Abdominal muscles

Multiple muscles make up the abdomen (stomach area), including the oblique muscles (external and internal); the rectus abdominus; and the transverse abdominis.

Aerobic activity

In this type of physical activity the body's large muscles move in a rhythmic manner for a sustained period of time. Aerobic activity, also called endurance activity, improves cardiorespiratory (heart and breathing) fitness. Examples include walking, running, and swimming, and bicycling.

Anaerobic activity

Anaerobic means "without oxygen." Anaerobic exercise (vs. aerobic exercise) doesn't require the body to process more oxygen. An example would be strength or weight training.

Back muscles

In addition to your spine, multiple muscles make up your back, including the trapezius and latissimus dorsi muscles.


the large muscle of the front of the upper arm between the shoulder and the elbow; the full name of this muscle is biceps brachii.

Body composition

the elements that make up a human body.  These include water, fat, protein, and minerals. This term usually refers to the amount of body fat a person has.

Body mass index (BMI)

a measure of body fat based on height and weight that applies to adult men and women. You can calculate your BMI at the National Heart, Lung, and Blood Institute site. A score of 18.5 or under indicates you are underweight; a score of 18.5 to 24.9 indicates you are at normal weight; a score of 25 to 29.9 indicates you are overweight; and a BMI of 30 or more indicates you are obese. The BMI is not accurate for everyone, though; it may overestimate body fat in athletes and those with a muscular build and it may underestimate body fat in older people and those who have lost muscle.


a unit of energy supplied by food. A calorie is a calorie regardless of its source. Whether you're eating carbohydrates, fats, sugars, or proteins, all of them contain calories.


Food is made up primarily of carbohydrate, protein, and fat. The primary role of carbohydrates (sugars and starches) is to provide energy to cells in the body, particularly the brain, which is the only organ in the body that depends on carbohydrates.


a shortened version of "cardiovascular exercise," which refers to any type of physical activity that increases your heart rate, such as running, bicycling, aerobics, or swimming.

Chest muscles

a group of muscles that includes the pectoralis major and pectoralis minor muscles (often shortened to "pecs").

Circuit training

a type of workout that alternates between cardio or aerobic exercise (like running or cycling, which gets your heart rate up) and strength/weight training.


the time at the end of the workout when you let your body gradually return to normal. A cool-down may include 5 to 10 minutes of slow walking after running, as well as stretching of the muscles used during your workout.


a general term that can refer to your stomach muscles (abdominals) or can also include your low back muscles as well as your stomach. Developing core strength is important to do all types of exercise and everyday activities.


one of the main muscles of the shoulder, sitting along the rounded part of the shoulders from the front to the back of the shoulder and continuing partly down the upper arm.

Endurance training

a type of exercise that's designed to build your stamina, or the ability to keep going or help your body endure over time during challenging physical activity. It's an important part of reaching many fitness goals, such as a running a marathon, and typically refers to aerobic/cardio training.


A subcategory of physical activity that is planned, structured, repetitive, and purposive in the sense that the improvement or maintenance of one or more components of physical fitness is the objective. "Exercise" and "exercise training" frequently are used interchangeably and generally refer to physical activity performed during leisure time with the primary purpose of improving or maintaining physical fitness, physical performance, or health.

Fat (body)

one of the elements that make up the human body, in addition to protein, water, and minerals. There are different kinds of body fat, including visceral fat, which is stored in the belly, and subcutaneous fat, which is fat just under the skin.

Fat (dietary)

one of the three main compounds of food (the others are protein and carbohydrate). Fat is a source of energy for the body and we need some fat in our diet for our body to function properly. The American Dietetic Association recommends that adults' diet should include no more than 20% to 35% of calories from fat.


the ability to move your joints through a complete range of motion.

Gluteal muscles

the group of muscles in the buttocks, including the gluteus maximus, gluteus medius, and gluteus minimus, as well as the tensor fasciae latae muscle, which is in the thigh.


the tendons at the back of the legs.

Heart rate

the number of beats per minute (BPM) at which a heart beats.


the water and fluids needed to maintain proper body function.


a type of training in which periods of intense exercise are alternated with periods of slower or moderate exercise. For example, an interval training session might include repeated intervals of 1 minute of running alternated with 2 minutes of walking. This type of training can improve speed, fitness, and endurance.

