Neuromuscular adaptations to electrostimulation resistance training.

Schulthess Klinik, Lengghalde 2, 8008 Zürich, Switzerland.
American Journal of Physical Medicine & Rehabilitation (Impact Factor: 2.01). 03/2006; 85(2):167-75. DOI: 10.1097/01.phm.0000197570.03343.18
Source: PubMed

ABSTRACT A combination of in vivo and in vitro analyses was performed to investigate muscular and neural adaptations of the weaker (nondominant) quadriceps femoris muscle of one healthy individual to short-term electrostimulation resistance training. The increase in maximal voluntary strength (+12%) was accompanied by neural (cross-education effect and increased muscle activation) and muscle adaptations (impairment of whole-muscle contractile properties). Significant changes in myosin heavy chain (MHC) isoforms relative content (+22% for MHC-2A and -28% for MHC-2X), single-fiber cross-sectional area (+27% for type 1 and +6% for type 2A muscle fibers), and specific tension of type 1 (+67%) but not type 2A fibers were also observed after training. Plastic changes in neural control confirm the possible involvement of both spinal and supraspinal structures to electrically evoked contractions. Changes at the single muscle fiber level induced by electrostimulation resistance training were significant and preferentially affected slow, type 1 fibers.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstract Background: Electrical muscle stimulation (EMS) is applied to critically ill patients in order to improve their muscle strength, thereby preventing hypotrophy and promoting functional recovery. Objective: To assess the effects of early EMS on the range of movement of the ankle joint, and on thigh and leg circumference in critically ill patients. Methods: This is a prospective randomized clinical trial comprising 11 patients undergoing mechanical ventilation. Before and after EMS the thigh and leg circumference in both lower limbs and the goniometry of the tibiotarsal joint were measured. The angle of 90° on the goniometer was taken as the standard neutral position (NP), with the arm fixed on the lateral malleolus of the ankle joint. Other measurements, namely dorsiflexion and plantar flexion, referred to as mobile arm, were taken from the NP. These recordings were obtained following an active contraction of the patients' muscles. Results: Compared with the electrostimulated limb, a difference in dorsiflexion of the control limb was observed (96.2 ± 24.9 versus 119.9 ± 14.1°; p = 0.01). A girth of 10 cm of the leg was found in limb reduction when compared to the electrostimulated one (24.7 ± 3.1 versus 26.4 ± 4.0 cm; p = 0.03). Conclusions: EMS used at low current intensity and for a short duration failed to prevent muscle atrophy in critically ill patients. However, we did find a significant improvement in active dorsiflexion of the ankle joint suggesting that it could help to prevent against stance plantar flexion in these patients.
    Physiotherapy Theory and Practice 12/2013;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Neuromuscular electrical stimulation (NMES) training is known to induce improvement in force production capacities and fibre-type transition. The aim of this study was to determine whether NMES training also leads to changes in the mechanical properties of the human triceps surae (TS) muscle. Fifteen young male subjects performed a training protocol (4 weeks, 18 sessions, 4-5 sessions per week) based on a high-frequency isometric NMES programme of TS muscle. Quick-release test was used to evaluate Musculo-Tendinous (MT) stiffness index (SIMT) as the slope of the linear MT stiffness-torque relationships under submaximal contraction. Sinusoidal perturbations allowed the assessment of musculo-articular stiffness index (SIMA) as well as the calculation of the maximal angular velocity ([Formula: see text]) of TS muscle using an adaptation of Hill's equation. After NMES training, Maximal Voluntary Contraction under isometric conditions and [Formula: see text] increased significantly by 17.5 and 20.6 %, respectively, while SIMT and SIMA decreased significantly (-12.7 and -9.3 %, respectively). These changes in contractile and elastic properties may lead to functional changes of particular interest in sport-related activities as well as in the elderly.
    Arbeitsphysiologie 03/2014; · 2.30 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Short periods of muscle disuse, due to illness or injury, result in substantial skeletal muscle atrophy. Recently we have shown that a single session of neuromuscular electrical stimulation (NMES) increases muscle protein synthesis rates To investigate the capacity for daily NMES to attenuate muscle atrophy during short-term muscle disuse. Twenty-four healthy, young (23±1 y) males participated in the present study. Volunteers were subjected to 5 days of one-legged knee immobilisation with (NMES; n=12) or without (CON; n=12) supervised NMES sessions (40 min sessions, twice daily). Two days prior to and immediately after the immobilisation period, CT-scans and single leg one-Repetition Maximum (1RM) strength tests were performed to assess quadriceps muscle cross-sectional area (CSA) and leg muscle strength, respectively. Furthermore, muscle biopsies were taken to assess muscle fibre CSA, satellite cell content and mRNA and protein expression of selected genes. In CON, immobilisation reduced quadriceps CSA by 3.5±0.5% (P<0.0001) and muscle strength by 9±2% (P<0.05). In contrast, no significant muscle loss was detected following immobilisation in NMES although strength declined by 7±3% (P<0.05). Muscle MAFbx and MuRF1 mRNA expression increased following immobilisation in CON (P<0.001 and P=0.07, respectively) whereas levels either declined (P<0.01) or did not change in NMES, respectively. Immobilisation led to an increase in muscle myostatin mRNA expression in CON (P<0.05) but remained unchanged in NMES. During short-term disuse, NMES represents an effective interventional strategy to prevent the loss of muscle mass, but it does not allow preservation of muscle strength. NMES during disuse may be of important clinical relevance in both health and disease. This article is protected by copyright. All rights reserved.
    Acta Physiologica 11/2013; · 4.25 Impact Factor