When it comes to training, I like to think about it as a spectrum. On one end of the spectrum we have muscles and on the other end we have movements. Now, obviously when we move, such as running, jumping sprinting, and playing you are using your muscles. However, unlike a traditional barbell lift, or an isolation exercise, like a bicep curl, the movement itself, is not solely determined by one or two specific muscle groups. Instead, the outcome of a movement is determined by the interaction of many different muscle groups working together. So we can think about the muscle end of the spectrum filled with movements that are solely determined by the action of a couple muscles and while on the movement side of the spectrum, we have movements that are made up of lots of muscles working together to produce an outcome.
For example, when we do a knee extension, the amount of weight you can lift, or the speed of the movement is going to be solely determined by your quadricep muscles. As for a back squat, your outcome of how much you can lift, or how fast you can move the bar is going to be determined by say your quads, your glutes, and maybe your low back. Yes, there are more muscles being worked in the back squat than the knee extension, the outcome is still determined by only a handful of muscles. When we juxtapose the squat to something like sprinting, it’s hard to say there is only one, two, or three muscle that are causal of the outcome. Instead, as mentioned earlier, it’s the dynamic interaction of many different muscle groups and coordinated efforts that determine the outcome of sprinting speed. One exercise we train “muscles” and the other we train “movements”.
Knowing which end of the spectrum the exercise is on can help you better determine the purpose of the exercise. For example, I don’t squat and happen to train my glutes and quads, I want to train my glutes and quads so I squat. The former places the squat as the centerpiece while the latter places muscles at the center and the exercise is used to fulfill these needs.
So, for one athlete, the back squat might be just fine, for another athlete maybe a Bulgarian split squat, a safety bar squat, a Smith machine squat, or some other variation that allows you to train the glutes and quadriceps to the highest degree. This is often an argument against the back squat, because many believe the back squat is limited by your low back muscles, and not necessarily your quadriceps or your glutes. So if your goal is to use the exercise to optimally train your quadriceps or glutes, but is limited by another muscle say your low back, then objectively speaking it is not the best exercise choice. Dietmar Schmidtbleicher talks about what he calls “the isolation principle”. In short, you want your target muscle of the exercise to be the rate limiting muscle of the exercise. If we think about that in terms of the back squat, then we want to miss our back squat, because our legs or are glutes are not strong enough, not because our low back is too weak.
Now let’s talk about the movement side of things. When it comes to training movements, we want to make sure we are actually doing the right movement. A classic example of this is when you first teach someone to do repeat hurdle jumps. Often that the athlete is most concerned with getting their legs over the hurdles and not necessarily jumping high. When this is the situation, you’ll often see an athlete perform hurdle jumps in an efficient manner, where they simply hit the ground and try and pull their legs up as fast as they can to ensure their legs clear the hurdle, versus jumping as high as they can, and then pulling their legs up to clear the hurdle. In the first example, the athlete actually doesn’t jump as high as they could, they cut the force production short, and they aren’t actually doing the movement correctly.
Another common issue with movements is that the purpose of the movement is lost on the athlete. For example, when we perform plyometrics, the athlete should try to “bounce” off the ground. We’re teaching them how to interact dynamically with rapid impacts, and how to use those impacts to produce a subsequent increase in force output. With this in mind, we need to make sure our movements are actually elastic and plyometric in nature. Often we see athletes hit the ground and make it a two-part movement. They first break themselves and then try and jump up again. Instead, I’d much prefer an athlete trying to “bounce off the ground”. This way we keep the movement patterns in the forefront and actually train what we’re trying to train.
So what are the major takeaways from all this? Know why you are doing something and make sure that “why” is actually done right. Don’t try and justify it through some weird illogical means like “but back squatting does X thing I can’t really explain”. No. Just know why you are doing an exercise, what the purpose of it is and train it. Having the idea of two different ends of a spectrum allows you to weigh the cost benefit of “skill” and interaction. For example, squatting isn’t being trained for the sake of a “skill” so you can have a large variety of substitute movements. If you are doing a max effort vertical jump, because it’s a skill there isn’t really any other exercise you can substitute. One has the movement as the centerpiece and the other places the working muscles as the centerpiece