Effects of aging on force variability, single motor unit discharge patterns, and the structure of 10, 20, and 40 Hz EMG activity

2003 ◽  
Vol 24 (1) ◽  
pp. 25-35 ◽  
Author(s):  
D Vaillancourt
Keyword(s):  
Motor Unit ◽  
Emg Activity ◽  
Force Variability ◽  
Unit Discharge ◽  
Single Motor Unit ◽  
Single Motor ◽  
Motor Unit Discharge ◽  
Discharge Patterns ◽  
Effects Of Aging ◽  
40 Hz

scholarly journals Discharge frequencies of single motor units in human diaphragm and parasternal muscles in lying and standing

2001 ◽  
Vol 90 (1) ◽  
pp. 147-154 ◽  
Author(s):  
J. E. Butler ◽  
D. K. McKenzie ◽  
S. C. Gandevia
Keyword(s):  
Tidal Volume ◽  
Motor Unit ◽  
Motor Units ◽  
Neural Drive ◽  
Unit Discharge ◽  
Single Motor Unit ◽  
Single Motor ◽  
Single Motor Units ◽  
Inspiratory Muscles ◽  
Motor Unit Discharge

Single motor unit discharge was measured directly in diaphragm and parasternal intercostal muscles to determine whether neural drive to human inspiratory muscles changes between lying and standing. The final discharge frequency of diaphragmatic motor units increased slightly, by 1 Hz (12%; P < 0.01), when subjects were standing [182 units, median 9.1 Hz (interquartile range 7.6–11.3 Hz)] compared with lying supine [159 units, 8.1 Hz (6.6–10.3 Hz)]. However, this increase with standing occurred in only two of six subjects, in one of whom tidal volume increased significantly during standing. Parasternal intercostal motor unit final discharge frequencies did not differ between standing [116 units, 8.0 Hz (6.6–9.6 Hz)] and lying [124 units, 8.4 Hz (7.0–10.3 Hz)]. The discharge frequencies at the onset of inspiration did not differ between lying and standing for either muscle. A larger proportion of motor units in both inspiratory muscles had postinspiratory or tonic expiratory activity for lying compared with standing (15 vs. 4%; P < 0.05). We conclude that there is no major difference in the phasic inspiratory drive to the diaphragm with the change in posture.

Contraction-induced potentiation of human motor unit discharge and surface EMG activity

1988 ◽  
Vol 20 (4) ◽  
pp. 391-395 ◽  
Author(s):  
SHUJI SUZUKI ◽  
KOJI KAIYA ◽  
SHIROH WATANABE ◽  
ROBERT S. HUTTON
Keyword(s):  
Motor Unit ◽  
Surface Emg ◽  
Emg Activity ◽  
Unit Discharge ◽  
Motor Unit Discharge ◽  
Human Motor
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