EMG-force relationship of the cat soleus muscle studied with distributed and non-periodic stimulation of ventral root filaments

1994 ◽  
Vol 186 (1) ◽  
pp. 75-93
Author(s):  
A. C. Guimaraes ◽  
W. Herzog ◽  
M. Hulliger ◽  
Y. T. Zhang ◽  
S. Day
Keyword(s):  
Soleus Muscle ◽  
Ventral Root ◽  
Electromyographic Activity ◽  
Fibre Type Composition ◽  
Type Composition ◽  
Periodic Stimulation ◽  
Relationship Of ◽  
Voluntary Contractions ◽  
Force Relationship ◽  
Stimulation Of

Distributed stimulation of ventral root (VR) filaments and pseudo-random interpulse intervals (based on a Gaussian distribution with a coefficient of variation of 12.5%) were used to modulate electromyographic activity (EMG) and force of the cat soleus muscle to assess the EMG-force relationship. A protocol consisting of addition and rate modulation of ten VR filaments that contain alpha motoneurones to the soleus muscle was adopted. EMG was measured using indwelling electrodes and forces were measured at the distal tendon using a strain transducer. EMG records obtained using this approach were similar in the time and frequency domains to those obtained during voluntary contractions. Force records obtained from stimulation of single VR filaments showed summation effects typical of irregular interpulse intervals. The overall relationship between integrated rectified EMG (IEMG) and mean force was found to be non-linear. At low and high stimulation levels, IEMG tended to increase proportionally more than mean force. In the intermediate stimulation region (i.e. producing forces between approximately 5% and 88% of the maximal tetanic force), the IEMG-mean force relationship was virtually linear. Muscles with a homogeneous fibre type composition, such as the cat soleus muscle, have been reported to have a linear EMG-force relationship.

scholarly journals Effects of muscle length on the EMG-force relationship of the cat soleus muscle studied using non-periodic stimulation of ventral root filaments.

1994 ◽  
Vol 193 (1) ◽  
pp. 49-64
Author(s):  
A C Guimaraes ◽  
W Herzog ◽  
M Hulliger ◽  
Y T Zhang ◽  
S Day
Keyword(s):  
Soleus Muscle ◽  
Muscle Length ◽  
Motor Units ◽  
Ventral Root ◽  
Length Relationship ◽  
Active Motor ◽  
Integrated Emg ◽  
Relationship Of ◽  
Force Relationship ◽  
Stimulation Of

The effects of changing the length of the cat soleus muscle on electromyographic (EMG) signals, muscle force and the corresponding EMG-force relationship were assessed using distributed stimulation of ten ventral root filaments and irregular interpulse intervals. EMG-force relationships were first determined for four muscle lengths using a protocol of simultaneous addition and rate modulation of ventral root filaments. In the second test, three submaximal levels of stimulation were applied at eight muscle lengths. EMG signals were obtained using surface and wire electrodes, and force was measured using a strain transducer. For most muscle lengths, the relationships between integrated EMG and mean force obtained using wire and surface electrodes were sigmoid with a linear intermediate region. The effects of muscle length on EMG signals were likely to be associated with movement of the recording electrodes relative to each other and to the active motor units. Mean forces increased with increasing muscle length and with increasing levels of stimulation. Mean force-length relationships obtained using submaximal stimulation were not simply scaled down versions of the force-length relationship obtained using supramaximal stimulation of the soleus nerve, but appeared to be shifted towards longer muscle lengths.

Spinal reflexes as a basis for tremor in the premammillary cat

1978 ◽  
Vol 56 (3) ◽  
pp. 375-383 ◽  
Author(s):  
T. R. Nichols ◽  
R. B. Stein ◽  
P. Bawa
Keyword(s):  
Soleus Muscle ◽  
Spinal Reflexes ◽  
Electromyographic Activity ◽  
Lateral Gastrocnemius ◽  
Electrical Recording ◽  
Spring System ◽  
Inertial Loading ◽  
Mass Spring ◽  
Fixed Delay ◽  
Stimulation Of

A maintained tremor observed in premammillary cats has been studied by varying the load attached to the soleus muscle, by electrical recording, and stimulation. The frequency and amplitude of the tremor varies widely with changes in elastic or inertial loading (springs or flywheels). These variations agree well with predictions based on the idea that the tremor is maintained by reflexes reinforcing a tendency for oscillation in a mass-spring system (which includes the elasticity of the muscle). Spinal stretch reflexes are probably responsible since a relatively fixed delay of 8.5 ± 2.9 ms is observed between the peaks of recorded afferent and electromyographic activity. Stimulation of the lateral gastrocnemius – soleus nerve completely resets the tremor, again suggesting a reflex origin.

