Page 106 - Journal of Special Operations Medicine - Summer 2016

Excessive stress and subsequent overtaxing of the human What can make detection of PICO even more difficult
system are well described by Seyle’s General Adaptation is the potential for its presentation to be obscure, such
Syndrome (GAS). The GAS highlights how the body ini- as the case where injuries occur in seemingly unrelated
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tially adapts positively to a stressor and then, if the load body sites or injuries that are chronic in nature. For ex-
exceeds capability, moves into an “exhaustive phase” in ample, one case where injuries to seemingly unrelated
which performance deteriorates. This “stage of exhaus- anatomical locations obscured PICO involved a change
tion” sees fatigue override performance and adapta- in a physical conditioning program. In this case, an
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tion, potentially increasing risks of injury and illness, added training task had been given to trainees to be com-
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the former through decrements in proprioception, the pleted in their barracks in the evening, in a well-intended
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ability of muscles to absorb load under stretch, joint effort to optimize their performance on a fitness assess-
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stability, changes in gait, and other factors. ment. The additional task involved trainees conducting
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a high volume of pushups, in the evenings. While the ex-
tra training task itself was well periodized with rest and
Examples of PICO
recovery, it was developed in isolation from the overall
Several examples can serve to further illustrate the PICO program and, more specifically, the embedded physical
concept in relation to causation of musculoskeletal in- training program. After an evening of high-volume push-
juries. First, consider the case of a trainee who is re- ups performed as part of this extra training requirement,
quired to complete a high volume of chin-up activities trainees completed an obstacle course the following
as part their unit’s scheduled physical training session morning. Due to the upper body fatigue and exercise-
in the morning. Subsequently, the trainee may complete induced soreness from the pushups, several recruits had
weapon training activities throughout that same day difficulty lowering themselves down the 12-foot wall to
that include a large number of repetitions of operating full arms’ length prior to dropping off. This resulted in
the cocking mechanism of the weapon system. Second, some recruits suffering lower limb injuries on descending
consider the case of another trainee who participates in the wall. In determining how injuries had occurred, an
programmed morning physical training that includes investigator would likely examine the technique used by
running and leg calisthenics (e.g., squats, lunges, short the trainee to descend from the wall or perhaps the land-
sprints, etc.). Later in that same day, the trainee may be ing area, or the level of difficulty of the obstacle itself.
required to carry heavy loads for a protracted period Instead, the true culprit was likely the fatigue and over-
while conducting military training (e.g., military opera- training induced by excessive exercise of the upper body
tions in urban terrain, patrolling, vehicle check points, during the preceding evening. The investigator would
etc.). While in both of these instances the musculoskel- likely ascribe the lower limb injury to the obstacle course
etal load may not have been overly taxing during any training, whereas the predisposing factor and strongest
one task, the cumulative load from all of the physical contributor to these injuries occurring was in fact upper
activity across the full day (or sometimes multiple con- limb fatigue caused by the evening push-ups.
secutive days) may be sufficient to overload the muscu-
loskeletal systems—a case of the “straw that breaks the PICO may also be chronic, such as when excess activ-
camel’s back.” In the first instance the brachialis muscle ity is entrenched within the entirety of the training pro-
may suffer overuse and injury, and in the second case the gram. In this case, multiple elements of the designed
lower limbs may be injured. training program lead to excessive physical activity over
a protracted period, and subsequent overuse and ulti-
Similar examples of PICO can undoubtedly be found mately a high number of injuries occur. This scenario is
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in many military training courses, from a load carriage exemplified in a study that found that in 50% of injury
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march prior to military drill on the parade ground, to cases, the affected trainee could not identify a single ac-
additional section conditioning for a brigade event (e.g., tivity that led to their injury, with the trainees claiming
brigade cross country run or brigade tug-o-war com- that the injury came on gradually over time; A presenta-
petition) following formally programmed unit physical tion typical of an overuse injury. 16,17
training. Often, the downstream effect of such PICO is
that the physical training component is considered to This chronic load can be primarily due to the program
be the cause of the injury rather than the cumulative designers not considering the total amount of physical ac-
loading that occurs from the program as a whole, with tivity within the program, despite the fact they may have
the physical training being but one contributor. As such, virtually total control over the program. For example,
injury prevention strategies may focus on physical train- excessive distance traversed on foot, possibly in various
ing to the neglect of other, perhaps more important sub- modes such as walking, running, and marching, have
stantial, contributing factors—a case of singling out one been associated with increasing the risk of lower limb
(possibly petty) criminal from among several (possibly injuries in trainees. 18,19 In one study, trainees were found
more dangerous) criminals for prosecution. to walk 7.5km per day when simply moving around the

92 Journal of Special Operations Medicine Volume 16, Edition 2/Summer 2016