(Note: this episode was extracted from a presentation Dr. Buckner gave during a recent Mastermind call among NeuFit practitioners. For a more complete experience, please check out this episode on YouTube which includes a slide presentation)

In this episode of the NeuFit Undercurrent podcast, Dr. Sam Buckner Ph.D. joins our monthly Mastermind call to go over the results of his study “The acute muscular response following a novel form of pulsed direct current stimulation (Neubie) or traditional resistance exercise.” In the study, he shows that the acute response to training with the Neubie and no external load is similar to traditional resistance training with 70% of maximum resistance. The measured responses include increased muscle thickness (as measured by ultrasound), and also fatigue and soreness.

While the Neubie is already FDA-cleared for reducing atrophy, this is the first research study directly demonstrating that it may be able to do more in the realm of hyptertrophy, or muscle growth. By showing an acute, short-term response, it also leads to more questions about long-term effects which Dr. Buckner brings up and that will be answered in his future studies. Questions like: can the Neubie grow muscle over a complete training cycle? And how does it compare to traditional weight training?

Listen in to hear the details of the study as well as the science behind low-load training and why it can be beneficial in many circumstances. A link to the published article is below:

https://www.ismni.org/jmni/accepted/JMNI_21M-08-159.pdf

Podcast Transcription

Dr. Sam: Direct post current seems to be a way to have, we think the potential for maximal activation with minimal effort, which is an intriguing idea. And I think it provides an interesting alternative to training that can fatigue a muscle and perhaps grow a muscle. And I think that’s something that everyone’s interested to see that data

Intro: I’m Garrett Salpeter, and I believe that the most powerful and transformative way to help people recover from pain and injury, heal from trauma and reach their highest levels of fitness and performance is to focus on the nervous system. In this podcast we’ll share knowledge from the frontiers of neuroscience and inspirational stories of how applying that knowledge has empowered people from all walks of life to heal, adapt, and grow.

Garrett: Today I am super excited to welcome to the call, Dr. Sam Buckner, who is a professor in the exercise science department at the University of South Florida in Tampa. And you may have heard the podcast episode that we did on the science of hypertrophy. And he’s got some real expertise there. If you haven’t listened to it, I would encourage everyone to go back and listen to that Neufit undercurrent podcast episode. And he did his research as he was coming up and getting his PhD, a lot of research on blood flow restriction. So he’s gotten a lot of knowledge there.

And then now as a professor running his own lab, he’s doing some really interesting research, including some projects and some studies with the neubie. And he is going to tell us today about the results of the first study, because it is just accepted for publication, which is awesome news. So the first published study peer review published study on using the newbie for hypertrophy will be out within days, any day now. So Sam, Dr. Buckner, thanks so much for coming on here. And I’ll turn it over to you to share whatever you’re willing and able share.

Dr. Sam: Right on. Well, yeah, thanks for having me. I’m happy to be here. And I do have some slides if I can pull them up.

Garrett: Yeah. Either Clay or I can make you. One of us will make you a host or a co-host and then will get you on there. Let’s see. Clay, I think since you logged in first. Thank you.

Dr. Sam: Awesome. So yeah, a little bit of my background. I study skeletal muscle growth and adaptation to various stimuli. I suppose I specialize in alternative to traditional high load training. So I think it does make a lot of sense that this is something that’s kind of in my wheelhouse and in my area of interest. So I titled this an examination of acute and chronic adaptations, following resistance training with direct pulse current. As Garrett mentioned, we just completed an acute study that’s accepted for publication in the journal of neuromuscular or muscle skeletal and neuronal interactions.

I submitted the proofs today, so that paper should be out any day now. But I may give you guys a little bit of background that kind of led my thinking in these experiments. Well we found an acute study and I’ll tease the chronic growth study that we’re working on or we’ve already completed. So we’re in the analysis stage. So the original belief with training is that lifting heavy weight is the way to grow muscle. And this belief was kind of the way of thinking for several years up until probably the eighties and nineties, and really not into the two thousands where people really considering alternatives to traditional high load training.

