PROJECT SUMMARY/ABSTRACT
Cerebral palsy (CP) is a movement disorder characterized by deficits in strength and coordination. The
subsequent gait deficits associated with CP lead to a progressive decline in function due to the secondary effects
of having a movement disorder during development. Interventions seeking to mitigate these effects have only
been partially successful because they have not addressed both muscle recruitment (i.e. strength) and
coordination within one, top-down therapy. Recently, we developed a wearable adaptive resistance therapy that
is able to address both of these aspects with promising results for improving neuromuscular control, metabolic
efficiency, and functional mobility. To maximize the efficacy of this intervention, two important considerations
must be addressed: 1) What is the appropriate level of resistance to prescribe for maximizing neuromuscular
response as children acclimate to the intervention? 2) What is the overall trajectory in training effects from this
therapy and are these effects maintained after the therapy stops? In addition, there is limited understanding of
the underlying mechanisms of observed improvements in neuromuscular control with this novel therapy. The
high levels of co-contraction in children with CP have been attributed to deficits in stretch reflex modulation, but
whether or not improvements in reflex modulation are responsible for the observed decreases in ankle co-
contraction with wearable adaptive resistance has not yet been explored.
The main objective of this research proposal is to further investigate a wearable adaptive resistance intervention
for children with CP. The first specific aim is to assess the acclimation to adaptive resistance by measuring the
neuromuscular response of children with CP, across five visits, as a low, moderate, and high level of resistance
is applied while walking. The second specific aim to quantify the time-course and maintenance of training effects
for the ten participants by measuring changes in neuromuscular control (i.e., co-contraction about the ankle and
the complexity of neural control) and reflex modulation (via H-reflex testing) across five training visits with
wearable adaptive resistance, as well as a two-week post-training follow-up visit. Our primary outcome variable
for Aim 1 ix plantar flexor activation magnitude, relative to baseline, while walking with resistance. Our primary
outcome variables for Aim 2 are ankle co-contraction level, neural control complexity (as determined by a muscle
synergy analysis), and reflex modulation (via H-reflex testing) while walking without resistance.
The completion of this work will improve our understanding of wearable adaptive resistance, including
fundamental knowledge about appropriate training levels and underlying mechanisms, with the ultimate goal of
developing an intervention that can enable physical activity for children with CP, allowing them to engage with
their peers and environment for healthy development and functional independence.
