May Angular Variation Be a Parameter for Muscular Condition Classification in SCI People Elicited by Neuromuscular Electrical Stimulation?

People with complete spinal cord injury (SCI) present a rapid process of muscle fatigue under neuromuscular electrical stimulation (NMES) due to neuromuscular impairment. Different NMES patterns interfere with the fatigue process and joint amplitude. The aim of this study was to evaluate muscle reactions using joint knee joint fatigue protocol with four NMES patterns in people with complete SCI. Ten subjects with complete SCI were submitted to 4 stimulatory profiles, with varying pulse duration and the modulating frequency (burst): P1 (100 mu s-50 Hz); P2 (100 vis-70 Hz); P3 (200 mu s-50 Hz); P4 (200 mu s-70 Hz). Subjects were classified according to theirselves angular responses as upper median (UPmed) and lower median (LOWmed). UPmed had lower angular variation and attenuation in the fatigue process than LOWmed in P1 (session I, trial 1 p = 0.06, trial 2 p = 0.009, trial 3 p = 0.029, session II, trial 1 p = 0.015), P2 (session I, trial 3 p = 0.024, trial 4 p = 0.034), P3 (session I, trial 3 p = 0.035), P4 without intergroup difference. The angular variation can be applied as a useful tool for muscular condition classification of complete SCI people. The best performance of UPmed has occurred in P1 and the worst in P4. The LOWmed performance did not stand out in any protocol.