Egan Mills and Blake Kusky Discuss Eccentric vs Concentric Weight Training

Image of body with labeled muscles during weightlifting.

Bodily movement without eccentric and concentric motion is impossible. When it comes to weight/strength training, the portion of the movement that tends to be more focused on is the concentric portion. In this analysis, the effects of both eccentric and concentric weight/strength training will be fully fleshed out with both their positive and negative results.

Transcript and Show Notes

Egan Mills: Hello, everybody. Welcome to our biomechanics podcast. My name is Egan mills. I am a junior Mechanical Engineer here at Notre Dame, and we will be discussing the effects of both eccentric and concentric training. I am lucky enough to have an expert in this field. His name is Blake Kusky. You want to introduce yourself?

Blake Kusky: Yes. So I’m Blake, I’m a junior computer science major here at Notre Dame, and I’m also a student-athlete and experienced weightlifter at the University of Notre Dame.

Pictured above is expert Blake Kusky, University of Notre Dame Student-Athlete and veteran weightlifter.

Egan Mills: Perfect. You obviously know a ton about weightlifting. He’s been doing this forever. I know him pretty well, and he’s very, very knowledgeable. Do you want to go into your credentials a little bit as a weightlifter?

Blake Kusky: Sure, yeah. I’ve been weightlifting ever since my freshman year of high school, and it’s all been geared towards making me more athletic for track and throwing. I’ve worked with many trainers and weightlifting coaches over the years who have all given me at least a little bit of wisdom when it comes to weight training.

Egan Mills: For sure. And over time, you’ve probably built up a whole lot of knowledge.

Blake Kusky: Also doing my own research, and for sure, just being interested in the subject.

Egan Mills: Yeah, me too. I became an athlete, as soon as I could walk. I only started lifting probably about my sophomore year of high school. So you started a little bit before me. But I also started as a much more casual lifter. I would lift with my sports teams, but didn’t really dive into the research side and get really serious until about my freshman year of college. And since then, I’ve built up a lot of knowledge, but I still have plenty to learn. I am very interested in this topic because I’m always trying to improve my physical and athletic performance. I still play club lacrosse here at Notre Dame and I plan to walk on (the varsity lacrosse team) in the fall if all goes well, and I think everyone should be interested in this stuff because when it comes to bodily movement at all, you can’t do just about anything without eccentric and concentric motion. So if we want to dive right into the study here, the goal of this study, to use their words, “the main problem that was investigated was to compare pure eccentric and concentric isokinetic training with respect to their possible specificity in the adaptation of strength and morphology of the knee extensor muscles.” To an average Joe, that will mean nothing. So to put it in layman’s terms, pure eccentric and concentric motion which to give you an example. The definition of eccentric motion in the context of biomechanics is the lengthening of the muscle fibers under a certain load, while the concentric is more commonly understood and is the shortening of the muscle fibers under a certain load. To give you guys a visualization of these two concepts, when doing a standing standard bicep curl, the concentric portion of the movement is the motion of lifting the hand from near the hip to near the shoulder while the eccentric portion of the movement is the lowering of the hand from near the shoulder back down near the hip. When they talk about the strength and adaptation of the morphology of the knee extensor muscles pretty much what they’re saying is any increase or change in the strength of the quadriceps (muscle right above the knee) and morphology, meaning any kind of volume increase or decrease. So, the technical term would be hypertrophy (increase) or muscle atrophy if it was if there was a decrease in volume. So the authors here we have Jan. Y Seger, B. Arvidsson, and A. Thorstensson, and they’re all working within the Department of Neuroscience at the Karolinska Institute in Stockholm, Sweden. And A. Thorstensson is also working within the Department of Human Biology at Stockholm University, within the College of Physical Education in sports. With their interests ranging from neuroscience to biology to sports and athletic performance, the research on this topic seems quite fitting. The equipment used in here the main source of equipment would be the SPARK isokinetic dynamometer. To describe isokinetic force, in a standard leg extension machine, you would choose the weight and move it over a certain range of motion, and you will exert force on the pad towards your lower ankle, and you would accelerate it. In the isokinetic machine, it is a constant speed movement of the pad. So whatever force is applied to the pad towards your ankle, the machine exerts an equal and opposite force to that part of your leg, which I think makes that piece of equipment very interesting. The general findings in the article were that when they used eccentric and concentric training, they saw an increase in muscle volume. So the participants experienced muscular hypertrophy, and an increase in strength, while they also did some isometric strength training, and they saw that there was no double-dipping, so no isometric training affected strength or hypertrophy, and the other way around. So to get into our experience with eccentric and concentric training, Blake, would you like to talk about your experience with the track team and their training regimen?

