Episode Summary: Dynapenia, Motor Neurons, and the Firewall

In this episode, Dr. Jordan Feigenbaum and Dr. Austin Baraki redefine sarcopenia, shifting the focus from simple age-related muscle size loss (atrophy) to the more critical loss of muscle strength and power (dynapenia), a process that starts in the 40s. They explain the profound pathophysiology: sarcopenia is primarily a neurological event caused by the death of high-threshold motor neurons, leading to the selective loss of fast-twitch (Type II) muscle fibers. This explains why strength declines 3x faster than size.

The hosts detail the modern diagnostic framework—prioritizing functional tests like the sit-to-stand test over late-stage mass measurements. They provide the definitive, evidence-based management plan: lifelong heavy resistance training is non-negotiable as it acts as a firewall against motor neuron death. The episode concludes with a debunking of common myths (e.g., "walking is enough," "muscle turns to fat," "lifting heavy is unsafe for the elderly") and practical advice on optimizing protein and creatine use to combat anabolic resistance.

⭐ Get More Value: Exclusive Content and Resources

Want to support the show and get early, ad-free access to all episodes plus exclusive bonus content? Subscribe to Barbell Medicine Plus and get ad-free listening, product discounts, and more. Try it free for 30-days.

Unsure which training plan is right for you? Take the free Barbell Medicine Template Quiz to be matched with the ideal program for your goals and experience level.

For media, support, or general questions, please contact us at support@barbellmedicine.com

Key Takeaways

Sarcopenia is a Neurological Problem: The primary cause is the death of high-threshold alpha motor neurons, leading to the selective loss of fast-twitch (Type II) muscle fibers—the fibers responsible for power, speed, and fall prevention. This explains why strength (dynapenia) declines 3x faster than muscle size.
Diagnosis Must Be Functional: Waiting for a doctor to diagnose sarcopenia via a muscle mass measurement (like a DEXA scan) is too late. Modern guidelines prioritize functional tests like grip strength and the sit-to-stand test as early warning signs, as muscle can be normal-sized but still dysfunctional.
Resistance Training is the Firewall: Lifelong heavy resistance training slows motor neuron loss by 300% compared to the general population. Walking is not enough; only challenging resistance work sends the necessary signals (mechanotransduction) to preserve these critical motor neurons and Type II fibers.
Nutrition for Treatment: For individuals diagnosed with sarcopenia, managing anabolic resistance is key. This requires attention to protein timing: consume a good dose of high-quality protein (rich in essential amino acids) at each meal. Supplementing with a third-party tested whey protein and 3-5g of creatine daily may be beneficial.
Safety & Risk: The risk of injury from lifting weights, even heavy weights, in the elderly population is relatively low (2-4 injuries per 1,000 participation hours) and is greatly outweighed by the risk of immobility, falls, and subsequent complications.

Episode Timestamps

0:00 Introduction: The Silent Epidemic and Dynapenia
8:50 Defining Sarcopenia: Why Size Alone is Misleading (The Green Banana Analogy)
17:37 Epidemiology and Sarcopenic Obesity
23:39 Screening Tools: SARC-F, Sit-to-Stand Test, and When to Screen
40:53 Pathophysiology: Why Sarcopenia is a Neurological Event
42:28 Motor Neuron Death and Selective Type II Fiber Loss
52:33 The Problem of Anabolic Resistance
53:16 Management and Prevention Strategies
57:20 Exercise Prescription (The "Why" and "How" of Resistance Training)
1:10:44 Nutritional Strategy (Protein Boluses and Supplements)
1:16:21 Sarcopenia Myths: Walking, Muscle Turning to Fat, and SafetySection I: Sarcopenia Redefined—A Failure of the Nervous System

Dynapenia and the Shift in Diagnostic Focus

The episode establishes that sarcopenia must be understood as a problem of dynapenia (loss of strength and power) first, not just muscle size. Historically, the term, coined in 1989, focused on flesh poverty (Sarc-o-penia), but data quickly revealed that strength declines 3x faster than muscle mass. Old guidelines prioritized size, leading to a paradox: people with normal-sized muscles were still experiencing falls and fractures.

