Fitness Glossary
Every fitness term explained, from A to Z.
Quick answer
Use the glossary for a fast definition, then follow related terms to understand the wider training concept. Each term page now includes a direct answer, practical context, related concepts, and structured question-and-answer data.
- 45 defined terms
- Plain-language explanations
- Related concept links
45 terms
B
BMI
Body Mass Index. A simple calculation using height and weight (kg/m²) that categorises people as underweight, normal, overweight, or obese. Useful as a population-level metric but doesn't account for muscle mass.
Body Fat Percentage
The proportion of your total body weight that is fat tissue. A more useful measure of body composition than BMI, as it distinguishes between fat and muscle mass.
Bulk
A phase of intentional calorie surplus aimed at maximising muscle growth. Typically involves eating 200-500 calories above TDEE with progressive resistance training.
C
Caloric Deficit
Consuming fewer calories than your body burns, resulting in weight/fat loss. Typically 300-500 calories below TDEE for sustainable fat loss.
Caloric Surplus
Consuming more calories than your body burns, necessary for muscle gain. Typically 200-400 calories above TDEE for lean bulking.
Cluster Sets
Breaking a set into mini-sets with short rest periods (15-30 seconds) between clusters. Allows more total reps at a given weight than traditional straight sets.
Compound Exercise
An exercise that works multiple muscle groups and joints simultaneously. Examples include squats, deadlifts, bench press, and rows. Compound movements are the foundation of effective training programmes.
Concentric Contraction
The lifting phase of an exercise where the muscle shortens under load. For example, pressing the bar up during bench press.
Cut
A phase of intentional calorie restriction aimed at losing body fat while preserving as much muscle as possible. Typically involves eating 300-500 calories below TDEE with high protein intake.
D
Deload
A planned reduction in training volume and/or intensity, typically lasting one week. Deloads allow your body to recover from accumulated fatigue and come back stronger.
DOMS (Delayed Onset Muscle Soreness)
Muscle soreness that peaks 24-72 hours after training, caused by eccentric muscle damage. Not an indicator of workout quality — it decreases as your body adapts.
Drop Set
A technique where you perform a set to failure, then immediately reduce the weight and continue for more reps. Repeated 2-3 times. Used to push muscles past their normal failure point.
E
Eccentric Contraction
The lowering phase of an exercise where the muscle lengthens under load. Responsible for more muscle damage and soreness than concentric.
EMOM
Every Minute On the Minute. A workout format where you perform a prescribed number of reps at the start of each minute, resting for the remainder. Excellent for pacing and conditioning.
I
Isolation Exercise
An exercise that targets a single muscle group by moving only one joint. Examples include bicep curls, leg extensions, and lateral raises. Used to bring up weak points.
Isometric Contraction
Holding a position under load without movement — the muscle contracts but doesn't change length. Examples: plank, wall sit, pause reps.
M
Macrocycle
The longest training cycle, covering an entire programme or season (typically 3-12 months). Made up of multiple mesocycles.
Macros
Short for macronutrients — protein, carbohydrates, and fat. The three main categories of nutrients your body needs in large amounts. Tracking macros means monitoring the grams of each you consume daily.
Maintenance Calories
The number of calories needed to maintain your current weight — equal to your TDEE. The baseline from which you create a deficit or surplus.
Mesocycle
A training block lasting 3-6 weeks with a specific focus (e.g., hypertrophy, strength, or peaking). Part of periodisation.
Microcycle
The shortest training cycle, typically one week. Contains the day-to-day workout plan within a mesocycle.
P
Periodisation
The systematic planning of training into distinct phases (mesocycles) with different focuses — e.g., hypertrophy, strength, peaking. Prevents plateaus and manages fatigue over time.
PR / PB
Personal Record (or Personal Best). The heaviest weight you've lifted or the best performance you've achieved for a given exercise or workout.
Progressive Overload
The gradual increase of stress placed on the body during training. This can mean adding weight, reps, sets, or reducing rest time. It's the fundamental principle behind getting stronger and building muscle.
Protein
A macronutrient essential for muscle repair and growth. Made up of amino acids. For active individuals, aim for 1.6-2.2g per kilogram of bodyweight per day. Found in meat, fish, eggs, dairy, and legumes.
R
Recomp
Short for body recomposition — the process of losing body fat and gaining muscle simultaneously. Most effective for beginners, returning lifters, and those eating at maintenance calories with high protein.
Rest-Pause Sets
An intensity technique where you perform a set to near-failure, rest 10-20 seconds, then continue for additional reps. Increases total volume in less time.
RIR
Reps in Reserve. The number of reps you could still perform before reaching failure. RPE 8 = 2 RIR.
RPE
Rate of Perceived Exertion. A subjective scale (typically 1-10) used to gauge workout intensity. RPE 7 means you could do 3 more reps, RPE 9 means 1 more rep, RPE 10 is absolute failure.
T
Tabata
A high-intensity interval protocol: 20 seconds of all-out effort followed by 10 seconds of rest, repeated 8 times (4 minutes total). Named after Japanese researcher Dr. Izumi Tabata.
TDEE
Total Daily Energy Expenditure. The total number of calories your body burns in a day, including basal metabolic rate, physical activity, and the thermic effect of food. The starting point for any nutrition plan.
Tempo Training
Controlling the speed of each rep phase, written as 4 numbers (e.g., 3-1-2-0 for 3s eccentric, 1s pause, 2s concentric, 0s top).
Time Under Tension (TUT)
The total time a muscle spends under load during a set. Manipulated through tempo training to increase hypertrophy stimulus.
Training Frequency
How often you train a muscle group per week. Most research suggests 2x per week per muscle group is optimal.
Training Intensity
How heavy you're lifting relative to your max, often expressed as a percentage of 1RM or using RPE/RIR.
Training to Failure
Performing reps until you physically cannot complete another with proper form.
Training Volume
The total amount of work performed, typically measured as sets x reps x weight, or simply hard sets per muscle group per week.
Using the fitness glossary
What is the PT Tracker fitness glossary?
It is an A-Z library of concise definitions for training, nutrition, CrossFit, strength, and programme-design terms, with links between related concepts.
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Read the plain-language definition first, then follow related terms and practical links to exercises, programmes, calculators, or guides.
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