RESUMEN
The application of transcutaneous electrical nerve stimulation (TENS) can improve motor performance in both healthy individuals and those who present with clinically detectable sensory impairments. The purpose of our study was to compare the influence of continuous and intermittent TENS applied to the anterior thigh and tibialis anterior muscles on walking endurance and kinematics in healthy, middle-aged adults. Twenty-seven participants completed 4 trials of the 6-min walk test: Baseline, Continuous TENS (0.2 ms pulses at 50 Hz), Fast burst TENS (seven 0.15 ms pulses in 5 Hz bursts), and Slow burst TENS (seven 0.15 ms pulses in 0.5 Hz bursts). Linear mixed-effects models revealed that participants walked further (p ≤ 0.046) during all three TENS trials compared with Baseline (560 ± 76 m) and that they walked even further during both burst TENS trials (576 ± 83 m and 576 ± 83 m) compared with Continuous TENS (566 ± 79 m). Increases in walking speed were predicted by increases in stride length (p < 0.001) and stride frequency (p < 0.001) with toe-off angle being the only significant predictor (p ≤ 0.013) of both kinematic variables for the increase in walking speed. Bursting TENS was more effective than Continuous TENS at improving walking endurance in middle-aged, healthy adults.
Asunto(s)
Estimulación Eléctrica Transcutánea del Nervio , Adulto , Humanos , Persona de Mediana Edad , Músculo Esquelético , Caminata/fisiologíaRESUMEN
Electrical stimulation modulates sensory feedback and improves motor performance, at least for individuals with compromised sensorimotor function. The purpose of this study was to determine the effectiveness of a 4-wk intervention with transcutaneous electrical nerve stimulation (TENS) at improving strength and balance in dancers. Nineteen dancers completed a timed, single-leg balance test, the Y-balance test, and contractions with the hip flexor and knee extensor muscles to assess maximal strength and force steadiness. They completed 4-wks of moderate-intensity bodyweight exercises (3x/wk) and were pseudo-randomized to either a Treatment or Sham group in a single-blind design. The Treatment group received constant TENS over the hamstring muscles during the exercises, whereas the Sham group was exposed to a brief TENS current. The data were pooled due to few significant between-group differences from before to after the intervention. Most outcome measures significantly improved: hip extensor muscles were stronger (P ≤ 0.01), time stood on a single-leg with eyes closed increased (P = 0.02), and the distance reached during the Y-balance test increased (P ≤ 0.001). The improvement in scores on the Y-balance test exceeded the minimal clinically significant change. Twelve sessions of moderate-intensity bodyweight exercises improved muscle strength and balance in experienced dancers. The addition of TENS, however, did not augment the gains in function.