Listen: 185: Andrs Hegyi on Hamstring Function and Impacts of Sprinting and the Weightroom | Sponsored by SimpliFaster
"In the gym and we are we are testing these exercises. What we do is at the really control? All the technique of the performance the technical performance and basically it means that the activity activity pattern of the hamstrings will be quite similar between individuals gas. They're doing the same movement. But what we've seen running or sprinting. Is that the individual differences are huge. It was really difficult to see any pattern pattern which was true for everyone. So I cannot say that you activate your by Morris more in late swing as compared it to like early stamps or whatever so it was really in the we Joel so basically it's really hard to replicate in the gym the activity patterns that was Andreas Hegi. And you're listening to the just fly performance podcast. I'm your host Stole Smith. Thanks for being here and we are on episode one eighty five so Andreas is a final stage. PhD Student working at the Neuromuscular Research Center at the University of Java the Skyla in Finland addresses PhD work focuses on regional and inter muscular hamstring EMC activity in different hamstring exercises and in running. So we've done on some awesome shows on hamstring injury prevention in the past such as Jake Schuster and Jabe Marine. This is another fantastic addition to this series as Andreas is a wealth wealth of knowledge in all things Jim exercises and their effects on hamstrings in a very specific way. As and comparing that to how the hamstrings are operating while sprinting printing and some of the mechanisms are looking at some of the mechanisms by which hamstrings get injured. So whether you're looking at it in terms of injury prevention or performance this this is an amazing show that really helps us to fully comprehend or have a very wide sweeping view of all things that of what the gym is an might not be he doing when it comes to hamstring performance injury prevention as well as being able to take some real staples of hamstring training such as the Nordic hamstring and really dissect it do a deep deep dive into it and I understand how changing some variables in that movement has an impact on the mechanics of the whole thing from a muscle tendon perspective e centric centric centric loading predators and a lot more so on the show. Today we're GONNA get into his background athlete and researcher some of the primary mechanisms for a hamstring strain from both of both physiological Antibiotic Mechanical Perspective. We're going to get into dynamics of isometric exercises muscle tendon activity thoughts on the Nordic Hamstring. And what's really going on. In terms of the KNOB muscle contractions and actions throughout the motion. And when at what point does it really become comedy central exercise. We're GONNA talk about the rotational elements of Nordic hamstring training. We're GONNA talk about various exercises for hampering health such as the diver the glider. We're GONNA talk talk about how doing various modes Nordic hamstring training have different physiological effects. We're going to chat about the role of sprinting and injury prevention. And we're GONNA talk about the final talked about the addict or Magnus and its role in the hamstring injury prevention equation. This is a really fantastic episode just adds to the field of knowledge in preventing hamstring washing injuries. Something that is always important to talk about all right that being said let's get onto the show episode. One eighty five with Andrei Hagi. Yeah so before we get started with a a lot of questions that topic some really looking forward to talking about Could you show us a little bit briefly of your background. Your background as an athlete and and how you got into research it a little bit of what you're doing right now. Yeah Sean thanks for asking well. I was a football player and that's how I got interested in in hamstrings basically and well. I never had the hamstring injury actually but it's probably because I finished being football player when I was around eighteen years old so quite early and and basically I studied theology and Dan after finishing my masters in two thousand thirteen I started my PhD HD in two thousand sixteen enough in in new vascular. And before that I was studying in Hungary and now I'm really focusing on Mechanics mechanical function of hamstring muscles. Yes I think we're mentioned this a little bit before but it seems like hamstrings. Mm strings are always happen. Hamstring injury is always one of the top the top three topics. I always reading about in sports science. It's and probably rightly so it's it's a really big issue and it seems like that a lot of really good studies are coming forward with a lot of really good information on it. The the first question I'd like to ask you is. What are some two from the work that you've done from Maybe in this being more from a physiological perspective or biomechanical if you want to separate those out in a physiological and biomechanical But what are some of the primary reasons for a hamstring strain from that perspective. Yeah so the thing is that Hamstrings are really complex. And especially Shauwie. Studying hamstrings in Vivo inhuman. It's very complicated. So probably to move back to some animal models and and be tried to understand strain injury mechanism and for example. We can see from from these models debt for example reach. Our Lieber has a lot of studies and studying stranger mechanic McKenna's them and and here reported that the magnitude of the fiber stretch is a good predictor of strain injury and some other studies it also showed it the energy. Absorption of the muscle is really important for example when stretched muscle to failure then. Dan Highly Activated Muscle. Absorbed absorbs more energy. Dan Less activated or passive muscle. And we know that the hamstrings must absorb a lot of energy in the late spring phase of running and the same research each team of Garrett Garrett also found that fatty has a large component here So when the force to muscle failure is reduced then basically there is lower ability to generate force so less energy is absorbed in the fatigue muscle so Basically the muscle cannot tolerate the same amount of stretch when it's fat. Eat but we have. Let's much less evidence from hamstring muscles. The the only thing we know is that the injuries seem to occur in the late. Spring phase of the running in the running cycle from bio-mechanics point of view we have stretch shortening cycle in the hamstrings and in stretching phase of the