Effects of Burst-Type Transcutaneous Electrical Nerve Stimulation on Cervical Range of Motion and Latent Myofascial Trigger Point Pain Sensitivity

Rodríguez-Fernández AL, Garrido-Santofimia V, Güeita-Rodríguez J, Fernández-de-las-Peñas C. Effects of burst-type transcutaneous electrical nerve stimulation on cervical range of motion and latent myofascial trigger point pain sensitivity.ObjectiveTo assess the effects of a burst application of transcutaneous electrical nerve stimulation (TENS) on cervical range of motion and pressure point sensitivity of latent myofascial trigger points (MTrPs).DesignA single-session, single-blind randomized trial.SettingGeneral community rehabilitation clinic.ParticipantsIndividuals (N=76; 45 men, 31 women) aged 18 to 41 years (mean ± SD, 23±4y) with latent MTrPs in 1 upper trapezius muscle.InterventionsSubjects were randomly divided into 2 groups: a TENS group that received a burst-type TENS (pulse width, 200μs; frequency, 100Hz; burst frequency, 2Hz) stimulation over the upper trapezius for 10 minutes, and a placebo group that received a sham-TENS application over the upper trapezius also for 10 minutes.Main Outcome MeasuresReferred pressure pain threshold (RPPT) over the MTrP and cervical range of motion in rotation were assessed before, and 1 and 5 minutes after the intervention by an assessor blinded to subjects' treatment.ResultsThe analysis of covariance revealed a significant group × time interaction (P<.001) for RPPT: the TENS group exhibited a greater increase compared with the control group; however, between-group differences were small at 1 minute (0.3kg/cm2; 95% confidence interval [CI], 0.1–0.4) and at 5 minutes (0.6kg/cm2; 95% CI, 0.3–0.8) after treatment. A significant group × time interaction (P=.01) was also found for cervical rotation in favor of the TENS group. Between-group differences were also small at 1 minute (2.0°; 95% CI, 1.0–2.8) and at 5 minutes (2.7°; 95% CI, 1.7–3.8) after treatment.ConclusionsA 10-minute application of burst-type TENS increases in a small but statistically significant manner the RPPT over upper trapezius latent MTrPs and the ipsilateral cervical range of motion.