Ep. #497: Menno Henselmans on the Myth of Central Nervous System Fatigue

Mike: Hey, Mike here. And if you like what I’m doing on the podcast and elsewhere, and if you want to help me help more people get into the best shape of their lives, please do consider picking up one of my best selling health and fitness books, including Bigger, Leaner, Stronger for Men, Thinner, Leaner, Stronger for Women, my flexible dieting cookbook, The Shredded Chef, and my 100 percent practical and hands on blueprint for personal transformation.

Inside and outside of the gym, the little black book of workout motivation. Now, these books have sold well over 1 million copies and have helped thousands of people build their best bodies ever. And you can find them on all major online retailers like Audible, Amazon, iTunes, Kobo, and Google Play, as well as in select Barnes and Noble stores.

Again, that’s bigger, leaner, stronger for men. Thinner, leaner, stronger for women, the shredded chef and the little black book of workout motivation. Oh, and I should also mention that you can get any of the audio books 100 percent free when you sign up for an audible account, which is the perfect way to make those pockets of downtime, like commuting.

Meal prepping and cleaning more interesting, entertaining, and productive. So if you want to take audible up on that offer, and if you want to get one of my audio books for free, go to www. legionathletics. com slash audible. That’s L E G I O N athletics slash a U D I B L E. And sign up for your account.

Hello, boys and girls. Welcome to another episode of Muscle for Life. I’m Michael Matthews, and if you are a veteran gym goer, you probably know what it’s like to feel fatigued. You know what it’s like to be drained and achy and lethargic, and you know what it’s like when the weights just feel oppressively heavy.

Heavy, and when you’d rather just go home and take a nap than grind your way through a workout. And if you go online, and you poke around for an answer as to what’s going on, why you feel this way, one of the first explanations you’re probably going to get is Runacross is related to something called central nervous system fatigue, CNS fatigue, or sometimes referred to as neural fatigue.

And the story goes like this, the reason you feel so down is your nervous system has become overtaxed and needs a break, not unlike a barrel of a gun that has overheated from intensive firing and now needs to cool off. Now, to resolve the problem, the solution offered is always some form of more rest and less stress, like taking a few days off the gym, deloading, or the like, and to avoid These types of problems in the future, the suggestions usually include training less frequently or intensely, taking special supplements, and sleeping or eating more.

In fact, some fitness gurus claim that minimizing CNS fatigue is a positive. vitally important and often overlooked aspect of getting jacked and especially for us natural weightlifters and these guys and gals also usually promote very low volume training plans as optimal for maximizing your overall long term results.

Now how reasonable is all of that? Is your body really so fragile? that it can only manage a handful of productive weightlifting workouts per week. Is CNS fatigue even real? To answer those questions and others, I invited the one and only Menno Henselman back on the podcast to break everything down.

And in case you’re not familiar with him, Menno is a bodybuilding coach, writer, and published scientist who’s also on the scientific advisory board of my sports nutrition company, Legion Athletics. And in this interview, Menno discusses the different types of fatigue that we can experience, what CNS fatigue really is, how much can result from training, how to deload properly, and why it’s important to do this, and more.

I hope you like the interview. Let’s get to it. Hey, Menno. Thanks for taking the time to come back on the podcast to chat. It’s been a while. 

Menno: My pleasure. Yeah. I think our last talk was on muscular potential. That was a good one. 

Mike: Yeah, it was something that I got a lot of good feedback on that and something I’ve continued to write and talk about.

And you have as well, you’re just telling me in the pregame chat, but we’re not here to continue that discussion. We’re here to talk about something else all together. And that is nervous system fatigue, CNS, central nervous system fatigue. And I think a good place to start the discussion, we’ll have to talk about what that is, but is to address, see when I get asked about it, it’s usually around the questions usually have to do with how much of what I feel like if I’m feeling run down and my weights are feeling heavy and my training’s not going well is this just.

too much CNS fatigue and how does training really drive that? So what types of training produces more fatigue? What types of training produces less fatigue? And then in some cases, it’s even is this even a thing or is it just all in my head? 

Menno: It’s not like metabolic damage where it’s like a complete myth, but to explain what CNS fatigue is, I think we should even go one step back further and talk about what fatigue is in the first place.

So most people, when they hear the word fatigue, they associate that with, as you’re already implying, subjective fatigue, the sensation, the feeling of being fatigued. And that is a very general thing. If you look on a medical database, for example, symptom checker, and you look at how many disorders and conditions there are that have subjective fatigue, subjective mental fatigue as a symptom.

That is. Pretty much everything. That’s not even just including the basics like sleep deprivation, just being sick of something that can also give this sensation of fatigue. If you, for example, for me, when I had to visit my grandmother, I was not there anymore. But when I visited her and I was there for maybe a couple hours, but she was half deaf by that time.

At the end, she wasn’t really 100 percent there anymore either. So it was really exhausting. And at the end of the day, When you drive back home, you are super fatigued. It’s Whoa, it’s just a sense of overall lethargy. That’s it makes you feel like you cannot train and you cannot stick to your diet, et cetera, but there is nothing physically giving that fatigue.

It’s not my contractile tissue, my muscle. was fatigued in any sense. So you have to distinguish or separate that, that sensation, that feeling from the objective exercise science definition of fatigue, which is a loss of force production. And that is very objectively What fatigue is. If you’re in the gym, you’re doing a set of squats.

You can do 10 reps. That’s your performance. Objectively your performance 10 reps on a squat with say 140 kilos. And after that, on your next set, you can only do say eight reps. So that is fatigue in action. You went from 10 reps to eight reps with that weight on the squat. That is fatigue in action. Your performance is now lower.