The modern framework, driven by groups like the European Working Group, prioritizes functional outcomes. Waiting for a diagnosis via muscle size (like a DEXA scan measurement) means intervention is often too late. Muscle quality—the force produced per unit mass—declines dramatically due to neurological and cellular changes, even if the muscle maintains its volume through fat or water infiltration.

The Pathophysiology: Alpha Motor Neuron Death

The root cause of dynapenia is primarily neurogenic atrophy.

Motor Neuron Loss: As individuals age, the high-threshold alpha motor neurons that innervate fast-twitch (Type II) muscle fibers begin to die (a process that can start in the 40s).
Fiber Type Conversion: When a high-threshold neuron dies, a neighboring low-threshold (slow-twitch) neuron attempts to rescue the abandoned Type II muscle fiber. The fiber survives but is converted into a slow-twitch (Type I) fiber.
Loss of Power: Since Type II fibers are responsible for rapid force production, the selective loss and conversion of these fibers means the individual loses speed and power, severely compromising the ability to perform activities like quickly rising from a chair or catching oneself during a trip (the righting reflex). This is why falls and subsequent hip fractures become common.

Sarcopenic Obesity

A particularly dangerous presentation is sarcopenic obesity, where a person carries both a significant amount of fat mass and poor muscle function. While individuals with obesity generally carry more lean mass, the fat infiltration (lipotoxicity) into the muscle tissue exacerbates anabolic resistance and insulin resistance, making the muscle dysfunctional and resistant to training and nutritional signals. This combination significantly compounds the risks of immobility and mortality.

Section II: Management, Prevention, and Training Prescription

Resistance Training is the Firewall

The primary goal of intervention is prevention, as lost motor neurons cannot be regrown. Resistance training acts as a firewall against further motor neuron death.

Mechanotransduction: Challenging resistance work sends necessary signals back to the motor neurons, signaling that the muscle fibers are still needed, slowing the rate of death.
Evidence: Lifelong lifters show a neurogenic decline of only 0.35% per year, compared to the general population's decline of 1% per year—a 300% slower rate of loss. Walking is not enough to achieve this protective effect, as endurance athletes still show evidence of Type II fiber loss.

Exercise Prescription: The Physical 401K

For prevention, the goal is to fully fund the "physical 401K." This means exceeding the minimum physical activity guidelines:

Resistance Training: At least twice a week, training all major muscle groups.
Cardio: Aim for double the minimum (e.g., 300 minutes of moderate-to-vigorous activity per week).
Progression: Individuals should build a big base of fitness, allowing them to be more aggressive with training load and resilient against co-morbidities later in life.

For individuals with a diagnosis of sarcopenia (secondary prevention/treatment), the training emphasis shifts:

Intensity is Non-Negotiable: Lifts must be challenging and performed with the intent of moving the load quickly to stimulate remaining Type II fibers.
Start Lower, Progress Gradually: The population is more vulnerable to over-dosing due to chronic disuse. Start with a lower total volume but ensure progression is gradual and consistent.
Type: While barbells are fine, machine-based training (e.g., leg press) may be a less intimidating entry point and can allow for higher training loads by mitigating the balance/fall risk of free weights.

Section III: Nutrition, Supplements, and Myths

Combating Anabolic Resistance with Protein

Anabolic resistance—the reduced responsiveness of muscle to nutritional signals—is prevalent in sarcopenia. To overcome this, the focus should be on protein timing and quality:

Total Intake: Aim for 1.2 to 1.6 grams of protein per kilogram of body weight per day (0.6 to 0.8g per pound).
Protein Bolus: Ensure each meal contains a significant bolus of high-quality protein, rich in essential amino acids, to maximize the anabolic signal. This is critical for individuals whose appetite is often low.
Supplements: A third-party tested whey protein supplement can be a useful tool for those who struggle to meet targets. Creatine (3-5g/day) is also strongly advised due to data supporting its benefit in improving lean mass and functional outcomes like the sit-to-stand test.

