Cardiorespiratory Fitness - Time and Type

Time, or duration, refers to how long one exercises. It is inversely related to intensity. The more intense the activity, the shorter the time needed to produce or maintain a training effect; the less intense the activity, the longer the required duration. To improve CR fitness, the soldier must train for at least 20 to 30 minutes at his THR.

Only aerobic exercises that require breathing in large volumes of air improve CR fitness. Worthwhile aerobic activities must involve the use of large muscle groups and must be rhythmic. They must also be of sufficient duration and intensity (60 to 90 percent HRR). Examples of primary and secondary exercises for improving CR fitness are as follows:

• Running.
• Rowing.
• Jogging.
• Skiing (cross-country).
• Walking (vigorous).
• Exercising to music.
• Road marching.
• Rope skipping.
• Bicycling (stationary).
• Swimming.
• Bicycling (road/street).
• Stair climbing.

SECONDARY (Done with partners or opponents of equal or greater ability.)
• Racquetball (singles).
• Basketball (full court).
• Handball (singles).
• Tennis (singles).

The primary exercises are more effective than the secondary exercises in producing positive changes in CR fitness.
The secondary activities may briefly elevate the heart rate but may not keep it elevated to the THR throughout the entire workout.
Every activity has its advantages and disadvantages. Trainers must weigh these and design programs that fit the unit’s needs.