And when we say traditional high load training, we mean a weight you can do probably 8 to 12 times, corresponding to somewhere around 70, 80% of your maximum strength. But in 2012, Cameron Mitchell and his colleagues from Stewart Phillips lab and McMaster did a series of studies examining low, low alternatives to training. So this first study you can see at the top resistance exercise load does not determine training mediated hypertrophic gains in young men. They had two groups, one group lifted 30% of one RM, and the other group lifted 80% of one RM.

So one group lifted really light and one group lifted relatively heavy. And over time they saw the same growth in both conditions. So that provided some evidence that growth is not driven by an external mechanical stimulus. And it perhaps relies on internal tension, creating stress within the fibers involved in a movement, not necessarily relying on external loads. And the study below, I think is just another remarkable foundational paper within exercise science by Ikea and Fuku Naga. They published this in 1970, and this study showed that isometric training. They train 3 times, 10 second bouts every day, except Sunday for a hundred days. And isometric means they literally just contracted their muscles several times, but didn’t have any movement and didn’t have an external load.

And they were able to see increases in muscle cross-sectional areas.

So these are two examples where growth does not rely on external load. So a more contemporary belief is that if you want to grow a muscle, you need sufficient muscle fiber activation, not necessarily sufficient external load or weight to be lifted. So this means we can remove the load. And in some studies, this is referred to as no load training or lifting without actually lifting a weight to maximize muscle growth over time, which is an interesting concept and a concept that we’re beginning to have more and more data to support.

For example, in 2016, my research group conducted a study called the acute and chronic effects of “no load resistance training.” This study was pretty fascinating because we had a group of individuals just contract their biceps as hard as they could pretending like they doing bicep curls, but they had no weight. So imagine just standing and contracting your biceps as hard as possible. They did four sets of 20, and we actually compared this to lifting heavy weight. So one arm did four sets of 20 with no weight. One arm did traditional high load training, 70% of the one around, they both did four sets. And this protocol over time, this is muscle thickness in the no load group and the high load group and looking at the different sites of the biceps, muscle growth was similar across time.

So the no load condition is on the left. You can see the 50, 60, and 70% measurement sites. What that refers to is 50% is the top of your bicep. 70% is the bottom of your bicep. But what was remarkable is that growth was the same between these conditions. And this helped demonstrate that external load is not necessary to produce maximum muscle growth. If there is a high level of internal tension and effort. And to me, this is one of the reasons why I think the neubie device was interesting for me to begin researching is because I already have data showing that you just need internal tension. And if this device does in fact create internal tension, then there’s a strong rationale to suspect that it induces growth over time.

But within this data set, within this no load study, we did observe one thing. And it, it was just mentioned in the paper, but it’s always been in the back of my mind. We said, no load training appears to have greater variability than high load training, which may be related to each participant’s ability to maximally contract during no load training. If you think about giving a voluntary effort, if everybody on this call tried to maximally contract their bicep with no weight, we probably would have variability in our ability to produce those maximal contractions. So not everybody’s great at giving full effort. So that got us to thinking that, okay, maybe we can combine simulation with no load training to maximize the activation and induce the maximum growth response. And we looked at some of the background, some of the research that does exist under neuromuscular electrical stimulation.

Most of this is with alternating current and there’s some really good studies looking at deep training and the ability to use electrical stimulation to prevent atrophy or muscle loss over time. So we looked at these studies and we began to develop a hypothesis. The study by Dirks at all in particular was a pretty cool study. There was a deloading phase where, two legs were mobilized essentially, and one had electrical stimulation. And over time, the group that had stimulation as opposed to the control group was able to attenuate the loss of muscle tissue. So we see here quadriceps cross-sectional area, the control group that had no stimulation loss muscle. The group that had stimulation did not lose any significant amount of muscle mass.