And if we look at it like that, then we can study it much more objectively and talk about it in a very concrete fashion. And that fatigue, we know, can have two origins. One of those is peripheral, and one of those is central. So peripheral fatigue is basically, it’s local, it’s regional, it’s in your muscles.

The two most important types of peripheral fatigue are metabolic stress, And muscle damage. And more generally speaking, this fatigue generally disrupts either a calcium metabolism, which interferes with the contraction of muscle tissue. Muscle tissue needs calcium to create the ectomyosin cross bridges that make a muscle contract and produce force.

They come together. Basically, like if you flex a muscle, it’s a tree, the tissue that’s binding together, otherwise it’s a limitation in the ATP generation, energy generation. to produce more energy that fuels the contraction. So that’s peripheral fatigue. And then central fatigue is objectively defined as a decrease in the net excitation supplied by the motor cortex to the muscle.

So basically motor cortex is the part of your brain that governs movement. This can also fatigue in a sense. In that the signal, the drive from, it’s like the driver in the car, the signal from the brain to the muscle that can also be impaired. And if that signal is not a hundred percent anymore, so you can measure that.

For example, the motor evoked potential. And when that goes down, that is basically the muscle not receiving the same inputs anymore. To contract as forcefully. And that leads into leads to a reduction in voluntary activation. And that means the, there isn’t really fatigue in the sense of damage or, a disruption of the process, but it is simply a difference or a fault in the input to the muscle.

Mike: Let’s say it’s like a more of a software problem as opposed to a hardware problem. 

Menno: Exactly. That’s a good analogy. 

Mike: So you’re just mentioning that you can have a situation where there’s mental fatigue or emotional fatigue, spiritual fatigue, whatever you want to call it. And so that, of course, is different than either the peripheral or central fatigue.

And I think that’s something, though, that. It can be easy to confuse those things, right? And is the fatigue you’re feeling, which can manifest itself in terms of less motivation to train less energy in your workouts, just feeling harder. The perceived effort is up. And so what are your thoughts on mixing those up?

Or, I don’t think there’s any obvious answer for, Oh, here’s how you could know it’s one or the other, but maybe there are some cues or some things that would indicate it might be more of one issue over another. 

Menno: Yeah. And there was a lot of research on it as well. 

Mike: Just to add on that, sorry.

It’s also even just general stress, right? So in times of higher stress, inevitably I’ve noticed that it does impact training to some degree. 

Menno: Yeah. And stress also impacts you physically. Stress is a really interesting one. It’s a bit of a borderline case in terms of it’s psychological, but it also really affects you physically.

But in terms of fatigue, a lot of research has affected or investigated the effect of mental fatigue, psychological fatigue on objective muscular performance. And there is no effect. Which of course makes perfect sense. Like I say, when I went to visit my grandmother, I really noticed it after a day of public speaking and I’ve been on my feet all day and I’m really fatigued.

But, and there was also even the sense of local fatigue in the sense of that my knees are very stiff when I’m taught for eight hours, I’m not used to standing for eight hours or let alone talking for eight hours. So I’ll be mentally fatigued and also have the sensation of stiff knees and. Just feeling, a bit rundown, but after a warmup, that is all gone.

So I’ve really forced myself. And that’s also what I try to empower my clients with that. This mental fatigue really doesn’t have to mean anything for your training. Now, in terms of during the training itself, you often get both because most people experience both subjective fatigue and an objective loss of performance.

If you don’t experience any objective loss of performance in your workouts, then. You have to really question if you’re actually training as hard as you think you might be. So then the question is, how do you attribute that to, is that local, is it mental, or is it central? And there is actually a good way you can test it to an extent.

For one, the mental component is mostly a mindset issue. So you have to try to push through it. And the realization that it might be mental in itself should already help you a lot in terms of, You know how much you can push through it because if you’re convinced, and there’s also research on this, for example, there’s research that people that are convinced they need carbs before their workouts, and if they didn’t miss their regular high carb pre workout meal, then their performance suffers.

But if that same scenario, if you have people that are not convinced they need the carbs and they miss their pre workout carb meal, then they don’t have a decrease in performance. And the same has been reported for habitual breakfast eaters. So if they you’re used to always having your breakfast, and then you miss it one time.

then you’re likely to have a crappy workout in the gym if you think you needed that breakfast. Whereas people that really didn’t have such a psychological investment in the breakfast, they only suffer the physical effects, which are much less than the combined mental effects. Now, if you have a certain amount of objective fatigue, so actual loss of performance, and in spite of you giving it all you got in the gym, then by far the easiest way to tell If your fatigue is central or peripheral is to see how much it affects other movements.

And this is a very fundamental feature of fatigue and exercise science is that it’s has very high task dependency. So it’s very specific to the movement pattern or exercise that you do. If it’s truly central, then it should affect everything. So after, for example, heavy squats, you should also notice that your biceps curls suffer.

Now, a lot of people do report this. But research actually, and my experience quite strongly find that there is no such effect. And I think any effect that would be there is probably the psychological fatigue in action. Because logically, if you think about it, it makes sense that purely from a muscular point of view, why would squats fatigue your biceps?

Let’s even make it front squat. So it’s crystal clear. There was no involvement of the biceps. You could argue the biceps are pulling the bar into your back during squats, that should be pretty trivial. Anything that has happened there is either CNS fatigue or, the psychological fatigue, just squats are very effortful and humans are fundamentally effort averse.

We are as creatures, evolutionarily lazy. And that’s a good thing from an evolutionary point of view, because If we were prone to expand a lot of energy on things that we don’t need to, that would be very bad for our survival. So it’s basically hardwired into our system that we are not enthusiastic about damaging our muscles, expanding a lot of energy and doing things in the, now in a gym or, basically tearing our bodies down.

