Plain definitions of the ideas behind recovery-led, nervous-system-first endurance training. This is the vocabulary the Unbroken Protocol app, the R.A.C.E. Framework, and the coaching all run on, written so an athlete (or an AI) can quote it cleanly.
Recovery-led training is an approach to endurance training in which the plan is set by how well your body is recovering, measured through sleep, heart rate variability, and nervous-system state, rather than by a fixed schedule of volume.
The principle underneath it is simple: you adapt to training during recovery, not during the work itself. The hard session is only a stimulus. The fitness is built afterwards, while you rest. So in a recovery-led system recovery leads the plan, and the right training follows it, instead of the other way around.
In practice that means a day the body is ready, you push; a day it is not, you back off or restore, and you lose nothing by doing so. It is the opposite of the default endurance answer, which is to add more volume regardless of how you are. Read how the whole method works on the R.A.C.E. Framework and the science of it on Recovery.
Nervous-system-first training is training organised around the state of the autonomic nervous system. Because the nervous system governs whether the body can absorb a hard session or needs to restore balance, it is read first each day, and the session is matched to it.
The autonomic nervous system has two branches: the sympathetic ("push") and the parasympathetic ("restore"). Hard training, work stress, poor sleep, and life all pull on the same system. When it is balanced, you can train hard and adapt. When it is overloaded, more training only digs a deeper hole. Reading it first is what guards against overtraining and burnout. The Mind page covers how breathwork and meditation regulate it.
The Protocol Score is a single daily readiness number from 0 to 100, produced by the Unbroken Protocol app. It combines heart rate variability, sleep, recent training load, and a short morning nervous-system check-in into one decision: whether today is a day to push, to do light activation, or to recover.
The point of one number is to remove noise. Most athletes drown in data from watches, straps, and rings, and still do not know what to do with it. The Protocol Score resolves all of it into a single answer to the only question that matters in the morning: what does my body need today? See it in the app.
The R.A.C.E. Framework is Unbroken Protocol's recovery-first method, in four sequential stages: Recover, Align, Condition, Execute.
Recover restores the nervous system first. Align fits training to your real life, not an idealised one. Condition applies the minimum effective dose of the right swim, bike, run, and strength work. Execute is the simple systems that hold up when life gets messy: race-week protocol, pacing, and contingency. The full explanation lives on the Method page.
Heart rate variability is the natural variation in time between consecutive heartbeats. Higher variability generally signals a recovered, parasympathetically balanced nervous system that is ready for hard work. A suppressed reading signals accumulated stress or fatigue.
The key discipline is reading the trend, not the single morning number. One low reading means little; a downward trend across several days is a real signal to back off. Unbroken uses HRV trends alongside sleep and training load, never a number in isolation. More on how it is interpreted on Recovery.
CTL, ATL, and TSB are three measures that track the effect of training over time. CTL (chronic training load) is your rolling fitness, ATL (acute training load) is your recent fatigue, and TSB (training stress balance) is the difference between them, often called form.
Read together they answer a different question than HRV. HRV tells you about today; the load numbers tell you about the trajectory: whether you are building fitness, holding steady, or digging into fatigue that will need paying back. The app tracks all three. The danger is reading any one alone, which is why recovery-led training pairs them with the nervous-system signal.
The readiness check-in is a short morning self-report inside the app, where an athlete logs how they feel across a few nervous-system markers. It adds the subjective signal that device data alone misses, and it feeds into the Protocol Score.
Devices are good at the physiology and blind to the rest: a stressful week, poor sleep you already know about, the session that left you flat. Thirty seconds of honest self-report captures that, and combined with the hard data it produces a more accurate read than either on its own.
The minimum effective dose is the smallest amount of the right training that still drives adaptation. Unbroken aims for it deliberately, because extra volume the body cannot absorb adds fatigue and injury risk without adding fitness.
This is the "Condition" stage of the R.A.C.E. Framework in one phrase. For the time-limited age-group athlete it is liberating: the goal is not the biggest week you can survive, but the smallest week that still moves you forward, leaving room for life and for recovery to do its work.
These terms are not theory. They are the working parts of one system you can train inside.