Stiffness regulation provided by short-latency reflexes in human triceps surae muscles

1982 ◽  
Vol 234 (1) ◽  
pp. 159-164 ◽  
Author(s):  
J.H.J. Allum ◽  
K.-H. Mauritz ◽  
H. Vo¨gele
Keyword(s):  
Short Latency ◽  
Triceps Surae ◽  
Human Triceps Surae ◽  
Triceps Surae Muscles

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.

Electromyogram patterns during plantarflexions at various angular velocities and knee angles in human triceps surae muscles

1996 ◽  
Vol 75 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Hiroyuki Tamaki ◽  
Kohji Kitada ◽  
T. Akamine ◽  
Takashi Sakou ◽  
Hiroshi Kurata
Keyword(s):  
Triceps Surae ◽  
Human Triceps Surae ◽  
Angular Velocities ◽  
Triceps Surae Muscles

Fatigue responses of human triceps surae muscles during repetitive maximal isometric contractions

2000 ◽  
Vol 88 (6) ◽  
pp. 1969-1975 ◽  
Author(s):  
Yasuo Kawakami ◽  
Kenji Amemiya ◽  
Hiroaki Kanehisa ◽  
Shigeki Ikegawa ◽  
Tetsuo Fukunaga
Keyword(s):  
Plantar Flexion ◽  
Triceps Surae ◽  
Peripheral Fatigue ◽  
Isometric Contractions ◽  
Electromyographic Activity ◽  
Full Extension ◽  
Flexor Muscles ◽  
Human Triceps Surae ◽  
Triceps Surae Muscles ◽  
Plantar Flexor Muscles

Nine healthy men (22–45 yr) completed 100 repetitive maximal isometric contractions of the ankle plantar flexor muscles in two knee positions of full extension (K0) and flexion at 90° (K90), positions that varied the contribution of the gastrocnemii. Electromyographic activity was recorded from the medial and lateral gastrocnemii and soleus muscles by using surface electrodes. Plantar flexion torque in K0 was greater and decreased more rapidly than in K90. The electromyographic amplitude decreased over time, and there were no significant differences between muscles and knee joint positions. The level of voluntary effort, assessed by a supramaximal electrical stimulation during every 10th contraction, decreased from 96 to 70% ( P < 0.05) with no difference between K0 and K90. It was suggested that a decrease in plantar flexion torque was attributable to both central and peripheral fatigue and that greater fatigability in K0 than in K90 would result from a greater contribution and hence more pronounced fatigue of the gastrocnemius muscle. Further support for this possibility was provided from changes in twitch torque.

Compensation for intrinsic muscle stiffness by short-latency reflexes in human triceps surae muscles

1984 ◽  
Vol 52 (5) ◽  
pp. 797-818 ◽  
Author(s):  
J. H. Allum ◽  
K. H. Mauritz
Keyword(s):  
Plantar Flexion ◽  
Maximum Velocity ◽  
Muscle Stiffness ◽  
Short Latency ◽  
Triceps Surae ◽  
Emg Activity ◽  
Base Line ◽  
Long Latency ◽  
Torque Response ◽  
Triceps Surae Muscles

The incremental torque resisting rotation of the foot about the ankle joint was studied in normal seated subjects. Prior to each rotation, subjects were required to activate triceps surae (TS) muscles and maintain a constant plantar flexion torque (range 6-14 N X m) on a platform whose position was controlled by a torque motor. Subjects were instructed to increase torque as rapidly as possible once rotation commenced. Rotations ranged from 0.5 to 14 degrees amplitude and from 20 to 300 degrees/s maximum velocity. The torque in response to rotations stretching TS muscles and releasing tibialis anterior (TA) muscles increased steeply and then rapidly decreased with stretch velocity. At approximately 60 ms from stretch onset, the torque reduction terminated, torque then increased again until it began to level off at approximately 120 ms. A further large increase in torque occurred at 180 ms. A burst of short-latency (SL) electromyographic (EMG) activity in soleus (SOL) commenced at 40 ms, and was followed by a second burst at approximately 68 ms, provided that stretch deceleration started later than 20 ms after stretch onset. A period of sustained EMG activity in SOL commenced at approximately 130 ms (long-latency (LL) activity). Incremental torque in response to stretch of TA and release of TS muscles initially showed a step decrease followed by a reversal of the torque trajectory back toward base line. This change was arrested at 60 ms and torque then remained approximately constant until a large increase in torque at 180 ms. Ischemia was used to reduce SL EMG reflexes without significantly modifying the background EMG activity. A comparison between torque curves under control and ischemic conditions indicated that SL EMG activity in TS muscles recruited the force responsible for terminating the torque reduction coincident with decreasing stretch velocity. The torque response prior to the onset of force recruited by SL activity was attributed to the intrinsic properties of active muscle fibers. Thereafter, until the onset of LL activity, the torque response was attributed to intrinsic and reflex-recruited force. Torque in these two time periods was compared under a variety of stretch conditions in order to test the hypothesis that force recruited by segmental reflexes compensates for the non-linear stretch properties of active TS muscles. The relationships of SL EMG amplitudes and areas to stretch velocity and acceleration were also examined.(ABSTRACT TRUNCATED AT 400 WORDS)