So these things cost a lot of mental effort, but it doesn’t have to mean that CNS is actually fatiguing them. If we look at research on this, the effect of strength training on CNS fatigue is really minimal. I mean that the best estimates, absolutely like the worst case scenario is usually like maybe 15 percent and most research settles more on a few percent at most.

And several studies have found that, for example, one study, I think it was like tell us all looked at high level athletes and I’m talking near Olympic level. So very much elite level athletes. And they did 12 sets of heavy compound work. I think you did. Four sets of five on the squats, the push press and split squat, and then no signs of CNS fatigue and other research even finds that not only is there no CNS fatigue in terms of several measures, usually the central activation ratio is best.

It’s basically the ratio of voluntary to involuntary activation of your muscle tissue, which is a check to see if the brain is activating your muscles as well as we can. And some of that research actually finds there’s up regulation. Of CNS activity. So when there is Objective fatigue, peripheral or neuromuscular fatigue.

Then the CNS upregulates its activity to compensate for that fatigue. So it’s actually the opposite of CNS fatigue. 

Mike: That’s interesting. And so how does that jive with the experiences that. We’ve probably all had of where you’re pushing hard in a training block. And I do, at least I’ll run into excessive muscle soreness that not that it has to do with a CNS fatigue.

So that’s I start to get sore and achy toward the end of a block when I need to deload. But I’ve also definitely experienced many times where the weights that I’ve been handling in that training block. Just start to feel heavier. The perceived effort of the workout goes up. Are you saying that you believe, or based on the evidence that you’ve reviewed, that by training intensely, let’s put a number to it.

Let’s say doing somewhere around, I don’t know, 12 to 15 hard sets per major muscle group per week, working in the rep range of, or let’s just say anywhere from 75 percent to maybe 90 percent of one rep max, ending sets a couple reps shy of technical failure. Okay. Working hard. That shouldn’t really have any residual CNS fatigue that can accumulate over the course of a training block that you can then clear out with either a week off or like a deload week?

Menno: Yes. So there is basically, there is no doubt there is a lot of neuromuscular fatigue. Neuromuscular fatigue is the sum for all fatigue. It’s the sum of peripheral and central fatigue. So there is no doubt there is neuromuscular fatigue, but especially what you feel. And the days or weeks over time, that is almost certainly exclusively peripheral fatigue, because the funny thing about CNS fatigue is that while many powerlifters and the like, they talk about it as if you do squats and then the days after you have CNS fatigue, actually CNS fatigue in several studies has been measured as.

Resolving very quickly, like literally within 10 seconds, there are signs of significant amelioration of the fatigue and a study I just mentioned in did the measurements 10 minutes post workout, which is why the researcher thought that any CNS fatigue that had. Accumulated that workout was already gone because the CNS or the motor cortex in general, our brain is more like software than hardware.

If you’re on a computer, that’s how you should think it. And the hardware is fine. If there is any alteration in the software, it’s not like it. It takes long to resolve because there is not like muscle tissue actually tears like muscle fibers literally tear with use. So you can actually see that like in with a biopsy, for example, you literally see that the muscle fibers are damaged.

You can also see the edema, the muscle swelling with MRI ultrasound and so you can actually observe that there is. It’s literally physical, mechanical wear and tear of the muscle fibers, but that does not happen with the CNS. The CNS fatigue is just neurons and some activate. It’s like you’re on a computer and you open words 2000 times in a row.

It doesn’t really fatigue that way in the sense that a muscle fiber literally tears. It has literal wear and tear mechanical fatigue. So the CNS fatigue is more thought to be related to imbalance of electrolytes, more metabolic stress actually. Okay. And an alteration in the system that’s probably in part intentional.

Like I said, the upregulation is actually a compensatory response. And there’s also evidence that, for example, grip failure and pain can also cause what is essentially central nervous system fatigue in the sense that it reduces voluntary activation. So it’s more a preservative effect. I’m not even sure if we could use the term CS fatigue, it’s already misleading term in itself.

Mike: It’s more just tapping into its resources, and then it sounds like it replenishes itself quickly is the point. Hey, before we continue, if you like what I’m doing here on the podcast and elsewhere, and if you want to help me help others, more people get into the best shape of their lives. Please do consider picking up one of my best selling health and fitness books.

My most popular ones are Bigger Leaner Stronger for Men, Thinner Leaner Stronger for Women, my flexible dieting cookbook, The Shredded Chef. And, my 100 percent practical hands on blueprint for personal transformation, The Little Black Book of Workout Motivation. Now, these books have sold well over 1 million copies and have helped thousands of people build their best body ever, and you can find them anywhere online, where you can buy books like Amazon, Audible, iTunes, Kobo, and Google Play, as well as in select stores.

Barnes Noble stores. So again, that is Bigger Leaner Stronger for Men, Thinner Leaner Stronger for Women, The Shredded Chef, and The Little Black Book of Workout Motivation. Oh, and one other thing is, you can get any one of those audiobooks 100 percent free when you sign up for an Audible account. And that’s a great way to make those pockets of downtime like commuting, meal prepping, and cleaning more interesting, entertaining, and productive.

Now if you want to take Audible up on that offer and get one of my audiobooks for free, just go to legionathletics. com slash Audible and sign up for your account. Is there any way to achieve a true kind of ongoing deficit? Has it been seen in anything, even if it’s like super extreme stuff that nobody would ever do?

Menno: There are basically two reliable ways. If you want to mess yourself up to get prolonged CNS fatigue, a funny enough, it’s all from marathons. So most people intuitively think that CNS fatigue is the highest with high intensity lifting. It makes sense because it’s neural fatigue and the neural requirements of high intensity lifting are the highest.

Plus, just intuitively high intensity sounds like it should be more fatiguing than low intensity, right? But that is not the case. It’s actually low intensity work that is more fatiguing and also cause more CNS fatigue. So to understand that, it’s good to think about fatigue again in terms of loss of force production.