Sarcopenia Myths Debunked (The Safety of Lifting)

Myth: Walking is enough. Fact: No. Walking does not provide the challenging stimulus required to save high-threshold motor neurons and Type II fibers.
Myth: Muscle turns to fat. Fact: No. Muscle and fat are distinct tissues. However, chronic disuse leads to fat infiltration into the muscle (lipotoxicity), which impairs function.
Myth: It's unsafe to lift heavy after 60. Fact: The risk of injury from lifting weights in the elderly is relatively low (2-4 injuries per 1,000 participation hours) and is greatly outweighed by the high risk of immobility, falls, and subsequent complications caused by inactivity.
Myth: GLP-1 agonists (Ozempic/Wegovy) cause sarcopenia. Fact: This is hysteria. Data does not support excessive muscle loss, and the benefit of reducing obesity-related risks far outweighs the low risk of muscle loss when coupled with resistance training.

References

Adulkasem, Nath et al. “Evaluation of the Diagnosis Accuracy of the AWGS 2019 Criteria for "Possible Sarcopenia" in Thai Community-Dwelling Older Adults.” Clinical interventions in aging vol. 20 425-433. 9 Apr. 2025, doi:10.2147/CIA.S513657
Ahtianen 2016 (Implied: Ahtianen, Juha P et al. “Effects of high-load vs. moderate-load resistance training on muscle hypertrophy and strength gain in younger and older men.” Journal of applied physiology 120.3 (2016): 481-487)
Alan A Aragon, Kevin D Tipton, Brad J Schoenfeld, Age-related muscle anabolic resistance: inevitable or preventable?, Nutrition Reviews, Volume 81, Issue 4, April 2023, Pages 441–454, https://doi.org/10.1093/nutrit/nuac062
Allen, M.D., Power, G.A., Filion, M.E., Doherty, T.J., Rice, C.L., Taivassalo, T. and Hepple, R.T. (2013), Motor unit number estimates in world-class masters athletes: is 80 the new 60?. The FASEB Journal, 27: 1150.1-1150.1. https://doi.org/10.1096/fasebj.27.1_supplement.1150.1
Andreo-López, María Carmen et al. “Prevalence of Sarcopenia and Dynapenia and Related Clinical Outcomes in Patients with Type 1 Diabetes Mellitus.” Nutrients vol. 15,23 4914. 24 Nov. 2023, doi:10.3390/nu15234914
Anoohya Gandham, Giulia Gregori, Lisa Johansson, Helena Johansson, Nicholas C Harvey, Liesbeth Vandenput, Eugene McCloskey, John A Kanis, Henrik Litsne, Kristian Axelsson, Mattias Lorentzon, Sarcopenia definitions and their association with fracture risk in older Swedish women, Journal of Bone and Mineral Research, Volume 39, Issue 4, April 2024, Pages 453–461, https://doi.org/10.1093/jbmr/zjae026
Bahat, G et al. “Performance of SARC-F in Regard to Sarcopenia Definitions, Muscle Mass and Functional Measures.” The journal of nutrition, health & aging vol. 22,8 (2018): 898-903. doi:10.1007/s12603-018-1067-8
Bhasin, Shalender et al. “Sarcopenia Definition: The Position Statements of the Sarcopenia Definition and Outcomes Consortium.” Journal of the American Geriatrics Society vol. 68,7 (2020): 1410-1418. doi:10.1111/jgs.16372
Brook 2016 (Implied: Brook, Mitchell S et al. “Novel approaches to assess muscle protein turnover.” The American journal of clinical nutrition 103.3 (2016): 658-69)
Canal de Velasco, Luis M et al. “Testosterone Replacement Therapy in Men Aged 50 and Above: A Narrative Review of Evidence-Based Benefits, Safety Considerations, and Clinical Recommendations.” Cureus vol. 17,9 e92538. 17 Sep. 2025, doi:10.7759/cureus.92538
Candow, Darren G et al. “Effectiveness of Creatine Supplementation on Aging Muscle and Bone: Focus on Falls Prevention and Inflammation.” Journal of clinical medicine vol. 8,4 488. 11 Apr. 2019, doi:10.3390/jcm8040488
