✦ LIBER ✦

Dissociation of the electrical and contractile properties in single human motor units during fatigue

✍ Scribed by K. Ming Chan; Leonard P. Andres; Yelena Polykovskaya; William F. Brown

Publisher: John Wiley and Sons
Year: 1998
Tongue: English
Weight: 106 KB
Volume: 21
Category: Article
ISSN: 0148-639X
DOI: 10.1002/(sici)1097-4598(199812)21:12<1786::aid-mus25>3.0.co;2-i

No coin nor oath required. For personal study only.

✦ Synopsis

The surface EMG area often exhibits progressive enlargement during a submaximal fatiguing contraction, but the underlying reasons still remain uncertain. Fatigue-induced changes in the surface-detected motor unit action potentials (S-MUAPs) of 10 human thenar motor units (MUs) with widely differing physiological properties were examined. After 2 min of repetitive 40-Hz stimulation, the size of the S-MUAPs of all MUs increased, the magnitude of which was negatively correlated with their tetanic tension changes. These findings suggest that during muscle fatigue, in addition to reflecting recruitment of new MUs and increases in firing rates of the active MUs, the surface EMG may also be markedly influenced by changes in the S-MUAPs, especially in fast fatigable muscles.

📜 SIMILAR VOLUMES

Longitudinal study of the contractile an

Longitudinal study of the contractile and electrical properties of single human thenar motor units

✍ K. Ming Chan; Timothy J. Doherty; Leonard P. Andres; Michelle M. Porter; Timothy 📂 Article 📅 1998 🏛 John Wiley and Sons 🌐 English ⚖ 403 KB 👁 2 views

Serial motor unit number estimates have shed important light on the extent and rates of motoneuron losses in aging and amyotrophic lateral sclerosis. However, the estimates alone provide few clues to the health and functional status of surviving motor units. A reliable means for assessing the functi

Contractile properties of the tongue's g

Contractile properties of the tongue's genioglossus muscle and motor units in the rat

✍ Thomas G. Sutlive; Mary S. Shall; J. Ross McClung; Stephen J. Goldberg 📂 Article 📅 2000 🏛 John Wiley and Sons 🌐 English ⚖ 338 KB 👁 2 views

The contractile characteristics of individual mammalian tongue muscles have rarely been investigated, in contrast to spinal cordinnervated and extraocular muscles. Therefore, whole muscle and motor unit contractile forces, plus muscle fiber types, were studied in the genioglossus, the major protruso

The effects of training through high-fre

The effects of training through high-frequency electrical stimulation on the physiological properties of single human thenar motor units

✍ K. Ming Chan; Leonard P. Andres; Yelena Polykovskaya; William F. Brown 📂 Article 📅 1999 🏛 John Wiley and Sons 🌐 English ⚖ 210 KB 👁 1 views

The relative impact of training on motor units (MUs) with differing physiological characteristics remains controversial. To examine this issue, we longitudinally tracked the contractile and electrical characteristics of six human thenar MUs in 2 young healthy subjects before, during, and following a

A longitudinal study of the pathophysiol

A longitudinal study of the pathophysiological changes in single human thenar motor units in amyotrophic lateral sclerosis

✍ K. Ming Chan; Daniel W. Stashuk; William F. Brown 📂 Article 📅 1998 🏛 John Wiley and Sons 🌐 English ⚖ 247 KB 👁 2 views

The sequence of pathophysiological changes in amyotrophic lateral sclerosis (ALS) at the single motor unit (MU) level is not well understood. Using a recently described technique, a comprehensive range of physiological properties in two thenar MUs in ALS were intensively studied. In the first MU, de