Lower-body muscles

The group of muscles that include the gluteal muscles (buttocks); iliopsoas; quadriceps (thigh muscles); hamstring (tendons in the back of legs); tibialis anterior; gastrocnemius; and soleusmuscles.


the chemical processes in the body's cells and tissues. It is often used to describe how efficiently the body processes food (calories).

Muscle strengthening

see strength training or weight training

Muscular fitness

physical activity that increases skeletal muscle strength, power, endurance, and mass.


two types of muscles (internal and external) the abdominal area on each side of the body.

Physical activity

This is a broader category that includes exercise, but also includes everyday activities like walking at work, cleaning, and gardening. Simply put, physical activity means moving your body in a way that causes you burn calories.

Physical fitness

The ability to carry out daily activities with vigor and alertness without feeling a lot of fatigue.


a molecule made up of amino acids. Proteins are needed for the body to function properly. They are the basis of body structures, such as skin and hair, and of other substances such as enzymes, cytokines, and antibodies. Protein is one of three main components of food (the others are carbohydrate and fat).

Quadriceps ("quads")

a group of four muscles at the front of the thigh.

Repetitions ("reps")

the number of times a person lifts a weight in muscle-strengthening activities. Repetitions are analogous to duration in aerobic activity.

Resistance training

see strength training or weight training

Rotator cuff muscles

a group of small muscles in the shoulders; rotator cuffs are prone to injury.


the number of sequences in a workout. For example, you might lift a weight 10 times (which equals 10 repetitions, or 10 reps) and repeat that sequence, with a rest in between, two more times. This would equal three sets of that exercise.

"SMART" goals

a type of goal-setting in which goals are set according to the acronym SMART: Specific, Measurable, Attainable, Relevant, and Time-bound. Some versions also include "ER" (for SMARTER), which stand for Evaluate and Re-evaluate. The creation of "SMART" goals is attributed to Paul J. Meyer, author of "Attitude is Everything."


activity in which muscles or tendons are stretched or flexed, usually to improve flexibility and release tension or discomfort. There are four types of stretches: static, dynamic, ballistic, and proprioceptive neuromuscular facilitation (PNF).

Strength training

Muscle-strengthening activity (strength training, resistance training, or muscular strength and endurance exercises). Physical activity, including exercise that increases skeletal muscle strength, power, endurance, and mass.


a way to increase or decrease the intensity and difficulty of exercise. If you want to make a workout harder, you can do it for more time; to make it easier, do it for less time. Similarly, you can increase or decrease the amount of sets and reps to adjust the difficulty of an exercise, and you can increase or reduce the weight (or resistance) if you want to make your workout harder or easier.

Transverse abdominis muscle

Transverse means cross-wise or across; these two muscles are placed cross-wise and deep inside the belly (abdomen).


a large muscle that runs from the base of the head down through the shoulder blades in the upper back.


the muscle on the back of the upper arm.

Upper-body muscles

A group of muscles that includes the trapezius; serratus anterior; pectoralis major and minor; latissimus dorsi; deltoid; rotator cuff muscles; humerus; triceps brachii; biceps brachii; brachialis; and brachioradialis.

Waist circumference

Measuring your waist circumference (the number of inches around your waist) helps screen for possible health risks that come with overweight and obesity. If most of your fat is around your waist rather than at your hips, you’re at a higher risk for heart disease and type 2 diabetes. This risk goes up with a waist size that is greater than 35 inches for women or greater than 40 inches for men. To correctly measure your waist, stand and place a tape measure around your middle, just above your hipbones.  Measure your waist just after you breathe out.


the period at the start of a workout when you gradually increase the intensity of the activity you're doing before you move into the full intensity of your workout, allowing your body and your muscles some time to transition into moderate or vigorous movement. For example, a warm-up may include 10 or more minutes of slow walking before you start running, as well as stretching of the muscles you'll use during your workout.

Weight training (also called strength training, resistance training, muscle-strengthening)

Physical activity that increases skeletal muscle strength, power, endurance, and mass. This type of exercise usually involves weight (free weights or weight machines), resistance bands, or objects that offer weight or resistance bands, but can also include body weight exercises (where you just use your body weight for resistance, without any equipment or objects).

Sources: Centers for Disease Control and Prevention; National Institutes of Health; U.S. Department of Agriculture; American Dietetic Association; National Cancer Institute; and original reporting



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