SPARK Isokinetic Dynamometer

Blake Kusky: Yeah, absolutely. Almost every movement that we do, during the offseason and even during the season has an element of eccentric training, that is a part of it. And the main reasoning behind that is generally, you are stronger in the eccentric movement than you are in the concentric movement. So you can move more weight. And from that, comes obvious benefits of just getting stronger building muscle mass.

Egan Mills: Exactly. And especially in a sport like throwing

Blake Kusky: Absolutely, that even in itself is why it’s so important because as a thrower, my job is to generate the maximum amount of force that I can, in a short period of time, it’s not like a football game where I have to have endurance, it is very much just max force, a small amount of time.

Egan Mills: Exactly, short duration and as much force as humanly possible, which makes weight training a huge part of it. And you’ve been doing it for long enough where you’ve learned a ton, and your training regimen has changed.

Blake Kusky: Yes, definitely. I’ve worked with many different coaches over the years. And even in high school, I was researching the topic and trying to figure out what what what’s the best way that I can improve my athletic ability. And a lot of that comes down to certain combinations of eccentric, concentric, and isometric movements.

Egan Mills: Yeah. Do you want to talk about the differences between eccentric, concentric, and isometric and their effect on your body?

Blake Kusky: Yeah, definitely. So eccentric and concentric go together as a pair, because almost every move you’re doing ever involves some sort of eccentric and concentric movement. And so any work that you do, whether it be a squat, or bench press or anything, those elements are a part of it. And you could do interesting things to change the load on that. We’ll get into that later. Isometric is more so been used in my experience for injuries and recovery.

Egan Mills: Yes, I’ve read a ton about that as well. Do you want to give us some examples on some of your favorite eccentric and concentric movements for your sport and some isometric ones to keep you healthy?

Blake Kusky: Yeah, definitely. So a very big one for eccentric would be, you know, lat pulldowns, something just very slow on the way up or like squat, for example, would be slowing down and like a five-second on the way down, or even split squat or anything where you’re training a large muscle group. You want to use the eccentric portion of that to really build a lot of strength because it affects the most of your athletic ability.

Egan Mills: And then when it comes to concentric motion, how does that affect it differently compared to eccentric.

Blake Kusky: So concentric motion would be like me exploding up out of the bottom of a squat or up on a bench press. Which would be like, for me personally, in terms of throwing would be useful in order to accelerate the implement as fast as possible,

Egan Mills: Which makes sense because in a sport like throwing that seems like a more logical way of training.

Blake Kusky: Yes. Yeah, that’s the thing that was definitely odd to me when I first got into weightlifting was that a lot, my idea as a naive weightlifter and a thrower was that just do these concentric movements and really focus on that more. And that should pay dividends. But the real dividends came with training, or putting more focus on the eccentric portion of it on top of the concentric. So really training the full range of motion of the workout.

Egan Mills: Yeah, that actually makes a ton of sense, even though slightly illogical thinking at the beginning or not illogical, but not as obvious, I would say. But do you want to talk about how you’ve had multiple coaches? Do you have a favorite way of training from one of those coaches? And what was a part of that way of training?

Blake Kusky: Yeah, I’d say, I guess my favorite way of training is a funny way to put it because it’s my favorite way training caused me the most pain in terms of movement, but it made me the strongest which we love to see, which is great. I would say my favorite coach, in the offseason, had a huge, huge, huge emphasis on single leg, eccentric movements. And then explosive out of the bottom of those eccentric movements. So it’s essentially getting the most out of both the eccentric and the concentric movements, rather than just, oh, move this amount of weight it was how you move the weight that I liked the most, I thought got me the most benefit in my sport.