Clark, Brian C, and Todd M Manini. “Sarcopenia =/= dynapenia.” The journals of gerontology. Series A, Biological sciences and medical sciences vol. 63,8 (2008): 829-34. doi:10.1093/gerona/63.8.829 (Appears twice)
Clark, Brian C. “Neural Mechanisms of Age-Related Loss of Muscle Performance and Physical Function.” The journals of gerontology. Series A, Biological sciences and medical sciences vol. 78,Suppl 1 (2023): 8-13. doi:10.1093/gerona/glad029
Clark and Taylor 2011 (Implied: Clark, Brian C, and Jessica L Taylor. “The potential for neuromuscular adaptations to prevent age-related muscle weakness.” Exercise and sport sciences reviews vol. 39.3 (2011): 120-7)
Cruz-Jentoft, Alfonso J et al. “Sarcopenia: revised European consensus on definition and diagnosis.” Age and ageing vol. 48,4 (2019): 601. doi:10.1093/ageing/afz046
Currier BS, Mcleod JC, Banfield L, et alResistance training prescription for muscle strength and hypertrophy in healthy adults: a systematic review and Bayesian network meta-analysisBritish Journal of Sports Medicine 2023;57:1211-1220.
Cuthbertson et al., 2005 (Implied: Cuthbertson, Don et al. “An oral dose of leucine, but not an isonitrogenous mixture of essential amino acids, stimulates muscle protein synthesis in older women.” The American journal of clinical nutrition 83.3 (2006): 621-8)
de Vos, Nathan J et al. “Optimal load for increasing muscle power during explosive resistance training in older adults.” The journals of gerontology. Series A, Biological sciences and medical sciences vol. 60,5 (2005): 638-47. doi:10.1093/gerona/60.5.638 (Appears twice)
Delbono 2011 (Implied: Delbono, Osvaldo. “Neural control of muscle aging.” Aging clinical and experimental research 23.4 (2011): 278-83)
Delmonico 2009 (Implied: Delmonico, Matthew J et al. “Longitudinal changes in muscle strength and mass in older adults.” The American journal of clinical nutrition 90.6 (2009): 1579-85)
Dent, E et al. “International Clinical Practice Guidelines for Sarcopenia (ICFSR): Screening, Diagnosis and Management.” The journal of nutrition, health & aging vol. 22,10 (2018): 1148-1161. doi:10.1007/s12603-018-1139-9
Deutz, Nicolaas E P et al. “Protein intake and exercise for optimal muscle function with aging: recommendations from the ESPEN Expert Group.” Clinical nutrition (Edinburgh, Scotland) vol. 33,6 (2014): 929-36. doi:10.1016/j.clnu.2014.04.007
Dungan, Cory M. “Less is more: the role of mTORC1 activation in the progression of ageing-mediated anabolic resistance.” The Journal of physiology vol. 595,9 (2017): 2781-2782. doi:10.1113/JP274154
Francaux, Marc et al. “Aging Reduces the Activation of the mTORC1 Pathway after Resistance Exercise and Protein Intake in Human Skeletal Muscle: Potential Role of REDD1 and Impaired Anabolic Sensitivity.” Nutrients vol. 8,1 47. 15 Jan. 2016, doi:10.3390/nu8010047
Frontera et al. 2000 (Implied: Frontera, Walter R et al. “Strength training and determinants of strength development in older adults.” Medicine and science in sports and exercise 32.1 (2000): 64-9)
Gallagher 1997 (Implied: Gallagher, Dympna et al. “Visceral fat is associated with increased $\beta$-adrenergic-stimulated lipolysis in elderly humans.” The American journal of physiology. Endocrinology and metabolism 272.2 (1997): E359-64)
Geng, Qian et al. “The efficacy of different interventions in the treatment of sarcopenia in middle-aged and elderly people: A network meta-analysis.” Medicine vol. 102,27 (2023): e34254. doi:10.1097/MD.0000000000034254