stretch shortening cycle the the muscle must absorb a lot of energy before shortening. And we the what we see with. Increasing running speed is dead. The peak muscle tendon force increases in the late late swing and the muscle tendon. Units stretched at a higher velocity so no basically the negative work done by muscle mass increase to decelerate shanking. The late swing whereby the muscles absorbed energy which she's returned in the early stance face and Dan additionally with increasing running speed than the the relative importance of this energy. Absorption Increase is. So what I WANNA get to is that there are basically two ways to acutely increase the energy absorbing the muscle. I use stretch the muscle more. However we know that's Dismay increase the risk for strain injury. which is not really good? But another way is to increase the activation of the muscle so the the muscle gets defer and seem elation studies. Also show that talk. Increased hamstrings activity decreases the magnitude and rate of fiber stretching the late swing face so basically reducing the amount of fiber or sacraments Stretch seems to be an important factor as well as the capacity to a highly activate the muscle. Yeah Oh yeah. I thought that was interesting. That and Only thought I just had had quickly was almost like a summarizing thought that it's the the the hamstrings are muscle that has a capacity for extreme stretch range under under load. And you're saying that the the muscle if increase muscle activation of the hamstrings is it decreases the amount the hamstring stretch under load. When we're sprinting? That just kinda summarize that yeah exactly I that would would that change the to you. Guys is knowledge with that change the bio mechanics at all like in the sense of how the Shin that Shin's snaps out as the athlete is moving forward or does that does it. Is it really just a physiological occurrence in the way the muscles and tendons interact kind of independent of bio mechanics. Or is that something that you guys have not. You said it was a complicated area and so I know. There's a lot of complicated topics here. Do you know if there's a difference or that that may the impact the bio mechanics. Well at really hard to say because because the bit fatty can make what we can see typically is that we have an anterior pelvic tilt which basically stretches wretches the muscle. More something we typically see with with fatigue about about me range of motion icon. Recall any studies on that. But it's I would assume that activation affects this muscle mechanics and yeah sure. Yeah sure thing and I hope I didn't break your train of thought there with where you're going as well and I I think the edge it's interesting you brought up the fatigue and the Pelvic tilt that's one of the things that I I'm I'm thinking of In working with multiple multiple athletes I even in running but also even swimming to see how fatigue as soon as the the basic trunk and Pelvic Position Start to change because of fatigue league and the way the breathing operates fatigues. How everything from that outward the Pelvis and the and the breathing cavity outward starts to change and so oh? I think that I am glad you mentioned that. Because I think it would be very easy to isolate things specifically to the hamstring in not the rest of the body with how other lovers are changing aging. And so I think that's that's interesting I. I hope I didn't break again. I hope I didn't break your train of thought with what you were going for their her when I kind of interrupted you know it's fine. You didn't feel the interrupt but but I wanted to. The point is as you mentioned that like there are several muscles acting here and which affect the keenum attics and the stretch of the muscle the stretch of the fast goals and of course it would be the best to see how the muscles actually burke during sprinting and there is a debates whether the the festivals rather isometric or a centric and actually this is how my PhD started because the laboratory where I work now in US gala. It's one of the oldest laboratories in now ultrasound imaging. We have like four of five ultrasound machines and a lot of experience appearance with the way the imaging of different muscles and there was this PhD Project Dame was under the supervision of Neil Krahn and Finley Dame bus to they examined festival behavior of the biceps Morris in different movements basically and in different situations but the thing. Is that the the muscles so complex and the fast goals are so long and basically when you are running than the muscle three-dimensional manner lead. It's really difficult to catch the two dimensional methods. What's what's happening there but it's probably Quite difficult at this point to see what happens a defensible level and we kind of try to measure some other other things which can potentially affect this fascel ascoli behavior for example the activation of the muscle or intramuscular coordination. With the you mentioned which in that it's hard to like you mentioned like the three d. or the three dimensions of the muscle motion versus I. Because I think that is a generality with a lot of people it's easier to put the body into a two dimensional model or just plain only and then as well as the assumption. Listen that when you're doing an and I'd like to get into this too when you're doing a Nordic hamstring that will. The body is moving in. I guess you could say e centric manner because you're we're doing negative work but what does that what's going on with the muscle. Tendon Complex at that point in terms of is the muscle. Is You know. How much is the muscle like thing? Or is the muscle pulling in his the tendons stretching and so I think that was the question that we were going to get into today as well and I'd love to get into the rotational elements to the muscle. Work as you were saying to but I I would like to get to. That is when we're doing a movement like Nordic Hamstring. What what is what do we think is going on there from muscle perspective? Is it actually center exercises there or is there more isometric contractions in the muscle. Even though there is negative work work being done. And how is you know is there. Is there some specificity loss potentially between there. And what's going on in sprinting. Yeah this is really fascinating an excellent question so as I mentioned. It's really hard to say what happens at the level. A fast calls and we know that the behavior of the fast cicle is not always the same as the behavior of the muscle tendon unit and it sames East soundtrack but at the level of festivals muscle fibers.."