Erasmus secular trend (1997 2007) of physical fitness

transcript

The terms physical activity and exercise were used interchangeably in the past; however, we

know now that they have two distinct meanings.

Physical Activity has been defined as any bodily movement produced by skeletal muscles

that results in energy expenditure (Caspersen, 1985) and includes activities of all intensities.

Therefore, things such as housework, gardening, and occupational activity may all be

considered types of physical activity.

Exercise is considered a subcategory of physical activity and has been defined as planned,

structured, and repetitive movements which result in the improvement and/or maintenance of

one or more facets of physical fitness (cardiovascular fitness, muscular strength and

endurance, body composition, and/or flexibility) (Caspersen, 1985).

Therefore, all exercise is considered physical activity; however, all physical activity is not

exercise. As a result, physical activity intervention efforts should focus on increasing total

physical activity and not just at increasing exercise.

Recommended Reading:

Caspersen CJ, Powell KE, Christenson GM (1985). Physical activity, exercise and physical

fitness: definitions and distinctions for health-related research. Public Health Reports; 100:

126-131.

The term structured physical activity is simply what comes to mind when we

think of exercise. It consists of planned bouts of physical activity and is often

times more straightforward to describe, in terms of intensity, time, and/or

frequency than unstructured physical activity.

Lifestyle physical activities are bouts of physical activity that are

incorporated into an individual’s everyday routine. Lifestyle physical activities

are often considered unstructured because they vary based on events and/or

situations that develop over the course of a given day. A few examples of

lifestyle physical activities include taking the stairs instead of the elevator or

escalator, parking the car further away in store parking lots, walking around the

home or office while chatting on a cordless telephone, etc.

Similar to structured physical activity, maintaining an “active head”, by making

“active” lifestyle choices where possible will also help improve one’s health.

The measurement of physical fitness is common practice in both preventative

and rehabilitative exercise programs. The purpose of fitness testing includes:

educating individuals about current fitness status relative to population norms,

collecting baseline and follow-up data to measure progress in an exercise

program, motivation of exercise participants, and risk stratification for chronic

disease development. Cardiovascular or Aerobic fitness will be emphasized in

this lecture.

American College of Sports Medicine (2000). ACSM’s guidelines for exercise

testing and prescription (6th ed.). Baltimore, MD: Lippincott Williams & Wilkins.

American College of Sports Medicine (2000). ACSM’s guidelines for exercise

testing and prescription (6th ed.). Baltimore, MD: Lippincott Williams & Wilkins.

Because physical activity is difficult to measure, Maximal Oxygen Uptake or

VO2 max is often used as a proxy measure of physical activity. However, VO2

max is actually a measure of physical fitness, not physical activity. Those who

are more active and expend more energy tend to have higher fitness

levels. Many VO2 max protocols are time consuming and may not be possible

in large epidemiological studies where there are great number of

participants. In addition, when examining population studies, there is only a

moderate relationship between physical activity and physical fitness (Siconolfi,

1985; Jacobs, 1993). This lack of a strong relationship could be due to the

fact that there are other factors besides activity, such as genetics (Bouchard,

1988), gender, age, and relative weight (Leon, 1981) that influence physical

activity.

Erasmus secular trend (1997 2007) of physical fitness

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