Objective: The present study aimed to determine the association between neuromuscular function, motor function impairment, and muscle and tendon structures in individuals with spinal cord injury (SCI) compared to a control (non-disabled) population.
Design: A cross-sectional study with a control group.
Setting: Center of Adapted Sports Training and Special Physical Education.
Participants: Fifteen individuals with SCI and motor function impairments participated in the study. A paired non-disabled group was recruited for comparison.
Interventions: Not applicable.
Outcome measures: Muscle (biceps brachii, rectus femoris, vastus lateralis, vastus medialis, and tibialis anterior) and tendon (quadriceps and patellar tendons) structures were assessed by ultrasound imaging (thickness, pennation angle, fascicle length, and echogenicity). Neuromuscular electrophysiological disorders were also assessed using electrodiagnosis techniques (stimulus non-responsivity and chronaxie) in the same muscles.
Results: Except for the biceps brachii muscle, muscle thickness, pennation angle, and fascicle length were lower (p < 0.01) while echogenicity and chronaxie were greater (p < 0.01) in SCI participants. The SCI participants had a higher prevalence of neuromuscular electrophysiological disorders for all muscles, except the biceps brachii.
Conclusion: Neuromuscular disorders occur in association with muscle and tendon maladaptation in individuals with chronic SCI. A higher prevalence of electrophysiological disorders suggests an acquired polyneuromyopathy for muscles with motor function impairment even though the muscle was innerved, in addition to widespread muscle atrophy.
Keywords: Chronaxie; Muscle; Nerve; Neuromuscular electrical stimulation; Ultrasonography.