Group 2 Activities where the rate of energy expenditure is highly related to skill, but for a given individual can provide a constant intensity. May also be useful in early stages of conditioning, but skill level must be considered. Examples include swimming and cross - country skiing.
Group 3 Activities where both skill and intensity of exercise are highly variable. Such activities can be very useful to provide group interaction and variety in exercise, but must be cautiously considered for high - risk, low - fit, and/or symptomatic individuals. Competitive factors must also be considered and minimized. Examples of these activities are racquet sports and basketball.
The risk of injury associated with high impact activities or high intensity weight training must also be weighed when selecting exercise modalities, especially for the novice exerciser or an obese individual. It may be desirable to engage in several different activities to reduce repetitive orthopedic stresses and involve a greater number of muscle groups. Because improvement in muscular endurance is largely specific to the muscles involved in exercise. It is important to consider unique vocational or recreational objectives of the exercise program when selecting activities. Finally, it is important to consider other barriers that might decrease the likelihood of compliance with, or adherence to, the exercise program (travel, cost, spousal or partner involvement, etc.).