Most people intuitively think that, like I said, high intensity set is more fatiguing than a low intensity set. But given the same proximity to muscle failure, let’s say we’re doing a set to full failure, how fatigued are you really after, say, a free RM on the squat? Objectively you are so fatigued that you cannot lift your free RM anymore.

So let’s say you can squat a hundred kilos or simplicity sake and your free RM is there for probably 90 percent of one RM. So you’re so fatigued. You cannot lift 90 kilos, but how fatigued are you after a set to failure with 60 percent of one RM? That’s probably a 20 rep set or so. That means you cannot lift 60 kilos anymore, let alone 90.

So objectively you can already logically deduce that you are much more fatigued After a high rep set, then a low rep set. And there was a lot of research now that supports this and subjectively also, I think there are a lot of people that are a bit overly invested in their one RM as if it’s like the one true measure of strength, especially, from a power listing background and therefore, they hype up for that, use caffeine and maybe therefore it also drains them a bit more.

But if you’re actually going to failure on both. And you can probably tell this from experience as well. A free arm squat is hard. Okay. But not like a 20RM squat. A 20RM squat, they call those widowmakers for a reason. A 20RM squat is, it’s like you’re doing the free RM at the end of a cardio workout. And that’s basically what it is for your muscles.

So the last three reps are like your free RM in terms of effort. And the 17 reps before that, are just absolute hell. It makes you realize why you’re doing strength training and not endurance training. CNS fatigue also goes up in proportion with the total fatigue marathons, super high rep work.

And in fact, most research that has been cited as proof that strength training causes CNS fatigue. If you look at it, they are often isometric contractions. Like one study used biceps curls like 60 seconds and then to failure. So you’re talking 60 seconds contractions and then a whole lot of those.

Basically it’s like a 10 minute set. Which is nothing like, eight reps with one, one tempo. Most sets we do in the gym and most people are like one minute tops, more like 30 seconds often. So followed by a couple minutes of rest, exactly, which is actually ample time for CNS fatigue to resolve based on the research that we have basically for your software to reset.

And the other way, which is a bit more mysterious, is that eccentric contractions, very heavy eccentric contractions. Now, that’s something that nobody really does because you need special machines for it, because you’re only doing the lengthening phase of your muscles. If you were to do that for the bench press, for example, with a spotter, you would get a super heavy weight.

And only lower it, and then the spotter on his own or her own, lifts the weights completely, you do nothing, and then you control the descent again. That would be eccentric training. Now, that kind of training induces major muscle damage and major total neuromuscular fatigue, as well as very prolonged CNS fatigue.

We’re still uncovering how that link can work. goes, why muscle damage causes that prolonged CNS fatigue, but it does seem related to both metabolic stress and muscle damage, that there are some feedback that is going through the brain and therefore basically putting it on a lower level or limiting the excitation that the brain supplies.

To the muscles. 

Mike: Interesting. So then there would be some connection between resistance training and CNS fatigue. Then if you’re doing, let’s say a high volume block of training that does cause a fair amount, maybe you’re not doing a bunch of negatives. Cause like you said, it’s impractical and not necessary to do but you are doing a fair amount of volume that is producing a fair amount of muscle damage and metabolic stress.

Then it’s reasonable to assume that there will be at least. more CNS fatigue occurring during that training block or that period of a training block compared to one where you’re doing maybe lower volume but more weight? 

Menno: Yeah, but it still won’t be much because every set doesn’t induce that much and it resolves basically within each set.

There are definitely research trends that by and large, basically, yeah, the total volume you do is the biggest risk factor, but because we’re doing it with rest intervals in between, the total CNS fatigue is still not that much. You’ll probably get more CNS fatigue, funny enough, if you do eccentric biceps curls.

For three sets only. Actually, that’s best. That’s exactly what one study did that found prolonged CNS fatigue. 

Mike: Sorry to interject, but what’s the effect size, so to speak? 

Menno: Yeah, a couple of days. So 

Mike: usually CNS 

Menno: fatigue is seconds to minutes with very high muscle damage, which is usually, there was an untrained individuals, they achieve or suffer much more muscle damage than trained individuals because the muscle.

It doesn’t have the repeated bout effect, as it’s called yet. So it’s much more prone to being damaged. It’s not as resilient yet. But then, yeah, you’re talking 72 plus hours. So which is still, not like weeks, not like you need a full deal a week to resolve that, but definitely more prolonged than the usual effects, which generally shouldn’t even affect your next workout.

Mike: That’s wild to think. So you have that, which isn’t in untrained people. And that definitely is a big caveat. If somebody who’s experienced trainee and is thinking that they have to now watch out, because if they cause too much muscle damage, even in a smaller muscle group, it’s going to screw with their squats the next day or something.

But if that’s been seen in research. You’d have to think that there would be some sort of residual effect if you were to do let’s say again, not that it’s necessary, but German volume training, 10 sets of 10 of squats or something. It’s going to be weird if it was like, Oh yeah, I know doing eccentric bicep curls that can actually, at least in untrained people, maybe in trained people, even if it’s a little bit, something as what would seem as benign as that could result in some residual CNS fatigue.

Oh, but if you’re doing 10 sets of 10 on squats, you should be fine. 

Menno: Yeah, that does pretty much appear to be the case. There was actually one study pretty recent. I’m not sure this year or last year. I don’t think it was German volume training, but they did do 10 sets of squats. I think they did sets of eight or five, not 10.

But still, and they found no CNS fatigue after that workout. 

Mike: And those are in resistance trained people? Yeah. 

Menno: Resistance trained 

Mike: individuals. Interesting. 

