Measuring Physical Activity. Physical activity is difficult to measure as it involves complex motions and provides different physiological stresses. Physical activity ranges from maximal exercise to fidgeting when at rest.
Physiological adaptation to training may be quantified through a number of diagnostic tests.
To date there is no formal training theory that quantitatively and accurately prescribes the pattern, duration and intensity of exercise to elicit a specific physiological adaptation.
Good descriptive epidemiology data can provide valuable insight:
According to statistics, young, educated males are the most likely to be active.
A problem with using age-adjusted, relative-intensity, classifications is that lower levels of fitness will increase relative intensity.
Total Daily Energy Expenditure (kcal/kg) (Several Countries)
Age 6 8 10 12 14 16 18
Boys 82 74 75 58 50 44 44
Girls 76 70 58 53 45 42 42