This topic has been up for debate for quite some time now but, common knowledge in the strength training community is that heavy compound movements tend to be relatively taxing on the Central Nervous System. However, there have also been scientific studies stating that heavy compound movements may not have as much of an effect on the CNS as we were first led to believe. So, which of these theses is correct? That's what we’re here to talk about today.
In response to the question compound movements are taxing on the CNS:
While the argument against saying that compound movements like the deadlift, bench press, squat, shoulder press, etc. don’t tax the nervous system may have some validity (with actual proof) lifters, physicians, etc. have been saying for years that intense compound movements are taxing on the CNS. Consider the function the CNS has for our bodies.
What does the CNS do?
The CNS controls the functions of both our bodies and mind. It’s made up of our spinal cord and brain and is what gives us the ability to recruit more of our muscle fibers. In a sense, the spinal cord ( a part of the Central Nervous System) is what gives us the ability to move parts of our bodies and muster the strength necessary for explosive force. The CNS is what allows our muscle groups to work together and successfully lift upwards of 90% of our 1rm. As with any system in our body the CNS can get fatigued, especially with heavy compound movements. When the CNS gets taxed it becomes more of a challenge for our body’s to make the same connections and perform at the same peak levels that they were performing at when you were lifting those max weights.
How does this tie into training?
While the entire goal of strength training and performing compound movements is to tax your body and produce enough stress to produce growth, you want to be smart about the way you train your body. Yes, heavy compound movements are taxing on the Central Nervous System (according to studies). Does that mean you shouldn’t train and wait until you completely recover? No. Just be smart about the way you use your body’s resources. You don’t want to perform heavy movements that use the same muscles groups back to back - you want to space those movements out.
An example of this would be the workout regime given below:
Monday: Deadlift Day
Wednesday: Bench Press Day
Thursday: Squat Day
Saturday: Assistance Day
This is just a sample workout plan but it spaces out all of the movements and gives your body adequate recovery time before the next workout. This was taken from Stan Efferding when he stated that certain movements need to be spaced out before they were performed.
*Check out the deadlifting and squatting articles if you want to know more about how many times per week you should do either.
*keep in mind that there have also been other people saying that our bodies inability to continually lift weights may be a mental thing that in effect deals with the Central Nervous System. However, this hasn’t been proven while the study stating that the CNS is taxed during heavy compound movements has been continually discussed and researched. Until new evidence comes out we are going to stick with the logical and thoroughly researched idea that the CNS is taxed after heavy compound movements.
Conclusion
Until scientists are able to provide concrete evidence stating that the central nervous system isn’t at all affected by heavy compound movements it’s safe to say that it is. Why? Well, coming from a logical point of view when systems in our bodies are used they get taxed. The CNS is what controls muscular coordination and the recruitment of muscle fibers (which is what we’re doing when we’re hitting pr’s). When you’re feeling reduced grip (muscular coordination) or feeling headaches and other symptoms of CNS failure or overtraining it’s your Central Nervous System telling you to relax. Does that mean that you shouldn’t train compound movements? No, just be smarter about the way you organize your workouts. Instead of training squats directly after you deadlift, bench after you deadlift. If further research comes out we’ll be sure to notify you of it here.
*If you're interested in seeing how else powerlifting can
Resources:
https://www.t-nation.com/training/tip-the-deadlift-the-nervous-system
https://www.christopherreeve.org/living-with-paralysis/health/how-the-spinal-cord-works
https://www.bodybuilding.com/fun/ask-the-super-strong-guy-cns-fatigue.html
https://insights.ovid.com/crossref?an=00005768-199701000-00008
https://www.cabdirect.org/cabdirect/abstract/19711405783
https://link.springer.com/article/10.1186/s40303-015-0010-8
https://link.springer.com/article/10.2165/00007256-199826010-00001