Menno: Definitely. And I think another reason you have the psychological fatigue and just total neuromuscular fatigue, like peripheral fatigue, which people can mistake for CNS fatigue, but there’s also connective tissue damage.

And I think a lot of people mistake that. Which is leaves you feeling banged up, a deadlift have this in particular, and I’ve actually been in three studies now that show that deadlifts do not produce more CNS fatigue than squats. Or even bench presses and also one study, I think, where they include deadlifts and there was no sign of CNS fatigue after the workout.

So deadlifts do not seem uniquely potent at inducing CNS fatigue, which also debunks the idea that CNS fatigue occurs strongly in proportion to the amount of muscle mass involved. There’s also another study showing that leg extensions with two legs don’t induce more CNS fatigue than leg extensions with one leg, which also debunks the idea that it’s strongly in proportion to muscle mass.

Contrast to endurance training, because in endurance training, if you bicycle with two legs, you get more CNS fatigue than if you bicycle with one leg, but that’s probably not due to the amount of muscle mass. It’s due to the amount of total work. If two legs are working, you’re just doing way more total work.

And that is the cause of the CNS fatigue. So with strength training, you 

Mike: simply don’t do that. Do that much work anyway, going back to what you’re saying about effort and that evolutionarily speaking, we, there are probably a number of factors. One, I would assume is food was once scarce. And so if we were inclined to run around and burn a bunch of calories unnecessarily, we would have killed ourselves off.

Whereas that’s not a problem anymore. We probably could get by with. Quite a bit more of a liking for effort considering good old times before the obesity epidemic. Yeah, exactly. To that point. Yeah, that would make sense that if the brain is going to tweak its software to basically just say, Nope, we’re not going to work as hard right now, which is what it sounds like CNS fatigue.

You could be thought of like that, that it would require a lot of output. There’s a point where it’s okay, we’ve worked really hard now. We’re going to chill out for the next few days, but to get there, it just requires a lot more work than many people think doing a one hour upper body workout is just not enough to set off the alarms.

Menno: Yeah, exactly. It’s probably more related to total energy expenditure and actual signs of serious muscle damage or. Extreme metabolic stress, then just a bit of normal muscle contraction or force outputs or something like that. 

Mike: Now, how does peripheral fatigue accumulate, say over a training block where you can, or does it, that’s my understanding is the implication is that you can start to feel the effects of muscle contraction.

More so as you go from, especially if, if you’re following a training program that has you training intensely and has you pushing to gain reps or add weight to the bar and so forth. 

Menno: Yeah, it definitely can. We also have research now that directly shows this, especially if you work out before. But again, the central principle is that you should think of total performance.

So if your performance is still going up, then you are recovering from the peripheral and the central fatigue and even super compensating. So in the general adaptation syndrome phenomenon, you have the stress phase, you have the recovery phase and the adaptive phase. You’ve gone through all of that. And your total performance, your fitness is now higher than before that workout.

If you do a workout, you do another workout. And by that time you were stronger. 

Mike: Yeah. There’s your answer. Good job. Or you wouldn’t have been able to increase your performance. 

Menno: Exactly. But I think that also goes back to connective tissue damage. Connective tissue, by the way, is like joints, tendons, the stuff that holds us together.

That’s not just our muscles. So for most people, I think tendons, ligaments and joints are the big ones that can get injured. Damage in those can rack up a lot more than the muscle tissue. So muscle tissue is highly plastic as it’s called, which is not like a plastic bottle, but it means it’s very adaptive.

It can change shape and form to accommodate different functions. That’s plasticity. Connective tissue is not so plastic. It’s pretty much more most people probably think of it the right way. Like bone, it does adapt. Some people think, and researchers for a long time thought it didn’t adapt at all, but actually your bone density increases.

Tendons also increase in a cross sectional area. So your tendons get bigger and stronger just like your muscles, but you do so much more slowly and the whole adaptive process is so slow. But the tissue itself is so much stronger that you can basically tear it down a little bit more and more up to the point that you’re getting some pain.

And if you, especially if you keep training through that, you’re going to aggravate it. And then at some point you have what we call an injury. Maybe you cannot train that muscle anymore at all without too much pain. So that type of damage, which is, it’s not peripheral fatigue, but it’s related to it. And I think a lot of people confuse it with that, especially that, the banged up feeling after that lifts for your back and the like.

That can be a reason that you also feel over time. You feel a lot more banged up, and that’s why you, for example, need a deload to get rid of that. Still doesn’t mean you have to deload, but that would be one argumentation at least for a deload week. 

Mike: I’m assuming that you generally recommend deloading on some frequency if you’re training intensely.

I 

Menno: actually recommend reactive deloads, as I call them. I’m not a fan of taking a whole week off. Pretty much, 

Mike: almost never. Yeah, same, because you end up usually coming back a little bit behind. 

Menno: Yeah, exactly, I think. And it’s actually, there’s research showing that is not due to neural adaptations, so that might actually already be some muscle loss if you’re highly advanced.

If you’re a novice, you take a week off, that’s Perfectly fine. You won’t get any muscle loss, maybe even you’re even stronger after that, but for an highly advanced individual, unless you were doing an overreaching block before that, there’s a good chance you’re actually going to lose some strength.

Mike: I’d be curious to look at that research because my assumption would be that it would be more related to just your technique that if it degrades even a little bit and you’re, let’s say squatting underneath. Large loads that can cause you to lose a rep or something when you come back. 

Menno: Yeah, you would think that my experience is also, it definitely varies a lot per individual.

A recent study showed that the voluntary activation at least is highly preserved. So if you take a week off, then it’s not going to be that you’re not going to get the same level of muscle activation anymore. It might be that. Neuromuscular coordination is still impaired, even though, the prime movers, if you’re squatting the quads and the glutes, they’re still producing as much force.

