Quadriceps femoris muscle torques and fatigue generated by neuromuscular electrical stimulation with three different waveforms (original) (raw)
Related papers
Influence of electrical stimulation frequency on skeletal muscle force and fatigue
Annals of Physical and Rehabilitation Medicine, 2010
Objective. -The aim of this study is to determine the impact of electrical stimulation frequency on muscle force and fatigue and propose application modalities in regards to sports or clinical rehabilitation training. Methods. -The maximal voluntary contraction (MVC) force of the quadriceps femoris muscle was recorded before, during and after electrical stimulation in 26 healthy adults during 20-minute sessions corresponding to 60 of 5-second contractions separated by 15-second rest periods. Three different frequencies were used: 100, 50 and 20 Hz.
Electrical Stimulation Frequency and Skeletal Muscle Characteristics: Effects on Force and Fatigue
European Journal of Translational Myology, 2017
This investigation aimed to determine the force and muscle surface electromyography (EMG) responses to different frequencies of electrical stimulation (ES) in two groups of muscles with different size and fiber composition (fast- and slow-twitch fiber proportions) during a fatigue-inducing protocol. Progression towards fatigue was evaluated in the abductor pollicis brevis (APB) and vastus lateralis (VL) when activated by ES at three frequencies (10, 35, and 50Hz). Ten healthy adults (mean age: 23.2 ± 3.0 years) were recruited; participants signed an IRB approved consent form prior to participation. Protocols were developed to 1) identify initial ES current intensity required to generate the 25% maximal voluntary contraction (MVC) at each ES frequency and 2) evaluate changes in force and EMG activity during ES-induced contraction at each frequency while progressing towards fatigue. For both muscles, stimulation at 10Hz required higher current intensity of ES to generate the initial f...
Effects of Electrical Stimulation Parameters on Fatigue in Skeletal Muscle
Journal of Orthopaedic & Sports Physical Therapy, 2009
N euromuscular electrical stimulation (NMES) is a promising tool in the rehabilitation of individuals with a limited ability to activate their skeletal muscles, as well as a method of strength training and short-term resistance training in athletic populations. During NMES application, the capacity to maintain performance is compromised compared to voluntary exercise, Experimental laboratory study.
Proceedings of the International Conference on Bio-inspired Systems and Signal Processing, 2015
Introduction: Neuromuscular electrical stimulation (NMES) is used by physical therapists in the clinic. The efficacy of NMES is limited by the rapid onset muscle fatigue. The role of NMES parameters is muscle fatigue is not clear. Objective: To determine the effects of shape waveform on muscle fatigue, during NMES. Methods: Twelve healthy subjects participated in the study. Subjects were assigned to 1 of 3 groups, randomly. Group assignment determined the order in which they were tested using 3 different shape waveforms. Maximal voluntary isometric contraction (MVIC) was measured during the first session. Fatigue test was applied with amplitude required to elicit 50% of the MVIC. In each 3 testing sessions torque of contraction and level comfort were measured, and percent fatigue was calculated. Analysis of variance tests for dependent samples was used to determine the effect of shape waveform on muscle fatigue and comfort scores Results: The results showed no one shape waveform was most fatigable and that SQ wave induced more uncomfortable stimulus.
Journal of sports science & medicine
This study was conducted to determine: 1) If healthy subjects can be conditioned to tolerate clinically useful electrically induced muscle contraction; and 2) If there is a gender difference in response to such conditioning. Healthy volunteers (10 males, 11 females, mean age of 27.6±5.8 yrs) were tested during each of 6 testing sessions. Maximal voluntary isometric contractions (MVIC) of the right quadriceps femoris (RQF) recorded by a computerized dynamometer. Electrical stimulation delivered through two surface electrodes and stimulation amplitude increased until the subject indicated to stop. After a 1 min rest the amplitude increased again to the same phase charge level, and the electrically induced contraction (EIC) was recorded by the dynamometer. Measurements of stimulation amplitude were repeated in each of 10 stimulation bouts per session. Measurements of EIC were repeated in session six. Statistical analyses included Multivariate ANOVAs, and Newman-Kuel's post-hoc tests (p < 0.01). Mean values of phase charge increased from session 1 to 6 for all subjects. Males tolerated significantly higher phase charge. The mean %MVIC torque generated by female subjects was initially only 11.2 ± 21.6% but reached 42.9 ± 25.4% at the end of the 6th session. Males' %MVIC torque values were significantly higher reaching 49.0 ± 41.6% and 73.5 ± 18.7% in the first and last trials respectively. Using the criterion that electrically induced contractions must be at least 25% of MVIC to be considered clinically useful, 36% of females were below this threshold at the end of the last session. In contrast, all males exceeded the 25% MVIC threshold at the end of the study. Most healthy subjects can be conditioned to electrical stimulation of the quadriceps, but depending on the criteria of therapeutic value and gender, some males and even more females may not reach the desired stimulation goal in 6 sessions. Females may require more conditioning sessions to reach contraction levels of therapeutic benefits. The reason(s) for the confounding factor of gender remains unknown.
