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Adaptations in maximal motor unit discharge rate to strength training in young and older adults
Author(s) -
Patten Carolynn,
Kamen Gary,
Rowland Daniel M.
Publication year - 2001
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.1038
Subject(s) - isometric exercise , motor unit , medicine , disinhibition , resistance training , physical medicine and rehabilitation , physical therapy , anatomy , psychiatry
Six young (mean = 23 years) and 6 older (mean = 76 years) adults participated in isometric resistance training 5 days/week for 6 weeks. The task involved isometric fifth finger abduction. Maximal motor unit discharge rates (MUDRs) were obtained from the abductor digiti minimi of each hand at 0, 2, 14, and 42 days of training using a quadrifilar needle electrode and automatic spike recognition software. In agreement with previous findings, maximal MUDR at baseline was significantly lower in older adults ( P < 0.001), averaging 51.5 (±17.13) H Z in young and 43.3 (±14.88) H Z in older adults. In response to resistance training, maximal voluntary force increased 25% in young and 33% in older subjects ( P < 0.001). Maximal MUDR increased significantly (11% young, 23% older) on day 2 [ F (3,36) = 2.58, P < 0.05], but in older subjects returned to baseline levels thereafter. These adaptations in abductor digiti minimi MUDR suggest a two‐part response to strengthening fifth finger abduction: early disinhibition followed by altered MU activation.© 2001 John Wiley & Sons, Inc. Muscle Nerve 24:542–550, 2001