Method Overview
The key to our approach is locating the true weaknesses that cause the injury.
Athletes and active adults rarely get hurt at the weakest point in the muscular chain. Instead, the stronger muscles overwork to compensate for other weaknesses in the chain, eventually breaking down and causing the injury.
For example, a hamstring pull almost always happens because the hamstring is overworking to make up for poor activation in the glute medius and minimus, not because the hamstring itself is weak.
The common mistake PTs and trainers make is to focus on strengthening the injured muscle as the top priority, like the hamstring pull example. This only reinforces the compensation pattern that caused the problem in the first place.
Our method does the opposite: We first strengthen the root cause and do not touch the injured area until those stabilizer weaknesses pass our activation testing. In the case of a hamstring pull, we focus on the weak medial hip rotators (glute medius, minimus, adductors) — get those up to standard, then focus on the hamstrings.
In short: Fully support the injured area first by strengthening the weaknesses in the chain, then safely rebuild the damaged tissue. This core principle applies to every injury we treat for the upper and lower body.
COREX12 – The Root Cause of Injuries
After more than 20 years working with hundreds of injured athletes, Zach Fuller, founder of the Feel It to Heal It method, has identified that almost every injury traces back to the same 12 muscular weaknesses. These are covered by the COREX12 Foundations (4 shoulder, 3 core, 5 hip/leg exercises).
These 12 exercises are not just for strengthening — they also serve as precise tests to identify and confirm the weakness. In nearly all cases, once the weakness is located and properly strengthened, the pain resolves naturally.
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Feeling the Correct Spot
The real key to fixing yourself using COREX12 is learning how to feel the exact weakness during each exercise, without involving compensation patterns.
For every one of the 12 movements, we show you a specific spot to touch with your hand. Then we teach you how to adjust your position, range, and form until you feel only that target muscle working — nothing else. Once you consistently feel the correct weakness spot (with no compensations), you can finally strengthen the root cause and resolve the injury for good.
That’s why we call it “Feel It to Heal It.”
Avoiding Compensations
Feeling the correct spot is easier said than done. Without guidance, most clients initially feel compensations more than the actual weakness.
Besides locating the right spot, a big part of early training is teaching you exactly where you do NOT want to feel the work (e.g., traps instead of rear delts, TFL instead of glute medius). Depending on the severity of compensations, it typically takes 1–3 weeks (2 sessions per week) to isolate the weakness and start making real progress.
Compensations are your body’s way of cheating: when one or more of the 12 key muscles can’t fire properly, other muscles jump in to do the job. Those compensations are the root of almost every injury and they must be eliminated at all costs.
Breaking Up Scar Tissue
Scar tissue and compensations go hand in hand. When an injury occurs, the body protects itself by locking down the area and creating more compensations. The longer the problem persists, the more scar tissue builds up in the injured area.
Important rule: Scar tissue will not fully release or break up until the 12 foundations are rebuilt.
If you attack scar tissue too early (through aggressive stretching or massage) while the stabilizers are still weak, you’ll often cause irritation and prolong the injury.
Instead, strengthen the root cause first (pass the 12 foundations with clean activation). Only then is it safe to stretch or massage to break up scar tissue. In most cases, when the stabilizers are fixed, the scar tissue softens naturally and the pain resolves long-term.
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