What’s the secret to an effective workout? More reps? More sweat? More weights? In this episode, Dr. James Fisher and Amy Hudson break down the science behind strength training, revealing why muscle fatigue, not time or reps, is the real key to results.

From type-2 muscle fiber recruitment to recovery strategies, what you’ll hear will help you rethink how you train and why less might actually be more.

• Dr. Fisher and Amy address the “million-dollar question:” What’s the secret to effective exercise?
• Dr. James Fisher is a fan of questions such as What is the stimulus? – He likes that once we have in mind that the exercise is the stimulus to adaptation, we can just stop blindly going and doing as much as we can.
• Dr. Fisher and Amy Hudson share the secret of effective exercise: fatiguing the muscle or working it at the right level of intensity.
• Dr. Fisher touches upon type-1 and type-2 muscle fibers – and why you should want your workouts to recruit type-2 muscle fibers…
• Amy and Dr. Fisher list a few signs that you may have recruited your type-2 muscle fibers the right way.
• Dr. Fisher cites some of his research on dissociating effort from discomfort and some interesting findings related to it.
• Some studies have shown that people who are averaging 6-10 hours of sleep per night will build strength in muscle size quicker than those sleeping an average of less than 6 hours.
• Remember: the workout is the stimulus; it’s the time after the workout that allows that muscle adaptation.
• “All the wonderful benefits that strength training delivers happen during those recovery days between your sessions,” says Amy.

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Previous episode – The Truth About Muscle Soreness: Myths, Recovery, and What to Do Next

Previous episode – The Truth About Sweating: What It Really Means for Your Exercise Routine

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SHOW TRANSCRIPT

To add muscle, to see a little bit more definition, to improve my metabolism, I really need to recruit my type 2 muscle fibers when I exercise.

One of the great things with the exerbotics devices at The Exercise Coach is we can actually physically see the amount of force that we’re producing.

Welcome to the Strength Changes Everything podcast, where we introduce you to the information, latest research, and tools that will enable you to live a strong, healthy life. On this podcast, we will also answer your questions about strength, health, and wellbeing. I’m Amy Hudson.

I own and operate three exercise coach studios. My co-hosts are Brian Saigon, co-founder and CEO of The Exercise Coach, and Dr. James Fisher, leading researcher in evidence-based strength training. And now for today’s episode.

Welcome back, everybody. If you’ve been with us for the past few weeks, you know that we’ve been talking about indicators or markers that are easy to look towards to conclude whether or not your exercise session was effective. For example, we’ve talked about things like soreness, we’ve talked about things like sweating. Does how much I sweat, does how sore I am, or does how long I’ve spent exercising indicate how effective my workout was? I think when it comes to thinking about whether a workout was effective, most people out there are thinking about the change that it delivers to their body. If I’m going to spend time exercising, what do I hope is the outcome of that? Nobody wants to spin their wheels or when it comes to exercise, it’s discouraging to spend years upon years doing something that you’re not sure is working. And so today we’re gonna reveal what is the secret to effective exercise? How do I know that what I’m doing is going to change my body? Okay? This is the million dollar question for those people who want to exercise as a means to achieve their goals, which is most of us, which is most of us, right? So Dr. Fisher is with me today. How are you doing, Dr. Fisher?

I’m doing fantastic, Amy. I love this question, so I’m really excited to get into it.

But first, how are you doing?

I am well.

I cannot wait to reveal the secret to the population of what is the secret to effective exercise. So, what is the secret to effective exercise?

First of all, I love these questions because they’re the right questions to ask. They’re asking what is the stimulus? What do I need to do to create an adaptation? And I think once we have in mind that the exercise is the stimulus to adaptation, we can just stop blindly going and doing as much as we can, because some people will take a really high volume approach to a lot of exercise, whether it’s running or strength training or cycling, whatever it might be, and they’ll think that more is better. And that’s really not the case. The secret really is the intensity of effort.

And this is often termed in different ways. I’m going to use the term intensity of effort because that’s what we’ve used in the scientific literature. In most cases in strength training, that’s talked about as fatigue or volitional fatigue. So that’s what the coaches may have used in their vocabulary. But really it’s about how hard we work. And that’s it. That’s the answer.

So now I know we’re going to get into more than that, but what are your thoughts on that so far? Okay, so mic drop. The secret to effective exercise is fatiguing the muscle or working it at the right level of intensity. We’ve talked before that the reason most people fail to see results in exercise is because they are not exercising at the right level of intensity. So fatiguing my muscle is the secret to it changing. Yes?

Correct?

