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Influence of stimulus pulse width on M‐waves, H‐reflexes, and torque during tetanic low‐intensity neuromuscular stimulation
Author(s) -
Lagerquist Olle,
Collins David F.
Publication year - 2010
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.21762
Subject(s) - isometric exercise , stimulation , h reflex , pulse (music) , reflex , stimulus (psychology) , physical medicine and rehabilitation , medicine , torque , anesthesia , physical therapy , physics , psychology , voltage , quantum mechanics , psychotherapist , thermodynamics
Neuromuscular electrical stimulation (NMES) has been shown to generate contractions that include a central recruitment of motoneurons; however, the effect of pulse width on electromyographic (EMG) and torque responses during NMES are not well documented. Soleus EMG and isometric plantarflexion torque were recorded from 14 subjects with NMES delivered to the tibial nerve using 50, 200, 500, and 1000 μs pulse widths. M‐waves were significantly smaller during 20 H Z NMES compared with responses evoked by single pulses of 200, 500, and 1000 μs, but not 50 μs pulse widths. At all pulse widths, stimulation at 20 H Z depressed soleus H‐reflexes compared with single pulses. Two seconds of 100 H Z NMES significantly increased H‐reflexes and torque during the subsequent 20 H Z NMES with 200, 500, and 1000 μs, but not 50 μs, pulse widths. NMES delivered using wide pulses generated larger contractions with a relatively greater central contribution than narrow pulses. This may help reduce atrophy and produce fatigue‐resistant contractions for rehabilitation. Muscle Nerve, 2010