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Rehabilitation Research and Practice
Volume 2017 (2017), Article ID 5107097, 6 pages
Research Article

Modulation of H-Reflex Depression with Paired-Pulse Stimulation in Healthy Active Humans

1Department of Physical Therapy, University of the Pacific, 3601 Pacific Avenue, Stockton, CA 95211, USA
2Department of Physical Therapy Rehabilitation Science, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, 500 Newton Road, 1-252 MEB, Iowa City, IA 52242, USA

Correspondence should be addressed to Richard K. Shields

Received 25 July 2017; Accepted 9 October 2017; Published 31 October 2017

Academic Editor: Velio Macellari

Copyright © 2017 Preeti D. Oza et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Depression of the Hoffman reflex (H-reflex) is used to examine spinal control mechanisms during exercise, fatigue, and vibration and in response to training. H-reflex depression protocols frequently use trains of stimuli; this is time-consuming and prevents instantaneous assessment of motor neuronal excitability. The purpose of this study was to determine if paired-pulse H-reflex depression is reproducible and whether paired-pulse stimulation adequately estimates the depression induced by the more traditional ten-pulse train. H-reflexes were elicited via ten-pulse trains at 0.1, 0.2, 1, 2, and 5 Hz in ten neurologically intact individuals on two separate days. We measured the depression elicited by the second pulse (H2) and the mean depression elicited by pulses 2–10 (Hmean). H2 was consistent at all frequencies on both days ( = 0.97, , and = 0.81). H2 did not differ from Hmean (). The results indicate that paired-pulse H-reflex depression has high between-day reliability and yields depression estimates that are comparable to those obtained via ten-pulse trains. Paired-pulse H-reflex depression may be especially useful for studies that require rapid assessment of motor neuronal excitability, such as during exercise, fatigue, and vibration, or to establish recovery curves following inhibition.