In order to implement a balanced fitness program, it’s important to include all of the essential components of fitness. When developing a fitness program, its good practice to incorporate the
F.I.T. Prescription = Frequency, Intensity, and Time. Utilizing the F.I.T. Prescription allows you to exercise safely while achieving steady improvements. In his book, “Fitness and Work Capacity, 2nd Edition,” Dr. Brian Sharkey has developed an Aerobics Fitness Index (page 9) that provides a good calculation for determining your level of aerobic fitness which is based on your level of physical activity.

Cardiovascular Fitness:

Cardiovascular fitness is the backbone of a general fitness program. The primary purpose of aerobic conditioning is to make the heart stronger and work more efficiently, while improving one’s health and enhancing the quality of life. Cardiovascular fitness includes both aerobic (moderate intensity) and anaerobic (vigorous intensity) activities. The word ‘aerobics’ means ‘with oxygen’ and refers to the continuous moderate activity that puts an increased demand for oxygen on the heart, lungs, and body systems. The purpose of aerobic conditioning is to train the heart and other muscles to use oxygen more efficiently allowing activity to continue longer.

A variety of exercises (typically using larger muscle groups) can be done to create an increased demand for oxygen over a period of time while maintaining the heart rate at 55%-85% of the estimated maximum heart rate. (THR = target heart rate) Good examples of aerobic activity include running a marathon or digging fireline where there is energy exerted over a longer duration at less intensity than anaerobic activities.

Anaerobic activity (vigorous intensity) occurs “when a muscle exceeds its capacity to produce energy aerobically. The (production of) lactic acid interferes with muscles’ contractile force and energy production, leading to reduced work output and fatigue.” Good examples of anaerobic activities include running sprints where you have short intense bursts of energy and speed. However, continued reliance on anaerobic energy rapidly leads to fatigue.

In order for wildland firefighters to achieve optimal fitness, it’s important to include both moderate and vigorous activities in their fitness program. This can also mitigate the occurrence of overuse injuries by providing less repetition and encouraging cross training and muscle balance.