Tim FerrissSimple Exercises That Can Repair Tendons — Dr. Keith Baar
At a glance
WHAT IT’S REALLY ABOUT
Why brief isometrics can rebuild tendons faster than eccentrics
- Dr. Keith Baar explains that tendon/ligament adaptation has a short signaling window (about 10 minutes) and benefits from being repeated after a 6–8 hour refractory period, which helps explain rapid grip gains seen in climbers using brief isometric “hang” protocols.
- He argues that isometrics can be superior to eccentrics for tendon rehabilitation because holding at zero velocity helps redistribute load across the tendon, while the classic eccentric benefits often came from slow tempo (reduced velocity) rather than the eccentric phase itself.
- He critiques standard immobilization practices (including boots and prolonged rest) as “stress shielding” that can promote scarring, and describes using early, low-jerk isometric loading—done with minimal pain—as a way to improve recovery after injuries and even post-surgery.
- He outlines practical rehab concepts such as overcoming vs. yielding isometrics, using multiple joint positions for tennis elbow/rotator cuff-type problems, and keeping pain very low (with “ice pick” point pain as a stop signal).
- Beyond rehab, he discusses nutrition and longevity trade-offs, including how ketogenic diets, low-protein diets, and low-dose rapamycin all aim to reduce mTOR activity, plus the role of mitochondria/mitophagy and the limitations of ketogenic diets for speed-focused athletes.
IDEAS WORTH REMEMBERING
5 ideasTendons and other connective tissues appear to max out their adaptive signal in about 10 minutes of optimized loading.
He described a “minimal effective dose” where connective tissue cells respond strongly for only a short window, after which additional work becomes mostly wear and tear rather than additional adaptive signaling.
An approximate 6–8 hour refractory period separates optimal tendon-loading sessions.
He said the key is spacing tendon-loading bouts so the tissue can respond again, and that his group found a similar timing pattern to what other researchers observed in bone.
Isometrics can outperform eccentrics for tendon healing because velocity (and load distribution), not “eccentric-ness,” is the core variable.
He argued isometrics help distribute load more evenly across healthy and weak regions by allowing strong regions to fatigue/relax, reducing “stress shielding” of weaker areas; he also said the success of eccentric rehab was largely a velocity/tempo effect, not something magical about eccentrics themselves.
Minimizing jerk—by ramping force slowly into and out of holds—helps reduce wear while still providing tendon signal.
He described “jerk” (rate of change of acceleration) as a major driver of tendon injury and said overcoming isometrics allow a slow force ramp-up and ramp-down to reduce jerk compared to yielding isometrics or dynamic work.
Early, carefully controlled loading can accelerate recovery compared with delayed loading or immobilization.
He criticized immobilization (boots, prolonged rest) as mechanical “stress shielding” that can promote scarring, and cited data and anecdotes supporting very early, low-jerk loading (with medical oversight) after injury/surgery to speed return.
WORDS WORTH SAVING
5 quotesIf I've told you that the thing that's gonna cause that tissue to get a scar is that you take off the tension, what I've just done is I've made the problem worse.
— Dr. Keith Baar
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 tendons stop getting the signal to adapt at ten minutes. Everything on top of that was just wear and tear that could, you know, slightly cause problems.
— Dr. Keith Baar
Jerk is the thing that's going to induce injury. Jerk is that rate of change of acceleration.
— Dr. Keith Baar
We get into this whole thing, this is like this macho business with lifting weights is a, oh, no pain, no gain. There's no reality to that, okay?
— Dr. Keith Baar
High quality AI-generated summary created from speaker-labeled transcript.