Well, absolutely. So what actually happens is when I start to contract a muscle, I recruit muscle fibers. So I think we’ve talked on a previous podcast about type 1 and type 2 muscle fibers. So I start to contract my muscles against the resistance and if it’s just the normal resistance like a dumbbell or a barbell then as I start to recruit those muscle fibers I’ll recruit low threshold motor units and the corresponding type 1 muscle fibers. But as the exercise gets harder, as my effort level gets higher, then I’ll start to recruit the type 2 high-threshold motor units and the type 2 muscle fibers. Now of course on the exobotics devices of the exercise coach where the resistance is immediately quite high because it’s isokinetic, the initial repetitions might already start to recruit some of those type two muscle fibers. And certainly in the eccentric phase, when we’re lowering the weight or when we’re resisting, maybe the leg press coming back towards us or the chest press coming back towards us, where we’re resisting that movement, there’s actually a higher preferential recruitment of type 2 muscle fibers. But fundamentally, this is the stimulus for adaptation. If we don’t recruit muscle fibers to work, we don’t stimulate them to grow.

We don’t stimulate them to get stronger, we don’t stimulate them to get bigger. So we have to recruit those muscle fibers. So if we stay within our limits, if I ever try and do exercise and all I do is I pick up a pencil and I do 20 or 50 bicep curls with a pencil, that’s not going to be hard work and it’s simply never going to recruit the higher threshold motor units and the type 2 muscle fibers that I want to make a change. So I’ve got to use, either use something a bit heavier or I’ve got to do more work until it gets hard enough to really recruit those muscle fibers to stimulate an adaptation.

Why is it so important to recruit type 2 muscle fibers?

Yeah, so type 2 muscle fibers are the ones that we lose as we age. They’re also the ones that are most responsive to strength and muscle size growth. So our type 1 muscle fibers can grow a little bit but not a huge amount and our type 1 muscle fibers are sort of great for endurance activity or for sustained low load contraction or sustained low force contraction but it’s our type 2 muscle fibers that produce high amounts of force that we really want to recruit and that can grow bigger as well that we really want to recruit. And they’re the ones that we lose as we, uh, as we age. So we really want to recruit them, build them while we can, um, or recover them as we get older. And we do that by working at that higher intensity of effort. And as we talked about before, a lot of time, that’s talked about as to fatigue or to volitional fatigue, to the point where you feel like, I just can’t push anymore or I just can’t pull anymore. That’s the sign that you’re truly working hard enough to really recruit those muscle fibers to stimulate a change?

Okay, so you’re saying that if my goal is to add muscle to see a little bit more definition to improve my metabolism, I really need to recruit my type 2 muscle fibers when I exercise. A walk maybe activates those type 1 muscle fibers, but if I really want to see some of the additional benefits, I need to focus on fatiguing and getting at recruiting those type 2 muscle fibers, digging deep enough to do that in my workout. One thing you just said then is getting to the point where you don’t feel like you can push or pull anymore. That is one sign.

What are some other signs that I have fatigued a muscle sufficiently? where you don’t feel like you can push or pull anymore. That is one sign.

What are some other signs that I have fatigued a muscle sufficiently? What should I be feeling or looking for in my workout? What does that look like and feel like?

Well, one of the great things with the exerbotics devices of the exercise coach is we can actually physically see the amount of force that we’re producing. So as I push against the leg press, I can see my curve compared to what I’m trying to achieve. So if I’m still able to go beyond it in my sixth or seventh or eighth repetition, then I can really push hard and really try to produce as much force as I can. If my force is dropping off, but I’m still really pushing as hard as I can, that’s simply a sign that my body’s now fatigued, those higher threshold motor units, and it’s not able to produce as much force. Now unfortunately, there aren’t any other really big markers. It’s not like, oh, we start sweating. We’ve talked previously about sweating, so it’s not like we suddenly start sweating when we recruit the high-threshold motor units. That’s just about our body temperature. It’s not even really about our heart rate, although our heart rate will generally get higher as we work harder. So I guess if our heart rate is getting higher, that’s probably a good marker, but it’s not the marker and not the only marker. Really it’s simply knowing that we’ve pushed as hard as or pulled as hard as we can with that single task. Now the great thing about this is it means that it’s not about how much we do, because once we’ve stimulated a muscle fiber to adapt, there’s not really much to be gained by re-recruiting those muscle fibers and doing it all again. So lots of people will go into the gym and they’ll do the typical old school approach of three sets of ten repetitions. And sometimes that’ll work out great if it’s hard enough, but sometimes it won’t work out at all if it’s not hard enough. So some people will go in the gym and they’ll spend hours in the gym doing three sets of 10 repetitions of bench press and three sets of 10 repetitions of leg press, but they will never get any stronger or any bigger. And that’s simply because that three sets of 10 repetitions is well within their capacity. Actually, they can up the weight and simply do one set of 10 to 12 repetitions and they’ll achieve much, much more.

Or come to the exercise coach and obviously do a single set of an exercise and that will be sufficient stimulus for those muscle fibers. And then obviously you’ll re-recruit them to some extent with different exercises, but there’s no need to spend hours and hours doing a workout.

Okay, so you said staying in my range or at my target or above my target if I’m working out at the exercise coach, I see right there on a screen in front of me my goal for my exercise to make sure I’m working at that level of intensity. You said heart rate, maybe, maybe not though. It’s not about number of reps. Another couple of signs that come to my mind is shaky muscles.