Changing stimulation patterns improves performance during electrically elicited contractions
Muscle & Nerve, 2003
The clinical efficacy of functional electrical stimulation (FES) is limited by the rapid onset of fatigue. FES applications use electrical stimuli separated by regular interpulse intervals (constant-frequency trains or CFTs) to activate muscles. However, doublet-frequency trains (DFTs) may produce greater forces than CFTs, but also produce more fatigue. DFTs contain a series of doublets, two pulses separated by a short (5-ms) interpulse interval. We hypothesized that a combination of CFTs followed by DFTs would improve performance compared to either train type alone. Quadriceps muscles of 15 normal subjects were fatigued with either 150 DFTs, or initially fatigued with CFTs until the targeted isometric force was no longer produced and then switched to DFTs. The combination reached the targeted isometric force (mean Ϯ SEM) more times (59.80 Ϯ 4.03) than either the CFTs alone (51.20 Ϯ 3.50) or DFTs alone (55.33 Ϯ 3.81). This finding suggests that combining train types may be a useful strategy to offset the rapid fatigue that persons with neurological dysfunction, such as spinal cord injury, experience when using FES.
Characterization of an electric stimulation protocol for muscular exercise
Annals of Physical and Rehabilitation Medicine, 2011
Objective. -The aim of this study is to evaluate the effect of rest time (ten minutes) on muscular strength production during a training session under electrical stimulation. Patients and methods. -The isometric force output of the quadriceps femoris muscle was recorded during four sessions of stimulation of five minutes (15 maximal contractions: five seconds on and 15 seconds of rest), on 13 healthy adults. These four sessions are spaced out of ten minutes of recovery. The frequency of current is 100 Hz.
Effects of chronic low frequency electrical stimulation on normal human tibialis anterior muscle
Journal of Neurology, Neurosurgery & Psychiatry, 1985
The loss of force that occurred during intermittent electrically evoked tetanic contractions was determined for the tibialis anterior muscle of normal subjects. Adult muscles showed a characteristic reduction of tension over the first two to three minutes until a steady plateau was reached. Muscles of young children showed no comparable decrease of the initial tension in response to this method of fatigue testing. After fatigue the muscles of both groups of subjects produced a higher proportion of tension at lower rates of stimulation. Following prolonged chronic low frequency stimulation at 8-10 Hz, adult muscles showed a significant increase (p < 0.01) in fatigue resistance compared to unstimulated control: the muscles of the normal child showed no measured change. It is concluded that it is possible to alter the properties of adult human muscle by superimposed low frequency electrical stimulation.
Experimental Physiology, 2006
Different combinations of stimulation frequency and intensity can generate a targeted force during functional electrical stimulation (FES). This study compared isometric performance and muscle fatigue during repetitive stimulation with three different combinations of frequency and pulse duration that produced the same initial peak forces: protocol 1 used long pulse duration (fixed at 600 μs) and 11.5 ± 1.2 Hz (low frequency); protocol 2 used 30 Hz (medium frequency) and medium pulse duration (150 ± 21 μs); and protocol 3 used 60 Hz (high frequency) and short pulse duration (131 ± 24 μs). Twenty and 60 Hz pre-and postfatigue testing trains were delivered at the pulse duration used by the fatiguing trains and at 600 μs pulse duration. The percentage decline in peak force between the first and last fatiguing train of each protocol was the measure of muscle performance. The declines in peak force of the 60 Hz testing trains were used to measure muscle fatigue. The 20 Hz:60 Hz peak force ratio was used as a measure of lowfrequency fatigue. The results showed that protocol 1 produced the least decline in peak force in response to the fatiguing trains, as well as the least muscle fatigue and low-frequency fatigue when the pulse duration was maintained at the level used by the fatiguing trains. Interestingly, protocol 2 produced the least muscle fatigue, and there were no differences in the levels of lowfrequency fatigue across protocols when a comparable motor unit population was tested using 600 μs pulse duration. The results suggest that if the frequency and intensity are kept constant during FES, using the lowest frequency and longest pulse duration may maximize performance.