So there is evidence that stimulation can induce protein synthesis response to increase the amount of tissue that we’re either holding onto or not losing over time, putting us in a favorable anabolic state, perhaps. So this led us to combine the two ideas. And I think with the neubie, this device is particularly favorable to this type of training because it allows ranges of motion. It allows eccentric muscle contractions. So we thought, why don’t we combine this no load training, which not everybody wants to give a voluntary maximal effort with electrical stimulation and see if we can maybe decrease some of the variability in the response and see if we can maximize muscle growth over time. And again, given the current knowledge on skeletal muscle adaptation, the fact that to grow your muscle, you don’t need weight. You just need internal activation. You need to turn on the fibers and through stressing them sufficiently you activate proteins that tell your muscle to grow.

So that was kind of our goal to get an initial look at these responses. So the study that will be published in the next few days is an acute study. And the purpose of this study was to do training with direct pulse current, and look at the acute muscle response. Now, an acute response to a training belt does inform us about the anabolic potential of that training belt. So essentially we had people lift weights, but they weren’t. They had a foam dumbbell in their hand and they’re doing four sets of 20. So the same protocol we used previously for no load training, except, instead of requiring the individual to contract their muscle maximally, we relied on neubie to contract the muscle maximally, which takes away a lot of that perceived effort of exercise, which I think is really cool.

So the study overview, people came in for their first visit. They did paperwork, we took their height and weight. We randomized either the right or left arm into the neubie condition or a high load training condition. And that was a condition that had began for the duration of the study. During the second visit, they performed either the high load. They performed both training bouts, one in each arm separated by 15 minutes. And we measured their muscle size. We measured their strength. We measured their perceived, different perceptions of emotion before and after exercise. And then we also measured muscle soreness and muscle swelling and muscle fatigue, 24 hours and 48 hours following these exercise bouts to see, do they lead  to similar muscle damage over time.

So we wanted to look at the acute response for muscle swelling and fatigue, but then we wanted to look at long term and I know 48 hours isn’t exactly long term, but when you’re studying muscle damage, it would typically be 24 and 48 hours following the exercise stimulus. So anyway, we did four sets of 20 in a direct pulse current group. The traditional group did four sets of exercise [to failure] with 70% of [13:22 inaudible]. So we’re comparing head to head. Neubie training with the gold standard of lifting weights. And we want to see, do these look similar, right? Do they result in a similar response within the muscle? And then perceptually as well, the neubie condition performed exercise at a 7 out of 10 on discomfort scale.

So we’d increased the current until they indicated that they were at a 7, which was discomfort without the presence of pain. They did four sets of 20 with 30 seconds of rest in between sets. Whereas the traditional group did 8 to 12 reps with one minute rest in between sets. We thought keeping the rest shorter in the neufit condition was important because we wanted to capitalize on residual fatigue, because really the goal over those four sets is to fatigue that muscle as much as possible. And the evidence we have does suggest that if we fatigue that muscle, that muscle will likely grow over time.

We measured muscle size and we measured muscle strength before and after these exercise bouts to capture the acute muscle response, which again, when we get into the results, I’ll explain what this means as far as the potential of this exercise bout. So this just lays out the entire visit. Before they exercise on whatever mode went first, that we had blood pressure, we measured their feelings. We measured their soreness level in the bicep specifically, we measured muscle thickness of the biceps using B mode ultrasound. We measured NBC. NBC is a fancy word for maximum strength and it was measured isometrically. So they pulled on a handle with their elbow at 90 degrees and we measured their force production.

They performed the exercise bout and immediately following the exercise bout, we measured force again, we measured blood pressure again, we measured muscle thickness again, we measured their feelings again, exercise induced feelings, and we measured the soreness. We rested for 15 minutes and we trained in the other arm, the other condition and measured the same responses. And then they came in 24 hours later. We measured muscle thickness, their strength and their soreness. And they came in 48 hours later. We measured their muscle thickness, their strength and their soreness.

So what did we find over time? When we look at muscle thickness we had a statistical interaction, but more importantly, you can see the direct pulse current condition on the left and the traditional training condition on the right. And both groups saw an increase in muscle size from pre to post exercise. In the direct pulse current, this swelling response, this is muscle swelling, it was elevated. It remained elevated at 24 hours. Returning near baseline by 48 hours. And we saw a similar pattern in the traditional training condition. Now there was a slight difference in muscle swelling immediately post exercise with a traditional condition, having a slightly greater, we don’t think it’s necessarily meaningful, but a slightly greater change post exercise.

