An idea that has recently proliferated in the fitness world is “sleepy muscles.” The basic concept as I understand it is as follows:
Our muscles each have a role they’re supposed to play in movement. Due to a number of factors (though usually long-term inactivity, bad movement patterns, and poor posture) some of the muscles don’t ‘fire’ when they’re supposed to, and thus don’t contribute their proper share of the work to the movement. When this happens, the muscles and joints above and below the joint/muscles that don’t fire have to do things they weren’t designed to do, and this creates imbalances and an overall sub-optimal performance, that is also more apt to lead to any number of injuries.
When I was first introduced to this concept, I was a bit skeptical. I understand that in today’s physically inactive society, movement would have to be re-learned as an adult. Things we do naturally as kids, like the widely circulated picture below are often forgotten through lack of use, and have to be re-learned.
This idea is intuitive, and made sense to me regarding whole movement patterns – we need to use our brains to coordinate the use of the many muscles and joints that work together to produce correct human movement. This requires embedding the proper motor pattern, and that can be forgotten and take time to learn again.
I was less confident about the claims made that individual muscles could ‘forget’ how to do their job(s) through inactivity. But the trend seemed well on its way, and the idea was so well-accepted in the circles I ran in, that I didn’t really bother to continue my skepticism much further. It stayed there quietly in the back of my mind – didn’t really go away, but didn’t bother me on a day to day basis, either.
However, I’ve returned to question these assumptions. Someone on the SS message board asked a question about this, and Rip answered as follows:
“If you are performing a movement that is only possible with the use of a muscle group moving a skeletal component through a defined ROM, then in the absence of neurological damage, you are using that muscle. For example, “gluteal amnesia” is quite popular right now. I just got another post about it. It is supposed to impair your ability to squat until you do special exercises that somehow remind your glutes what they are anatomically positioned to be doing anyway. The reality is that the nervous system manages the many dozens of muscles involved in the squat through a pattern of neurological action called a motor pathway. No single component of the pathway need be micromanaged by your conscious activity, because you can’t separate the single component from all the other activity — there are too many muscles doing their jobs all at the same time. This is why we chose the exercise in the first place: we want lots of muscles working together under a load, because that is how the body works, and this is how it should be trained. The way you ensure that all the muscles are working correctly is to use perfect technique, i.e. move the skeletal components in a way that most efficiently accomplishes the task. We spend quite a bit of time in the book explaining what that means and why. Muscles move bones, so if you are moving your skeletal components in the correct way, the muscles that move them correctly — in the absence of nerve damage — are moving them, because bones don’t move by themselves. The muscles are thus “working” or “firing” or “activating”, whatever your PT wants to call it this week. So, when you squat, your hips extend because that’s how you get back up. The glutes, originating on the ilium and inserting on the greater trochanter, extend the hips and externally rotate the femurs when they contract, because when you pull their origin and insertion closer together, that’s what happens. If you keep your femurs in external rotation (abduction) at the bottom, and you stand back up, your glutes have “fired”, because firing the glutes is how you extended your hips with your knees out. IF, THEN. Very simple, really. In the absence of neurological damage, hamstrings work the same way. Read about it in the excellent book you have just purchased.”
Very well said. And to me, the take-away from this is the key: The issues that people are observing regarding lack of movement quality are real; but the problem isn’t muscles that forget how to fire. The problem could be coaches who aren’t yet skilled at teaching the movement. The problem could be general, overall weakness that is solved by a general strength program. But in the absence of neurological damage, execution of absolutely correct technique will use all the associated muscles in their anatomically pre-determined amounts, based on the leverages of the system in that particular lift.
While I find a few sets with the empty bar or a light weight to be a perfectly sufficient warm-up for some people, sure, there can be a place for a more extensive warm-up protocol that addresses people’s mobility issues. But when people take a whole bunch of time away from training to do activation exercises to activate muscles that must necessarily be activated in the correct performance of a movement pattern, that just seems like the focus is in the wrong place.