The reflex effects of nonnoxious sural nerve stimulation on human triceps surae motor neurons

1994 ◽  
Vol 71 (5) ◽  
pp. 1897-1906 ◽  
Author(s):  
C. G. Kukulka
Keyword(s):  
Motor Neurons ◽  
Sural Nerve ◽  
Short Latency ◽  
Triceps Surae ◽  
Reflex Response ◽  
Cutaneous Afferents ◽  
Onset Latency ◽  
Human Triceps Surae ◽  
Low Threshold ◽  
Stimulation Of

1. The effects of low-intensity electrical stimulation of the ipsilateral sural nerve on the reflex response of human triceps surae motor neurons were examined in 169 motor units recorded in 11 adult volunteers: 69 units from soleus (SOL), 48 units from lateral gastrocnemius (LG), and 52 units from medial gastrocnemius (MG). The reflex effects were assessed by the peristimulus time histogram (PSTH) technique, categorized according to onset latencies, and the magnitudes of effects were calculated as percent changes in baseline firing rates. 2. Sural stimulation evoked complex changes in motor-unit firing at onset latencies between 28 and 140 ms. The two most common responses seen in all muscles were a short-latency depression (D1) in firing (mean onset latency = 40 ms) in 42% of all units studied and a secondary enhancement (E2) in firing (mean onset latency = 72 ms) in 43% of all units. In LG, the D1 effect represented a mean decrease in firing of 52% which was statistically different from the changes in MG (42% decrease) and SOL (38% decrease). The magnitudes of E2 effects were similar across muscles with an average of 47% increase in firing. 3. No differences were found in the frequencies of occurrence for the enhancements in firing among the muscles studied. The main difference in reflex responses was the occurrence of an intermediate latency depression (D2) in 27% of the LG units with a mean onset latency of 72 ms. 4. Based on estimates of conduction times for activation of low-threshold cutaneous afferents, the short-latency D1 response likely represents an oligosynaptic spinal reflex with transmission times similar to the Ia reciprocal inhibitory pathway. These findings raise the question as to the possibility of low-threshold cutaneous afferents sharing common interneurons with low-threshold muscle afferent reflexes that have identical onset latencies. The complex reflex effects associated with low-level stimulation of a cutaneous nerve indicate a rich assortment of peripheral responses that may influence a given movement. The predominance of a specific effect is most likely determined by the interaction of this input with other peripheral signals and descending commands specific to a given motor task.

scholarly journals Strain distribution within human triceps surae muscles during isometric contraction: in vivo study by Tagging MRI

2008 ◽  
Vol 22 (S1) ◽  
Author(s):  
Toshiaki Oda ◽  
Ryuta Kinugasa ◽  
Mayoran Rajendra ◽  
Ryutaro Himeno ◽  
Hiroyuki Kataoka ◽  
...  
Keyword(s):  
Isometric Contraction ◽  
Strain Distribution ◽  
Triceps Surae ◽  
In Vivo Study ◽  
Human Triceps Surae ◽  
Triceps Surae Muscles ◽  
Tagging Mri

Architectural and functional features of human triceps surae muscles during contraction

1998 ◽  
Vol 85 (2) ◽  
pp. 398-404 ◽  
Author(s):  
Yasuo Kawakami ◽  
Yoshiho Ichinose ◽  
Tetsuo Fukunaga
Keyword(s):  
Plantar Flexion ◽  
Triceps Surae ◽  
Passive Condition ◽  
Human Triceps Surae ◽  
Functional Features ◽  
The Subject ◽  
Triceps Surae Muscles ◽  
Ultrasonic Images ◽  
Elastic Characteristics

Architectural properties of the triceps surae muscles were determined in vivo for six men. The ankle was positioned at 15° dorsiflexion (−15°) and 0, 15, and 30° plantar flexion, with the knee set at 0, 45, and 90°. At each position, longitudinal ultrasonic images of the medial (MG) and lateral (LG) gastrocnemius and soleus (Sol) muscles were obtained while the subject was relaxed (passive) and performed maximal isometric plantar flexion (active), from which fascicle lengths and angles with respect to the aponeuroses were determined. In the passive condition, fascicle lengths changed from 59, 65, and 43 mm (knee, 0°; ankle, −15°) to 32, 41, and 30 mm (knee, 90° ankle, 30°) for MG, LG, and Sol, respectively. Fascicle shortening by contraction was more pronounced at longer fascicle lengths. MG had greatest fascicle angles, ranging from 22 to 67°, and was in a very disadvantageous condition when the knee was flexed at 90°, irrespective of ankle positions. Different lengths and angles of fascicles, and their changes by contraction, might be related to differences in force-producing capabilities of the muscles and elastic characteristics of tendons and aponeuroses.

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