My muscles may start to shake, tremble as I fatigue. Our form can be, start to suffer the more fatigue we get. It’s just harder to maintain proper form because we’re fatigued so that might be a sign heavy breathing may be a sign and then one other indication that comes to mind from a previous podcast that muscle burn is your friend having a little bit of muscle burn during that workout is a good sign it means that you’re recruiting your muscles or you’re depleting them sufficiently of the energy stored in them, which is what you want to do, right? That’s a good thing.

So there are really interesting points. So certainly we will breathe harder when we exercise harder. We cannot help that. And it’s really important that we do keep breathing because some people will hold their breath. They’ll perform what’s called a Valsalva maneuver and that’s really not beneficial. It will cause a sudden drop in blood pressure as they hold their breath and then a sudden spike in blood pressure as there’s a kind of recovery. So we definitely don’t want to hold our breath when we’re performing strength training exercise. You then also mentioned the discomfort or the burn. Now this is really fascinating. We’ve done a lot of efforts, I’ve done a lot of research dissociating effort from discomfort. So you can work really hard and sometimes not feel that high level of discomfort and sometimes you work really hard and you feel a huge amount of discomfort and you really feel that burn.

Um, one of the things that’s, that’s really clear in the literature is we’ll feel more discomfort from the lower body muscles. So you’re more likely to feel that burn if you’re training the quadriceps. So a knee extension exercise or a leg press exercise will probably get you that muscular burn as you called it, Amy. Whereas a chest press or an overhead press or pull down, we might not feel the same degree of burning sensation within the muscle. The other thing that we know is that the discomfort can be higher with a longer set of exercise. So that’s time under load. So if we have a longer time under load, our discomfort is likely to get much, much higher compared to a shorter time under load set. Whereas actually our effort level can be equally high in both sets.

Absolutely. Okay.

So, all right. So the secret is fatigue. in both sets. Absolutely. Okay, so all right, so the secret is fatigue. The secret to effective exercise is fatigue and intensity. And when I think about two isotonic exercises, so those exercises not performed on extrabiotics machines, you know, we really are looking for, um, that to get to that point where our muscles feel like they really cannot do any more reps. Um, that’s how we know we have really truly fatigued that muscle. We, we want to get to that point. That’s actually a good sign, right? Um, because then when we go home, if we can get our muscles to that point and deplete them thoroughly enough and fatigue them thoroughly enough, that’s when we can trigger them to change. How does that change happen, Dr. Fischer, at a high level after a workout like this?

Yeah, absolutely. So we stimulate the muscle to adapt. We’ve recruited this neural process within our brain. We’ve sent this neural signal through our neurophysiology to recruit these muscle fibers. That’s caused some microscopic trauma within the muscle. And then there’s kind of a catalyst response of different enzymes to recover those muscles and to replenish and rebuild them for strength and for muscle size as it were. So we know that this takes a degree of time. We know that there’s, you know, sleep is a big marker for recovery of muscle growth and muscle strength, both at an acute level as well as over a chronic period of time. There have been studies that have shown that people that are averaging sort of six to 10 hours of sleep per night will build strength and muscle size much quicker than people that are averaging sort of less than six hours of sleep per night. We also know that good nutrition’s really important, so protein’s essential for sort of muscle protein synthesis and strength and recovering our muscle fibers. So there’s a few different factors there and of course not re-stimulating the muscle. If we do something every single day because we think that’s good, then we’re probably just gonna fatigue the muscle over and over and over and over again, but not give it that time to grow. The workout is the stimulus, it’s the time after the workout that allows that adaptation.

And for many clients at The Exercise Coach, honestly, that’s the best news because that means that those recovery days are just as beneficial as the workout days. And so for people who do not like to spend hours and hours a week exercising, they can put in 20 challenging minutes, let their body recover for the next couple days, and then come back and do it again. And as that recovery happens, like you just mentioned, the repair happens and their muscles get stronger. And that’s what we’re looking for because when our muscles grow and get stronger, that’s what delivers the fitness results that most people are after. All of the wonderful benefits that we talk about every week on this podcast that strength training delivers happen during those recovery days, those magic days between your sessions. And that’s why it doesn’t take longer. And that’s great news for a lot of people who are busy. So thank you for breaking the secret down for us Dr. Fisher. Do you have any final thoughts on this topic? No that’s great it was another great list of questions so really excited to have answered that one. Yes all right well thank you thank you and please keep those questions coming. We will see you next week on the podcast. Hope you remember, strength changes everything. Thanks for listening. If you enjoyed today’s episode, please share it with a friend. You can submit a question or connect with the show at strengthchangeseverything.com.

Join us next week for another episode and be sure to follow the show on Apple Podcasts, YouTube, or wherever you get your podcasts so that you never miss another episode. so that you never miss another episode. Here’s to you and your best health.