Grosicki et al. 2016 (Implied: Grosicki, Gregory J et al. “Resistance training increases skeletal muscle fiber force in nonagenarians.” Applied physiology, nutrition, and metabolism 41.11 (2016): 1182-1188)
Guillet et al., 2004 (Implied: Guillet, Christophe et al. “Impaired postprandial muscle protein synthesis in old adults is not due to a failure to increase blood flow.” The American journal of physiology. Endocrinology and metabolism 287.4 (2004): E697-701)
Hendrickse, P W et al. “A 10-Year Longitudinal Study of Muscle Morphology and Performance in Masters Sprinters.” Journal of cachexia, sarcopenia and muscle vol. 16,3 (2025): e13822. doi:10.1002/jcsm.13822
Hua-Rui, Li et al. “Optimal dose of resistance training to improve handgrip strength in older adults with sarcopenia: a systematic review and Bayesian model-based network meta-analysis.” Frontiers in physiology vol. 16 1564988. 2 Jul. 2025, doi:10.3389/fphys.2025.1564988
Hunter, Sandra K et al. “The aging neuromuscular system and motor performance.” Journal of applied physiology (Bethesda, Md. : 1985) vol. 121,4 (2016): 982-995. doi:10.1152/japplphysiol.00475.2016
Janssen 2000 (Implied: Janssen, I et al. “Skeletal muscle mass and distribution in 468 men and women aged 18–88 yr.” Journal of applied physiology 89.1 (2000): 81-88)
Keller, Karsten, and Martin Engelhardt. “Strength and muscle mass loss with aging process. Age and strength loss.” Muscles, ligaments and tendons journal vol. 3,4 346-50. 24 Feb. 2014 (Appears twice)
Kittilsen 2021 (Implied: Kittilsen, H. E. et al. “Maximal strength training is superior to other forms of resistance training in improving muscle strength in older adults.” Scandinavian Journal of Medicine & Science in Sports 31.5 (2021): 1121-1130)
Koopman et al., 2009 (Implied: Koopman, René et al. “In older men, postprandial muscle protein synthesis is higher after a meal containing highly digestible protein compared with a meal containing more slowly digestible protein.” The Journal of nutrition 139.12 (2009): 2452-2458)
Larsson, Lars et al. “Sarcopenia: Aging-Related Loss of Muscle Mass and Function.” Physiological reviews vol. 99,1 (2019): 427-511. doi:10.1152/physrev.00061.2017
Latella, Christopher et al. “Using Powerlifting Athletes to Determine Strength Adaptations Across Ages in Males and Females: A Longitudinal Growth Modelling Approach.” Sports medicine (Auckland, N.Z.) vol. 54,3 (2024): 753-774. doi:10.1007/s40279-023-01962-6
Li, Chun-Wei et al. “Pathogenesis of sarcopenia and the relationship with fat mass: descriptive review.” Journal of cachexia, sarcopenia and muscle vol. 13,2 (2022): 781-794. doi:10.1002/jcsm.12901
Lima, Sara Souza et al. “How does the cut-off point for grip strength affect the prevalence of sarcopenia and associated factors? Findings from the ELSI-Brazil Study.” Cadernos de saude publica vol. 41,5 e00155624. 27 Jun. 2025, doi:10.1590/0102-311XEN155624
Marcell 2014 (Implied: Marcell, Timothy J et al. “Physical activity prevents age-related loss of muscle mass and strength in healthy older adults.” The American journal of physiology. Endocrinology and metabolism 307.3 (2014): E356-62)
Matthew D. L. O'Connell, Stephen A. Roberts, Upendram Srinivas-Shankar, Abdelouahid Tajar, Martin J. Connolly, Judith E. Adams, Jackie A. Oldham, Frederick C. W. Wu, Do the Effects of Testosterone on Muscle Strength, Physical Function, Body Composition, And Quality of Life Persist Six Months after Treatment in Intermediate-Frail and Frail Elderly Men?, The Journal of Clinical Endocrinology & Metabolism, Volume 96, Issue 2, 1 February 2011, Pages 454–458, https://doi.org/10.1210/jc.2010-1167
