What are the basic terms of the fitness industry and how are they defined?

A glossary of key terms generally accepted by the scientific community was published in 2008 by the US Department of Health and Human Services in their Physical Activity Guidelines Advisory Committee Report.

The report groups the key terms under four headings:

1. Physical Activity and Exercise

2. Physical Fitness

3. Health

4. Study Design and Measurement

Focusing on the first three headings, the key terms may be outlined as follows:

(1) Physical Activity and Exercise:

• Physical activity is any bodily movement produced by the contraction of skeletal muscle that increases energy expenditure above a basal level.

• Mode is the type of activity or exercise that is being performed. Biking, walking, rowing, and weight lifting are all examples of different modes of activity.

• Intensity refers to how much work is being performed or the magnitude of the effort required to perform an activity or exercise. Intensity can be expressed either in absolute or relative terms.

• Absolute intensity is determined by the rate of work being performed and does not take into account the physiologic capacity of the individual.

  For aerobic activity, absolute intensity typically is expressed as the rate of energy expenditure. For example:

  • METs (millilitres per kilograms per minute of oxygen being consumed, kilocalories per minute)

  • Speed (walking at 3 miles per hour or jogging at 6 miles per hour)

  • Physiologic response (heart rate).

  • For resistance activity, intensity is frequently expressed as the amount of weight lifted or moved.

• Relative intensity takes into account or adjusts for a person’s exercise capacity.

  • For aerobic exercise, relative intensity is expressed as a percent of a person’s aerobic capacity (VO2max) or VO2 reserve, or as a percent of a person’s measured or estimated maximum heart rate (heart rate reserve).

  • It also can be expressed as an index of how hard the person feels they are exercising. A person’s subjective assessment of how hard they are working relative to their own capacity is called rating of perceived exertion.

• Exercise is a subcategory of physical activity that is planned, structured, repetitive and purposive in the sense that the improvement or maintenance of the components of physical fitness is the objective.

  • Exercise and exercise training are often 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.

• Aerobic Exercise is exercise that primarily uses the aerobic energy-producing systems, can improve the capacity and efficiency of these systems, and is effective for improving cardiorespiratory endurance.

• Anaerobic Exercise is exercise that uses the anaerobic energy-producing systems and can improve the capacity of these systems and increase the tolerance of acid-base imbalance during high-intensity exercise.

• Balance Training refers to static and dynamic exercises that are designed to improve individuals’ ability to withstand challenges from postural sway or destabilizing stimulus caused by self-motion, the environment, or other objects.

• Endurance Training refers to exercises that are repetitive and produce dynamic contractions of large muscle groups for an extended period of time (e.g., walking, running, cycling, swimming).

• Flexibility Training concerns exercises that enhance the ability of a joint to move through its full range of motion.

• Resistance Training is defined as exercise training primarily designed to increase skeletal muscle strength, power, endurance, and mass.

(2) Physical Fitness:

• Physical fitness is defined as the ‘ability to carry out daily tasks with vigour and alertness, without undue fatigue and with ample energy to enjoy leisure-time pursuits and meet unforeseen emergencies.’ It is made up of several components, including:

  • Cardiorespiratory endurance (aerobic power)

  • Skeletal muscle endurance

  • Skeletal muscle strength

  • Skeletal muscle power

  • Flexibility

  • Balance

  • Speed of movement

  • Reaction time

  • Body composition

Because these components differ in their importance to athletic performance versus health, a distinction is made between performance-related fitness and health-related fitness: 

• Performance-related fitness includes those attributes that significantly contribute to athletic performance and places emphasis on:

  • aerobic endurance or power

  • muscle strength and power

  • speed of movement

  • reaction time

• Health-related fitness includes:

  • cardiorespiratory fitness

  • muscular strength and endurance

  • body composition

  • flexibility

  • balance

The components are defined (or remain undefined) as follows:

• Cardiorespiratory endurance (aerobic power): A health-related component of physical fitness that is the ability of the circulatory and respiratory systems to supply oxygen during sustained physical activity. Usually expressed as measured or estimated maximal oxygen uptake (VO2max).

• Skeletal muscle endurance: Undefined

• Skeletal muscle strength: A health and performance-component of physical fitness that is the ability of a muscle or muscle group to exert force.

• Skeletal muscle power: A performance-related component of physical fitness that describes the rate (or speed) at which work can be applied.

• Flexibility: A health and performance-related component of physical fitness that is the range of motion possible at a joint. Flexibility is specific to each joint and depends on a number of specific variables, including but not limited to the tightness of specific ligaments and tendons.

• Balance: A performance-related component of physical fitness that involves the maintenance of the body’s equilibrium while stationary or moving.

• Speed of movement: A performance-related component of physical fitness that is the ability to perform movements rapidly or within a short period of time.

• Reaction time: Undefined

• Body composition: A health-related component of physical fitness that applies to body weight and the relative amounts of muscle, fat, bone and other vital tissues of the body. Most often, the components are limited to fat and lean body mass (or fat-free mass).

(3) Health:

• Health is a human condition with physical, social and psychological dimensions, each characterized on a continuum with positive and negative poles. Positive health is associated with a capacity to enjoy life and to withstand challenges; it is not merely the absence of disease. Negative health is associated with morbidity, and in the extreme, with premature mortality.

This summarizes the key terms generally accepted within the scientific literature.

Appendix

Health is often defined in the negative sense of not being physically ill. However, in 1948, the World Health Organization (WHO) proposed a new definition: ‘a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.’

This was an ambitious concept as it overcame the negative definition (absence of disease) and included the physical, mental and social aspects of health. However, the word ‘complete’ made it impossible to measure health, blurred the difference between short-term and long-term disease, and made it highly likely that all of society was ‘unhealthy’ most of the time.

• In 2008, a British Medical Journal (BMJ) editorial called for a conference of international health experts in a global conversation on health, and proposed another definition: ‘the ability to adapt and self-manage’ in the face of social, physical and emotional challenges.

This concept acknowledges changing needs, especially regarding age, culture and personal responsibility. However, it ignores how some social challenges prevent people from adapting or self-managing, and implies blaming people for bad health and praising them for good health. Arguably, health is to a large extent determined by a person’s environment:

• Social Environment

  • Income and social status

  • Education

  • Social support networks

• Individual Characteristics and Behaviours

  • Genetics

  • Gender

  • Nutrition and health

• Physical Environment

  • Waste

  • Energy

  • Urbanization

  • Water

  • Radiation

• Economic Environment

  • Housing

  • Transport

  • Industry

  • Food and Agriculture

  • Health services

References

Huber, M., Knottnerus, J., Green, L., Horst, H., Jadad, A., Kromhout, D., Leonard, B., Lorig, K., Loureiro, M., Meer, J., Schnabel, P., Smith, R., Weel, C. and Smid, H., 2011. How should we define health?. BMJ, 343(jul26 2), pp.d4163-d4163.

U.S. Department of Health and Human Services, 2008. [online] Europarc.org. Available at: <https://www.europarc.org/wp-content/uploads/2018/03/Physical-Activity-Guidelines-Advisory-Committee-Report-2008.pdf> [Accessed 13 October 2021].

Who.int. 2021. Home. [online] Available at: <https://www.who.int/> [Accessed 19 October 2021].

World Health Organization, 1946. Constitution of the World Health Organization. [online] Who.int. Available at: <https://www.who.int/about/governance/constitution> [Accessed 19 October 2021].