Journal article
Sustained submaximal contraction yields biphasic modulation of soleus Post‐activation depression in healthy humans
Scandinavian journal of medicine & science in sports, Vol.29(7), pp.944-951
07/2019
DOI: 10.1111/sms.13421
PMCID: PMC7702212
PMID: 30892718
Abstract
The amplitude of the H‐reflex during the development and progression of fatigue reflects a complex interplay between central and peripheral factors. The purpose of this study is to characterize H‐reflex homosynaptic post‐activation depression (PAD) in an online fashion during a sustained submaximal fatigue task. The task required a high motor output in order to increase the likelihood of creating partial muscle ischemia with accumulation of fatigue metabolites, an important potential inhibitory influence upon the H‐reflex during the progression of fatigue. Eleven subjects without neurologic impairment maintained volitional, isometric plantar flexion at 60% of maximal voluntary contraction until exhaustion. A paired‐pulse stimulus (2 Hz) was delivered to the tibial nerve to elicit paired H‐reflexes before, during, and after the fatigue protocol. The normalized amplitude of the second H‐reflex (depression ratio) served as an estimate of PAD. Depression ratio increased during the first half of the fatigue protocol (P < 0.001), indicating a diminution of PAD, and then returned as exhaustion approached. The biphasic behavior of homosynaptic H‐reflex depression during fatigue to exhaustion suggests a role for metabolic mediators of post‐activation depression during fatigue.
Details
- Title: Subtitle
- Sustained submaximal contraction yields biphasic modulation of soleus Post‐activation depression in healthy humans
- Creators
- Preeti D Oza - University of the PacificShauna Dudley‐Javoroski - The University of IowaRichard K Shields - The University of Iowa
- Resource Type
- Journal article
- Publication Details
- Scandinavian journal of medicine & science in sports, Vol.29(7), pp.944-951
- DOI
- 10.1111/sms.13421
- PMID
- 30892718
- PMCID
- PMC7702212
- NLM abbreviation
- Scand J Med Sci Sports
- ISSN
- 0905-7188
- eISSN
- 1600-0838
- Number of pages
- 0
- Grant note
- Eunice Kennedy Shriver National Institute of Child Health & Human Development (R01-HD084645; R01-HD082109)
- Language
- English
- Date published
- 07/2019
- Academic Unit
- Orthopedics and Rehabilitation; Physical Therapy and Rehabilitation Science
- Record Identifier
- 9984047754602771
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