Temperature dependence of soleus H-reflex and M wave in young and older women

Dewhurst, Susan and Riches, Philip E. and Nimmo, Myra A. and De Vito, Giuseppe (2005) Temperature dependence of soleus H-reflex and M wave in young and older women. European Journal of Applied Physiology and Occupational Physiology, 94 (5-6). pp. 491-499. ISSN 1439-6327

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Abstract

The purpose of this study was to investigate the effect of altered local temperature on soleus H-reflex and compound muscle action potential (M wave) in young and older women. H-reflex and M wave responses were elicited in 10 young (22.3±3.3 years) and 10 older (72.5±3.2 years) women at three muscle temperatures: control (34.2±0.3°C), cold (31.3±0.5°C) and warm (37.1±0.2°C). H-reflex output, expressed as the ratio between maximal H-reflex and maximal M wave (Hmax/Mmax), was lower in the older, compared with the younger, group, regardless of temperature. In control temperature conditions, for example, the Hmax/Mmax ratio was 36.8±24% in the young and 25.4±20% in the older (P<0.05). Warming had no effect on the H-reflex output in either group, whilst cooling increased H-reflex output only in the younger group (+28%). In both groups, cooling increased (+5.3%), and warming decreased (-5.5%) the H-reflex latency. This study confirms that older individuals experience a reduced ability to modulate the reflex output in response to a perturbation. In a cold environment, for example, the lack of facilitation in the reflex output, along with a delayed reflex response could be critical to an older individual in responding to postural perturbations thus potentially compromising both static and dynamic balance.

ORCID iDs

Dewhurst, Susan, Riches, Philip E. ORCID logoORCID: https://orcid.org/0000-0002-7708-4607, Nimmo, Myra A. and De Vito, Giuseppe;