Here it is:
Strength training is anything that makes you stronger.
Sound obvious? Maybe as if it doesn’t even need to be written? Maybe. But maybe not. There’s a lot more “under the surface” of this definition, so let’s break it down.
When you go from being a couch potato, to doing anything, even if it’s just going for a walk for 20 minutes, 3 times per week. That walk will strengthen your legs. Not by much, but it will do it. So in this very early stage, even walking would be strength training, because it fits our definition – it makes you stronger. At first.
Walking isn’t a high-demand activity, so it’ll only make you stronger for a week or two, before it stops making you stronger. You can walk longer and longer distances, at faster and faster paces, but it won’t make you stronger anymore. It might give you more endurance. But it won’t give you strength.
So what used to be considered “strength training” is no longer strength training, after the first week or two. It’s now time to perform more traditional strength training. So you get in the gym, you jump on the machines in random order, based on which machine is free, and you pick a random weight to lift.
If you’ve never done those exercises before, any weight will make you stronger. Again though, only at first. After another 2-4 weeks of doing this consistently what used to make you stronger no longer does. After this initial period of adaptation, it just maintains your strength – it doesn’t increase it.
The threshold for strength improvements rises.
By the time you’ve been strength training consistently, correctly and progressively (with gradually increasing sets, reps, or weight) for 6-12 months, what it takes to make you stronger is now substantially more than what was required to make you stronger when you were a beginner. After all, if when you started, you could only lift 5 pounds, after 6 months of training, you might lift 15 or 20 pounds. Five pounds will no longer do much for you, so that’s no longer strength training.
Capisce?
The Physiology of Strength
So now, let’s dig a bit deeper, to understand the physiology of strength. This is going to get technical, so turn off your phone, close the other tabs in this window, close other applications, go in a quiet room, and focus. Ready?
Humans have 3 major muscle fibres:
- Slow twitch (AKA “type 1”)
- Fast twitch A (AKA “type 2A”)
- Fast twitch X (AKA “type 2X”)
Although this is a bit oversimplified, it will work for our purposes. To use a broad generalization, slow twitch fibres have a lot of endurance, but very little strength/power. They are used to keep you upright (you don’t want your postural muscles fatiguing), and to do activities longer than about 70-90 seconds (like rowing, swimming, biking, jogging, and most activities considered to be “cardio”). Fast twitch fibres are the opposite: they have lots of strength/power, but very little endurance. They are used to very short activities, from 0-90 seconds. An example would be lifting weights (one set rarely lasts longer than 90 seconds). Or if something falls from your kitchen cupboard, and you need to catch it quickly, before it hits the ground, etc.
It’s the type 2X fibres that have the greatest potential for strength, speed and power (and conversely, the lowest potential for endurance). And different fibres are activated at different thresholds of contraction. You know those colourful bars on sound systems, that tell you how quiet or loud the sound is? Like if it’s quiet, it might be red, a bit louder is orange, louder is yellow, and loudest is green? Muscle fibres work the same way. This is called the “Size Principle.” That is, smaller muscle fibres (that is, slow twitch, type 1 fibres) are activated before larger muscle fibres (that is, fast twitch, type 2A and 2X). And the threshold for activation is different for the 3 fibres.
The slow twitch fibres activate with the most miniscule force necessary. Once the force crosses to more than about 40% of your maximal voluntary contraction (which is the most amount of force your muscles can produce in one contraction), your fast twitch, type 2A fibres activate. And once you cross 70-80% of your maximal voluntary contraction, then the fast twitch, type 2X fibres activate.
And it’s really not until the activation of the type 2X fibres that an exercise is considered strength training. So we need a minimum contraction of 70-80% of your full force for something to be considered “strength training.” You might be lifting weights, but if the weights you’re lifting are under that threshold, you’re not truly doing strength training. You’re doing endurance training – with weights. Not that it’s bad for you. It’s just not strength training. And it also doesn’t matter what tool you use to reach that 70-80% threshold. It could be dumbbells and barbells, it could be machines, it could be elastic bands, your own body weight, or anything else. Your body only knows tension – not what tool you’re using to create that tension.
Knowing these thresholds helps us answer our question from the beginning of this article:
Why are classes like Group Power or Body Pump considered endurance and not strength training? I mean, participants are lifting substantial weights, and doing multiple sets on each muscle group, just faster than you would in a typical strength training setting. So why does it not ‘count’ towards increased muscular strength?
Because the weights aren’t substantial enough to cross that 70-80% threshold. Let’s use an example: in any group power, or body pump class, you rarely see people lifting over 15 pounds. In any exercise. But let’s use the shoulder press as an example. If you’re lifting 15 pounds in the shoulder press, you’re already considered really strong. But chances are that you can do maybe 25-35 pounds for just a single rep. Because again, our 70-80% threshold is based on your single maximal voluntary contraction – not how much you can lift for multiple reps. And 70% of 25 pounds is 17.5 pounds (doesn’t seem like a large difference between 15 and 17.5 pounds, until you realize that the 2.5 pound difference is actually nearly 17%. That’s a lot. It’s like the difference between 100 pounds, and 117 pounds). 70% of 30 pounds is 21 pounds. And that’s why those 15 pound dumbbells don’t produce strength improvements, after the first few weeks. Endurance improvements – yes. Strength improvements – no.
Again, not that this is bad for you. It’s probably not. But it’s not strength training.
