Acute Effect of Trans Spinal Direct Current Stimulation on Muscle Strength and Respiratory Muscle Endurance in Healthy Community-dwelling Women Elderly

Research Objectives: To assess the muscle strength and respiratory endurance in healthy elderly individuals following a session of trans spinal direct current stimulation (tsDCS).

Design: A Randomized, Controlled, Blind study.

Setting: Community-dwelling healthy women elderly through the public call.

Participants: Thirty female elderly volunteers were selected and randomized into two groups stratified by age, body mass index, forced volume in the first second, and forced vital capacity.

Interventions: 30 minutes of 2mA of tsDCS or Sham stimuli in the C3-C5 region, with the cathode placed anteriorly on the neck and the anode placed posteriorly.

Main Outcome Measures: On the first day, participants underwent clinical evaluation and spirometry assessed. On the second day, participants underwent assessment of respiratory resistance using maximal voluntary ventilation (MVV) by spirometer and dynamic respiratory muscle strength (Sindex), and peak inspiratory flow (PIF). ANOVA two-way (between-within) post hoc Bonferroni was used. A significance level of p < 0.05 was accepted.

Results: tsDCS acutely increased dynamic inspiratory muscle strength in the stimulated group without effect in sham stimulation (tsDCS: before: 77.9 ± 17.8 cmH2O; after: 87.1 ± 20 cmH2O, p=0.04; Sham: before: 77.2 ± 15.2 cmH2O; after: 82.8 ± 9.7 cmH2O, p=0.31,eta square: 0.053), increased PIF in the stimulated group without effect in placebo stimulation (tsDCS: before: 4.22 ± 0.87 l/s; after: 4.72 ± 1.01 l/s, p=0.026; Sham: before: 4.31 ± 0.75 l/s; after: 4.68 ± 0.5 l/s, p=0.60,eta square: 0.057), and increased predicted MVV stimulated group without effect in sham stimulation (tsDCS: before: 66.9 ± 13%; after: 74.1 ± 6.90%, p=0.047; Sham: before: 64.9 ± 10.9%; after: 62.7 ± 12.1%, p=0.22,eta square: 0.044).

Conclusions: Acute tsDCS stimulation can increase muscle strength and ventilatory endurance in community-dwelling elderly women. Treatment using the tsDCS associated to inspiratory muscle strength can amplify the effects of training.

Author(s) Disclosures: All authors denied conflicts of interests.