Fitness glossary

Plain-English definitions of gym and nutrition terms: 1RM, RPE, progressive overload, TDEE, macros, DOMS, deload, hypertrophy and more. From SweatByte.

Basal metabolic rate (BMR): BMR is the number of calories your body needs at complete rest to keep basic functions like breathing and circulation going.
Body mass index (BMI): BMI is a number calculated from your weight and height that is used as a rough screening guide for weight category.
Body recomposition: Body recomposition is the process of losing fat and building muscle at roughly the same time.
Bulking: Bulking is a phase of eating in a calorie surplus and training hard with the goal of gaining muscle size.
Calorie deficit: A calorie deficit means eating fewer calories than your body burns, which is how body weight generally goes down.
Calorie surplus: A calorie surplus means eating more calories than your body burns, which provides extra energy for weight gain and muscle growth.
Compound exercise: A compound exercise is a movement that works several joints and muscle groups at the same time, like a squat or a deadlift.
Cool-down: A cool-down is a few minutes of light movement and gentle stretching after training to help your body settle back to normal.
Creatine: Creatine is a naturally occurring compound in the body, also sold as a supplement, that helps muscles produce quick energy for short, hard efforts.
Cutting: Cutting is a phase of eating in a calorie deficit while still lifting weights, with the goal of losing fat and keeping muscle.
Delayed onset muscle soreness (DOMS): DOMS is the muscle ache and stiffness that shows up a day or two after a new or hard workout.
Deload: A deload is a planned lighter week of training that lets your body recover before you push hard again.
Drop set: A drop set is a set taken close to fatigue, after which you lower the weight and keep going without resting.
High-intensity interval training (HIIT): HIIT is a style of cardio that alternates short, hard bursts of effort with easier recovery periods.
Hypertrophy: Hypertrophy is the increase in the size of your muscle fibres, which is what we usually mean by building muscle.
Isolation exercise: An isolation exercise focuses on one joint and mainly one muscle, like a biceps curl or a leg extension.
Lean body mass: Lean body mass is everything in your body that is not fat, including muscle, bones, organs and water.
Low-intensity steady-state cardio (LISS): LISS is cardio done at a gentle, steady pace for a longer time, like brisk walking or easy cycling.
Macros (macronutrients): Macros are the three main nutrients your body needs in large amounts: protein, carbohydrates and fat.
Mind-muscle connection: Mind-muscle connection is the skill of focusing on the muscle you are training so you can feel it working during each rep.
Muscle protein synthesis: Muscle protein synthesis is the body's process of building new muscle proteins to repair and grow muscle tissue.
One-rep max (1RM): One-rep max is the heaviest weight you can lift for a single clean repetition of an exercise with good form.
Plateau: A plateau is a period when your progress stalls and your weights, reps or body measurements stop improving.
Progressive overload: Progressive overload is gradually making your training harder over time so your body keeps adapting and getting stronger.
Range of motion: Range of motion is how far a joint and muscle can move through an exercise, from start to finish.
Rate of perceived exertion (RPE): RPE is a 1 to 10 scale you use to rate how hard a set or workout felt, where 10 means you could not do another rep.
Reps and sets: A rep is one complete movement of an exercise, and a set is a group of reps done in a row before you rest.
Reps in reserve (RIR): Reps in reserve is the number of good-form reps you could still have done when you ended a set.
Rest interval: A rest interval is the time you wait between sets before starting the next one.
Split routine: A split routine divides your training across the week so that different muscle groups are worked on different days.
Superset: A superset is two exercises performed back to back with little or no rest between them.
Tempo: Tempo is the speed at which you perform each part of a rep, such as lowering, pausing and lifting.
Time under tension: Time under tension is how long a muscle stays working during a set, from the first rep to the last.
Total daily energy expenditure (TDEE): TDEE is the total number of calories your body burns in a whole day, including rest, daily movement, workouts and digesting food.
Training to failure: Training to failure means continuing a set until you cannot complete another rep with good form.
Warm-up: A warm-up is a short, easy block of movement before training that raises your heart rate and prepares your muscles and joints.