- [Simple Exercises That Can Repair Tendons, Isometrics vs. Eccentrics, and More — Dr. Keith Baar](https://www.youtube.com/watch?v=BnFzjcPTSsc)
- [Transcript](https://tim.blog/2025/02/27/dr-keith-baar-transcript/)
- [3 Isometric Exercises for Strengthening Tendons and Ligaments](https://www.youtube.com/watch?v=GJuzyy2YRRk)

### Podcast Summary

**1. Introduction and Emil Abrahamsson's Climbing Success:**

* Ferriss introduces Baar and explains how he discovered his work through a YouTube video by climber Emil Abrahamsson.
* Abrahamsson dramatically improved his grip strength by incorporating short isometric hangboard sessions (10 minutes, 10 seconds on, 50 seconds off) based on Baar's research.
* This success leads to the core question: what physiological adaptations allowed for such significant strength gains in connective tissue?

**2. Strength Beyond Muscle Size (Force Transfer):**

* Baar explains that strength isn't solely about muscle size (cross-sectional area). It also involves the efficiency of *force transfer* from muscle to bone, mediated by tendons, ligaments, and connective tissues.
* He describes his early research on muscle hypertrophy and the mTORC1 pathway (mechanistic target of rapamycin), which is crucial for muscle growth.
* He shifts to discussing how athletes, like cyclists, can gain strength *without* significant muscle hypertrophy by improving force transfer.

**3. Engineered Ligaments and the "Minimal Effective Dose":**

* Baar details his work with engineered ligaments, aiming to create lab-grown replacements for injured ligaments (like ACLs).
* This research led to key discoveries:
* **Short Duration:** Tendons and ligaments respond to loading for only a short time (around 10 minutes) before becoming "desensitized."
* **Refractory Period:** A 6-8 hour rest period is needed between loading sessions for optimal adaptation, similar to bone's response to stimuli.
* This "minimal effective dose" concept is central to Baar's approach.

**4. Rapamycin, mTOR, and Hypertrophy:**

* Ferriss asks about the potential interaction between rapamycin (used for longevity) and muscle hypertrophy.
* Baar explains that at longevity doses, rapamycin's negative impact on muscle growth is minimal, but it could hinder maximal hypertrophy.
* He discusses how endurance exercise and metformin can counteract mTORC1, creating a balance between muscle growth and other metabolic effects.

**5. Isometrics vs. Eccentrics for Tendinopathy:**

* Ferriss brings up common tendon injuries (golfer's/tennis elbow) and asks about optimal loading protocols.
* Baar explains the crucial role of *velocity* in tendon loading:
* **Isometrics (static holds):** Distribute load more evenly across the tendon, including weaker areas.
* **Eccentrics (lengthening contractions):** Traditionally prescribed for tendinopathy, but Baar argues their benefit comes from *slowed velocity*, not the eccentric nature itself.
* **Jerk:** Rapid changes in acceleration are detrimental and contribute to injury.
* He advocates for isometrics because they minimize jerk and ensure load is distributed across the entire tendon, promoting healing in injured areas.

**6. Specific Isometric Protocols:**

* **Duration:**
* Healthy tendons: 1-10 second holds.
* Injured tendons: 30-second holds (due to greater stress shielding in injured areas).
* 30 seconds is chosen because it achieves ~85% of tendon stress relaxation, with diminishing returns beyond that.
* **Rest Intervals:** 2 minutes rest between 30-second holds (for 4 total repetitions, totaling ~8 minutes of loading).
* **Overcoming vs. Yielding Isometrics:**
* **Overcoming:** Pushing against an immovable object (e.g., tennis racket under a counter). Preferred for injured tendons due to lower jerk and better load control.
* **Yielding:** Holding a weight (e.g., cast iron pan). Can be useful for progressive loading, but carries a higher risk of jerk.
* **Rate of Perceived Exertion (RPE):** For overcoming isometrics, focus on feeling tension in the target area, not maximal effort. A 50% effort, avoiding shaking, is often sufficient.