But overall, this demonstrated that both types of exercise induced a fluid shift into the muscle. So I know y’all probably don’t measure muscle swelling, but everybody in here is probably exercise and experienced the muscle pump. So you felt your muscles get a little bit bigger and feel swollen following exercise. Physiologically that’s important because the fluid shift from outside of the muscle to into the muscle cell brings proteins with it and helps trigger this muscle protein synthetic response that leads to growth. So we think that the fact that we observe similar swelling in these conditions would be favorable or help us predict that muscle growth would occur over time.

For isometric torque. Both conditions did induce significant fatigue. So both conditions saw a decrease in torque from pre to post exercise. The decrease was slightly greater in the traditional condition, but both conditions remained depressed at 24 hours and 48 hours. post-exercise bout. Meaning both groups had fatigue and both groups were not recovered 48 hours later. Now in the literature, the best indicator, the most reliable indicator of muscle damage is a depression and isometric torque. So this data would suggest, I believe that both conditions had low levels of muscle damage, not extreme muscle damage, but a typical amount of muscle damage that you’d observe following heavy training. And that existed in both conditions, 48 hours with no difference.

And then we measured muscle soreness across time, and both conditions increased soreness across time. You can see the direct pulse current 24 and 48 hours, a traditional condition, 24 and 48 hours. And there was a interaction with the neubie condition having greater soreness, 48 hours following exercise about. So they were a little above, a 3 out of 10, whereas the traditional condition was somewhere closer to a 2 out of 10. So both of them experienced muscle soreness, but that level of soreness was a little bit greater in the neubie condition. And I won’t mention, we did recruit resistance, trained individuals. So it’s individuals who had trained their biceps on a regular basis.

So it is reasonable to suggest that neubie was a novel form of training for those individuals. So that might explain some of the heightened soreness we observed with the neubie condition. We also looked at exercise induced feelings and really there was nothing too noteworthy here. We had increase in physical exhaustion in both conditions, but there were no differences. We saw a decrease in trend quality in both conditions, but there were no differences between conditions and there were no changes in revitalization or positive engagement.

So I suppose nothing too noteworthy here, overall neubie induced a similar emotional response as traditional high load training. However, I will note that these two exercise protocols, the traditional training condition had a higher perceived exertion. So people felt like they were working harder when they were lifting heavy weight. And with the neubie condition, they didn’t feel like they were working as hard, but they did experience more discomfort. And part of that I would say is we use a 7 out of 10 discomfort as kind of our anchor for the stimulus. So we kind of guarantee that neubie training would have greater discomfort than traditional training over time.

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Dr. Sam: Our conclusions of this initial study, this current appears to be a safe training modality. It might be effective for individuals who are seeking to have lower exertion during training. And obviously I think a lot of you recognize other benefits. We only obviously speak in the scope of our data, which is why we say lower RPE because they have lower exertion despite remarkably similar changes in all of our physiological variables. Direct post current seems to be a way to have, we think the potential for maximal activation with minimal effort, which is an intriguing idea. And I think it provides an interesting alternative to training that can fatigue a muscle and perhaps grow a muscle. And I think that’s something that everyone’s interested to see that data once we’re finishing with our analysis.

We suggest in this paper that further research is needed to examine neuromuscular responses, to direct pulse current training over long periods of time. And of course stay tuned. I don’t know. Maybe I’ll be back on here once we have this data, but we did finish conducting a quadriceps growth study in resistance training individuals, following knee extension exercise. And in this study one leg is assigned again to a traditional high, low training condition. So lifting 70% of the water for four sets, two failure. And the other group is lifting a significantly lighter weight with the addition of electrical stimulation from the neubie device. And we’re pretty excited to finish the analysis and the writing of this paper so we can share these results, but our initial look into the neufit from the acute data would be promising for growth, potential.

