Aerobic base
The foundation of steady, lower-intensity work that supports longer efforts. It is usually built over weeks and months, and it is discussed in more detail in the training section.
Editorial note: Nebula provides general education. Training decisions should reflect individual medical history and professional advice.
Glossary
Plain definitions for training and physiology terms
Training writing can feel like a private language. This glossary explains the terms Nebula uses across its articles, from aerobic base to progressive overload, in short and neutral definitions. Where a term is contested, the entry says so.
Definitions are educational. They do not describe a prescription for any individual, and readers with health concerns should consult a qualified professional. Related reading is gathered in methods and physiology.
Endurance and cardiovascular terms
VO2 max
The highest rate at which the body can use oxygen during hard exercise. Laboratory measurement is precise, whereas wrist-worn estimates vary and should be treated as rough indications.
Heart-rate zones
Ranges of heart rate used to describe effort. Different systems use three, five or seven zones, so a number from one scheme cannot be compared directly with another.
Lactate threshold
The intensity above which blood lactate accumulates faster than it can be cleared. In practice it is often described as the pace that feels “comfortably hard”.
Resting heart rate
The number of beats per minute at complete rest, ideally measured on waking. Day-to-day variation is normal, and a single reading says little.
Talk test
A simple check in which the ability to speak in full sentences indicates a moderate effort. It requires no equipment and works across ages.
Strength and movement terms
Progressive overload
Gradually increasing the demand placed on the body, through load, repetitions or complexity, so that adaptation continues. The increase is small and planned, not abrupt.
Functional training
Exercise that uses movement patterns found in daily life, such as squatting, hinging, pushing, pulling and carrying. The term is used loosely, so Nebula always states which movements are meant.
Range of motion
The distance a joint can move in a given direction. Mobility work aims to use the range available in a controlled way, as discussed on the mobility page.
Rate of perceived exertion
A self-reported number, often on a scale from one to ten, describing how hard an effort feels. It is subjective yet useful, particularly alongside heart rate.
Repetitions in reserve
An estimate of how many more repetitions could have been completed with good form. Two in reserve means two further clean repetitions were possible.
Deload
A planned, lighter period in a training plan that allows accumulated fatigue to settle before work resumes.
Recovery and monitoring terms
| Term | Short meaning | Common misunderstanding |
|---|---|---|
| Heart-rate variability | Variation in time between heartbeats | That a higher figure is always better for every person |
| Readiness | A general sense of capacity to train on a given day | That an app score replaces how you actually feel |
| Training load | The combined volume and intensity of recent sessions | That a single number captures stress from work and sleep |
| Supercompensation | A model in which capacity rises after adequate rest | That it works on a fixed schedule for everyone |
More on rest practices is available in the recovery section.
Using the glossary well
- Treat each definition as a starting point and follow the links to the articles that place it in context.
- Check whether a device or app uses its own meaning for a familiar word such as “zone” or “score”.
- Note the date on an entry; the desk revises definitions when guidance changes.
- Find the term in the relevant panel above.
- Read the short definition and any caveat attached to it.
- Open the linked article if you want worked examples.
- Send a question to the desk if a definition remains unclear.
A definition is useful only if two people reading it would picture the same thing. When they would not, the entry should say so.
Suggest or correct an entry
The glossary is maintained by the editorial desk and reviewed twice a year, most recently on 1 October 2026. Readers are encouraged to point out missing terms, unclear wording or a reference that deserves an update.
Corrections are acknowledged within seven business days, and substantive changes are listed with a date at the end of the entry. Write through the contact page, or telephone +62 856 9317 4825 during business hours. The editorial office is at Jalan Cendrawasih No. 45, Duren Sawit, Jakarta Timur 13440, Indonesia.
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