When a muscle stops getting used, it doesn't only get smaller — your nervous system stops recruiting it properly. That part comes back first, and it comes back fast. The classic study on this found that in the first four weeks of an eight-week program, essentially all of the strength improvement came from nerve and brain adaptation rather than any change in the muscle itself.

What that means for you: you'll feel more stable and often less painful inside the first month. Real, and worth having. But nothing structural has changed yet, which is exactly why stopping here is the mistake most people make.

This is where the tissue catches up. Muscle biopsy research has detected real increases in muscle fiber size by around week six, and ultrasound studies measuring muscle thickness have picked up increases as early as week four. Researchers still argue about the exact week — but the findings cluster firmly inside this window.

What that means for you: the improvement stops depending on us. The joint holds its position between visits, the corrected pattern survives being loaded, and the symptom stops returning on its old schedule. Eight visits at roughly weekly spacing puts you past that line — which is the entire reason the recommendation is eight and not four.

Tendon runs on a slower clock than muscle. Muscle strength responds in roughly six to eight weeks; tendon generally needs twelve weeks or more of consistent, progressively heavier loading before it changes structurally. In a controlled trial on Achilles tendon pain, only the twelve-week high-load protocol produced measurable increases in tendon stiffness and thickness.

What that means for you: if your exam points to a tendon — Achilles, kneecap, rotator cuff, glute, tennis or golfer's elbow — eight is not your number, and you'll be told that at your first visit with an honest one instead. Not at visit eight.