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Astorino et al. Neuroimmunol Neuroinflammation 2020;7:40-50 I http://dx.doi.org/10.20517/2347-8659.2019.11 Page 41

Keywords: Body satisfaction, depression, rehabilitation, fat free mass, paralysis

INTRODUCTION
The paralysis associated with spinal cord injury (SCI) compromises locomotion and, in turn, diminishes
[1]
physical function and leads to various secondary complications including obesity and insulin resistance .
Above and beyond the physical effects of SCI is the onset of various psychological issues that may affect
perceived quality of life (PQOL), which encompasses aspects of happiness, health, quality of family
[2]
relationships, and financial and physical independence . In fact, in men and women with SCI, well-
[3]
being is negatively associated with self-reported overweight status and onset of secondary complications ,
which emphasizes the need to also consider participants’ psychological state during rehabilitation. Data
on persons with SCI demonstrate that aerobic and resistance exercise training improves PQOL compared
[4]
to non-exercising controls , although PQOL was reduced after a decline in physical activity three months
later . Incidence of pain is also common in SCI, as, in a survey of 200 individuals, 25% had more severe
[5]
[6]
pain and 44% reported that it interfered with daily activities . Moreover, pain decreases quality of life
[6]
and serves as a barrier to regular exercise participation in SCI . In addition, more pain is consequent
[8]
[7]
with greater incidence of depression , which is widely studied in persons with SCI , and incidence of
substantial pain may negatively influence participation in rehabilitation. Moreover, depression is associated
with body image disturbances and body dissatisfaction, which are common in persons with disability such
[9]
[4]
as SCI . With exception of one study showing positive effects on quality of life , little is known about
efficacy of exercise training to modify quality of life and body satisfaction in SCI.
As stated above, quality of life is associated with body composition that is severely altered after SCI. For
[10]
example, Moore et al. reported that persons with chronic incomplete or complete SCI have 14%-32%
lower muscle cross sectional area in the calf than controls. Moreover, lower extremity fat deposition is up
to fourfold higher in SCI versus able-bodied persons , and there is a loss of lean body mass in the trunk
[11]
[12]
and arms that reduces physical function and capacity for day-to-day activities including wheelchair
ambulation, all leading to altered quality of life. In addition, visceral adipose tissue is typically higher ,
[13]
which increases the risk of cardiovascular disease and diabetes [14,15] . Chronic aerobic and resistance
exercise training can modify body composition in SCI, but the majority of data showing positive effects
[16]
are from studies employing lower extremity functional electrical stimulation (FES) using leg cycling ,
resistance training , or subtetanic contractions [18,19] that are often inaccessible for people with SCI. Recent
[17]
studies show no change in body composition in response to completion of chronic upper-body resistance
training or arm ergometry , two widely-used exercise modes in this population. Consequently, a
[20]
[13]
[21]
recent review concluded that there is insufficient evidence to support exercise training to modify body
composition in SCI.
One rehabilitation modality frequently used in this population is activity-based therapy (ABT), which
targets activation of the neuromuscular system below the injury level, with a goal of retraining the nervous
[22]
system to recover a specific motor task such as locomotion . Institution of ABT using modalities including
load bearing, locomotor training, resistance training, and/or FES typically targets the paralyzed or partially
paralyzed muscles and may also aid in prevention or treatment of various secondary health complications
[23]
seen after SCI. In a randomized controlled trial, Jones et al. showed that ABT significantly improved
walking-related outcomes in persons with incomplete SCI. Nevertheless, exercise training such as ABT
requiring voluntary contractions may have a lesser ability to modify body composition [24,25] , although this is
[26]
not universal . Therefore, it is unclear if body composition can be modified with voluntary exercise in SCI
such as ABT, and if any change in body composition is consequent with a change in quality of life. If ABT
does not elicit changes in body composition, alternative exercise modalities may need to be implemented
to improve this outcome in this population.