But maybe, for example, there’s more co contraction in other muscles, which decreases force production. So if the hamstrings contract too forcefully, they sabotage the effect of the quads in terms of extending the knees. During a squat, which means that less of the force you’re producing results in net upwards momentum.

So there’s that, but it’s still, it’s a sign that muscle damage may or muscle loss may kick in a bit sooner than we probably thought. Like most people would probably have said it until a few years ago. It’s at least two weeks before you have any muscle loss. 

Mike: Two or three weeks of no training, assuming you’re not like starving yourself and eating no protein, but 

Menno: yeah.

And there’s also, it was a recent study in elderly individuals during, I think, immobilization bedrest, but still, and they had muscle loss and performance losses within a week. So obviously if you’re still staying active, also a big factor is if you’re an energy deficit, because if you are an energy surplus, you’re not going to lose muscle nearly as quickly, but you’re of course more likely to put on fat.

Depending on those factors, you’re going to have more of a transplant. It may already be a week now, I’m definitely not saying like everyone panic if you cannot train for a week of holiday or whatever, it’s going to be minor anyway, and it’s going to be relatively easy to get back.

Mike: I’ll get people that reach out where they’re usually not worried about a week, but it might be a couple of weeks might be even a month or longer where they’re not going to be able to train or do their normal thing or not be able to train as much as they would like to. And that’s something I always remind them Look, just do what you can.

And for example, if it’s a two week vacation and you don’t want to completely go out of your way and inconvenience yourself and everyone else, so you can get in your proper correct workouts, just do what you can. And if you do lose anything. You’re going to gain it back really quickly. Like muscle memory is really within take two weeks off, just doing what you can do, come back.

And within a couple of weeks, you’ll be right back to where you were. So just don’t stress over it. 

Menno: It does recommend on who you tell, because I generally do want people like to say, do what you can, that’s priority one, try maybe bodyweight workouts. If you want to, at least, and even with no equipment, if you have to do half assed workouts, or you just get one session into the gym, maybe you have 20 minute workouts, just pushups, pistols, and chin ups, something like that, it can go a very long way and even allow you to maybe gain some muscle, especially if you’re overeating a lot in that period.

But yeah, if you lose a lot of muscle, maybe due to a big injury, for example, or. I have some clients that go off working on an oil rig. The gym was broken there. So then, yeah, you’re pretty much screwed in terms of what you can do. Also on a non stable boat or oil platform, because of two reasons, you can regain all of that muscle that you lost or any muscle that you lost relatively quickly.

And that’s one, basically the same reason I said before that the voluntary activation is quite well preserved. So your nervous system actually retains the ability quite well over time to activate your muscles. More trained individuals can achieve higher levels of muscle activation than untrained individuals.

So that’s one thing that helps you. And then second, the myonuclei, which are the command centers in your muscle fibers that you build, they are semi permanent. So they’re not going to be lost in a matter of weeks, generally, or even months, even years based on research we have. So once you’ve built those myonuclei, those command centers, those extra cell ports in your muscle fibers, they help upregulate protein synthesis.

For future muscle growth. So when you get back to training, that’s the infrastructure is already there. It’s like you’ve built a city and maybe a lot of the citizens leave some of the regions, but the infrastructure, the roads, the electricity network and stuff, they’re still there. So it’s only a matter of moving the participants.

Back into their buildings and you don’t have to actually build the whole block and install internet cables, et 

Mike: cetera. That’s a good analogy for it. You just got to come on guys. Come back in. I need bigger biceps. There’s room for everyone. Yeah, exactly. So getting back to the reactive DLO, just cause I’m sure some people listening are wondering like, Oh, wait a minute.

So what is that then? What’s your DLO? I’m also curious myself. 

Menno: Yeah. So basically the traditional form of deloading, which is basically influenced mostly by the polyclinic era and the like is a week off every fourth week or so. And that is, it’s very proactive, which is normally a good word, right?

But it’s also, it’s not auto regulated. So you basically, you take that week off it’s planned in advance. But you may not even actually need the week off at that time. So I prefer to do it reactively based on objective muscle performance and also some subjective feedback to see if you notice that you’re maybe getting extra sore.

Your performance is decreasing where it should be increasing. Dan take. Maybe some days off. Factor two is that it’s a week, which is, convenience in our Gregorian calendar. But a lot of things we base our training on basically arbitrarily sets in relation to the speed at which the earth rotates in the Milky Way, et cetera, and not actual human physiology.

So the week, it’s not based on actual time required for neuromuscular tissue recovery. It’s completely arbitrary. And usually you really don’t need a full week. Factor three is that the traditional. Deload is whole body. Or as we know, as we basically, as we just discussed, most neuromuscular fatigue.

Peripheral in nature. So it’s local. If your biceps is suffering too much fatigue or, connective tissue, maybe your biceps tendon is getting inflamed and degenerating. It does not mean you should stop squatting. So usually the fatigue is centralized to a region. There’s. A certain culprit exercise, for example, that may be at fault, that’s giving an injury, or maybe you are overtraining your upper body, but not your lower body.

And therefore you need to give those muscles or those body parts rest, but there’s no need to do it for the others. So basically I do reactive deloads on an exercise specific basis. In general, a good rule of thumb is that when you see your performance is decreasing, when it should be increasing, do a reactive deload right then in that session, and then maybe go back one increment of weight.

The next workout, something like that. You have to set it based on the exercise and what realistic rate of progress is for that exercise. But the general idea is that when you see for an exercise or body part performance is going down, when it should be going up, then you de load and you only de load that exercise slash.

Body parts. And that’s basically a more ultra regulated, 

Mike: more advanced. You have to have a good sense of your training and your body and how even your mindset and how your psychology is affecting your training, cause sometimes. You get stuck just because you’re not working as hard as you should be in your workouts.

