Statistical analysis
As this was a pilot study, a formal sample size calculation was not conducted. The main aim of this pilot study was to determine feasibility of the 4-channel NMES for the main study and to estimate the effect size to inform a future sample size calculation for the main clinical trial. Therefore, a sample of 24 participants was chosen (12 in each group). Considering a dropout rate of 10%, the final sample size was determined to be a total of 26 participantsDescriptive statistics were used to summarize participant characteristics using mean (SD) or number (percentage) as appropriate. Continuous data were assessed for skewness by visual inspection and using a normality test. The Mann − Whitney test was used to compare the two groups. The paired t-test or Wilcoxon signed rank test (if the assumptions of parametric statistical analysis were not satisfied) was used to compare data from the initial and follow-up evaluations. The Statistical Package for the Social Sciences software (version 25.0; SPSS Inc., Chicago, IL, USA) was used for all statistical analyses. Statistical significance was set at P < 0.05.