Egan Mills: Yeah, and I’ve talked to Blake a ton about his training because I think it’s so interesting. And he brought up a very good point when he was talking about athletics. Very few sports. You’re designed in the way of a squat with two legs down, and you’re just pushing up, everything is moving. You got single-leg movements, and you’re in different positions. So training different kinds of positions can greatly improve your athletic ability, and especially in something like throwing

Blake Kusky: No definitely. I think that’s where a lot of people struggle and make the jump from casual weightlifting to something that an athlete needs to do for weightlifting is in really focusing hard on how you’re doing the movements.

Egan Mills: Yeah, for sure. And I think even between us we have had different goals. So, over the years, I started weightlifting about sophomore year high school. And it was purely for athletic performance. I wanted to get recruited to play division one lacrosse. And anything that I could do to get bigger, faster, stronger, and become more desirable to college coaches is what I did. But as I got into college and with some hiccups in the recruiting process, I’ve been my focus has shifted slightly more towards bodybuilding. Because my entire life I was very skinny, very small, even to give an interesting stat here at coming into my freshman year high school, I was only five foot two sub 100 pounds. Blake is laughing on the other side here because he came in much bigger than I. But yeah, so that was always a focus of mine being so much smaller than everyone else. I felt like I wanted to grow much more. So I was always focused on the hypertrophy side, which means an increase in muscle volume, which when it comes to basic physics here, I mean, we know mass moves mass. So even though there are some nuances in powerlifting, you see some crazy statistics I saw the other day. I saw 125-pound man squat 650 pounds. And for people who don’t lift or don’t know how absurd that is, I was floored even as an experienced weightlifter and I’ve seen some crazy feats in my day. But seeing that Instagram, it almost didn’t even seem humanly possible. But yeah, so when, when I focus on something like hypertrophy, I’m focusing more on like higher repetitions, less strength stuff, but also sprinkling some of that in there as well

Blake Kusky: Just breaking down the muscle as much as possible exactly

Egan Mills: When it talks about the morphology of the muscle or that knee extensor muscles in their prompt in their thesis there. They’re pretty much talking about an increase in muscle volume, so hypertrophy. And do you want to talk a little bit about how your coaches have implemented both hypertrophy style training and strength training to give you the greatest athletic performance?

Blake Kusky: Yeah, so like you can set at the end of the day, force equals mass times acceleration. And what I’m trying to do is get the most force that I can out of my muscles. And so the big thing was not wasting half of the movement. A lot of people tend to only focus on the concentric part of like, a bench press or something, they’ll let the bar just come down really fast, and then really focus on the up. But if you can bring the bar down slowly, you’re tearing apart muscle fibers more, which leads to more hypertrophy and more muscle growth, which equals mass.

Egan Mills: Exactly. And that phenomenon is known as time under tension, the more time you can put your muscles under tension. The more work is done and the more tearing is done in the muscle fibers.

Blake Kusky: Yeah, which allows when you recover and build back the muscle to end up growing that muscle more. And so you get more mass as a result, of course, and since mass moves mass, you get stronger. So it’s kind of a positive feedback loop that’s interesting. The more weight you put on, the stronger you get, the stronger you get, the more weight you put on.

Egan Mills: Exactly, kind of a snowball effect. Yeah. And you can also think of it to give another physics analogy. Work is force times distance. So if you’re putting force or putting forces on the downward and upward portions, you’re putting in more work, and the more work requires more exertion from your muscle fibers, which tears them down. And given you are implementing the right nutrition, you will build back those muscle fibers bigger and stronger.

Blake Kusky: Which was a huge thing in my personal favorite way. Because where I thought that I got the strongest was hitting the movements being very deliberate in what you’re doing with the concentric and eccentric motions.

Egan Mills: Yeah, of course. So I have a couple of things written down here. One of the things that I wanted to talk about was isometrics. For your injury and recovery. Do you want to give us some examples of some isometric movements that have kept you healthy over the years?