Meaning the reason we measure swelling, the reason we measure fatigue is to inform us on, okay, does this exercise stimulus? Is it comparable to other things that we know? And I suppose if there were a take home of our first study, it would be that neubie training looks a lot like lifting heavy, even though you aren’t lifting heavy. And does it mean it has growth? I’ll be excited to share those results, but I have a lot of reasons to think that it would. So that’s what we’ve been working on. I’m an independent researcher at a university, so I have no no bias here. I like answering questions and discovering things and I think we’re pretty good in our lab at doing that. And we try to do good science to answer important questions. So I think that was my last slide.

So hopefully I didn’t go too quick. Oh this is the paper that we will be dropping any day now. [24:03 inaudible] muscle skeletal and [24:04 inaudible] interactions and this paper will essentially be a more detailed look into kind of all that data I presented at the beginning, looking at the emotional response and the acute muscular response. So keep your eyes toed for that. I’m sure it’ll be shared out once it is published. But yeah, that’s all I have as far as a formal presentation. I’m happy to discuss or answer any questions y’all might have.

Female: Sam, we’ve got one question from JP. He was curious about the pad placement for the study, where it was on the biceps or on triceps and biceps.

Dr. Sam: Yeah, it was on the triceps and biceps at the 50% site. So we measured acute swelling at the 70% site, which was distal to the pad. But the pads were placed basically in the middle of the bicep. And then on the opposite side of the arm on the tricep as well, same site. We used 7 out of 10 as our marker of intensity for both the acute study and the follow up training study.

Female: So I have a question for you about the follow up training study. Is it going to be the same markers or are you going to add additional markers?

Dr. Sam: Our primary outcome of interest are changes in muscle thickness. So I think we measured 9 different sites in the quads for growth. And the reason we do that is growth is not homogenous across the muscle belly. So for example, the top of your quads might grow, but maybe the bottom of your quads doesn’t grow. So we measured lateral aspects, medial aspects and interior aspects of the quads. So we wanted to get a full picture of all the musculature. So that’s why it’s taken me a little bit longer is because with each person I have pre and post data. I have two images at each site and I have 9 sites. So it’s just a lot of [26:13 inaudible] to go through, but that would be our primary outcome and our secondary outcome is strength.

Male: I have a question as well. Would you have any theory on what would happen if you added weight to the neubie as we do kind of in traditional fitness settings? Would it be kind of significant, more swelling or more growth or is that sort of so many variables we need to do another study on that?

Dr. Sam: So yeah, that’s a good question. And my thinking on this is it’s just a balancing act I believe, in that, if you add some weight, you probably need less reps. Whereas if you don’t have weight, you probably need more reps. Because a lot of the data we have suggests that if you lift 30% of your 1RM, you can do 30 reps. If you lift 70%, you can do 10 reps. If you lift 30% with BFR, you can now get away with 15 reps instead of 30 reps and cause the same growth. BFR is blood flow restriction. And I think this technique could be similar to blood flow restriction and that it could be a volume reducer because the scientific recommendation to induce maximal growth is to train two or near failure.  

And maybe one of the difficult things with neubie training is that, do you necessarily fail? Maybe if you add some weight, you could reach a more clear marker of failure. But what I would suspect there is that you could probably get away doing less reps if you add some external load. That would be my thinking. Does that make sense?

Male: Yeah. Thank you very much for that.

Garrett: That makes a lot of sense. Thank you so much, Dr. Buckner. One other question that I have, when you talk about how muscles don’t grow homogenously, you can get more growth immediately, laterally, approximately, distally, you know, does that speak to an application of, in body building for example, if people want to bring up the size of their lateral quad or their middle or posterior [28:31 inaudible] that putting a pad on there and focusing specifically there perhaps can increase muscle, precisely there under the pad or in the area of that stimulation or is that too much to infer from that necessarily?

