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Assessment of Neuromuscular Function Using Percutaneous Electrical Nerve Stimulation
Published on: September 13, 2015
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Neuromuscular electrical stimulation pulse duration and maximum tolerated muscle torque
Wayne Scott1, Kathleen Flora, Barbara J Kitchin
1Department of Physical Therapy, Husson University, One College Circle , Bangor, ME , USA.
Physiotherapy Theory and Practice
|January 1, 2014
Summary
Neuromuscular electrical stimulation (NMES) using a 500 μs pulse duration was better tolerated than a 200 μs duration. This finding may improve NMES therapy efficacy for muscle weakness.
Area of Science:
- Physical therapy
- Rehabilitation medicine
- Biomedical engineering
Background:
- Neuromuscular electrical stimulation (NMES) is a key physical therapy for muscle weakness.
- NMES-induced forces correlate with strength gains.
- Patient discomfort can limit NMES force output, potentially hindering treatment effectiveness.
Purpose of the Study:
- To investigate the impact of two NMES pulse durations (200 μs vs. 500 μs) on tolerated knee extensor muscle torques.
- To determine if pulse duration influences patient comfort during NMES therapy.
Main Methods:
- A within-subjects design compared 200 μs and 500 μs pulse durations in 15 participants.
- Identical NMES parameters included monophasic square-wave pulses, 75 Hz frequency, and 1-second train duration.
- The primary outcome was the percentage of maximum voluntary isometric contraction (MVIC) tolerated.
Main Results:
- Subjects tolerated significantly greater MVIC torques with the 500 μs pulse duration (49.3 ± 18.7%) compared to the 200 μs duration (44.5 ± 17.9%).
- The difference in tolerated MVIC was statistically significant (p = 0.02).
Conclusions:
- A 500 μs pulse duration may allow for higher tolerated forces during NMES compared to a 200 μs duration.
- Further research is warranted to assess clinical significance for strength gains and generalizability to other NMES waveforms.
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