**7. Practical Examples (Tennis Elbow, Achilles Rehab):**

* **Tennis Elbow:** Baar recommends a combination of overcoming isometrics targeting both extension and rotation of the forearm. He advises multiple arm positions (bent, straight, overhead) to engage different muscle/tendon units.
* **Achilles Tendon Surgery:** Baar advocates for *very early loading* (within days), even after surgery. He suggests gentle plantarflexion (toe pointing) isometrics to stimulate the native tissue, even within a boot.
* He criticizes the standard practice of using strong, non-resorbable sutures, which can stress-shield the healing tendon. He prefers resorbable sutures combined with early loading.

**8. Collagen Synthesis and Supplementation:**

* Baar recommends hydrolyzed collagen peptide powder (from skin sources, not bone, to avoid heavy metals) combined with vitamin C.
* **Dosing:** 15 grams of hydrolyzed collagen + vitamin C.
* **Timing:** 30-60 minutes *before* exercise to maximize delivery to the target tissues.
* He clarifies that the specific type of collagen (I, III) doesn't matter as it's broken down into amino acids.

**9. Orthobiologics (PRP, Prolotherapy, etc.):**

* Baar is generally skeptical of orthobiologics (PRP, prolotherapy, stem cells) for lower body injuries, as the injected substances are quickly displaced by movement.
* He emphasizes that *loading* is the primary driver of adaptation (95%+) and that supplements or injections offer only marginal benefits.
* He briefly mentions BPC-157, stating that it has no direct effect on tendon cells in his research.

**10. Potential Future Interventions:**

* Baar mentions an FDA-approved drug class (JAK-STAT inhibitors, ending in "-nib") that has shown promise in improving tendon properties in animal studies.
* He hints at an unpublished hormone that can increase tendon stiffness.
* He discusses drugs that *increase* tendon rupture risk:
* Fluoroquinolone antibiotics (e.g., Ciprofloxacin).
* Angiotensin receptor blockers (sartan drugs) – significantly increase risk (7.6-fold).

**11. Estrogen, Women, and Injury Risk:**

* Baar explains how estrogen fluctuations during the menstrual cycle affect tendon stiffness.
* Estrogen inhibits lysyl oxidase, an enzyme that cross-links collagen, making tendons *less* stiff.
* This explains the higher ACL injury rate in women and lower muscle pull rate.
* Testosterone has the opposite effect, increasing lysyl oxidase activity and creating stiffer, but potentially more brittle, tendons.

**12. Protein Intake and Mitochondria:**

* Baar discusses protein intake, stating that the focus has shifted from frequent, small doses (every 4 hours) to a total daily intake of 1.2-1.6 grams per kilogram of body weight.
* He connects the ketogenic diet to mitochondrial biogenesis and longevity:
* Ketogenic diets, like low-dose rapamycin, decrease mTOR activity, potentially increasing lifespan.
* They force the body to use mitochondria, improving mitochondrial quality.
* They also activate mitophagy (breakdown of damaged mitochondria).
* He cautions against ketogenic diets for athletes needing to sprint, as they impair high-intensity performance.
Ketogenic diets may decrease bone mass.

**13. Inflammation and Anti-Inflammatories:**

* Baar emphasizes that inflammation is *essential* for adaptation.
* He advocates for using *load* as an anti-inflammatory, rather than pharmaceutical interventions.
* Short isometric holds (even 5 seconds) can help squeeze out excess fluid and reduce pain.
* For ice baths, he suggests spacing them out from workouts (e.g., ice bath in the morning, strength training in the afternoon) to minimize interference with muscle adaptation.

**Overall, Dr. Baar's approach emphasizes the critical role of *controlled loading* in tendon and ligament health and rehabilitation. He advocates for isometrics, early loading after injury, and a nuanced understanding of inflammation and the limitations of supplements and injections. He highlights the importance of considering individual factors (injury history, sex, activity level) when designing training and recovery programs.**

### Treating Golfer's Elbow

Based on the podcast transcript, here's what Dr. Keith Baar would likely recommend for treating golfer's elbow (medial epicondylitis):

**Core Principles:**

* **Isometric Loading:** The primary treatment would revolve around isometric exercises. Baar emphasizes that isometrics distribute load evenly across the tendon, including the injured and weaker areas, promoting healing. He specifically states that isometrics are superior to eccentrics because it's the *reduced velocity* that matters, and isometrics have zero velocity.
* **Overcoming Isometrics:** He would likely recommend *overcoming* isometrics (pushing against an immovable object) over *yielding* isometrics (holding a weight). This is because overcoming isometrics minimize jerk (rapid changes in acceleration), which is detrimental to injured tendons. They also offer better control over the load.
* **Minimal Effective Dose:** The loading should follow the principle of the "minimal effective dose." This means short duration, high-intensity (within a pain-free range) holds with sufficient rest.
* **Load, Not Rest:** Baar strongly advocates for loading the injured area rather than prolonged rest. Rest can lead to stress shielding and further weakening of the tissue.
* **Pain Management:** Keep the pain during exercise at a 2/10 or below. He distinguishes between point-specific pain (bad) and warm, burning soreness (acceptable).

