Premium
Short‐term training adaptations in maximal motor unit firing rates and afterhyperpolarization duration
Author(s) -
Christie Anita,
Kamen Gary
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.21539
Subject(s) - afterhyperpolarization , motor unit , physical medicine and rehabilitation , duration (music) , physical therapy , medicine , motor unit recruitment , psychology , electromyography , cardiology , electrophysiology , anatomy , art , literature
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. Muscle Nerve, 2010