Fig. 3: Evaluation of function of TA in SCI mice after EEMS, EES, MS, or EEShc.

a–f Left (black), the graphs show surface EMGs for the TA muscles in the sham (a), untrained (b), 10−20 Hz EES (c), 10−20 Hz MS (d), 10−20 Hz EEMS (e), and 10−20 Hz EEShc (f) groups over a period 5 s, selected from a 30-second recording. Right (blue), enlarged view of the EMGs burst in the dashed box on the left. Mice from the sham group exhibited five steps within 5 s, while both untrained and trained groups displayed three to four steps. g The maximum amplitude of surface EMG bursts continuously for 5 s in the sham, untrained, 10−20 Hz EES, 10−20 Hz MS, 10−20 Hz EEShc, and 10−20 Hz EEMS groups (n = 6 mice per group). h Average duration of a single TA burst in 5 s in the sham, untrained, 10−20 Hz EES, 10−20 Hz MS, 10−20 Hz EEShc, and 10−20 Hz EEMS groups (n = 6 mice per group). i Schematic diagram showing the experimental approach for measuring muscle strength. When the muscle was relaxed, the current through the sensor was denoted as I₀; when the muscle contracted, the current through the sensor was I. Schematic was created with BioRender.com. j, k TA muscle contraction and its corresponding relative current in mice of the sham (j) and untrained (k) groups. l–n TA muscle contraction curve for mice in the 10- to 20- HzEEMS (red), EES (green), MS (black), and EEShc (orange) groups. o, p The intensity (o) and frequency (p) of TA muscle contraction in mice in the sham, untrained, and 1- to 40-Hz EEMS, 1- to 40-Hz EES, 1- to 40-Hz MS, and 1- to 40-Hz EEShc groups (n = 6 mice per group). Data represent the mean ± SEM; ns: no statistically significant difference, *p < 0.05, **p < 0.01, ***p < 0.001, one-way ANOVA followed by the Bonferroni post hoc test.