System identification of human triceps surae stretch reflex dynamics

1983 ◽  
Vol 51 (1) ◽  
Author(s):  
R.E. Kearney ◽  
I.W. Hunter
Keyword(s):  
System Identification ◽  
Stretch Reflex ◽  
Triceps Surae ◽  
Human Triceps Surae ◽  
Stretch Reflex Dynamics

Effects of contraction intensity on muscle fascicle and stretch reflex behavior in the human triceps surae

2008 ◽  
Vol 105 (1) ◽  
pp. 226-232 ◽  
Author(s):  
Neil J. Cronin ◽  
Jussi Peltonen ◽  
Masaki Ishikawa ◽  
Paavo V. Komi ◽  
Janne Avela ◽  
...  
Keyword(s):  
Stretch Reflex ◽  
Force Production ◽  
Voluntary Contraction ◽  
Short Latency ◽  
Afferent Feedback ◽  
Triceps Surae ◽  
Medial Gastrocnemius ◽  
Stretch Reflexes ◽  
Muscle Fascicle ◽  
Human Triceps Surae

The aims of this study were to examine changes in the distribution of a stretch to the muscle fascicles with changes in contraction intensity in the human triceps surae and to relate fascicle stretch responses to short-latency stretch reflex behavior. Thirteen healthy subjects were seated in an ankle ergometer, and dorsiflexion stretches (8°; 250°/s) were applied to the triceps surae at different moment levels (0–100% of maximal voluntary contraction). Surface EMG was recorded in the medial gastrocnemius, soleus, and tibialis anterior muscles, and ultrasound was used to measure medial gastrocnemius and soleus fascicle lengths. At low forces, reflex amplitudes increased despite a lack of change or even a decrease in fascicle stretch velocities. At high forces, lower fascicle stretch velocities coincided with smaller stretch reflexes. The results revealed a decline in fascicle stretch velocity of over 50% between passive conditions and maximal force levels in the major muscles of the triceps surae. This is likely to be an important factor related to the decline in stretch reflex amplitudes at high forces. Because short-latency stretch reflexes contribute to force production and stiffness regulation of human muscle fibers, a reduction in afferent feedback from muscle spindles could decrease the efficacy of human movements involving the triceps surae, particularly where high force production is required.

Identification of time-varying dynamics of the human triceps surae stretch reflex

1993 ◽  
Vol 97 (1) ◽  
pp. 115-127 ◽  
Author(s):  
Robert F. Kirsch ◽  
Robert E. Kearney ◽  
J. Bart MacNeil
Keyword(s):  
Stretch Reflex ◽  
Triceps Surae ◽  
Time Varying ◽  
Human Triceps Surae

Influences of experimental factors on spinal stretch reflex latency and amplitude in the human triceps surae

2006 ◽  
Vol 16 (1) ◽  
pp. 42-50 ◽  
Author(s):  
J. Troy Blackburn ◽  
Richard G. Mynark ◽  
Darin A. Padua ◽  
Kevin M. Guskiewicz
Keyword(s):  
Stretch Reflex ◽  
Triceps Surae ◽  
Reflex Latency ◽  
Human Triceps Surae ◽  
Spinal Stretch Reflex
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