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Updated: Jun 18, 2026

Time-dependent Increase in the Network Response to the Stimulation of Neuronal Cell Cultures on Micro-electrode Arrays
Published on: May 29, 2017
Short-term training adaptations in maximal motor unit firing rates and afterhyperpolarization duration
1Department of Kinesiology, University of Massachusetts, 110 Totman Building, 30 Eastman Lane, Amherst, Massachusetts 01003-9258, USA. achristie@kin.umass.edu
Abstract:
In this study we investigated age- and training-related adaptations in maximal motor unit firing rates and the duration of the motoneuron afterhyperpolarization (AHP) in the dorsiflexor muscles of the foot. Subjects included 30 young (21.9 +/- 3.1 years) and 30 older (72.9 +/- 4.6 years) individuals, who were randomly assigned to a control or training group. Maximal voluntary force (MVC), maximal motor unit firing rate, and motoneuron AHP duration were measured on two occasions. The training group participated in six dorsiflexor exercise training sessions between test and retest. At baseline, young subjects had higher MVC force and maximal motor unit firing rate, and shorter AHP duration, compared with older subjects. Young and older subjects in the trained group demonstrated a respective 17.4% and 19.8% increase in MVC force, a 6.8% and 24.3% increase in maximal MUFR, and a 7.4% and 14.2% decrease in AHP duration. These results indicate that age-related changes in neuromuscular function are not a necessary consequence of aging.
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