The science of tendon healing

Why this program works the way it does.

Your tendons are built from collagen fibers. In a healthy tendon, those fibers are packed together in tight, parallel lines — almost like the strands of a strong rope. That organized structure is what lets the tendon transmit force efficiently every time you stand, walk, climb stairs, or run.

Muscle transmits force through the tendon — built from bundled collagen fibers (magnified).

When a tendon becomes irritated, that orderly structure starts to break down. This is the key thing to understand: the problem usually isn't "damage" the way a tear is. It's a change in the quality and organization of the tissue. And tissue quality is something you can rebuild.

Here's a piece that surprises most people. An irritated tendon doesn't have poor blood flow, as you might expect. It actually grows new, abnormal blood vessels — and those new vessels bring new nerve endings in alongside them.

That ingrowth of new nerves is a big part of why an irritated tendon hurts, even though it isn't "inflamed" in the way a fresh injury is. So when you feel pain, it's real and it's meaningful — but it's a signal about load and irritation, not a sign that something is tearing or being damaged.

This matters because it explains why the fix works. As you calm the tendon down and progressively rebuild its capacity, this abnormal vessel and nerve activity settles, and the pain reduces over time. You're not just masking a symptom — you're changing the tissue itself.

Your gluteal tendons — the ones involved in this kind of hip pain — wrap over the bony point on the outside of your hip. That anatomy matters. When your leg moves across the midline of your body, the tendon gets pressed, or compressed, against that bony point. This happens more often than you'd think:

Red arrows show compression — the tendon pressed against the bony point of the hip.

Compression is a completely different stressor from the healthy, productive loading you do in this program — and it's one of the biggest drivers of ongoing tendon irritation. This is the reason your program includes a list of positions and stretches to avoid. It isn't that movement is bad for you. It's that this specific kind of squashing keeps the tendon irritated and works directly against everything you're building.

This is also why the old advice to "stretch it because it feels tight" so often backfires. That stretch feels like it should help, but for this tendon, it's adding compression to a tissue that's already irritated. (See your program's avoid-list for the specifics of what to limit and why.)

When you load a tendon the right way, the cells inside it respond by building new, better-organized collagen and rebuilding the tissue's tolerance for load. In other words, loading directly reverses the disorganization that caused the problem in the first place.

This is something stretching simply cannot do. And it's something rest cannot do either — in fact, extended rest lets the tendon lose even more of its capacity, which is why pain so often comes roaring back the moment you return to activity.

Only progressive loading rebuilds your tendon's ability to handle your actual life — your walks, your hikes, your runs, your stairs, your travel. That's why this is a strength-based program, not a stretch-and-rest program. Every session is an investment in tissue that's measurably getting stronger and better organized.

A tendon adapts to the load you give it — and then that same load stops being enough to drive change. That's why this program is built in Tiers: each stage asks a little more of the tissue than the last, so it keeps adapting instead of plateauing.

It's also why the early weeks lean on isometric holds — steady, controlled loading that builds capacity when the tendon is most irritable — before progressing into fuller, dynamic strength work as your tolerance grows. The exercises evolve because you evolve.