You don’t need necessarily a deload. You just need to work harder. But no, that does make sense. And also that I’m assuming, this is something that you’re doing not just yourself but with your clients. And so then your clients have that. Benefit as well, that they have your direct help and you are monitoring their progress and helping them also understand and go through it successfully.

So then maybe they could replicate it themselves, whereas it might be more difficult if they didn’t have your help. I would think 

Menno: yes, definitely. And I think it may be good. I’m not saying that the weekly deload is like it’s a myth. You should never do it. It’s silly because I can’t imagine if you create a program for someone, for example.

That you can anticipate some reliability that they may need a deload, or maybe they’re just, it’s a safe method. I think Mike Israzel mostly does deloads for Connected Tissue Health. If he creates a program for someone, maybe after this amount of time, we just do a deload to be safe. Because, as you say, that individual may not be able to do it reactively.

Mike: Yeah. Like I’m working on a second edition of a book that I wrote. That’s a sequel to my men’s beginners book. So the beginner book is bigger, leaner, stronger, and the sequel is beyond bigger, leaner, stronger. And it’s meant for intermediate weightlifters. So it’s meant for the guy who has. Gained probably his first 20 or 25 pounds of muscle and which bigger, leaner, stronger gives him everything he needs for that.

But now wants to see what has he got left? And eventually what really one of the main things is that bigger, leaner, stronger doesn’t provide enough volume for that. So it’s nine or 10 hard sets per major muscle group per week, which I think is a fair place to start, but eventually that just becomes a maintenance program.

And so in the intermediate, the volume goes up and there’s a bit of periodization, but the deloading, this is currently like working through the program myself and doing it myself. And what I’m doing right now that I’m enjoying is currently it’s every fourth week. And so the program is progressing from higher.

Each training block is starting higher volume, lower weights, and progressing to a lower volume, higher weights, and then a deload. And the deload is it’s the normal workouts. But what I’m doing is I’m cutting the volume in half. So I’m doing instead of four sets per exercise, I’m doing two sets per exercise.

And I’m taking a couple reps off of what I was doing in my previous working week, but I’m still working with heavy weights. And that seems to be a sweet spot, at least. There’s me and there’s some other people that I’m working with in the program, just to see how they respond to it, where maybe it’s a little bit conservative or overly proactive, but when I’m asking people to train hard, I don’t know, I just.

I prefer to be a little bit, if I’m going to air, I want to air on that side. If I’m trying to give people a kind of one size fits all, here’s a program that is going to help you get to that next, ideally it would really bring people probably close to the top of their genetic potential.

And I think you have to get very specific in the end to really get there, but that’s how I’m going about my de loading right now. And it seems to be a nice balance between the training stimulus and then the recovery back off. 

Menno: I think that’s sensible. I think also I like that a lot more than the idea of just taking the whole week off because I think that can also, especially like a whole week off every fourth week is can also give some, what I’ve noticed at least in motivated individuals, it breaks them out of their routines and some people actually have extra trouble getting back into the training afterwards because they’ve gotten used to life with a bit more time on their hands and training is not so bad.

And they’ve also forgotten that they feel better after the workouts. So the, the obstacle to do the next workout seems a lot bigger. 

Mike: Yeah, totally. In the past, when I had tried taking weeks off versus deloading, I would do it every two months, take a week off. And I found that I found deloading. I enjoyed more one for that reason.

It’s. Going to the gym is part of my routine. I like it. It’s a good way to start the day. And also I found that as I became more advanced, and at that time I was pushing even harder for trying to gain whatever strength and muscle I had left, that week off would just set me back. And it would take me the first week and sometimes the second week, just to get back to the weight and reps that I was at before I took a rest.

Whereas if I de loaded and especially in this way, where I still am handling heavy weights, I’m just backing off on the volume to give my body a chance to catch up in terms of the peripheral fatigue, really is what I guess we’re talking about those elements. Then I found that I was able to just carry on when I got back to the heavy training and I hadn’t lost anything in terms of performance.

Menno: And there’s also actually research showing that. Also for your connective tissues, active recovery works better than total time off. A lot of people have probably noticed that if you ever had a serious injury and you took a whole week off, then after that week, it’s like, it’s still the same. It’s it didn’t improve much.

That’s because if you’re sedentary, the amount of blood flow, especially blood flow, and therefore oxygenation, nutrient delivery, et cetera, to connective tissues like tendons is really low. It’s, I think it’s about seven times as low. As a muscle tissue, so they’re basically, there’s no nutrients, no blood, no, no oxygen, et cetera, being delivered to those tendons when they’re completely inactive.

So there’s not much remodeling taking place. And if you do some relatively light workouts, like your case, your kind of deload week, for example, you’re actually promoting. Huge amounts of blood flow, like the increase in blood flow during exercise to connect the tissues is huge. I also often joke that squats are like a miracle healing exercise, but actually they, I think they do because they’re a full body exercise, nothing truly magical about squats, but they do have a serious effect that’s noticeable.

The healing rates, in my experience of many, minor injuries that you can do if you can squat pain free at least. 

Mike: That’s interesting. Yeah, that absolutely makes sense. And it’s something that anybody who has had to work through an injury has probably experienced if they’ve made the mistake of just remaining immobile and thinking that rest is the key, you just have to rest it.

Initially maybe you do, but then you have to actually start working it. And that’s true of, I’ve experienced that. I haven’t had any major injuries fortunately, but I’ve had joint aggravations. I’ve had some biceps tendonitis and completely avoiding the problem. was not the solution. It was backing off and not like overly aggravating it, but continuing to work it and stimulate it.

So the body could do what it needs to do. And of course it needs blood getting to the area to fix the problem, or it’s just going to never resolve. 

