#68 - Muscle fiber types revisited with Professor Wim Derave
Oct 15, 2023
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Guest Professor Wim Derave challenges prevailing views on muscle fiber types. He discusses non-invasive methods of estimating muscle fiber type and the effects of antihistamines on training. The podcast also explores the coexistence and variations in muscle fiber types, power requirements in swimming, measuring muscle fiber type composition in athletes, and the relationship between muscle fiber types and the risk of hamstring strains. It delves into muscle fibers and training adaptation, sex differences and age-related changes in muscle fiber types, and the importance of preprints and evaluating author expertise.
Most people may not have type 2x muscle fibers, challenging the traditional understanding of muscle fiber types.
Humans are predominantly slow-twitch or endurance species due to our ancestral hunting techniques of persistence hunting.
Muscle fiber type can impact metabolic diseases such as insulin resistance and type 2 diabetes.
Understanding muscle fiber types is important in sports for talent identification, injury prevention, and performance optimization.
Deep dives
Understanding Muscle Fiber Types
The podcast episode explores the different types of muscle fiber and their adaptations to exercise. In humans, there are three main types of muscle fiber: type 1 (slow twitch), type 2a (fast oxidative glycolytic), and type 2x (fast glycolytic). However, recent research suggests that most people have no type 2x muscle fibers at all. The speaker discusses the importance of muscle fiber types in athletic performance and mentions that muscle fiber types can be estimated non-invasively using techniques such as MRI spectroscopy and 30-second sprint tests.
Evolutionary Perspective on Muscle Fiber Types
The podcast delves into the evolutionary significance of muscle fiber types. It is suggested that humans are predominantly a slow-twitch or endurance species, as evidenced by the high proportion of slow fibers in our muscles. This adaptation is attributed to our ancestral hunting techniques of persistence hunting, where we wore down animals over long distances. The discussion highlights how humans have suppressed the expression of type 2x fibers over time, making endurance running our defining characteristic.
Insights into Muscle Fiber Types and Metabolic Diseases
The podcast episode explores the relationship between muscle fiber types and metabolic diseases such as insulin resistance and type 2 diabetes. Research indicates that individuals with a higher proportion of fast fibers may be more susceptible to metabolic diseases, while those with more slow-twitch fibers exhibit better insulin sensitivity. Non-invasive estimators such as carnosine measurements and lactate levels after exercise can provide insights into an individual's muscle fiber composition and potential metabolic risks.
Practical Applications of Muscle Fiber Types in Sports
The podcast highlights practical applications of understanding muscle fiber types in sports. It is mentioned that muscle fiber type can influence athletic performance and injury risk. For example, athletes with a higher proportion of fast-twitch fibers may excel in power-based sports, while those with more slow-twitch fibers may be better suited for endurance activities. The significance of muscle fiber types in talent identification and injury prevention, particularly hamstring strains, is emphasized. The discussion also touches on the use of non-invasive techniques, such as MRI spectroscopy and 30-second sprint tests, to assess muscle fiber types in athletes.
Misconceptions about Muscle Fiber Types
There is a common misconception that there are three distinct types of muscle fibers: slow-twitch (Type 1), fast-twitch oxidative (Type 2a), and fast-twitch glycolytic (Type 2x). However, recent research challenges this idea and suggests that there are only two main types of muscle fibers, with slow-twitch being distinct from the other two. This calls into question the traditional understanding of muscle fiber types in both animal and human studies.
The Dominance of Endurance Capacity in Humans
Humans have evolved with a strong emphasis on endurance capacity, which sets us apart from other animals. This focus on endurance may explain why humans are gradually losing extreme fast-twitch muscle fibers over time. Understanding the importance of endurance and its impact on muscle fiber types can help shape training and performance strategies in sports.
The Influence of Non-Muscle Cells in Muscle Physiology
While much research has traditionally focused on muscle fibers themselves, recent studies have highlighted the significant role of non-muscle cells in muscle physiology. These cells, including immune cells and other mono-nuclear cells, play an essential role in exercise-induced signaling and adaptation. Exploring these non-muscle cells can lead to a deeper understanding of muscle fatigue, recovery, and adaptation, potentially uncovering new insights into training strategies and effective interventions.
Dr Glenn McConell chats with Professor Wim Derave from the Ghent University in Belgium. We talked about the different muscle fibres/fiber types in humans and his recent evidence that pure Type 2X muscle fibers may not really exist or maybe only in some sedentary individuals. He also made the point that muscle fiber type info is not used enough in sports contexts. He outlined some non invasive ways of estimating your muscle fibre types. Finally we discussed remarkable and important findings that antihistamines may reduce some exercise training adaptations. A very interesting, long chat. Twitter: @TeamDerave. 0:00. Introduction and how Wim got into exercise research 7:02. Different types of muscle fiber types 10:10. Humans tend to be a slow fiber type species 12:10. Humans hunt by wearing down our prey 17:50. Can ex training change muscle fiber type? 22:00. For sprinters the more fast fibers the better? 24:00. The different types of muscle fibers 26:58. He finds no type 2X muscle fibers in humans 31:00. Some sedentary people may have a few type 2X fibers 34:50. New methods to determine muscle fibre type 37:20. Coexistence of more than one fiber type within a fiber? 42:50. Slow twitch fibers are more efficient 43:44. Sedentary/tapering and type 2X fibers 46:30. More fast twitch fibers in insulin resistance 50:51. Non invasive ways to estimate muscle fibre type 57:20. Swimming vs muscle fiber type 1:00:02. 30 second cycling sprint to estimate muscle fiber type 1:05:10. Coaches and muscle fiber type 1:07:10. Applying muscle fiber type info to sport 1:09:20. Hamstring strains, overtraining, tapering and muscle fiber type 1:17:45. Slow fibers barely fatigue 1:19:30. Diet and muscle fiber type 1:30:30. Non muscle cells needed for skeletal muscle training adaptations 1:38:50. Antihistamines may reduce ex training adaptations 1:46:20. Sex differences and muscle fibre type 1:47:33. Age and muscle fibre type 1:49:35. Takeaway messages 2:00:51. Outro (9 seconds) Inside Exercise brings to you the who's who of research in exercise metabolism, exercise physiology and exercise’s effects on health. With scientific rigor, these researchers discuss popular exercise topics while providing practical strategies for all. The interviewer, Emeritus Professor Glenn McConell, has an international research profile following 30 years of Exercise Metabolism research experience while at The University of Melbourne, Ball State University, Monash University, the University of Copenhagen and Victoria University. He has published over 120 peer reviewed journal articles and recently edited an Exercise Metabolism eBook written by world experts on 17 different topics (https://link.springer.com/book/10.1007/978-3-030-94305-9). Connect with Inside Exercise and Glenn McConell at: Twitter: @Inside_exercise and @GlennMcConell1 Instagram: insideexercise Facebook: Glenn McConell LinkedIn: Glenn McConell https://www.linkedin.com/in/glenn-mcconell-83475460 ResearchGate: Glenn McConell Email: glenn.mcconell@gmail.com Subscribe to Inside exercise: Spotify: shorturl.at/tyGHL Apple Podcasts: shorturl.at/oFQRU YouTube: https://www.youtube.com/@insideexercise Anchor: https://anchor.fm/insideexercise Google Podcasts: shorturl.at/bfhHI Anchor: https://anchor.fm/insideexercise Podcast Addict: https://podcastaddict.com/podcast/4025218 Not medical advice
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