Neuromuscular Adaptations to Low-Frequency Stimulation Training in a Patient with Chronic Heart Failure
Electrical myostimulation (EMS) has recently been proposed as an interesting rehabilitation tool in patients with chronic heart failure (CHF). Although its beneficial effects on exercise capacity and muscle strength have been demonstrated, the neuromuscular adaptations responsible for improved performance are not well understood. This preliminary case report was therefore planned to investigate the neural and muscular adaptations to a 5-wk EMS program in one patient. An increase in maximal strength (10.5%) was accompanied by increased twitch torque (13.9%) and slowing of muscle contractile properties (half-relaxation time, time to peak torque, and maximal rate of relaxation increased by 7.1…
Effects of electrical stimulation pattern on quadriceps force production and fatigue
Introduction: Mixed stimulation programs (MIX) that switch from constant frequency trains (CFT) to variable frequency trains have been proposed to offset the rapid fatigue induced by CFT during electrical stimulation. However, this has never been confirmed with long stimulation patterns, such as those used to evoke functional contractions. The purpose of this study was to test the hypothesis that MIX programs were less fatiguing than CFTs in strength training-like conditions (6-s contractions, 30-min). Methods: Thirteen healthy subjects underwent 2 sessions corresponding to MIX and CFT programs. Measurements included maximal voluntary isometric torque and torque evoked by each contraction. …
One year of training with FES has impressive beneficial effects in a 36-year-old woman with spinal cord injury
International audience; CONTEXT:Reductions of muscular and cardiorespiratory functions are often observed in people with spinal cord injury (SCI) and several studies demonstrated the benefits of aerobic and strengthening exercise training for this population. Functional Electrical Stimulation (FES) of paralyzed muscles has been proposed as a strategy to assist patients in executing functional movement but its utilization during long durations has never been investigated. The purpose of the present study was to assess the effects of a one-year training program with FES (strengthening and rowing) in one subject with SCI. Evoked torque, quadriceps muscle thickness, aerobic exercise capacity an…
Time Course of Neuromuscular Alterations during a Prolonged Running Exercise
PLACE, N., R. LEPERS, G. DELEY, and G. Y. MILLET. Time Course of Neuromuscular Alterations during a Prolonged Running Exercise. Med. Sci. Sports Exerc., Vol. 36, No. 8, pp. 1347–1356, 2004. Purpose: This study investigated the time course of contractile and neural alterations of knee extensor (KE) muscles during a long-duration running exercise. Methods: Nine well-trained triathletes and endurance runners sustained 55% of their maximal aerobic velocity (MAV) on a motorized treadmill for a period of 5 h. Maximal voluntary contraction (MVC), maximal voluntary activation level (%VA), and electrically evoked contractions (single and tetanic stimulations) of KE muscles were evaluated before, aft…
Effects of soluble milk protein or casein supplementation on muscle fatigue following resistance training program: a randomized, double-blind, and placebo-controlled study
International audience; Background: The effects of protein supplementation on muscle thickness, strength and fatigue seem largely dependent on its composition. The current study compared the effects of soluble milk protein, micellar casein, and a placebo on strength and fatigue during and after a resistance training program. Methods: Sixty-eight physically active men participated in this randomized controlled trial and underwent 10 weeks of lower-body resistance training. Participants were randomly assigned to the Placebo (PLA), Soluble Milk Protein (SMP, with fast digestion rate) or Micellar Casein (MC, with slow digestion rate) group. During the 10-week training period, participants were …
Effects of electrical stimulation pattern on quadriceps isometric force and fatigue in individuals with spinal cord injury
Introduction Variable frequency trains (VFT) or train combinations have been suggested as useful strategies to offset the rapid fatigue induced by constant frequency trains (CFT) during electrical stimulation. However, most studies have been of short duration with limited functional application in those with spinal cord injury (SCI). We therefore tested force and fatigue in response to VFT, CFT, and combined patterns in strength training-like conditions (6-s contractions). Methods Ten SCI individuals underwent either CFT or VFT patterns until target torque was no longer produced and then switched immediately to the other pattern. Results Target torque was reached more times when VFT was use…
Comparison of low-frequency electrical myostimulation and conventional aerobic exercise training in patients with chronic heart failure.