Menno: Definitely. That’s exactly my 

Mike: experience. Awesome. Those are the main points that I had that I want to pick your brain on in terms of CNS fatigue and just fatigue in general.

Is there anything that we haven’t covered that you think is worth sharing before we wrap up? 

Menno: No, I think we we touched on all the important parts. Don’t be no seaboat by the CNS fatigue. I wouldn’t call it a fairy, but she’s definitely overrated and make sure that, what fatigue you feel is a lot of that’s mental.

You can push through it. Make sure, you don’t try to push through pain related to connective tissue damage, like injuries and the like, if it’s just muscular discomfort and, training is hard. Suck it up, push through it. It should be empowering for yourself. You don’t have to worry too much about CNS fatigue, breaking down your workouts, et cetera.

Training hard is priority one. Train smart. Get your rest. Happy gains. 

Mike: Love it. Said. And just to interject on that, there are some people out there who harp on CNS fatigue. It’s like their thing, right? And they’ll say, Oh, if you train more, that’s usually it’s I only trained two or three days a week because that maximizes neural recovery.

And if you train more than two or three days a week, you’re going to run into problems related to CNS fatigue, and you’re not going to be able to progress as faster or as fast as you would be able to progress if you were. Training less frequently. And that is certainly not true. You couldn’t do that.

Even if you tried, maybe if you sat in the gym, maybe if your workouts were like eight hours long, yeah, maybe, but practically speaking. And this is also just one of the things to throw out there for people is this is a, an example of something where. I think of David Goggins, who’s a popular guy right now, and his idea that like, when you think you’ve reached your limit, like you’re only 40 percent there or whatever, and just the point that you can push yourself a lot harder than you think you can, and you can then achieve a lot more than you think you can, et cetera, et cetera.

And while that doesn’t work in the case of something. Like total muscle gain, it doesn’t matter just because you can shut your brain off and go run an ultra marathon like he can do doesn’t mean that you can shut your brain off and get infinitely big, but it does mean that in your workouts, you certainly can and apply, I’d say for me, I’ve experienced this.

Anybody who’s been in the gym long enough has experienced this, where you can push yourself harder than you think you can sometimes. Especially if. You do feel a bit tired and you don’t feel very motivated. Sure, man. I’m sure you’ve had it before where you go into the gym feeling like that, but then you just decide like, all right, I’m going to have a good workout and I’m going to give it everything I’ve got.

And then you end up having a great workout, but you came in feeling like this is, should I even be here? Should I just go home? 

Menno: Yeah, for sure. And I think the key is just do your warmup. And then I often tell my clients as well. Maybe try the first set. And if you really notice your performance isn’t there, feel free to call it a day.

Go back home. Maybe you actually need it then, but you won’t know until at least you’ve done your warmup and you’ve started ideally at least, one work set. 

Mike: Yeah. I agree. That makes sense. Awesome. Great. Let’s wrap up with where people can find you and your work. And what do you have coming up?

That’s new and exciting. What would you like people to know about? 

Menno: Yeah. My website’s menohanselmans. com. Probably can’t spell that. So look at the show notes or wherever where Mike 

Mike: for people listening, I’m just going to, spell it out for him. So H E N S E L M A N S Hensel men’s, but I guess at this point they can just probably Google probably just Menno and you come up, right?

I’m not sure. Pretty good chance, oh no. Okay, good. If you are not catching his last name, then you’re gonna have to put in Menno bodybuilding and then there you go. You’ll find it. 

Menno: Yeah, that works. Maybe I should change my name to that. Or muscle just mental muscle, the alliteration will be good for marketing, it’s hard to forget.

Yeah. And someone stole the best marketing name. Yeah, that’s my real name. So yeah, that’s my site. I publish everything there. I’m also active on Instagram and Facebook. Probably best way. If you’re new to all my stuff, I have a very big free email course. If you go to my main page, it’s like right there on the front and best way To sign up for that, you get a lot of free content.

It’s basically a tour of my best offs. Otherwise, it’s if you direct people to your website and you have to dig through all the stuff, you don’t know what’s dated and what still makes sense. So I basically created that email course. It’s like a tour to, to see, what people like the most, what are my most popular contents that you still have referring for yourself.

And then of course, at the end, I’ll plug you with my online PT course. If you were interested in really taking your education to the next level. 

Mike: Yeah, that’s the deep dive and that’s available at your website as well, right? Yeah. Awesome. And then maybe it’s also worth mentioning just to put it out there that you are going to be coming here to the States.

You don’t really have a home base, right? You just move around or do you? 

Menno: That’s right. I’m a digital nomad. Literally all of my life belongings fit into two suitcases. And where are you at right now? I’m currently in Sao Paulo, Brazil but only be here for one more week. Got two big speaking engagements in the Netherlands and in India, but I am indeed, I haven’t announced it yet.

So here’s the premier. I’m coming to the U. S. I’m going to do a seminar there. Not sure if I can announce the other one yet, but also going to be a big collab with some more people. Probably going to be March, April. 

Mike: Cool. So anybody listening who would like to know more about that, just go follow, go get on Menno’s email list, follow him on Instagram.

And I’m sure the details will 

Menno: be revealed to you in due time. 

Mike: Yeah, we’ll follow. All right, man. Thanks again for doing this. I look forward to the next one. 

Menno: My pleasure. We’ll keep in touch. 

Mike: Hey, Mike here. And if you like what I’m doing on the podcast and elsewhere, and if you want to help me help more people get into the best shape of their lives, please do consider picking up one of my best selling health and fitness books, including Bigger, Leaner, Stronger for Men, Thinner, Leaner, Stronger for Women, my flexible dieting cookbook, The Shredded Chef, and my 100 percent practical and hands on blueprint for personal transformation.

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