Fitness Glossary
Every fitness term you need to know, with clear definitions and links to calculators and guides. Bookmark this page as your quick reference.
TDEE (Total Daily Energy Expenditure)
The total number of calories your body burns in a 24-hour period, including your basal metabolic rate, physical activity, and the thermic effect of food.
TDEE is the foundation of any nutrition plan. Eat below it to lose fat, at it to maintain, or above it to build muscle.
Calculate your TDEE →BMR (Basal Metabolic Rate)
The number of calories your body needs at complete rest to maintain basic life functions like breathing, circulation, and cell repair.
BMR is the largest component of TDEE (60-75%). It's determined mainly by lean body mass, age, and sex.
Calculate your BMR →Macronutrients (Macros)
The three categories of nutrients that provide calories: protein (4 cal/g), carbohydrates (4 cal/g), and fat (9 cal/g).
Tracking macros instead of just calories gives you control over body composition, not just weight, but the ratio of muscle to fat.
Calculate your macros →Muscle Protein Synthesis (MPS)
The biological process of building new muscle protein to repair and grow muscle tissue after exercise or adequate protein intake.
MPS is stimulated by resistance training and protein consumption. Optimizing both is the key to muscle growth.
Calculate your protein needs →Caloric Deficit
The state of consuming fewer calories than your body burns, forcing it to use stored energy (primarily body fat) to make up the difference.
A sustained caloric deficit is the only way to lose body fat. The size of the deficit determines the rate of fat loss.
Plan your deficit →Caloric Surplus
The state of consuming more calories than your body burns, providing excess energy for tissue growth.
A moderate surplus (200-500 cal/day) combined with resistance training maximizes muscle growth while minimizing fat gain.
Calculate your surplus →Progressive Overload
The principle of gradually increasing the demands placed on the body during training through more weight, reps, sets, or reduced rest.
Progressive overload is the single most important principle for continued muscle and strength gains. Without it, adaptation stalls.
Read the full guide →One-Rep Max (1RM)
The maximum amount of weight you can lift for a single repetition with proper form on a given exercise.
1RM is used to calculate training percentages. Most programs prescribe loads as a percentage of 1RM (e.g., 'squat at 75% 1RM').
Calculate your 1RM →Hypertrophy
The increase in muscle cell size resulting from resistance training and adequate nutrition. Distinct from strength, which is a neural adaptation.
Hypertrophy training typically uses moderate loads (65-85% 1RM) for 6-12 reps with 60-90 second rest periods.
Periodization
The systematic planning of training into distinct phases (blocks) that vary in volume, intensity, and exercise selection over time.
Periodization prevents plateaus, manages fatigue, and ensures long-term progression. Common models include linear, undulating, and block periodization.
Understand periodization →RPE (Rate of Perceived Exertion)
A subjective 1-10 scale measuring how hard a set felt, where 10 is absolute failure and 7 means you had about 3 reps left in reserve.
RPE autoregulates training intensity based on daily readiness. It accounts for sleep, stress, and nutrition without rigid percentage prescriptions.
AMRAP (As Many Reps As Possible)
A set performed to technical failure. You do as many quality reps as you can before form breaks down.
AMRAP sets are used to test progress, build mental toughness, and accumulate volume at the end of a training session.
Compound Movement
An exercise that works multiple joints and muscle groups simultaneously, like squats, deadlifts, bench press, rows, and overhead press.
Compound movements recruit more muscle mass per exercise, making them the most time-efficient way to build strength and size.
Isolation Exercise
An exercise that targets a single joint and primarily one muscle group, like bicep curls, lateral raises, or leg extensions.
Isolation exercises are used to address weak points, add volume to specific muscles, and create balanced aesthetics.
Metabolic Adaptation
The body's response to prolonged caloric restriction: reduced energy expenditure through lower NEAT, reduced TEF, and hormonal changes.
Metabolic adaptation is why weight loss plateaus occur. It's managed through diet breaks, refeeds, and reverse dieting.
Body Recomposition (Recomp)
The process of simultaneously losing body fat and gaining muscle mass, typically achieved at or slightly below maintenance calories.
Recomposition is most effective for beginners, overweight individuals, and those returning after a training break. Advanced lifters may need dedicated bulk/cut cycles.
Read the recomp guide →Lean Bulk
A controlled caloric surplus (200-300 cal/day above TDEE) combined with progressive resistance training to maximize muscle gain while minimizing fat gain.
A lean bulk is more sustainable and requires less aggressive cutting afterward compared to a traditional 'dirty' bulk.
Cut (Cutting Phase)
A period of intentional caloric deficit aimed at reducing body fat while preserving as much muscle mass as possible through high protein and continued training.
Cutting reveals muscle definition built during a bulk. Typical cuts last 8-16 weeks with a 500 cal/day deficit.
Plan your cut →Maintenance Calories
The number of calories at which your body weight stays stable over time, essentially your TDEE.
Knowing your maintenance level is the reference point for both cutting (subtract 500) and bulking (add 200-500).
Find your maintenance →NEAT (Non-Exercise Activity Thermogenesis)
All calories burned through daily movement that isn't formal exercise: fidgeting, walking, standing, cooking, cleaning.
NEAT accounts for 15-30% of total daily energy expenditure and is the most variable component. It drops significantly during a caloric deficit.
TEF (Thermic Effect of Food)
The energy required to digest, absorb, and process nutrients. Protein has the highest TEF (~20-30%), followed by carbs (~5-10%) and fat (~0-3%).
TEF is one reason high-protein diets are effective for fat loss. You burn more calories just processing the food.
Deload
A planned reduction in training volume and/or intensity (typically 40-60% reduction) lasting 1 week, designed to allow recovery and adaptation.
Deloads prevent overtraining, reduce injury risk, and often lead to a 'supercompensation' effect where you come back stronger.
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.
Volume is the primary driver of hypertrophy. Most research suggests 10-20 hard sets per muscle group per week for optimal growth.
Time Under Tension (TUT)
The total duration a muscle is under load during a set, including the concentric (lifting) and eccentric (lowering) phases.
Longer TUT (especially the eccentric phase) can increase metabolic stress and mechanical tension, both drivers of hypertrophy.
DOMS (Delayed Onset Muscle Soreness)
Muscle pain and stiffness that appears 24-72 hours after unaccustomed or intense exercise, caused by microscopic muscle fiber damage.
DOMS is NOT an indicator of workout quality. It decreases as your body adapts. Don't chase soreness. Chase progressive overload.
Supercompensation
The body's tendency to rebuild itself slightly stronger and more resilient than before, if adequate recovery (sleep, nutrition) follows a training stimulus.
The entire basis of progressive training. Train → recover → adapt → train harder. Without recovery, you get regression, not supercompensation.
Read about recovery →MPS (Muscle Protein Synthesis)
The biological process by which the body repairs and builds new muscle protein. Elevated for 24-48 hours after resistance training.
MPS is maximized by consuming 20-40g of protein within a few hours of training, with total daily protein being the most important factor.
Calculate your protein needs →Ready for a Full Personalized Plan?
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