Comparative Effects of One-Shot Electrical Stimulation on Performance of the Flexor Hallucis Longus Muscle in Professional Dancers: Percutaneous Versus Transcutaneous?

Abstract

Objective High demand of flexor hallucis longus (FHL) in the positions of extreme flexion of the ankle and toes is required in the dance. The aim was to investigate the effects of single-shot of ultrasound-guided percutaneous neuromodulation (PNM) vs. single-shot of transcutaneous electrical nerve stimulation (TENS) in performance of the FHL muscle in professional dancers.

Materials and Methods Thirty-two female healthy dancers were divided into two groups: TENS group and PNM group. The stimulation interventions consisted in the application of a square wave biphasic electrical current for a total of 1.5 mins. Range of motion (ROM) of first metatarsophalangeal joint, balance test, and unilateral heel raise fatigue test were performed in dominance limb.

Results There were no differences between both groups in the baseline measurements. Compared to their baseline values, the TENS group statistically improved balance (p < 0.01, d = 0.6), ROM (p < 0.001, d = 0.3), and endurance (p = 0.04, d = 0.5). The PNM group only statistically improved balance and endurance (p < 0.001), with a large effect size for both test (d = 0.8 and d = 2.24, respectively). After interventions, there were no significant differences between TENS and PNM groups for all variables. However, PNM was qualitatively more effective because the percentage change in mean was greater and effect size was large for the balance test and endurance test.

Conclusions Simple single-shot procedure with percutaneous or TENS provided immediate performance improvement of FHL muscle in dancers, being PNM the more effective intervention.