Page 134 - Journal of Special Operations Medicine - Spring 2015

Table 1 A Sample of Various Definitions of Physical Fitness cancers, greater bone health, better lipid profiles, and
8,9
A set of attributes that allow individuals to carry out daily a more effective functioning immune system. Besides
tasks with vigor and alertness, without undo fatigue, and cardiorespiratory fitness, health­related fitness compo­
with ample energy to enjoy leisure­time pursuits and to nents include muscular strength, muscular endurance,
meet unforeseen emergencies 12 body composition, and flexibility. Skill­related compo­
The ability to perform muscular work satisfactorily 13 nents are those that assist in the optimal performance
The functional ability of an individual to perform certain of occupation tasks. For example, coordination would
kinds of tasks requiring muscular activity 2 be required for Soldiers to quickly move over, under,
A state of ability to perform sustained physical around, and through obstacles while under hostile fire.
work characterized by an effective integration of Skill­related fitness includes all the components of fit­
cardiorespiratory endurance, strength, flexibility, ness in Table 2. 10,11
coordination, and body composition 14
Those factors that determine one’s ability to perform heavy Fitness and Injuries
physical work and contribute to maintaining good health
and appearance 15 A higher level of fitness is associated with reduced risk
of injury. Figure 1 shows the results of two studies that
was given names like “velocity,” “speed,” and “dynamic looked at this relationship in infantry Soldiers. The first
strength,” although today we commonly call this fac­ study involved 298 light infantry Soldiers at Ft. Rich­
2,3
tor “muscular endurance.” Other task groups resulted ardson, Alaska, and the other, 643 light infantry Sol­
in the identification of other fitness components. The diers at Ft. Polk, Louisiana, a few months before they
2–7
factors or components that were identified depended to deployed to Afghanistan. Soldiers performed their semi­
a large extent on the tests that were administered as part annual APFT, which included a 2­mile run and sit­ups.
of the test batteries. Early studies concentrated on vari­ Soldiers’ medical records were screened for injuries after
ous measures of strength and muscular endurance and the APFT. At Ft. Richardson, injuries were tracked for
few studies included what we would now consider car­ 6 months and at Ft. Polk for 2.5 months (this largely
diorespiratory endurance measures. As particular factors accounted for the differences in injury incidences in the
emerged, later studies included additional tests that might figures). Soldiers were separated into quartiles of fitness
be related to a particular factor and the components of (i.e., groups representing 25% of the unit) and the num­
physical fitness were further refined. Table 2 presents a ber of Soldiers injured was examined in each quartile.
summary of the most commonly identified components As clearly seen in Figure 1a and 1b, there was a dose­
of physical fitness and those generally accepted today. response relationship, meaning that as cardiorespiratory
fitness decreased, injury rates increased. In the Ft. Polk
Fitness components have been separated into those that study, the least aerobically fit Soldiers were at twice the
are health related and those that are skill related, al­ risk of injury compared to the most fit. Not only was
though there is considerable overlap between these two. cardiorespiratory fitness important for injury prevention
Health­related components are those that have been but other components of fitness were also important. Us­
shown to be related to well­being. For example, a higher ing the same procedures in the same groups of infantry
level of cardiorespiratory endurance has been shown to Soldiers, Figure 1c and 1d shows the association between
be related to reduced risk of overall mortality, lower risk sit­up performance and injuries. Again, the group who
of cardiovascular disease, lower risk of certain types of did the most sit­ups had the lowest injury risk. 17,18

Table 2 Physical Fitness Components a
Examples of Tests
Generic Fitness Component Physical Measurement to Measure Fitness Component
Muscular strength Maximal force, kg One­repetition maximum bench press
Muscular power Maximal power, W Vertical jump
Muscular endurance Short­term sustained force or average power Push­ups, pull­ups, sit­ups
Cardiorespiratory endurance Very long­term sustained force/power 2­mile run
Coordination Deviation from desired movement Speed and accuracy of object transfer
Balance Deviation from desired posture Balance beam
Flexibility Range of motion Knee range of motion
Body composition Body mass, fat mass, lean body mass Body weight, body mass index, circumference,
or underwater weighting
Note: Modified from Knapick et al. 16
a

124 Journal of Special Operations Medicine Volume 15, Edition 1/Spring 2015