Dr. Sam: That’s a great question. I don’t necessarily have an answer for you because we have no data to I guess, speak to it, but I’d be interested in doing some studies like that, to be honest. We just did a study where we tried to grow the calf muscles and we had really strict criteria, so it was growing calf on people who habitually train their calf. So it’s like, it’s a troublesome muscle for a lot of people to grow and we compared lifting heavy to just BFR. So low, low training on BFR and over, I think it was just a six week study. So it did have limitations, but we didn’t have calf muscle growth over time. And calf is a tricky muscle. It’s really hard to fatigue your calves. It’s really hard to get to that point of failure with the calves. I do wonder if neufit or neubie would be a better alternative to an advanced training technique.

So I’d be really curious. I don’t have an answer to that question. But I’m open to studies where we could look into like site specific growth with neubie. I think that’s a cool idea. And maybe there’s antidote. I mean, I know a lot of people, a lot of bodybuilders do use it because I’m a little tapped into that community and I guess the initial anecdotal findings would suggest that it’s possible.

Garrett: The best studies always bring up more questions, right?

Dr. Sam: Yeah, exactly.

Garrett: Yeah. That’s great. I think that was a wonderful presentation. Thank you so much for sharing that and answering these questions. Before we let Sam go here, does anyone else have any questions for him while we have a muscle physiology expert on the line?

Male: I have a question. It might be, let me know if it’s too broad, but like for performance athletes, let’s say I’m a javelin thrower and I use a lot of muscles at once in conjunction. Do you have any comments as to how this might help, this isolated muscle training might be expanded to help someone who does like a javelin throw for example or anything else that’s like full body like that?

Dr. Sam: Yeah. I mean that’s a tough question because with such a complex skill, I mean, I think we could have a whole philosophical debate on what training for that sport should look like. How much does increasing your strength, for example, through lifting, improve your sports performance. And I actually have somewhat controversial views on that sort of thing, because specificity seems so important. So perhaps you could combine the neubie with some more sports specific movements that you wouldn’t be able to do with equipment. And again, I think this is also an untapped area where I’m not really aware of any research that does exist.

But one of the issues with sport is, if you increase the strength of your quads through a knee extension and you want to see how much stronger your quads are in other movements, but you expect some crossover of that strength. Now from perhaps the best example I can give you is an isometric bicep curl. If you do isotonic, if you lift dumbbells and you increase your strength 50%, isometric strength in your bicep will increase, let’s say 20%. So you’ve already lost a lot of that adaptation. Now, by the time you get to a sports specific movement, you might only realize 2 to 3% of that strength. So you’ve made a muscle 50% stronger in a movement, but the sports performance benefit is hardly measurable by the time you get to it.

So I think you raise a question that’s a larger question of sports performance and it’s how much of a role does increasing strength play in sports performance? And I don’t know, this is very speculative, but I think it’s possible that you could use the device in some more sports specific fashions that might be beneficial because a lot of our training is general training, which I think has injury prevention, benefits. And I think newbie might have applications for injury prevention as well. But traditional strength training or strengthen our muscles through crude movements. The data isn’t super compelling as far as a crossover to sport. And I’m sorry for the long-winded answer, but hopefully it’s somewhat helpful.

Male: Yeah, thank you. That’s kind of a question I try to wrap my head around as well. So I appreciate.

Dr. Sam: Yeah, I have a paper called it’s like muscle strength and sports performance, but if you Google Buckner minority report, I write on some of my ideas on this topic.

Garrett: That awesome. We’ll have to look that up. And that’s fascinating for me. I know there’s always a question of the transfer of training and weight room improvements onto the field of play. I have never heard that quantified before where if you see a 50% improvement in a single joint weightlifting exercise, for example, that perhaps as little as 2% of that will carry over into force increases. A lot of it would probably depend on where the sporting action falls on the force velocity curve too.

As opposed for how much of it, how much a strength improvement is going to transfer versus how much of it is more velocity based, or whether we’re talking about more reactive strength or acceleration strength or these different traits and qualities of course. But that’s really instructive I think to even look at it from a percentage basis. Thank you for that.

Dr. Sam: Yeah. You’re welcome.

Garrett: Awesome. Well, Sam, thank you so much for joining us.

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