Dr. Keith Baar is a Professor at the University of California, Davis in the Department of Physiology and Membrane Biology.

During his Ph.D. studies, his research revealed that mechanical strain on muscle fibers activates the mammalian target of rapamycin (mTOR) signaling pathway, a crucial regulator of muscular hypertrophy. 
Subsequently, he studied the molecular dynamics of skeletal muscle adaptation to endurance training under the guidance of Dr. John Holloszy, a legend in the field of exercise physiology, considered the father of modern exercise biochemistry.

Building on all of this experience, he conducted research into tendon health and the potential for engineering ligaments, which could have implications for treatment and recovery from injuries.

Dr. Baar now runs the Functional Molecular Biology Lab at UC Davis. His lab’s work ranges from studying molecular changes in our cells to conducting studies to effect real-world improvements in people’s health, longevity, and quality of life.

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Want to hear another episode that explores the possibilities of rapamycin? Have a listen to the conversation I had with Peter Attia, David M. Sabatini, and Navdeep S. Chandel at the source of this miraculous compound: Easter Island. Here, we discuss how one of the most important discoveries of medical science was almost lost, why metabolism (along with longevity) research is key to treating a long list of diseases, intermittent dosing of rapamycin, parenting advice from scientists on confidence and conflict, the necessary failures of good science, good fonts versus bad fonts, “non-potato” relationships, and much more.

What was your favorite quote or lesson from this episode? Please let me know in the comments.

SELECTED LINKS FROM THE EPISODE

• Connect with Dr. Keith Baar:

Website | Bluesky | LinkedIn

Physiology & Biology
Strength Physiology

Molecular Biology

Exercise Physiology

Injury & Recovery

Training & Rehabilitation Methods

Substances & Interventions

Supplements

Pharmaceuticals

Orthobiologics (Critiqued)

Diets

Institutions & Places

Movies

Research

Relevant Resources

SHOW NOTES

• [00:07:12] How I discovered Keith’s work through a tweet about tennis elbow and rock climbing.
• [00:07:54] Emil Abrahamsson’s hangboard training protocol.
• [00:09:20] The fundamental principles of strength training and connective tissue adaptation.
• [00:10:36] mTOR complex 1 and its role in muscle growth.
• [00:12:06] Engineered ligaments and the discovery of minimal effective doses for tendon adaptation.
• [00:13:50] The refractory period between optimal tendon loading sessions.
• [00:16:42] Rapamycin’s effects on muscle hypertrophy.
• [00:18:49] Protocols for tennis elbow rehabilitation.
• [00:20:28] Why isometrics work better than eccentrics for tendon healing.
• [00:22:14] Stress shielding and how load distribution affects tendon healing.
• [00:29:07] The misconception about eccentric loading for tendon injuries and why velocity matters.
• [00:29:58] Ideal duration for isometric holds (10-30 seconds) based on injury status.
• [00:33:50] My elbow issues and current rehab approach.
• [00:36:02] Overcoming vs. yielding isometrics and optimal loading strategies.
• [00:47:11] Dr. Barr’s movement prescription for my tennis elbow.
• [00:52:18] Loading timing post-surgery and RICE protocol criticism.
• [00:56:58] Achilles tendon rehabilitation after surgery.
• [01:00:18] Critique of orthopedic suturing techniques and recommendation for resorbable sutures.
• [01:04:02] Multiple position isometrics for tennis elbow rehabilitation.
• [01:07:26] Collagen synthesis, supplementation, and vitamin C timing.
• [01:12:59] Critique of BPC-157 and other injectable peptides for tendon healing.
• [01:18:19] Evaluation of orthobiologics’ (PRP, prolotherapy, stem cells) effectiveness.
• [01:21:37] JAK-STAT inhibitor drugs and their effects on tendon growth.
• [01:25:35] Drugs that increase risk of tendon ruptures (fluoroquinolones, AT-1 receptor drugs).
• [01:29:33] How estrogen affects tendon stiffness and injury risk in women.
• [01:32:48] Testosterone’s opposite effects on tendon compared to estrogen.
• [01:35:31] Protein intake recommendations and timing.
• [01:40:11] Ketogenic diet effects on mitochondrial biogenesis and longevity.
• [01:41:57] Comparison of ketogenic diet, low protein diet, and rapamycin for longevity.
• [01:47:19] Inflammation’s role in adaptation and when to reduce it.
• [01:51:17] Timing of ice baths relative to training for optimal recovery.
• [01:52:33] Parting thoughts.

MORE DR. KEITH BAAR QUOTES FROM THE INTERVIEW

“The number one cost to the US medical system is actually musculoskeletal sprains, strains and tears, the back and the neck, as well as the rest of the body. It’s more than diabetes and heart disease combined.”
— Dr. Keith Baar

“If passive flexibility was really important for decreasing tendon injury, then the women’s gymnasts who have the most passive flexibility wouldn’t be the NCAA sport with the highest rate of Achilles tendon rupture.”
— Dr. Keith Baar

“Injury related to flexibility is a U-shaped curve. So our injuries are really high when we’re very inflexible. When we get into that sweet spot where we have good mobility, we can do the full range of motion, actually the injury rate is very low. If we become hyper-mobile, we actually have that injury rate go up as well.”
— Dr. Keith Baar

“We don’t use a ketogenic diet if we want to go fast, but if we’re training for life, we see that it increases longevity, that the ketones themselves are really good for brain function.”
— Dr. Keith Baar

“The first recorded immobilizer for an ankle or a leg is from Egyptian hieroglyphs where they showed pictures 4,500 years ago. If I took you and you said you had cancer, you would not want a treatment that was developed 4,500 years ago. You would hope that something new has been developed in the last 4,500 years. That is where we are for our orthopedic situations.”
— Dr. Keith Baar

“The reality is that there are especially certain athletes like climbers where they’re doing all kinds of heavy lifts, they’re doing all kinds of heavy work, they’re doing all kinds of really dynamic moves. And what happens, what breaks down is they break down in their finger tendons and they break down in the little pulleys within the tendons.”
— Dr. Keith Baar

PEOPLE MENTIONED

Vincent Van Gogh

Emil Abrahamsson

David Sabatini

Navdeep Chandel

Dwayne “The Rock” Johnson

Kozaburo Hayashi

Håkan Alfredson

Michael Kjær

Monika Lucia Bayer

Rod Whiteley

Natalie Gilmore

Timo Nyyssönen

Venus Williams

Luc van Loon

Stuart Phillips

Jon Ramsey

Valter Longo

Ron Maughan

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