| Primary energy system (short bursts) | Anaerobic (phosphocreatine & glycolytic) (ACSM Guidelines for Exercise Testing and Prescription) |
| Primary energy system (sustained cardio) | Aerobic (oxidative) (ACSM Guidelines for Exercise Testing and Prescription) |
| Standard RPE scale range | 6–20 (Borg) or 1–10 (modified) (Gunnar Borg, original scale developed 1970) |
| Common hypertrophy rep range | 6–12 reps per set (National Strength and Conditioning Association) |
| Recommended weekly moderate cardio (general adults) | 150–300 minutes (U.S. Department of Health and Human Services Physical Activity Guidelines, 2018) |
| MET value for brisk walking (~3.5 mph) | Approximately 3.5 METs (Ainsworth et al., Compendium of Physical Activities) |
Why Fitness Vocabulary Matters
Walk into any gym, open a training app, or flip through a wellness magazine and you'll encounter a dense shorthand — VO2 max, EPOC, progressive overload, RPE. For newcomers and casual exercisers alike, that jargon can feel like a barrier. It doesn't have to be.
A working knowledge of core fitness terminology helps you decode workout instructions, set smarter goals, and have more productive conversations with trainers or healthcare providers. This glossary covers the terms you're most likely to encounter across strength training, cardio, and general exercise science — explained in plain language, no lab coat required.
For a broader look at wellness language beyond the gym, see our practical wellness glossary.
VO2 Max
The maximum rate at which your body can consume oxygen during intense exercise, expressed in milliliters per kilogram of body weight per minute. It is widely used as a benchmark of aerobic fitness and cardiovascular efficiency.
RPE (Rate of Perceived Exertion)
A self-reported scale — commonly 1 to 10 or 6 to 20 (Borg scale) — that measures how hard exercise feels in the moment. It allows individuals to regulate intensity without heart rate monitors or lab equipment.
Progressive Overload
The principle of gradually increasing the demands placed on the body over time — through added weight, reps, sets, or reduced rest — to stimulate continued adaptation and avoid plateaus.
EPOC
Excess Post-exercise Oxygen Consumption, sometimes called the 'afterburn effect.' It refers to the elevated rate of oxygen intake your body maintains after a workout to restore itself to its resting state.
Hypertrophy
An increase in muscle cell size resulting from resistance training. Hypertrophy-focused training typically involves moderate loads and higher repetition ranges to maximize muscle growth stimulus.
1RM (One-Rep Max)
The maximum amount of weight a person can lift for exactly one complete repetition of a given exercise with proper form. It is commonly used to set training loads as a percentage of maximal strength.
Anaerobic Threshold
The exercise intensity at which lactate accumulates in the blood faster than the body can clear it, forcing a shift from primarily aerobic to anaerobic energy production. Training near this threshold can improve endurance performance.
Compound Movement
An exercise that engages multiple muscle groups and joints simultaneously — such as a squat, deadlift, or pull-up — as opposed to isolation exercises that target a single muscle group.
Periodization
A structured approach to programming exercise that divides training into phases (e.g., hypertrophy, strength, power, recovery) to manage fatigue, optimize adaptation, and peak performance at planned times.
Active Recovery
Low-intensity movement performed on rest days or between hard sessions — such as walking or light stretching — to promote blood flow, reduce muscle soreness, and support recovery without adding significant training stress.
Metabolic Equivalent (MET)
A unit that expresses the energy cost of physical activities as a multiple of resting metabolic rate. Walking is roughly 3–4 METs; vigorous running can exceed 10 METs.
Functional Fitness
Training that focuses on movements mimicking real-life activities — lifting, pushing, pulling, rotating — to improve everyday physical capability, balance, and injury resilience.
Training Concepts at a Glance
Before diving deeper, here's a snapshot of where these concepts fit across common exercise categories. Whether you're building a cardio base or adding resistance work, knowing which terms apply to which context matters.
| Primary energy system (short bursts) | Anaerobic (phosphocreatine & glycolytic) (ACSM Guidelines for Exercise Testing and Prescription) |
| Primary energy system (sustained cardio) | Aerobic (oxidative) (ACSM Guidelines for Exercise Testing and Prescription) |
| Standard RPE scale range | 6–20 (Borg) or 1–10 (modified) (Gunnar Borg, original scale developed 1970) |
| Common hypertrophy rep range | 6–12 reps per set (National Strength and Conditioning Association) |
| Recommended weekly moderate cardio (general adults) | 150–300 minutes (U.S. Department of Health and Human Services Physical Activity Guidelines, 2018) |
| MET value for brisk walking (~3.5 mph) | Approximately 3.5 METs (Ainsworth et al., Compendium of Physical Activities) |
Understanding how cardio and strength training differ — and what each actually does for your physiology — is a natural next step. Our explainer on cardio vs. strength training walks through those distinctions in detail.
If you want to see how high-intensity methods apply these principles in practice, the HIIT explainer is a useful companion. And because fitness needs shift considerably across a lifetime, fitness across life stages provides helpful context on how goals and recovery change over time.
These Terms Are Tools, Not Targets
Understanding concepts like VO2 max or 1RM is useful context, but don't let unfamiliar metrics create pressure. Fitness progress looks different for every person depending on age, health history, and goals. A certified personal trainer or exercise physiologist can help you apply these concepts safely to your individual situation — especially if you're managing a health condition or returning to activity after a break.
This article is for general informational and educational purposes only and does not constitute medical or fitness advice. Consult a qualified healthcare professional or certified fitness professional before beginning or significantly changing any exercise program, particularly if you have existing health conditions.