The addition of electrical stimulation to progressive resistance training does not enhance the wrist strength of people with tetraplegia: a randomized controlled trial.

OBJECTIVE: To determine whether the addition of electrical stimulation to progressive resistance training increases the voluntary strength of the wrist muscles in people with tetraplegia. DESIGN: Assessor-blind within-subject randomised controlled trial. SETTING: Two Australian spinal cord injury units and the community. PARTICIPANTS: Sixty-four wrists of 32 people with tetraplegia and bilateral weakness of the wrist extensor or flexor muscles (grade 2 - 4 Medical Research Council grades). INTERVENTIONS: Participants' wrists were randomly allocated to one of two conditions. Wrist muscles of the experimental arm received electrical stimulation superimposed on progressive resistance training. The wrist muscles of the contralateral arm received sham electrical stimulation superimposed on progressive resistance training. Both arms received 6 sets of 10 contractions three times a week for eight weeks such that the only difference between arms was the application of electrical stimulation. MAIN MEASURES: The primary outcome was maximal voluntary isometric strength. Secondary outcomes were a fatigue resistance ratio representing voluntary and electrically-stimulated endurance. Measurements were taken at the start and end of the eight-week treatment period. RESULTS: The mean treatment effect (95% Confidence Interval) of electrical stimulation for voluntary strength was 0.04 Nm (95% CI, -0.5 to 0.6; p =0.89). The mean treatment effect (95% CI) for fatigue ratio representing voluntary endurance and electrically-stimulated endurance was -0.01 (95% CI, -0.1 to 0.1; p =0.78) and -0.07 (95% CI, -0.3 to 0.1; p =0.47), respectively. CONCLUSIONS: Voluntary strength of the wrist is not enhanced by the addition of electrical stimulation to progressive resistance training programs in people with tetraplegia.

Efficacy of electrical stimulation to increase muscle strength in people with neurological conditions: a systematic review.

BACKGROUND AND PURPOSE: Weakness in partially paralysed muscles is a disabling impairment for people with neurological conditions. Strength training programmes are widely administered to address this impairment. There is a common belief that the effectiveness of strength training programmes can be enhanced by the addition of electrical stimulation. The purpose of this systematic review was to assess the efficacy of electrical stimulation for increasing voluntary strength in people with neurological conditions. METHOD: Eligible randomized trials of electrical stimulation were identified by searches of computerized databases. The search yielded 11,267 abstracts, of which 60 were retrieved. Two assessors independently reviewed full text versions of these articles. RESULTS: Eighteen studies satisfied the inclusion criteria. These studies involved participants with spina bifida (n = 1), cerebral palsy (n = 1), peripheral nerve lesion (n = 1), multiple sclerosis (n = 1), spinal cord injury (n = 3) and stroke (n = 11). The mean (SD) PEDro score for trial quality was 4.9 (1.0) out of 10. Meta-analyses of studies involving similar patients were not done because of insufficient data or lack of homogeneity. The results of all studies were analysed individually. CONCLUSION: Several studies suggest a modest beneficial effect of electrical stimulation in patients with stroke. It is not clear whether patients with other types of neurological disabilities benefit from electrical stimulation in the same way.