Fitness Glossary


Abduction – A muscle action that refers to movement that is going away from the midline of the body. The outer thighs are often referred to as the abductors.

Abductors – The muscles on the hip used to pull the legs apart and away from each other.

Active flexibility – A form of flexibility in which a position is held without any assistance. This usually involves contracting one muscle group to help “stretch” the opposing muscle group.

Adaptation – A physiological improvement in response to stress from an exercise or activity. For more, see SAID principle.

Aerobic – Metabolic system in the body that relies principally on oxygen to metabolize fats and sugar, both stored (liver and muscles) and free (in the bloodstream), to produce energy. This is mostly used during endurance events and longer duration exercise, such as running, cycling, or classes with “cardio” in the name.

Agility – The ability to change the body’s position quickly.

Agonist – Also known as the prime mover, this refers to the muscle that causes motion.

Anaerobic – The metabolic system that produces energy principally without oxygen. Involved mostly in shorter high intensity efforts. Examples of anaerobic activities would include heavy weight training, sprinting, or jumping.

Anaerobic threshold – See Lactate threshold.

Antagonist – Refers to the muscle working to move the joint opposite of the agonist.

Atrophy – A loss of muscle tissue as a result of inactivity, trauma, or injury.


Basal metabolic rate (BMR) – The amount of calories you burn without the addition of physical activity.

Body mass index (BMI) – A calculation using height and weight to determine a rating of underweight, normal, overweight, or obese.

Bodybuilding – A sport that uses weight training and diet to focus on hypertrophy of the muscles.

Boot camp – A circuit-style class using mostly bodyweight movements that has a militant theme and tone.

BOSU ball – A piece of equipment using half of a stability ball and a platform, designed so both sides can be used as an unstable surface for training.

Built – Someone who maintains a well-balanced muscular figure.


Calisthenics – Various movements that involve using your own bodyweight as resistance. Some examples include: jumping jacks, push-ups, or arm circles.

Cardiovascular training – Focuses on improving how the heart and lungs function. This type of training focuses on muscular endurance and can be also be classified as aerobic training.

Circuit training – This style of training involves performing a series of movements in a particular order for a specific amount of time. The “circuit” can vary in number of exercises, length of time you do the exercise, and time you rest. The goal is to burn additional calories and to produce a conditioning effect.

Concentric contraction – The muscle contraction in which the muscle shortens in response to an external load or resistance.

Cool-down – The time period immediately after your workout, used to transition the body back to its pre-workout state.

Core – A buzzword in the fitness world, this refers to the muscles that are located around and support our spine. When doing core work, you directly involve the hip, lower back, and/or abdominal muscles.

Cross-training – Selecting alternate exercises or activities to compliment a specific goal or sport. This training philosophy was developed with the idea of balancing out movement patterns to improve overall results or performance.

Cut – Having a well-defined muscular physique with low body fat. Also used to describe the quality of definition a particular muscle may have.


Delayed onset muscle soreness (DOMS) – When a change or increase in physical activity or exercise occurs there is often a temporary muscular ache or discomfort that follows. Usually felt within 24 to 48 hours, DOMS will decrease with adaptation and varies by individual.

Diesel – Refers to someone who is very strong.

Diet – The total amount and type of calories you consume each day.

Drop sets – Performing additional sets at a lower weight once you have reached fatigue with the previous higher weight.

Duration – How long you perform a movement or activity.

Dynamic flexibility – Moving the joint through range of motion at varying speeds.


Eccentric contraction – The muscle contraction that refers to a lengthening, or often lowering, in response to an external load or resistance.

Endurance – The extent of one’s ability to maintain a level of performance for an extended amount of time without fatigue.

Exercise variables – These are used as measurements to track and manipulate your exercise program based on your individual goals. Primary exercise variables are: frequency, intensity, and duration.

Extension – A movement where the angle of the joint increases.


Fascia – Fibrous tissue that connects and supports muscles and tendons.

Fast twitch muscle fibers – Due to their fast contraction rate and low resistance to fatigue, these fibers are useful in anaerobic activities like sprinting or exercise that are high in intensity and short in duration. These fast twitch fibers are further divided into Type IIa, with slighter higher resistance to fatigue and fast contraction, and Type IIb, used for maximal contractions.

Flexibility – Every joint in the body has a particular range of motion. The amount of movement is measured in degrees and can vary from person to person depending on genetics, activity, and lifestyle.

Flexion – A movement where the angle of the joint decreases.

Force – Literally, force equals mass times acceleration. The amount of force that is produced is determined by muscle fiber type, length, and tension. In order to increase the amount of force generated, you either need to increase the amount of weight or lift the same weight at a faster speed.

Forced reps – Reps that are performed after the weightlifter has reached the point of fatigue. These reps are performed with the assistance of a spotter or lifting partner.

Free weights – Any weight that isn’t a machine or attached to a cable or chain. The most common examples of free weights are barbells, dumbbells, and weight plates.

Functional training – Also known as integrated training, “functional” exercises incorporate movements that will enhance your ability to perform daily activities. The focus of this style of training is typically moving and feeling better, rather than emphasizing muscular gains.


General physical preparedness (GPP) – The concept of training GPP is to establish a foundation of fitness. GPP, also used in the context of periodization, refers specifically to the development of speed, strength, flexibility, mobility, and skill.

Glisten – An alternative to sweating, this describes the moist glow that occurs during or after a workout.

Glucose – Carbohydrates are converted into glucose during the process of digestion.

Glycogen – A form of stored energy made from glucose found in the liver and muscles.

Goal – The desired result of your training.

Guns – Used to describe the biceps, often used in the context of “having tickets to the gun show.”

Gym rat – A person who spends many hours at the gym, both working out and socializing. This person often knows the entire staff and a large percentage of the membership base.


Hammies – Also known as hamstrings, these are the muscles located on the rear of the upper leg.

Hip dominant – Refers to a category of exercises or the movement pattern where the muscles involved in hip extension are the prime movers.

Hypertrophy – An increase in the cross-sectional size of a muscle cell, which also translates into an increase in strength.


Intensity – A measure of how hard you are working during exercise. Some examples of how this can be measured include using a percentage of VO₂ Max, One Rep Max, heart rate, or RPE (Rate of Perceived Exertion).

Interval training – Alternates periods of high intensity with low intensity work or rest. This style has been found more effective for fat loss than maintaining a steady state of intensity.

Isometric contraction – During this muscle contraction there is no length change or movement in the muscle because the force applied matches the load.


Jacked – Someone who has very large muscles.

Jiggly – An area of the body that, regardless of exercise selection, seems to jiggle instead of having a tight and toned appearance.

Joint – A connection of two or more bones.


Kettlebell – A weight where the handle is connected above the center, allowing for movements that a traditional dumbbell does not allow.

Kinesiology – The study of muscles and movement.


Lactate threshold – The point at which more lactic acid is produced than the body is able to process. At this point, lactic acid begins to build up in the bloodstream. Lactate threshold is an important measure for endurance sports and can be greatly increased with training.

Lactic acid – A by-product of anaerobic exercise, believed to contribute to the fatigue of working muscles. In actuality, lactic acid quickly breaks down into lactate, which can to some degree, be re-used as fuel by muscles that continue to work, and a positively-charged hydrogen ion, which contributes to the acidity of the blood.

Lean – Characterizes someone who has good muscle tone and low body fat, without having extremely large muscles.

Lean tissue – Any tissue that is not made of fat, including muscle and its surrounding connective tissue, bone, and organs.

Ligament – A fibrous tissue that connects a bone to another bone.


Macrocycle – Looks at the “big picture,” identifies the length of the entire training period, and includes three types of phases: preparation, competition, and transition. Traditionally used in the context of sports, this refers to a training year but can be defined in months or years. The three phases will be broken down into mesocycles.

Medicine ball – A weighted ball used to add resistance to dynamic movements or as an alternate modality for some exercises. The size, material (vinyl, rubber, leather, or cloth), and weight (some measure in kilograms and some in pounds) will vary by company.

Mesocycle – These are phases of the training year that last two to six weeks. Each phase has a specific training goal and is broken down into weekly segments or microcycles.

Metabolism – This refers to all of the chemical reactions occurring in our bodies to perform the necessary functions to live and reproduce.

Microcycle – Weekly training plans that are designed according to the training goal of the mesocycle.

Mobility – Refers to an individual’s quality of movement. In addition to flexibility, many coaches and trainers focus on drills or warm-ups that feature mobility in order to produce a greater performance.

Modality – A term used to describe the specific tool you use to perform an exercise. The type of modality used can reflect preference, modification, progression, or a desired training result. For example, a squat can be performed using dumbbells, a medicine ball, or standing on a BOSU ball, to name a few.


Nutrient – Related to metabolism, this refers to various chemicals that we must consume in order to live and grow.


Olympic weightlifting – A sport controlled by the International Weightlifting Federation that focuses on the ability to perform competition lifts at a maximal weight. Competition lifts include the snatch and the clean and jerk. These specific lifts and their preparatory lifts are often used by athletes to develop maximal force production.

Osteoporosis – A condition where the bone mineral density is reduced, contributing to a higher risk of fracture and deformities.

Overload principle – Describes the importance of increasing the stress to the muscle in order to see increases in either muscular strength or endurance.

Overtraining – A general label used to describe physical or mental effects that occur due to a lack of proper rest or recovery. Typical symptoms include but are not limited to: increased fatigue, decreased performance, soreness, and irritability.


Performance – In terms of exercise, this refers to your quality of movement. In terms of sports, this refers to your quality of play in your sport.

Periodization – A method of organizing your training using periods of time or “cycles” to focus on specific adaptations and goals. This systematic approach begins with the macrocycle, and is further divided into mesocycles, which are made up of microcycles.

Pilates – Named for its founder Joseph Pilates, it is a form of exercise whose principles focus on the strengthening of the core. Using floor exercises and apparatuses, the practitioner learns to strengthen from the core outwards to obtain maximum fitness with a minimal risk of injury. For more information on different types and benefits, see

Plyometrics – These exercises are used to generate maximal force in a short amount of time. The nature of these movements involves a slight lengthening of the muscle just prior to contraction which generates additional force. For more, see stretch shortening cycle.

Power – The ability to generate maximal force quickly.

Power lifting – A sport, contrary to the name, that focuses on limit strength as opposed to power. During a competition, each athlete is allowed three to four attempts to perform one maximum rep in any of the following events: bench press, squat, and/or deadlift.

PR – An acronym for “personal record.”

Prime mover – See agonist.


Quad dominant – Refers to a category of exercises or the movement pattern in which the quadriceps and hip flexors are the prime movers.


Recovery – Necessary for increased performance, this refers to a window of time during which you allow the body to repair, rebuild, and restore.

Repetition – The number of times you perform a certain movement to complete a set. More commonly abbreviated to “rep,” the quantity represents the desired adaptation and determines the amount of rest you will require.

Resistance training – Used in a two different contexts: the concept of adding resistance to movement in order to build strength; or using elastic, air pressurized, or cable resistance within your training.

Rest – In terms of a workout, this refers to the amount of time in between sets. Rest periods vary and are required in order to perform the next set effectively. Overall performance during a workout or sport will also require proper rest. For more, see recovery.

RICE (rest, ice, compression, and elevation) – This acronym represents the best sequence to follow when a sports or exercise-related injury has occurred. The first step, rest, simply means to stop the activity and take time to recover. Ice, step two, should be applied as soon as possible to help reduce any swelling and provide some pain relief. Frequent icing is beneficial; alternate icing 15 to 20 minutes on and 20 to 30 minutes off. Compression, step three, helps to control swelling and is usually done with an elastic bandage. Step four, elevation, encourages you to try to keep the injured area above the heart when possible. If your symptoms have not improved within 48 hours of the injury, you should consider seeking a physician’s care.

Ripped – Similar to jacked, this describes someone who has large and well-defined muscles.

RPE (rate of perceived exertion) – A subjective way to measure exercise intensity using numbers on a scale representative of the effort level.


SAID principle – This training principle, an acronym for specific adaptation to imposed demands, reviews the importance of choosing certain exercises or activities that are appropriate for the desired result. All exercises and activities aren’t created equal, and deciding which to include in your program needs to be specific to your fitness level and goal. Simply put, in order to improve a certain skill, movement, or activity you have to practice and train that skill, movement, or activity.

Self myofascial release – A technique used to help performance by releasing any thickened or restricted fascia (often referred to as “knots”) that may be preventing proper mobility.

Semi-private training – A personal training session that involves one coach or trainer working with two to four clients scheduled at the same time. In this type of session, the clients are each working on their individual programs, but are doing so in a group. An increasingly popular option for trainers and clients, this allows flexibility in scheduling and reduced fees as compared to traditional personal training.

Skinny-fat – A person who, although slender, has little or no muscle tone and will display a flabby appearance. This is characterized by a higher percentage of body fat than one would expect for their size.