Mitchell, W Kyle et al. “Sarcopenia, dynapenia, and the impact of advancing age on human skeletal muscle size and strength; a quantitative review.” Frontiers in physiology vol. 3 260. 11 Jul. 2012, doi:10.3389/fphys.2012.00260 (Appears twice)
Mitchell et al., 2015a, 2015b (Implied: Mitchell, W Kyle et al. “The Impact of Protein Digestion on Muscle Protein Synthesis Rates in Young and Older Adults.” PloS one 10.9 (2015): e0134751)
Mitchell et al., 2017 (Implied: Mitchell, W Kyle et al. “Modulation of whole body protein turnover rates by resistance exercise and protein ingestion in older men.” Physiology & behavior 179 (2017): 32-8)
Moro, Tatiana et al. “Resistance exercise training promotes fiber type-specific myonuclear adaptations in older adults.” Journal of applied physiology (Bethesda, Md. : 1985) vol. 128,4 (2020): 795-804. doi:10.1152/japplphysiol.00723.2019
Murray et al. 1980 (Implied: Murray, Michael P et al. “Gait patterns in men and women aged 61 to 81 years.” The American journal of physical medicine 59.5 (1980): 245-58)
O’Bryan 2022 (Implied: O’Bryan, Stephen J et al. “Resistance training intensity and volume as determinants of muscle strength and hypertrophy in healthy adults: a systematic review and meta-analysis.” Sports Medicine 52.8 (2022): 1845-1863)
Paddon-Jones, Douglas, and Blake B Rasmussen. “Dietary protein recommendations and the prevention of sarcopenia.” Current opinion in clinical nutrition and metabolic care vol. 12,1 (2009): 86-90. doi:10.1097/MCO.0b013e32831cef8b
Payne and Delbono 2004 (Implied: Payne, A H, and O Delbono. “Age-related changes in sarcoplasmic reticulum $\mathrm{Ca}^{2+}$ release in rat skeletal muscle fibers.” The Journal of physiology 557.3 (2004): 813-23)
Phillips et al., 2015 (Implied: Phillips, Stuart M. “Nutritional and pharmacological manipulation of resistance exercise-induced muscle protein synthesis.” Nutrition Reviews 73.suppl 3 (2015): 238-245)
Phillips et al., 2016 (Implied: Phillips, Stuart M. “The science of muscle hypertrophy: making sense of the molecular pathways for muscle growth.” Comprehensive physiology 6.2 (2016): 655-681)
Propst, David & Biscardi, Lauren & Dornemann, Tim. (2023). Clinical sarcopenia identification: Justification for increased sensitivity in SARC-F scores for probable sarcopenia. 10.1101/2023.10.31.23297840.
Ran, Jianxin et al. “Dose-response effects of resistance training in sarcopenic older adults: systematic review and meta-analysis.” BMC geriatrics vol. 25,1 849. 5 Nov. 2025, doi:10.1186/s12877-025-06559-4 (Appears twice)
Rieu et al., 2009 (Implied: Rieu, Isabelle et al. “Leucine-enriched essential amino acid supplementation enhances muscle protein synthesis and amino acid availability in the elderly.” Clinical nutrition 28.1 (2009): 74-78)
Rogeri, Patricia S et al. “Strategies to Prevent Sarcopenia in the Aging Process: Role of Protein Intake and Exercise.” Nutrients vol. 14,1 52. 23 Dec. 2021, doi:10.3390/nu14010052
Rosenberg, I H. “Sarcopenia: origins and clinical relevance.” The Journal of nutrition vol. 127,5 Suppl (1997): 990S-991S. doi:10.1093/jn/127.5.990S
Sanchez-Tocino, Maria Luz et al. “Definition and evolution of the concept of sarcopenia.” Nefrologia vol. 44,3 (2024): 323-330. doi:10.1016/j.nefroe.2023.08.007
Shin, Hyung Eun et al. “Sex-Specific Differences in the Effect of Free Testosterone on Sarcopenia Components in Older Adults.” Frontiers in endocrinology vol. 12 695614. 22 Sep. 2021, doi:10.3389/fendo.2021.695614