Physical training is recommended as an efficient therapy in patients with chronic heart failure (CHF). Low-frequency electrical myostimulation (EMS) has recently been suggested as a good alternative to conventional aerobic training. The aim of this study was to compare the effects of EMS and conventional exercise training in patients with moderate to severe CHF.Twenty-four patients with stable CHF (56.7+/-7.3 years, New York Heart Association grades II and III) underwent 5 weeks of exercise training, 5 h a week, using EMS (n=12) or conventional (n=12) training programmes. At baseline and after the training period, patients performed a symptom-limited cardiopulmonary test, a 6-min and a 200-…
Hybrid Functional Electrical Stimulation Exercise Training Alters the Relationship Between Spinal Cord Injury Level and Aerobic Capacity
Objective To test the hypothesis that hybrid functional electrical stimulation (FES) row training would improve aerobic capacity but that it would remain strongly linked to level of spinal cord lesion because of limited maximal ventilation. Design Longitudinal before–after trial of 6 months of FES row training. Setting Exercise for persons with disabilities program in a hospitaL. Participants Volunteers (N=14; age range, 21–63y) with complete spinal cord injury (SCI) (T3-11) who are >2 years postinjury. Intervention Six months of FES row training preceded by a variable period of FES strength training. Main Outcome Measures Peak aerobic capacity and peak exercise ventilation before and after…
Effects of combined electromyostimulation and gymnastics training in prepubertal girls.
This study investigated the effects of a 6-week combined electromyostimulation (EMS) and gymnastic training program on muscle strength and vertical jump performance of prepubertal gymnasts. Sixteen young women gymnasts (age 12.4 ± 1.2 yrs) participated in this study, with 8 in the EMS group and the remaining 8 as controls. EMS was conducted on knee extensor muscles for 20 minutes 3 times a week during the first 3 weeks and once a week during the last 3 weeks. Gymnasts from both groups underwent similar gymnastics training 5-6 times a week. Isokinetic torque of the knee extensors was determined at different eccentric and concentric angular velocities ranging from -60 to +240° per second. Jum…
Effects of Constant and Doublet Frequency Electrical Stimulation Patterns on Force Production of Knee Extensor Muscles
International audience; This study compared knee extensors' neuromuscular fatigue in response to two 30-minute stimulation patterns: constant frequency train (CFT) and doublet frequency train (DFT). Fifteen men underwent two separate sessions corresponding to each pattern. Measurements included torque evoked by each contraction and maximal voluntary contractions (MVC) measured before and immediately after the stimulation sessions. In addition, activation level and torque evoked during doublets (Pd) and tetanic contractions at 80-Hz (P80) and 20-Hz (P20) were determined in six subjects. Results indicated greater mean torque during the DFT stimulation session as compared with CFT. But, no dif…
Pea proteins oral supplementation promotes muscle thickness gains during resistance training: a double-blind, randomized, Placebo-controlled clinical trial vs. Whey protein
The effects of protein supplementation on muscle thickness and strength seem largely dependent on its composition. The current study aimed at comparing the impact of an oral supplementation with vegetable Pea protein (NUTRALYS®) vs. Whey protein and Placebo on biceps brachii muscle thickness and strength after a 12-week resistance training program. One hundred and sixty one males, aged 18 to 35 years were enrolled in the study and underwent 12 weeks of resistance training on upper limb muscles. According to randomization, they were included in the Pea protein (n = 53), Whey protein (n = 54) or Placebo (n = 54) group. All had to take 25 g of the proteins or placebo twice a day during the 12-…
Effects of a one-year exercise training program in adults over 70 years old: a study with a control group
Background and aims: Exercise training is known to improve exercise tolerance in elderly subjects. Therefore the present study aimed at investigating the effects of one year of combined endurance and resistance training in healthy older people. Methods: After baseline evaluation, subjects were assigned to either the training group (n=24, age 77.2±3.6) or the control group (n=16, age 76.1±4.8). Subjects in the control group did not change anything in their everyday activities, whereas subjects in the training group underwent moderately intensive combined exercise training, 3 hours a week over the course of one year. Breath-by-breath oxygen uptake and heart rate were measured at each workload…