The Effect of Rest Intervals on Knee-Extension Torque Production with Neuromuscular Electrical Stimulation

Abstract

Context:Previous studies using neuromuscular electrical stimulation (NMES) have suggested that 30-second rest intervals are too short for sufficient recovery.Objective:To compare the effect of rest interval on knee-extension torque production.Design:Counterbalanced mixed design to test independent variable, rest interval; ANOVA to analyze dependent variable, percentage decline.Setting:Athletic training research laboratory.Participants:24 healthy men and women.Intervention:Participants performed knee extension under 2 contraction conditions, maximum voluntary isometric contraction (MVIC) and NMES with either 30- or 120-second rest between repetitions.Main Outcome Measure:Peak torque produced during each repetition of a 5-repetition set.Results:The main effect for rest interval was significant (F1,23= 30.30,P= .001), as was the main effect for condition (F1,23= 11.18,P= .003).Conclusions:A 120-second rest between repetitions is recommended when using NMES in early rehabilitation because force decline across repetitions with 30-second rest during NMES is greater than with MVIC.

Improving the Efficiency of Electrical Stimulation Activities After Spinal Cord Injury

“…However, Holcomb et al reported force declines of 8.2 % over 5 NMES repetitions even when rest intervals were lengthened to 2 min between each repetition. Under the same conditions force declines with voluntary contractions were only 2.8 % [7]. Gorgey et al [8] reported that decreasing the frequency from 100 to 25 Hz decreased fatigue from 76 to 39 % during NMES knee extension exercise accounting for just under half of the fatigue presented.…”

Subcutaneous Tissue Thickness Alters the Effect of NMES

“…A Vectra Genisys electrical stimulation unit (Chattanooga Group, TN), utilizing a combination protocol of high volt stimulation current with an ultrasound head to mimic a motor point probe, was used to find the specific motor point of the vastus medialis oblique (VMO) of the right quadriceps and upper thigh, similar to the procedures used in a previous study. 12 The VMO motor point and 6 inches above the VMO motor point were marked with a permanent marker. Skinfold measurements were taken at both sites using a Lange skinfold caliper (Beta Technology Inc, Cambridge, MD) by a certified athletic trainer who was trained and certified as a Michigan High School Athletic Association (MHSAA) wrestling skinfold assessor to ensure intrarater reliability of measurements.…”

“…The OrthoDx TM has been used in previous research and has been shown to be a sufficient provider of NMES. 12 Current was delivered via two active electrodes. A 4″ × 6.75″ self adhesive Stimcare™ electrode (Rehabilicare, New Brighton, MN) was centered on the anterior thigh six inches above the VMO motor point, and a 4″ × 2″ self adhesive Stimcare™ electrode was placed over the marked motor point of the VMO after shaving and cleaning the sites.…”

Effects of Multipath and Conventional NMES on Maximum Comfortable Stimulus and Torque Production

“…The menstrual cycle has been shown to influence self-reported discomfort levels (Teepker, Peters, Vedder, Schepelmann, Lautenbacher, 2010), thus due to our study design requiring repeated measurements over time we felt it was necessary to exclude females. In addition, during exploratory NMES studies, similar in nature to our study, it is common practice to use healthy participants (Alon, Smith, 2005;Dantas et al, 2015;Gorgey, Dudley, 2008;Holcomb et al, 2007;Holcomb, Rubley, Miller, Girouard, 2006;Holcomb, Rubley, Randolph, 2011;Maffiuletti et al, 2014).…”