Jul 5, 2026

Make yourself injury proof, from first principles

Our physical bodies are tasked with getting us food, safety, mates, and other emergent goals downstream of evolution.

Mechanically, this means developing the right hardware and software (tendons, muscles, ligaments, sensors, nerves, neurons) to move in the ways we would like. The body does not know the demands on it from the get-go. It learns them through contact with reality and adapts accordingly. It has developed a feedback loop. This feedback loop is about whether or not the body is adequately serving the goal of the ape.¹

The prototypical example of feedback loops in the body is the muscle:

1. Sensors in the muscle measure strain above capacity
2. Sends out “damage” signal
3. Body rebuilds muscle, plus a buffer!

Why the buffer? The muscle is not only responding to the first-order consequence (strained tissue) but also the second-order consequence (this body will be stressed again, so let us allocate more resources to it). It is an investment of current resources to save on future energy.

Say this “damage” signal is sent out at the bicep, which contracts between your elbow and shoulder, moving your arm along a very specific plane. Does the body rebuild every other muscle in the body, anticipating future stress? No! The body has evolved to be efficient, so feedback loops must be narrow. The “damage” signal develops the bicep, and the bicep alone, and in a very particular way. It responds to the force, speed, angle, and coordination demands of the “damage signal” on the bicep.

Now, what is injury? Injury is when the body is loaded in a way it cannot mechanically handle. It is a failure mode of the body.

How do we injury-minimize? Two options: (1) reduce loads on the body or (2) increase ability to cope with load (we call this strength). If reducing the load was possible, we would simply do this, and never be injured. End of story! Of course, injuries occur precisely because we cannot predict the load on our body at any given moment. There is some randomness. This forces us to increase our strength.

There are three (primary) dimensions to measure the strength of the body on a specific plane:

1. Force-load (weight on movement)
2. Tempo (speed of movement)
3. Range of motion, or ROM (end-points of movement).

Consider the strict-form barbell squat. We are told to develop strength by increasing the force-load. This is called progressive overload, and the body responds by being able to withstand more and more weight each time.

Now, an interesting question: what is the shape of the (random) loads our body is put under? Say you are playing a game of pickup basketball: you jump up for a rebound, land hard, and injure your knee (the load surpassed your strength).

Landing from a jump is comparable to the eccentric part of a squat. You can squat 4x your bodyweight, yet landing from a simple jump injured you. One may predict that there would be some positive transfer: your body’s ability to bear force-load in the squat should protect you from a fall, right? But your preparation was incomplete. You never increased varied tempo or ROM.

The loads on our body are diverse, unpredictable, require different parts to fire in the right sequence. Now, for the finale: our exercise routines must mimic the shape of loads on the body.

1. The set of loads is diverse, so our routines must be diverse.

Remember, injury is all about the weakest-link. It does not matter if your quadriceps are giant; if your ankle is weak, you will injure yourself while running. This is because we do not get to choose how loads are distributed onto our body.

So we must develop all parts of the body through greater force-loads, varying tempos, and greater ROM. Trail-running is a great example. The lower legs are tested along all dimensions. There is sufficient diversity. If you simply progress in intensity (which you can measure by speed, heart rate, choose your metric), you will naturally bulletproof your lower legs.

2. The body is loaded through movements, not body parts.

Exercise routines are generally oriented around body parts: pecs, deltoids, triceps, lats, traps, biceps, glutes, hamstrings, quadriceps, calves, etc. Why is this the right level of resolution? Loads on the body require different parts to coordinate work, together. A different level of resolution might be pushing, pulling, rotating. Or even something like generating force around a limb (throwing, kicking, punching).

How does this inform our routine? We should be developing strength through movements that require different body parts to work together.

On being skeptical of doctors

I recently injured my foot after a run in Central Park. I was wearing Adidas Sambas, which are flat and have little to no foot support. It was a bad idea, I know. I fell victim to peer-pressure, or that’s my excuse.

My first instinct was to consult Claude, and it told me it was likely damage to a nerve or strain on the plantar fascia (thick band of connective tissue that lines the bottom of your foot). It should heal in 4 weeks. After 6 weeks, I went to a foot doctor. I know this foot doctor well because I’ve had foot injuries in the past. I’ve always thought he was sharp. Or at least intellectually honest, which is what most doctors lack.

He diagnosed it as a plantar fascia strain, and I asked him how I could prevent this from happening next time. He explained that unlike the rest of the body, the foot cannot be developed, and gave some abstruse justification. “Orthotics are your best option.” They are basically like wearing crutches for your foot (because my feet are flat).

Why? Why does the foot not develop? I see the rest of my body develop in the gym through overload, via these feedback loops, why is the foot different? All my intuitions around the body as a system of control that responds to feedback disagreed with his blanket statement.

Thinking for myself, from first principles, his advice felt misguided. Remember, no one has a monopoly on truth. Not even above-average doctors.