Group II muscle afferents probably contribute to the medium latency soleus stretch reflex during walking in humans
Research output: Contribution to journal › Journal article › Research › peer-review
Standard
Group II muscle afferents probably contribute to the medium latency soleus stretch reflex during walking in humans. / Grey, Michael James; Ladouceur, Michel; Andersen, Jacob B.; Nielsen, Jens Bo; Sinkjær, Thomas.
In: Journal of Physiology, Vol. 534, No. 3, 2001, p. 925-933.Research output: Contribution to journal › Journal article › Research › peer-review
Harvard
APA
Vancouver
Author
Bibtex
}
RIS
TY - JOUR
T1 - Group II muscle afferents probably contribute to the medium latency soleus stretch reflex during walking in humans
AU - Grey, Michael James
AU - Ladouceur, Michel
AU - Andersen, Jacob B.
AU - Nielsen, Jens Bo
AU - Sinkjær, Thomas
N1 - Keywords: Adrenergic alpha-Agonists; Adult; Anesthetics, Local; Ankle; Clonidine; Cold; Electromyography; Female; Foot; Humans; Ischemia; Lidocaine; Male; Muscle, Skeletal; Neurons, Afferent; Reaction Time; Reflex, Stretch; Time Factors; Walking
PY - 2001
Y1 - 2001
N2 - 1. The objective of this study was to determine which afferents contribute to the medium latency response of the soleus stretch reflex resulting from an unexpected perturbation during human walking. 2. Fourteen healthy subjects walked on a treadmill at approximately 3.5 km h(-1) with the left ankle attached to a portable stretching device. The soleus stretch reflex was elicited by applying small amplitude (approximately 8 deg) dorsiflexion perturbations 200 ms after heel contact. 3. Short and medium latency responses were observed with latencies of 55 +/- 5 and 78 +/- 6 ms, respectively. The short latency response was velocity sensitive (P < 0.001), while the medium latency response was not (P = 0.725). 4. Nerve cooling increased the delay of the medium latency component to a greater extent than that of the short latency component (P < 0.005). 5. Ischaemia strongly decreased the short latency component (P = 0.004), whereas the medium latency component was unchanged (P = 0.437). 6. Two hours after the ingestion of tizanidine, an alpha(2)-adrenergic receptor agonist known to selectively depress the transmission in the group II afferent pathway, the medium latency reflex was strongly depressed (P = 0.007), whereas the short latency component was unchanged (P = 0.653). 7. An ankle block with lidocaine hydrochloride was performed to suppress the cutaneous afferents of the foot and ankle. Neither the short (P = 0.453) nor medium (P = 0.310) latency reflexes were changed. 8. Our results support the hypothesis that, during walking the medium latency component of the stretch reflex resulting from an unexpected perturbation is contributed to by group II muscle afferents.
AB - 1. The objective of this study was to determine which afferents contribute to the medium latency response of the soleus stretch reflex resulting from an unexpected perturbation during human walking. 2. Fourteen healthy subjects walked on a treadmill at approximately 3.5 km h(-1) with the left ankle attached to a portable stretching device. The soleus stretch reflex was elicited by applying small amplitude (approximately 8 deg) dorsiflexion perturbations 200 ms after heel contact. 3. Short and medium latency responses were observed with latencies of 55 +/- 5 and 78 +/- 6 ms, respectively. The short latency response was velocity sensitive (P < 0.001), while the medium latency response was not (P = 0.725). 4. