Fitness Glossary

Definitions for Commonly Used Fitness Terms

Abdominal Muscles:  The muscles that form the supporting wall for the organs of the abdomen and pelvic regions.

Aerobics:  A variety of vigorous exercise routines and activities performed to music.

Body composition:  The relative amounts of the structural components of the body -- muscle, bone and fat.

Body Density:  A term used to describe the compactness of the body and is equal to the body weight divided by the body volume.

Cardiorespiratory Endurance:  The capacity of your heart, blood vessels and lungs to function efficiently during vigorous sustained activity such as running, swimming or cycling.


Cardiorespiratory Fitness:  This is the efficient functioning and health of the circulatory and respiratory systems.

Calisthenics:  Exercises in cadence for the purpose of muscular development.

Circuit Training:  This is a routine of selected exercises or activities performed in sequence at individual stations as rapidly as possible.

Concentric Contraction:  This is a contraction in which the muscle shortens and works against gravity.

Conditioning Period:  The main exercise portions of a workout at a heart-rate intensity that is between 60 and 80 percent of the difference between resting and maximal heart rates.

Continuous Training:  This is training that involves sustaining a constant tempo of exercise for 20 minutes or more. In beginning programs, bouts of lighter exercise such as brisk walking are generally alternated with short bouts of more vigorous exercise.

Cool Down:  The tapering-off period after completion of the main conditioning bout, including activities such as slow jogging, walking, and stretching the major muscle groups.

Distance Repeats:  Repeated bouts of alternate running and walking using specified distances as the determinant of workload.

Duration:  The time length of training sessions. For example, 30 minutes at an intensity of 70 percent heart-rate reserve is the recommended duration for developing and maintaining physical fitness.

Eccentric Contraction:  This is a contraction in which the muscle lengthens and works with gravity.

Explosiveness:  The muscle's ability to create strength as quickly and as forcefully as possible.

Extensors:  These are the muscles that increase the angle at a joint. For example, the quadriceps extend the knee (straighten it).

Fast Twitch Muscle Fiber:  This is a type of muscle fiber with fast contractile characteristics that has a low capacity to use oxygen. These fibers are the first to be used in short sudden bursts of activity.

Fat Free Weight:  Your bodies weight free of fat; often called lean body weight.

Fat Weight:  The absolute amount of body fat.

Field Tests:  Tests that take place outside the laboratory.

Flexibility:  The range of movements of a specific joint and of its corresponding muscle groups.

Flexors:  These are the muscles that decrease the angle at a joint. For example, the hamstrings flex the knee (bend it).

Frequency:  This is the number of workouts. Frequency should be adjusted to the intensity and duration of the workouts to reach a training effect.

Half Marathon:  This is a foot race of 13.1 miles, half the distance of a marathon.

Hamstring Muscles:  The large muscles at the back of the thigh that primarily flex the knee.

Hip Flexors:  The large muscles that are powerful flexors of the hip joint.

Hypertrophy:  The increase in size or mass of a cell, tissue, or organ, such as the increase in muscle fiber size resulting from strength training.

Intensity:  The physiological stress on the body during exercise. Your level of intensity can be readily determined by measuring your pulse rate (heart rate) immediately following an exercise bout.

Interval Training:  Training made up of successive bouts of exercise at near maximal intensity alternated with periods of rest or lighter exercise such as brisk walking or slow jogging.

Isometric:  This is a type of muscle contraction in which the muscle generates force but does not undergo significant shortening, such as pushing against a wall.

Isotonic:  This is a type of muscle contraction in which the muscle generates force against a constant resistance resulting in movement, such as curling a 40-pound barbell.

Lean Body Weight:  Your body weight minus the percentage of body weight that is stored fat.

Low Impact Aerobics  Low impact aerobics are routines where one foot is always in contact with the floor. High-impact routines involve more vigorous movements including skips, hops, and jumps where both feet may be off the floor at the same time.

Marathon:  A foot race covering 26.2 miles.

Motor Skill:  The ability of muscles to function harmoniously and efficiently, resulting in smooth coordinated muscular movement. Motor skill is a reflection of general athletic skill.

Muscular Endurance:  The ability of muscles to function harmoniously and efficiently, resulting in smooth coordinated muscular movement. This is a reflection of general athletic skill.

Plyometrics:  These are exercises designed to generate the greatest amount of force in the shortest amount of time.

Quadriceps:  These are the muscles on the front side of the thigh that extend the knee.

Recovery Index:  The sum of three 30-second heart-rate recoveries counts after a step test.

Relative Body Fat:  The proportion of fat tissue in the body often expressed as a percentage of body weight (percent of body fat).

Skinfold Caliper:  An instrument used to measure a selected thickness of a fold of skin that has been pinched up on the body.

Slow Twitch Muscle Fiber:  This is a type of muscle fiber with slow contractile characteristics. They have a high capacity to use oxygen. These fibers are used primarily during endurance type activities such as running, swimming, and cycling.

Static Stretching:  Increasing the length of a particular muscle or muscle group.

Step Aerobics:  This is a form of aerobics that is described as low impact and high intensity. It involves stepping on and off a bench ranging in height from four to twelve inches using a variety of step and arm combinations to music.

Step Test:  A testing procedure for assessing the heart-rate recovery after stepping on and off a bench for a three minute time period at a predetermined cadence.

Strength:  The capacity of a muscle to exert a force against a resistance.

Timed Repeats:  The repeated bouts of alternate running and walking using time as the determinant of the workload.

Training Heart Rate:  A heartbeat rate (or pulse rate) per minute during exercise that produces significant cardio-respiratory benefits.

Triathlon:  This is a competitive event involving three endurance type activities such as swimming, cycling and running.

Warm-up:  This is the portion of your exercise workout that prepares your body for a more vigorous exercise bout. Generally walking, stretching, major muscle groups, and exercises that stimulate the heart, lungs and muscles moderately and progressively are done during the warm-up period.