Fitness Glossary
Decipher fitness jargon and understand the science behind your training.
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1RM (One-Rep Max)
The maximum amount of weight you can lift for a single, proper repetition. It is the standard anchor for defining "Intensity." For example, 80% of 1RM is a common hypertrophy load. We use the "1RM Continuum" to predict how many reps you will lose when you add weight.
C
Compound Exercise
An exercise that involves movement at multiple joints and engages two or more muscle groups simultaneously. Examples include Squats (hips and knees moving; quads and glutes working) and Bench Press (shoulders and elbows moving; chest and triceps working). These are the most efficient movements for building overall strength and muscle mass.
D
Double Progression
A progression model where you manipulate two variables: first volume (reps), then intensity (weight). You visualize it as a step function: keep weight static and add reps until you hit the top of your range (e.g., 12 reps). Once hit, you increase the weight and drop the reps back down (e.g., to 8).
F
Fat Loss
Fat loss is a goal of reducing body fat percentage. It differs from general weight loss in that the aim is to lose primarily fat while keeping as much lean muscle as possible. Achieving fat loss requires burning more calories than you consume (creating a calorie deficit) through a combination of diet and exercise. Workouts for fat loss often incorporate cardio and circuit-style training to increase calorie burn, but also include strength training to preserve muscle. In essence, fat loss means lowering your body fat while maintaining muscle mass, resulting in a leaner physique.
G
General Fitness
This refers to a broad, balanced fitness goal without a specialized focus on any single attribute. A general fitness program seeks to improve a bit of everything – strength, cardiovascular endurance, flexibility, and body composition – for overall health and functional ability. It's great for those who want to be fit and healthy but are not targeting extreme muscle gain or specific performance metrics. The training routine for general fitness mixes cardio and strength moderately. In other words, "General Fitness" involves a balanced routine for strength, endurance, and overall health.
H
Hypertrophy
In fitness, hypertrophy refers to an increase in muscle size. Training for hypertrophy means using strategies that make muscles grow in cross-sectional area. For example, bodybuilding-style workouts aim to stimulate muscular hypertrophy through higher volume (more sets and reps) and moderate weights. In short: Hypertrophy = muscle growth. It is "an increase in muscular size achieved through exercise".
J
Junk Volume
Training volume (sets/reps) that is too easy or too fatiguing to result in adaptation. Doing 30 reps with a weight you could lift 50 times is junk volume—it builds endurance, not size. Effective training minimizes junk volume by ensuring every set is close enough to failure to be stimulating.
M
Mechanical Tension
The primary driver of muscle growth (hypertrophy). Tension is the physical stress detected by mechanoreceptors in your muscle fibers. It is maximized by lifting heavy loads or taking lighter loads close to failure. Effective reps are those performed under high mechanical tension.
Metabolic Stress
Often felt as "the burn," this is the accumulation of metabolites like lactate and hydrogen ions during high-rep training. While secondary to mechanical tension, it plays a role in signaling growth and cell swelling ("the pump"). It is often associated with shorter rest periods and higher volumes.
P
Progressive Overload
The foundational principle of training: for a biological system (your muscles) to adapt, it must be subjected to a stressor that exceeds its current capacity. This doesn't just mean "add weight." It can be adding reps, improving technique, or increasing density. Without progressive overload, the body has no reason to change.
R
RPE / RIR
Tools for "Autoregulation." RPE (Rate of Perceived Exertion) scales how hard a set felt (1-10). RIR (Reps In Reserve) asks "how many more reps could I have done?" RPE 10 = 0 RIR (Failure). RPE 8 = 2 RIR. For hypertrophy, most sets should be between RPE 7 and 10.
S
Strength
Muscular strength is the ability to exert force – basically, how much weight you can lift or how powerfully you can perform an effort. Strength-focused training involves lifting heavy weights for low repetitions to improve the maximum force your muscles can generate. Compound movements (engaging multiple muscles, like squats or bench presses) are staples of strength programs. Our planner might label a strength-focused routine as "Shift Heavy," meaning the goal is to "increase strength and lifting capacity" rather than muscle size or endurance.