**Specific Exercise Recommendations:**

1. **Overcoming Isometric with Rotation:**
* Use a golf club or tennis racket (or similar object).
* Place the elbow by the side, with the club/racket head pointing upwards.
* Rotate the hand *inward* (palm facing down – pronation) so that the club/racket is pressing against a stable, immovable surface (like the underside of a kitchen counter or door jamb).
* Gradually increase the pressure over 3-5 seconds until you feel tension in the forearm (medial side for golfer's elbow). It shouldn't be maximal effort, but a noticeable, controlled tension (perhaps around 50% of max effort).
* Hold this position for 30 seconds.
* Slowly release the pressure over 3-5 seconds.
* Rest for 2 minutes.
* Repeat for a total of 4 repetitions.

2. **Wrist Flexion Isometrics (Overcoming):**
Imagine doing wrist curls.
*Start in the bottom, or flexed, position.
*Hold position for 30 seconds
* Rest for 2 minutes between sets.
* Perform 4 sets in total.

3. **Varying Arm Positions:**
* Baar would likely recommend performing the isometric exercises with the elbow at different angles (e.g., 90 degrees, fully extended, and somewhere in between). This engages different parts of the muscle-tendon unit and ensures comprehensive loading. *Not* all in one session. Instead, cycle through different positions on different days, or during different sets.

**Frequency and Progression:**

* **Frequency:** Initially, one session per day. After 6-8 hours, the tendon can be loaded again.
* **Progression:** Gradually increase the hold time *if needed*, but 30 seconds is the target for injured tendons. The primary way to progress is to very gradually increase the *perceived effort* during the hold, *always staying within a pain-free range*.

**Additional Considerations:**

* **Collagen and Vitamin C:** Baar recommends taking 15 grams of hydrolyzed collagen peptide powder (from a skin source) with vitamin C 30-60 minutes *before* the isometric exercises. This provides the building blocks for collagen synthesis and ensures optimal delivery to the injured area.
* **Avoid High Jerk Activities:** During the recovery period, avoid activities that involve rapid changes in acceleration (e.g., swinging a golf club, throwing, fast movements).
* **Listen to Your Body:** Pain is a crucial guide. Stop if you experience sharp, point-specific pain.

**Important Note:** While Baar's advice is based on his research, it's essential to consult with a healthcare professional (doctor, physical therapist) for a proper diagnosis and personalized treatment plan. This summary is based on the podcast transcript and should not be taken as a substitute for professional medical advice.

### Vitamin C

Whether Dr. Baar is "right" about taking vitamin C before exercise in the context of tendon/ligament health is a nuanced question. Here's a breakdown of the evidence and considerations:

**Dr. Baar's Rationale (and supporting evidence):**

* **Collagen Synthesis:** Vitamin C (ascorbic acid) is an essential co-factor for the enzymes (prolyl hydroxylase and lysyl hydroxylase) that are crucial for collagen synthesis. Collagen is the primary structural protein in tendons and ligaments. Without sufficient vitamin C, collagen production is impaired. This is well-established science.
* **Targeted Delivery:** Baar's recommendation of taking vitamin C *before* exercise is based on the idea of maximizing its delivery to the target tissues (tendons and ligaments). These tissues have relatively poor blood supply. The theory is that by increasing blood levels of vitamin C *prior* to loading, the mechanical action of exercise (compression and release) will help "pump" the nutrient-rich fluid into the tendon/ligament, enhancing collagen synthesis in that specific area. This is the less-proven, but logical, part of his recommendation.
* **Combined with Collagen:** He recommends taking it *with* hydrolyzed collagen. The idea is to provide both the building blocks (amino acids from collagen) and the necessary co-factor (vitamin C) simultaneously.
* **Research:** The 2017 study cited shows that consumption of gelatin (similar to hydrolyzed collagen) with Vitamin C one hour before short exercise bouts doubled markers of collagen synthesis.