Blake Kusky: Yes, definitely. So one issue that I’ve been dealing with, my entire weightlifting career has been bicep tendonitis in both arms, and I think that’s just a result of the sport that I chose rather than just some genetic thing. For me, it’s I think it’s just a lot of stress on my bicep tendon, of course, as a thrower, but one huge thing that my trainer, like multiple trainers and lifting coaches had me do has been using isometric movements. So just keeping your muscle in one spot with a load on it without moving it to help recover. And the idea behind that is, is when you hold something in an isometric position like for me and my biceps would be holding like a 10-pound plate in a half-curl position. And the idea behind that is, the longer you do that, the more blood is going to get to that area, which allows it to heal.

Above is a bicep isometric hold biomechanics graphic.

Egan Mills: Exactly. And also, when it comes to bicep tendonitis, your tendons going all up and around your elbow, when held in a lengthened position with a load on the hand, the lengthening of those tendons on your elbow also will increase the flexibility on those standards, increasing length of those tendons, and increasing the health of those joints.

Blake Kusky: Yeah, definitely. It’s interesting because it’s like, it’s this combination of eccentric concentric and isometric motions that is best designed for an athlete. A lot of people, if you’re like a casual weightlifter, you’re new aren’t really thinking about how those combinations can affect your strength and muscle volume building. And it’s just it’s so interesting to learn about like, what the optimal combination is. And for me, at least in this point in my life, it’s eccentric, having the offseason more concentric in the season and then isometric just for injury recovery.

Egan Mills: And general health I mean to keep definitely the longevity in your sport.

Blake Kusky: Yeah, I plan on doing isometric movements my entire life, because I want to be able to throw a ball with my grandson.

Egan Mills: Exactly. I mean, at the end of the day, being able to do this for the rest of your life is always going to be the goal. It’s not always going to be throwing a 16-pound ball 60 meters, but definitely not playing ball out in the yard with one of your children or just being able to go through your day and not have to experience pain.

Blake Kusky: Absolutely. Like that’s why I am a huge advocate for weightlifting for everybody and knowing about the different kinds of weightlifting is so beneficial to everybody, any person ever who moves, which is everybody, can benefit from this knowledge.

Egan Mills: Yeah, and we were talking about it before, I think everyone should be really interested in this type of research. Because it literally applies to everyone, like you were saying. Eccentric, and concentric motion is a part of pretty much all body movements. I mean, 

Blake Kusky: I think literally all body. Yeah, I mean, can you think of a movement where like, I’m sure there’s an obscure movement, but

Egan Mills: I think the only possible thing would be an isometric movement. Which, how often do you do that in a day?

Blake Kusky: Yeah, I mean, if you’re carrying like a box or something, but like,

Egan Mills: but then again, any movement, now both of your legs are doing the eccentric and concentric motion. So at the end of the day, everything comes down to eccentric and concentric motion, I mean, getting out of bed, lifting a coffee mug up to your face to take a drink, pulling luggage through the airport. These are all just like, daily things that utilize both. And like the results from this research can be applied to athletes trying to improve athletic performance, injured athletes or citizens trying to recover from their injury, bodybuilders powerlifters trying to increase muscular size or strength, or just the general public wanting to alleviate any kind of pain, or increase their physical fitness because I mean, fitness at the end of the day, applies to everyone. Everyone wants to be healthy. And that just improves overall happiness and enjoyment of life.

Blake Kusky: Yeah, definitely. I can’t imagine all the people I know who are in the later stages of life, they’re just going through constant joint and back pain that I never, ever see do any sort of weight training at all.

Egan Mills: I know. And I feel like there’s so much that they could do to alleviate that pain. I mean, you don’t have to live with it. I mean, it’s a choice to get up and actually do something about that pain if you want to live a more pain-free life. Definitely. Absolutely. So I appreciate you guys popping out and listening to our biomechanics podcast. This concludes the episode. But I feel like we touched upon a bunch of things that are really applicable to just about everybody. Blake, thanks for popping out.

Blake Kusky: Thanks for having me.

Egan Mills: Absolutely. You guys have a great night.


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