Sklivas, Alexander B et al. “Efficacy of power training to improve physical function in individuals diagnosed with frailty and chronic disease: A meta-analysis.” Physiological reports vol. 10,11 (2022): e15339. doi:10.14814/phy2.15339
Souza Rocha 2024 (Implied: Souza Rocha, I. R. et al. “Effects of Resistance Training Volume and Frequency on Muscle Strength Gains in Older Adults: A Systematic Review and Meta-analysis.” Sports Medicine 54.2 (2024): 379-397)
Steps et al., 2015 (Implied: Stephens, Jacalyn M. et al. “The obesity-induced inflammatory state and skeletal muscle anabolic resistance.” The Journal of clinical endocrinology and metabolism 100.2 (2015): 655-666)
Talbot, Jared, and Lisa Maves. “Skeletal muscle fiber type: using insights from muscle developmental biology to dissect targets for susceptibility and resistance to muscle disease.” Wiley interdisciplinary reviews. Developmental biology vol. 5,4 (2016): 518-34. doi:10.1002/wdev.230 (Appears three times)
Tezze, Caterina et al. “Anabolic Resistance in the Pathogenesis of Sarcopenia in the Elderly: Role of Nutrition and Exercise in Young and Old People.” Nutrients vol. 15,18 4073. 20 Sep. 2023, doi:10.3390/nu15184073 (Appears twice)
Titova, Angelina et al. “Muscle Aging Heterogeneity: Genetic and Structural Basis of Sarcopenia Resistance.” Genes vol. 16,8 948. 11 Aug. 2025, doi:10.3390/genes16080948
Trombetti, A et al. “Age-associated declines in muscle mass, strength, power, and physical performance: impact on fear of falling and quality of life.” Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA vol. 27,2 (2016): 463-71. doi:10.1007/s00198-015-3236-5
Verdijk et al., 2014 (Implied: Verdijk, Lex B et al. “The role of muscle mass in the reduced muscle protein synthesis rate in older men.” The American journal of clinical nutrition 100.2 (2014): 584-93)
von Haehling, Stephan et al. “An overview of sarcopenia: facts and numbers on prevalence and clinical impact.” Journal of cachexia, sarcopenia and muscle vol. 1,2 (2010): 129-133. doi:10.1007/s13539-010-0014-2 (Appears three times)
Wang, Yichen, and Jeffrey E Pessin. “Mechanisms for fiber-type specificity of skeletal muscle atrophy.” Current opinion in clinical nutrition and metabolic care vol. 16,3 (2013): 243-50. doi:10.1097/MCO.0b013e328360272d (Appears three times)
Zaromskyte, Gabriele et al. “Evaluating the Leucine Trigger Hypothesis to Explain the Post-prandial Regulation of Muscle Protein Synthesis in Young and Older Adults: A Systematic Review.” Frontiers in nutrition vol. 8 685165. 8 Jul. 2021, doi:10.3389/fnut.2021.685165
Zhu, Yang et al. “Advances in exercise to alleviate sarcopenia in older adults by improving mitochondrial dysfunction.” Frontiers in physiology vol. 14 1196426. 5 Jul. 2023, doi:10.3389/fphys.2023.1196426

Our Sponsors:
* Check out Express VPN: https://expressvpn.com/BBM
* Check out FIGS and use my code FIGSRX for a great deal: https://wearfigs.com
* Check out Factor and use my code bbm50off for a great deal: https://www.factor75.com
* Check out Rosetta Stone and use my code TODAY for a great deal: https://www.rosettastone.com
* Check out Uncommon Goods: https://uncommongoods.com/bbm
* Check out Washington Red Raspberries: https://redrazz.org

Support this podcast at — https://redcircle.com/barbell-medicine-podcast/donations

Advertising Inquiries: https://redcircle.com/brands

Privacy & Opt-Out: https://redcircle.com/privacy

Episode #375: The Sarcopenia Deep Dive- ...