**Counterarguments and Considerations:**

* **General Vitamin C Sufficiency:** Most people in developed countries consuming a reasonably balanced diet are *not* deficient in vitamin C. Severe vitamin C deficiency (scurvy) is rare. The question is whether *supraphysiological* doses (above the RDA) provide additional benefits *specifically for tendon/ligament repair*.
* **Antioxidant Interference:** There's some evidence that high-dose antioxidant supplementation (including vitamin C) *can* interfere with some of the beneficial adaptations to exercise, particularly *muscle* adaptations. This is because reactive oxygen species (ROS), which antioxidants neutralize, are signaling molecules involved in muscle growth and mitochondrial biogenesis. However, Baar addresses this, saying that it could blunt, but not eliminate, gains, and that for tendon health, the benefits might outweigh the muscle-related drawbacks.
* **Limited Direct Evidence:** While the 2017 study is supportive, it's a single study, and more research is needed to definitively confirm the benefits of *pre-exercise* vitamin C *specifically for tendon healing*. Most studies on vitamin C and musculoskeletal health are related to general deficiency or osteoarthritis (which involves cartilage, not just tendons/ligaments).
* **Timing Specificity:** The "30-60 minutes before" timing is based on the idea of peak blood levels coinciding with exercise. While plausible, the precise optimal timing hasn't been rigorously established.
* **Dosage:** Studies that showed positive benefits in collagen synthesis often use much higher doses of Vitamin C than found in a standard supplement.

**Conclusion:**

Dr. Baar's recommendation is based on sound physiological principles (vitamin C's role in collagen synthesis) and a logical, though not definitively proven, mechanism (targeted delivery via exercise-induced fluid flow).

* **Is it likely harmful?** No, for most people, taking a reasonable dose of vitamin C (e.g., 50-500mg) with hydrolyzed collagen before exercise is unlikely to be harmful. Excess vitamin C is water-soluble and excreted.
* **Is it definitively proven to be beneficial?** Not yet. More research is needed to confirm the *magnitude* of the benefit, the optimal *timing* and *dosage*, and whether it truly accelerates tendon/ligament healing beyond what adequate general vitamin C intake and proper loading would achieve.
* **Is it a reasonable approach?** Yes, it's a reasonable, low-risk strategy to try, *especially* if someone is recovering from a tendon/ligament injury and is engaging in a structured rehabilitation program involving isometric loading (as Baar recommends). It's a more targeted approach than simply taking vitamin C at any time of day.

**In summary, it's a plausible and potentially beneficial strategy, but not yet a definitively established best practice. It's best viewed as a potentially helpful adjunct to the core treatment, which is controlled loading of the injured tissue.** It's more likely to be beneficial for someone actively trying to heal an injury than for someone already healthy and just seeking general tendon/ligament maintenance.

### Best Tendons to Strengthen

**1. Rotator Cuff Tendons (Shoulder):**

* **Tendons:** Supraspinatus, Infraspinatus, Teres Minor, Subscapularis.
* **Why:** Extremely common site of injury, especially with age and overhead activities (sports, work). Degenerative changes are common, and full tears can significantly impact function. The shoulder joint is inherently unstable, relying heavily on the rotator cuff for stability.
* **Exercises (as per Baar's principles):**
* *Overcoming* isometrics are preferred. Use a doorframe, wall, or stable object.
* **External Rotation (Infraspinatus/Teres Minor):** Elbow bent at 90 degrees, press the back of the hand outwards against the resistance. Also perform with arm straight, and arm overhead.
* **Internal Rotation (Subscapularis):** Elbow bent at 90 degrees, press the palm inwards against the resistance. Also perform with the arm straight, and arm overhead.
* **Abduction (Supraspinatus):** With arm slightly away from the body, press outwards against resistance (as if lifting the arm to the side). Can be done with a slight forward angle to target the supraspinatus more specifically.
* Hold each for 30 seconds, 2 minutes rest, 4 repetitions.

