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

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Sgt. Robert Schaffner, 3d ID Public Affairs

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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.
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September-October 2014  MILITARY REVIEW