Military Review English Edition September-October 2014 - Page 18

P = Fd/t In this equation— P = Power (energy) F = Force (cause of motion) d = Distance (of displacement) t = Time Power output can be increased or attenuated through manipulation of any one of the three variables: force (the cause of motion, which is greater if the cause of motion is heavier), the distance that weight travels, and the time it takes to move the weight through that distance. In terms of application, therefore, the goal should be to train soldiers to move large loads over long distances quickly. This concept can be expressed as intensity. Intensity is exactly equal to average power output as discussed above, and its presence or lack thereof in exercise programming should be defined as how large the load, how far the distance, and how much time it takes to perform the movement. Infantrymen are taught from their first day in the Army that their job is to close with and destroy the enemy; their job often requires hours of foot • Sgt. Robert Schaffner, 3d ID Public Affairs • • • • movement followed by short bursts of explosive energy. Intensity describes both physical modalities. The time domain refers to various approaches to training that take into account the duration of tasks, such as tasks performed quickly using high force, or tasks that require endurance over time using less force. To be proficient and efficient, soldiers routinely need to perform short, explosive movements; intense movements lasting up to two minutes; and sustained exercise. Efficient recruitment of muscle fibers and metabolic pathways must be trained, within the domains that each muscle fiber type and pathway is the primary source of power.8 Different muscle fiber types contract for different kinds of muscular power production over different durations. Moreover, the metabolic pathways that fuel muscles differ, depending on the intensity, duration, and type of physical activity. The fibers that make up the muscles of the body comprise at least three different types: Type I fibers have a high level of aerobic endurance but generate less peak power. Chuck Carswell, an instructor from the CrossFit Decatur, Ga. branch, explains how to correctly do the front squat during a CrossFit certification at the Caro Fitness Center (CrossFit Fort Stewart), 31 January 2012. 16 September-October 2014  MILITARY REVIEW