387: Chris Bramah and JB Morin on Sprint Biomechanics and Advancing Injury Risk Factors

Today’s podcast is with Chris Bramah and JB Morin. Chris is a consultant Physiotherapist and Researcher at the Manchester Institute of Health & Performance, specializing in biomechanics for injury prevention, especially in running-related concerns like hamstring strains. With over a decade in elite sports and a Ph.D. in biomechanics, he collaborates with World and Olympic Medallists, providing consultancy services focused on sprint running mechanics and their connection to hamstring strain injuries for clients. JB Morin, a full professor and head of sports science at the University of Saint-Etienne, brings over 15 years of research experience. Having published 50 peer-reviewed journals since 2004, he is a world-leading researcher in sprint-related topics, collaborating with top sprinters like Christophe Lemaitre. As a two-time previous podcast guest, JB shares valuable insights applicable to team sports, including his expertise in force-velocity profiling and heavy sled training. Sprinting and sports injuries are complex. Hamstring injuries are common, yet there is not one “unicorn” of a risk factor that determines whether or not an athlete will sustain one. As the roadmap of injury risk is continually unfolding, understanding what is happening from the coaching practices and observations, sports science, and research lenses can all work together to improve our global understanding of building fast and robust athletes. On the episode today, Chris and JB go into various running factors that play into robust sport running performance. These range from force-velocity profiling elements to kinematics and sprint technique, and rotational-based factors. This was a podcast that really digs into the sprint injury equation on a detailed and informative level. Today’s episode is brought to you by Lost Empire Herbs, TeamBuildr and the Plyomat. For 15% off your Lost Empire Herbs order, head to lostempireherbs.com/justfly. 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Timestamps and Main Points 2:00 – Recent research updates from Chris and JB on mechanics and running 5:30 – Primary aspects of connecting running mechanics with on-field injury 29:55 – The importance of fatigue state in the role of injury mechanisms and running 43:45 – Nuances of force-velocity profiling and potential injury risks in athletes 52:19 – What JB and Chris are seeing and studying from a “3D” perspective in terms of running injury and performance 59:20 – Foot strength, and it’s importance in athletic performance and ability 1:04:40 – Trunk rotation as it pertains to sprinting and injury risk Chris Bramah and JB Morin Quotes “All things equal, if you have the same capacity to play your sport, and move with less mechanical strain, then maybe you are tilting the balance (in favor of reduced injury risk)” “We define that as macroscopic strain (GPS, playing hours, etc.). I could have the same 200 meters, and have a different microscopic strain, because my body and my lever arms, put a different level of microscopic strain on my tissues, and especially my hamstrings” “Sometimes you get injuries where the macroscopic load is managed, and there is still an issue” “Because methods are more complex to assess, and to contextualize this as part of a whole system approach, people look at just big microscopic things, and I think sometimes we shy away from them” “When assess my hamstring strength, you have 2-3 ways to do it and 2-3 main variables. When you ask me to run all out at my maximum speed and have a couple of cameras, you are quickly going to end up with 50 variables” “We’ve got evidence showing associations between anterior pelvic tilt in particular and hamstring tissue strains” “Just a 7 degree increase in anterior pelvic tilt increased passive tension in bicep femoris by around 35 percent” “When scanning force output in football/rugby, we see that players who had a drop in the maximal force output ability in linear sprinting, had a higher chance of getting a hamstring strain in the weeks or months after the test” “There is 5-6 big rocks (that have strong anatomical theory or roots in research that lead to hamstring injury), trunk lean is one, trunk rotation is one, and so on. Movements that lead to higher strain in hamstrings” “You have some players with pretty low number of red flags on their kinematics, but a good number of red flags on their kinetics and their strength; in my experience at least, athletes who have a low number of red flags all along the spectrum, they are pretty safe” “If we just simply assess these singular things such as tissue capacity, fitness, etc. and fail to contextualize what they did from a mechanical perspective, we will often struggle to really understand why they get injured” “You almost know nothing until you have behavior under fatigue; if I am 1 or 5 (out of 5) in a fresh state, it doesn’t mean I am that in a fatigued state” “Among football players we tested (under fatigue), people who didn’t change, we had people who changed in a way that would supposedly induce higher strain, and people who changed in a way that would produce less strain” “Under fatigue, our body is adjusting, but we don’t adjust the same” “When you look at the maximal running velocity, it was very close between rehabbers, and those who haven’t been injured; statically the only variable that was differentiating the players with ongoing risk and those who were safe throughout the season was maximal force output” “Some players get hold and get less injuries, because their maximum running speed gets slower” “We have more players with ongoing risk when they are very fast, and very low on the maximal force side of things” “It’s very interesting to target the entire spectrum (of sprinting) from high speed low force, to low force, high speed; if you want to have a comprehensive rehab, you have to target the entire spectrum” “If you have excessive trunk rotation, you are going to wind up all these tissues that interconnect with each other” “If you look back at the modeling work from Elizabeth Tumenov, they found that the oblique musculature has a direct influence on reducing hamstring strain, so my interpretation of this is that the better functioning oblique musculature, the better controlled your trunk rotation, and the less tissue strain applied to your hamstring” “If you are looking from the side, and you can see the opposite armpit, they have poor rotational control” “You a lack of torsional control with athletes with high markers of lower limb strength” “You have athletes who have defined abdominal musculature, they can hold the longest planks, but they can’t dynamically control rotation at all” About Chris Bramah Dr. Chris Bramah is a consultant Physiotherapist, Lecturer and Researcher based at the Manchester Institute of Health & Performance and the University of Salford. His research and practice focuses on the clinical application of biomechanics to inform injury causation, prevention and rehabilitation strategies with a specific focus on running related injuries such as hamstring strain injuries. Clinically he has worked in elite sport for more than 10 years working in both Rugby League and Track and Field where he has worked with World & Olympic Medallists and supported athletes across multiple major championships. Chris has a PhD in biomechanics and currently works at the Manchester Institute of Health & Performance where he provides consultancy biomechanics services for clients including Olympic track athletes and Professional Football Clubs with the aim of informing rehabilitation and return to sport decision making following complex injuries. His current work is focused on the in-field assessment of sprint running mechanics and their association to hamstring strain injuries. About JB Morin Jean-Benoit (JB) Morin is currently full professor and head of sports science and the physical education department at the University of Saint-Etienne. He was formerly full Professor at the Faculty of Sport Sciences of the University of Nice Sophia Antipolis (France), and has been involved in sport science research for over 15 years, and has published over 50 peer-reviewed journals since 2004. He obtained a Track & Field Coach National Diploma in 1998 and graduated in Sport Science at the University of Besançon, France in 2000. He obtained his PhD in Human Locomotion and Performance in 2004 at the University of Saint-Etienne, France (Prof. Alain Belli), in collaboration with the University of Udine, Italy (Prof. Pietro diPrampero). JB’s field of research is mainly human locomotion and performance, with specific interest into running biomechanics and maximal power movements (sprint, jumps). He teaches locomotion and sports biomechanics, and strength training and assessment methods. JB’s has collaborated with French sprinter Christophe Lemaitre and his group/coach, and he is member of the French Soccer Federation research group, teaching professional coaches about sprint mechanics and training for acceleration. He also collaborates with New-Zealand professional and national rugby teams, and with professional soccer clubs in France and Spain. He practiced soccer in competition for 10 years, practiced and coached track and field (middle distance and 400m hurdles) for 8 years,