**2. Achilles Tendon (Ankle):**

* **Why:** Largest tendon in the body, subject to high loads during walking, running, and jumping. Common site of tendinopathy (inflammation/degeneration) and rupture, especially in middle-aged and older individuals.
* **Exercises:**
* **Standing Calf Raise (Gastroc Emphasis) - Overcoming Isometric:** Stand on a slightly elevated surface (e.g., a step). Push up onto the balls of your feet as if doing a calf raise, but against an immovable object above (e.g., a low ceiling or doorframe). Focus on controlled, slow force development.
* **Seated Calf Raise (Soleus Emphasis) - Overcoming Isometric:** Sit with knees bent at 90 degrees. Place a heavy, immovable object on your thighs (or use a seated calf raise machine, but don't allow movement). Push upwards with your toes against the resistance.
* 30-second holds, 2-minute rest, 4 reps.

**3. Patellar Tendon (Knee):**

* **Why:** Connects the kneecap (patella) to the shinbone (tibia). Common site of "jumper's knee" (patellar tendinopathy), especially in athletes involved in jumping sports.
* **Exercises:**
* **Isometric Leg Extension (Overcoming):** Use a leg extension machine, but set the weight to an immovable level. Slowly try to extend your leg against the resistance, developing force gradually.
* **Isometric Wall Sit (Overcoming, combined with Quad Tendon):** Back against the wall, slide down until thighs are parallel to the floor (90-degree angle at hips and knees). Hold this position. This targets both the patellar tendon and the quadriceps tendon.
* 30-second hold if there is pain or injury.

**4. Quadriceps Tendon (Knee):**

* **Why:** Connects quadriceps muscle to the patella. Less prone to complete ruptures than the patellar tendon, but tendinopathy can occur.
* **Exercises:**
* **Isometric Leg Extension (Overcoming):** As described above for the patellar tendon.
* **Isometric Wall Sit (Overcoming):** As described above for the patellar tendon.
* **Isometric Lunge:** One leg is extended forward with knee bent, and other leg is extended behind, with knee hovering just above the ground.

**5. Wrist Extensor Tendons (Forearm - "Tennis Elbow"):**

* **Why:** Common site of lateral epicondylitis ("tennis elbow"), even in people who don't play tennis. Often related to repetitive gripping and wrist extension.
* **Exercises:**
* **Overcoming Isometric with Extension:** Use a tennis racket, golf club, or similar object. Place it under a stable surface (e.g., kitchen counter). With your palm facing down, try to lift the object (wrist extension) against the resistance.
* **Overcoming Isometric with Rotation:** As described for tennis elbow in the podcast summary, rotate the hand outwards (supination) against resistance.

**6. Wrist Flexor Tendons (Forearm - "Golfer's Elbow"):**

* **Why:** Common location of medial epicondylitis.
* **Exercises:**
* **Overcoming Isometric with Flexion:** Use a tennis racket, golf club, or similar object. Place it under a stable surface (e.g., kitchen counter). With your palm facing up, try to lift the object (wrist flexion) against resistance.
* **Overcoming Isometric with Rotation:** As described for golfer's elbow in the podcast summary, rotate the hand inwards (pronation) against resistance.

**7. Plantar Fascia (Foot):**

* **Why:** Although technically a ligament, the plantar fascia acts like a tendon, supporting the arch of the foot. Plantar fasciitis (inflammation) is a very common cause of heel pain.
* **Exercises:**
* **Isometric Toe Extension (Overcoming):** While seated, place a towel or strap under your toes and pull upwards, creating tension in the plantar fascia. Hold. Can also be done by pressing the toes against a wall.

**General Principles for Proactive Strengthening:**

* **Consistency:** Regular loading, even with short sessions, is more important than infrequent, intense workouts.
* **Progressive Overload:** Gradually increase the load (effort) over time, *within a pain-free range*.
* **Specificity:** Choose exercises that target the specific tendons you want to strengthen.
* **Pain as a Guide:** Avoid sharp, localized pain. Mild soreness is acceptable.
* **Nutrition:** Ensure adequate protein intake and consider hydrolyzed collagen with vitamin C (as per Baar's recommendations).

By proactively strengthening these key tendons, individuals can reduce their risk of injury and maintain function throughout their lives. The focus on *overcoming isometrics* is particularly important, as it minimizes the risk of exacerbating existing issues or causing new injuries.