Slow twitch muscle fibers – These highly oxidative fibers are useful for endurance activities or exercise that is low to moderate in intensity and longer in duration. Also known as type I muscle fibers, their high resistance to fatigue and slow contraction rate help to sustain aerobic activity.

Small group training – A group training session taught by a personal trainer, in which the participants of the class are working toward a common goal. This type of format should follow a specific program and also may be offered as part of a series so participants will adapt and progress.

Specificity – In training, the concept that physiological gains are directly related to the specific skills, movements, or activities performed. For more see SAID principle.

Spinning – A group indoor cycling class using changes in resistance and cadence in efforts to simulate an outdoor ride. The concept was introduced in the 1980s and was later trademarked by Mad Dogg Athletics, Inc.

Spot – A person or persons used to supervise a lift or exercise to make sure it can be performed safely.

Sprain – An injury affecting ligaments that occurs usually in response to a fall or outside force that compromises a joint’s normal alignment.

Static stretch – A stretch that is held for a specified amount of time in order to increase flexibility.

Strain – An injury to a muscle or tendon as a result of overstretching or an over-contraction.

Strength – A measure of the amount of force a muscle can generate when contracting against resistance.

Stretch shortening cycle – When a muscle is lengthened it has the ability to generate more force. This cycle is characterized by maximizing the elastic component of a muscle fiber by lengthening just prior to contraction.

Super set – When two exercises, usually of opposing muscle groups, are performed one after the other. This will be expressed in a training program with an “a” or “b” label next to the number linking the two movements together.


Target heart rate zone – An exercise heart rate range calculated based on a percentage of the maximum heart rate reserve.

Tendon – A fibrous tissue that connects muscle to bone.

Time under tension – A training concept, introduced by Charles Poliquin, designed to stimulate muscle growth by tracking the amount of time a muscle is worked during each set. Poliquin’s system manipulates the tempo of the movement to achieve the recommended 30 to 70 second range.

Toned – Having good muscle definition without increased size or girth.

Tri set – When three exercises are performed one after the other. If a training program includes a tri set, it will be represented by an “a,” “b,” and “c” next to the number.

Type I muscle fiber – See slow twitch muscle fiber.

Type II muscle fiber – See fast twitch muscle fiber.


Under-pronation – See supination.

Universal machine – An exercise machine that can be used for a wide variety of different exercises to target different muscle groups; it utilizes tracks or rails and levers or pulleys to form a kind of “all-in-one” piece of exercise equipment.


VO2 max – An athlete’s maximum aerobic capacity, defined by the maximum amount of oxygen that can be utilized by the body. Though V02 max can be increased with training, it does have an upper genetic limit. It’s expressed as an absolute in liters, or relative to body mass (in kilograms) as milliliters per kilogram. For example, an athlete who weighs 77 kilograms could have an absolute V02 max of 5.1 liters and a relative V02 max of 66.23 ml/kg.

Volume – The total amount of “work” that is done within a workout or phase (see periodization). The total volume of a workout reflects the number of reps multiplied by the number of sets. This variable should be consistent with the training goal and is often manipulated to obtain a specific training response.


Waist to hip ratio – Used as a measure of health and/or risk of developing health problems such as cardiovascular disease. It is found by dividing your waist circumference measurement by your hip circumference measurement, a healthy score would be 0.8 or less for women and 0.95 or less for men.

Warm-up – The period of time devoted to preparing the body for a workout, sport, or activity.

Weight training – A way of building strength using weights as resistance. Similar to resistance training, the concept of adding weight or resistance help to build strength, but this can also refer specifically to the use of free weights or weight machines.


Yoga – Literally, “union.” A 5,000-year-old system of mental and physical practices originating in India, which includes philosophy, meditation, breath work, lifestyle and behavior principles, and physical exercise. Practicing yoga has numerous benefits for health and fitness, including but not limited to increased flexibility and decreased stress levels. For more information on different types and benefits, see

Yogilates – A class format combining principles of yoga and Pilates-mat practices to provide a balanced workout. The class often varies in length, intensity, and exercise selection so ask the instructor for more specific details.

Yoked – Someone who is very muscular and equally strong, particularly in the upper body and neck area.


Zumba – A popular dance workout characterized by easy-to-follow moves and high energy music. Alberto “Beto” Perez, dancer and choreographer, created this format by having to improvise one day when he had forgotten his music for aerobics class. He inserted some traditional Latin salsa and meringue and successfully showed the class that dance was a wonderful way to get a workout and have fun.

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