Sweep Frequency of Interferential Currents Therapy Attenuate Fatigue of Biceps Brachia Muscle in Normal Male Subjects: A Randomized Placebo Control Trial (original) (raw)
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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.
Blood flow and muscle fatigue in SCI individuals during electrical stimulation
Journal of Applied …, 2003
Our purpose was to measure blood flow and muscle fatigue in chronic, complete, spinal cord-injured (SCI) and able-bodied (AB) individuals during electrical stimulation. Electrical stimulation of the quadriceps muscles was used to elicit similar activated muscle mass. Blood flow was measured in the femoral artery by Doppler ultrasound. Muscle fatigue was significantly greater (three-to eightfold, P Յ 0.001) in the SCI vs. the AB individuals. The magnitude of blood flow was not significantly different between groups. A prolonged half-time to peak blood flow at the beginning of exercise (fivefold, P ϭ 0.001) and recovery of blood flow at the end of exercise (threefold, P ϭ 0.009) was found in the SCI vs. the AB group. In conclusion, the magnitude of the muscle blood flow to electrical stimulation was not associated with increased muscle fatigue in SCI individuals. However, the prolonged time to peak blood flow may be an explanation for increased fatigue in SCI individuals.
Effects of stimulation frequency versus pulse duration modulation on muscle fatigue
Journal of Electromyography and Kinesiology, 2008
During functional electrical stimulation (FES), both the frequency and intensity can be increased to increase muscle force output and counteract the effects of muscle fatigue. Most current FES systems, however, deliver a constant frequency and only vary the stimulation intensity to control muscle force. This study compared muscle performance and fatigue produced during repetitive electrical stimulation using three different strategies: (1) constant pulse-duration and stepwise increases in frequency (frequency-modulation); (2) constant frequency and stepwise increases in pulse-duration (pulse-duration-modulation); and (3) constant frequency and pulse-duration (no-modulation). Surface electrical stimulation was delivered to the quadriceps femoris muscles of 12 healthy individuals and isometric forces were recorded. Muscle performance was assessed by measuring the percent changes in the peak forces and force-time integrals between the first and the last fatiguing trains. Muscle fatigue was assessed by measuring percent declines in peak force between the 60 Hz pre-and post-fatigue testing trains. The results showed that frequency-modulation showed better performance for both peak forces and force-time integrals in response to the fatiguing trains than pulse-duration-modulation, while producing similar levels of muscle fatigue. Although frequencymodulation is not commonly used during FES, clinicians should consider this strategy to improve muscle performance.
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.
The Etiology of Muscle Fatigue Differs between Two Electrical Stimulation Protocols
Medicine & Science in Sports & Exercise, 2016
This study aimed at investigating the mechanisms involved in the force reduction induced by two electrical stimulation (ES) protocols that were designed to activate motor units differently. Methods: The triceps surae of eleven healthy subjects (8 men, age: ~28 yrs) was activated using ES applied over the tibial nerve. Two ES protocols (Conventional (CONV): 20 Hz-0.05 ms vs. Wide-Pulse High-Frequency (WPHF): 80 Hz-1 ms) were performed and involved 40 trains (6 s on-6 s off) delivered at an intensity (I ES) evoking 20% of maximal voluntary contraction. In order to analyze the mechanical properties of the motor units activated at I ES , force-frequency relation was evoked before and after each protocol. H-reflex and M-wave responses evoked by the last stimulation pulse were also assessed during each ES protocol. Electrophysiological responses (∑EMG) were recorded after each train in order to analyze the behavior of the motor units activated at I ES. Metabolic variables, including relative concentrations of phosphocreatine and inorganic phosphate as well as intracellular pH, were assessed using 31 P-MR spectroscopy during each protocol. Results: Larger H-reflex amplitudes were observed during WPHF as compared to CONV whereas opposite findings were observed for M-wave amplitudes. Despite this difference, both the force reduction (-26%) and metabolic changes were similar between the two protocols. The CONV protocol induced a rightward shift of the force-frequency relation whereas a significant reduction of the ∑EMG evoked at I ES was observed only for the WPHF. Conclusion: These results suggest that a decreased number of active motor units mainly contributed to WPHF-induced force decrease while intracellular processes were most likely involved in the force reduction occurring during CONV stimulation.
Reduction of muscle fatigue in man by cyclical stimulation
Journal of Biomedical Engineering, 1988
In order to develop a control system for electrical stimulation of paralysed muscle and improve muscle resistance to fat&e, it is useful to investigate the possibilities of simulating the control systems of the normal body. One way is the periodic shafting of stimulation from one muscle to another. This technique is called sequential stimulation and allows suficient rest time for each muscle to reduce fatigue and consequently prolong muscle strength. It can also be seen to improve the muscle recovery time. In the following study, the muscles rectus femoris, vastus lateralis and vastus medialis were used to keep the knee locked and extended during stimulation. Several experiments were carried out using a three-channel computer controlled stimulator. The results for three-phase sequential stimulation (33 70 duty cycle per muscle) were most effective and significantly improved the muscle fatigue characteristics.
Physical therapy, 1993
Muscle fatigue can be defined as a decrease in the force-generating ability of a muscle that resulted from recent activity. Recent studies of muscle fatigue are reviewed that are relevant to two areas of interest to physical therapists: clinical assessment of muscle fatigue and neuromuscular electrical stimulation. Volitional and electrical tests have been used to quantify muscle fatigue. Several variations on each type of test are discussed, as are the possible sites in which fatigue might occur. The rate of fatigue during the therapeutic application of electrical stimulation of skeletal muscle is much greater than that seen during volitional contractions. Factors contributing to this phenomenon are examined. The unique requirements affecting how stimulus variables can be manipulated to minimize muscle fatigue in three specific therapeutic uses of neuromuscular electrical stimulation are addressed.