Stiffness of cat soleus muscle and tendon during activation of part of muscle

1984 ◽  
Vol 52 (3) ◽  
pp. 459-468 ◽  
Author(s):  
U. Proske ◽  
D. L. Morgan
Keyword(s):  
Soleus Muscle ◽  
Muscle Fibers ◽  
Isometric Tension ◽  
Muscle Stiffness ◽  
Ventral Root ◽  
A Value ◽  
Wide Range ◽  
Whole Muscle ◽  
Tendon Compliance ◽  
Stimulation Of

Experiments have been carried out on the soleus muscle and its tendon in the anesthetized cat. Measurements of isometric tension and muscle stiffness were made during contraction of whole or part of the muscle in response to stimulation of ventral root filaments. In an attempt to determine the distribution of tension in different portions of the tendon during activation of only part of the muscle, the free tendon of insertion was split longitudinally into two halves and a strain gauge attached to each piece. From a large number of measurements, it was found that the mean fraction of tension recorded in one-half of the tendon remained about the same, over a wide range of tensions. However, the scatter of values, which increased as the portion of muscle contracting was reduced, was greater than expected if muscle fibers were randomly distributed throughout the muscle. Measurements of muscle and tendon stiffness were made from length and tension changes during stretch of the actively contracting muscle. Ventral root stimulation that engaged 20% or more of the muscle yielded a value for tendon compliance (0.09 mm/N), which was the same as for stimulating the whole muscle. This result suggested that for contraction of portions as small as 20% of the muscle, fibers were effectively attached to the whole tendon, indicating that tendinous attachments of individual muscle fibers ran independent of one another over only a short distance and were bound together over most of their remaining course. It was concluded that groups of muscle fibers selected by stimulation of ventral root filaments are not entirely randomly distributed throughout the muscle. However, for groups representing larger fractions of the total tension, (greater than 20%) the distribution is uniform enough and the connections between their tendinous attachments firm enough for the force applied by such a group to act through a tendon compliance, which is the same as that seen by the whole muscle.

Modulation of H Reflex of Pretibial Muscles and Reciprocal Ia Inhibition of Soleus Muscle During Voluntary Teeth Clenching in Humans

2000 ◽  
Vol 83 (4) ◽  
pp. 2063-2070 ◽  
Author(s):  
Yoshiyuki Takada ◽  
Takao Miyahara ◽  
Tatsuya Tanaka ◽  
Takashi Ohyama ◽  
Yoshio Nakamura
Keyword(s):  
Soleus Muscle ◽  
Peroneal Nerve ◽  
Common Peroneal Nerve ◽  
H Reflex ◽  
Electromyographic Activity ◽  
Dependent Manner ◽  
Teeth Clenching ◽  
Ia Inhibition ◽  
The Common ◽  
Stimulation Of

A previous study has demonstrated that the soleus H reflex is facilitated in association with voluntary teeth clenching in proportion with biting force in humans. The present study tried to elucidate the functional significance of this facilitation of the soleus H reflex, by examining 1) whether the facilitation of the H reflex is reciprocal or nonreciprocal between the ankle extensors and flexors and 2) whether the reciprocal Ia inhibition of crural muscles is facilitated or depressed in association with voluntary teeth clenching. The H reflex of the pretibial muscles was evoked by stimulation of the common peroneal nerve in seven healthy subjects with no oral dysfunction. The pretibial H reflex was facilitated in association with voluntary teeth clenching in a force-dependent manner. The facilitation started preceding the onset of electromyographic activity of the masseter muscle. Stimulation of the common peroneal nerve at low intensities subthreshold for evoking the M wave of the pretibial muscles inhibited the soleus H reflex after a short latency corresponding with a disynaptic inhibition, indicating that the reciprocal Ia inhibition was depressed in association with voluntary teeth clenching. Thus, the present study has shown that voluntary teeth clenching evokes a nonreciprocal facilitation of ankle extensor and flexor muscles and attenuated reciprocal Ia inhibition from the pretibial muscles to the soleus muscle. It is concluded that voluntary teeth clenching contributes to improve stability of stance rather than smoothness of movements.

Influence of 12 weeks of hypobaric hypoxia on fibre type composition of the rat soleus muscle

1995 ◽  
Vol 154 (3) ◽  
pp. 417-418 ◽  
Author(s):  
K. ITOH ◽  
M. ITOH ◽  
A. ISHIHARA ◽  
C. HIROFUJI ◽  
H. HAYASHI
Keyword(s):  
Soleus Muscle ◽  
Fibre Type ◽  
Hypobaric Hypoxia ◽  
Fibre Type Composition ◽  
Type Composition ◽  
Rat Soleus Muscle
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