Fig. (3) Sum and difference of sciatic pain reduction. (A) The sum of pain reduction had been calculated by adding pain changes during the first and second phase of intervention within each group. (B) Difference of pain reduction had been calculated by subtracting the pain reduction during the second phase of intervention from those achieved during the first phase of intervention within each group. #p<0.05; H1: first intervention phase with HTEMS; H2: second intervention phase with HTEMS; T1: first intervention phase with TENS; T2: second intervention phase with TENS.