Fitness Terms

A reference guide to the key terms and concepts you need to understand how your body responds to exercise — from structuring workouts and measuring intensity to tracking progress and optimizing recovery. Whether you're new to the gym or fine-tuning an advanced training program, these definitions will help you train smarter.

• Basal Metabolic Rate (BMR) Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest just to maintain basic physiological functions — representing the largest component of your total daily energy expenditure.
• Bench Press The bench press is a foundational upper-body strength exercise where you lie on a bench and press a barbell or dumbbells upward from chest level — the primary movement for building chest strength and size, also training the shoulders and triceps.
• Body Fat Percentage Body fat percentage is the proportion of your total body weight that consists of fat mass — as opposed to lean mass (muscle, bone, water, organs) — and is considered a more useful health and fitness metric than weight or BMI alone.
• Body Mass Index Body Mass Index (BMI) is a numerical value calculated from a person's height and weight, used as a screening tool to categorize weight status — but it has well-documented limitations as a measure of individual health or body composition.
• Caloric Deficit A caloric deficit occurs when you consume fewer calories than your body burns in a day, creating the energy shortfall required for fat loss over time.
• Cardio Cardio (cardiovascular exercise) is any physical activity that raises your heart rate and keeps it elevated for a sustained period — improving heart and lung health, burning calories, and building aerobic endurance through activities like running, cycling, and swimming.
• Circuit Training Circuit training is a workout format where a sequence of exercises is performed back-to-back with minimal rest, combining strength and cardiovascular conditioning in a single session that keeps heart rate elevated throughout.
• Deadlift The deadlift is a fundamental weightlifting exercise where you lift a loaded barbell from the floor to a standing position — one of the most effective compound movements for building total-body strength, targeting the hamstrings, glutes, back, and core.
• DOMS DOMS (Delayed Onset Muscle Soreness) is the muscle pain and stiffness that typically develops 12–48 hours after unfamiliar or intense exercise, caused by microscopic damage to muscle fibers during eccentric contractions.
• Drop Set A drop set is a training technique in which you perform a set to or near failure, then immediately reduce the weight by 20–30% and continue repping without rest, extending a set beyond what you could achieve at the original load.
• Foam Rolling Foam rolling is a self-myofascial release technique that uses a foam cylinder to apply pressure to muscles and fascia, helping reduce muscle soreness, improve mobility, and aid recovery between training sessions.
• HIIT HIIT (High-Intensity Interval Training) is a workout format that alternates short bursts of near-maximal effort with brief recovery periods, producing significant cardiovascular and metabolic gains in less time than traditional steady-state cardio.
• Intermittent Fasting Intermittent fasting is an eating pattern that cycles between defined periods of eating and fasting — not a specific diet, but a scheduling framework that many people use to support fat loss, metabolic health, and simplicity.
• Isolation Exercise An isolation exercise targets a single muscle group by moving through only one joint, allowing focused attention on a specific muscle for development, rehabilitation, or correcting imbalances.
• Active Recovery Active recovery is low-intensity exercise performed on rest days or between training sessions to promote blood flow, reduce muscle soreness, and speed up recuperation without taxing the body further.
• Compound Exercise A compound exercise is any movement that recruits multiple muscle groups and works across more than one joint simultaneously, making it the most efficient and effective category of exercise for building strength and muscle.
• Creatine Creatine is one of the most researched and effective sports supplements — a naturally occurring compound that helps your muscles produce energy during high-intensity exercise, leading to gains in strength, power, and muscle mass.
• Deload A deload is a planned period of reduced training volume and/or intensity — typically one week — allowing the body to recover from accumulated fatigue, repair tissue, consolidate strength gains, and return to training fresher and stronger.
• Fat-Burning Heart Rate The fat-burning heart rate zone is a moderate-intensity exercise range — typically 60–70% of your maximum heart rate — where your body relies more heavily on fat as a fuel source compared to carbohydrates, though total calorie burn is lower than at higher intensities.
• Flexibility Training Flexibility training is a form of exercise focused on improving the range of motion (ROM) of joints and muscles through stretching techniques — including static, dynamic, and PNF stretching — to enhance mobility, reduce injury risk, and improve movement quality.
• Heart Rate Zones Heart rate zones are defined ranges of exercise intensity — expressed as a percentage of maximum heart rate — that correspond to different physiological effects, from active recovery and fat burning to anaerobic threshold and maximum effort.
• Macros Macros — short for macronutrients — are the three main categories of nutrients that provide energy: protein, carbohydrates, and fat. Tracking macros allows you to manage not just how much you eat but what you eat to support specific fitness goals.
• Muscle Hypertrophy Muscle hypertrophy is the process of muscle growth — the increase in the size of muscle fibers in response to resistance training — and is the primary physiological mechanism behind getting bigger and stronger through exercise.
• One-Rep Max A one-rep max (1RM) is the maximum amount of weight a person can lift for a single complete repetition of a given exercise, and serves as the benchmark for measuring absolute strength and programming training loads.
• Pre-Workout Supplement A pre-workout is a dietary supplement — typically a powder mixed with water — taken before exercise to enhance energy, focus, endurance, and performance, usually containing stimulants like caffeine, nitric oxide precursors, and performance compounds.
• Progressive Overload Progressive overload is the foundational training principle that muscles must be consistently challenged with increasing demands — through more weight, reps, sets, or reduced rest — in order to grow stronger and larger over time.
• Protein Intake Protein intake refers to the amount of dietary protein consumed daily — a critical variable for muscle building, fat loss, and overall health, with recommendations varying significantly based on your goals and activity level.
• Reps and Sets Reps (repetitions) are the number of times you perform a movement in one continuous effort; sets are groups of reps. Together, reps and sets form the basic unit of volume in any strength or resistance training program.
• Rest Day A rest day is a scheduled day away from structured exercise that allows the body to repair muscle tissue, replenish energy stores, and recover neurologically — making rest an active part of any effective training program, not a sign of laziness.
• Squat The squat is a foundational compound lower-body exercise that targets the quadriceps, hamstrings, glutes, and core — widely considered one of the most effective movements in any strength or fitness program.
• Strength Training Strength training is a form of exercise that uses resistance — free weights, machines, bodyweight, or bands — to make muscles work against load, building muscular strength, size, endurance, and function over time.
• Superset A superset is a training technique where two exercises are performed back-to-back with no rest in between, increasing workout density, saving time, and often maximizing the stimulus on the targeted muscles.
• Tabata Tabata is a specific high-intensity interval training protocol consisting of 8 rounds of 20 seconds of maximal effort followed by 10 seconds of rest, totaling 4 minutes, originally shown to improve both aerobic and anaerobic capacity simultaneously.
• Tempo Training Tempo training is a resistance training technique that involves controlling the speed (tempo) of each phase of a lift — typically using a four-number code for eccentric, pause, concentric, and pause phases — to increase time under tension and maximize muscle growth.
• VO2 Max VO2 max is the maximum rate at which your body can consume oxygen during intense exercise, and is widely regarded as the gold standard measure of cardiovascular fitness and aerobic capacity.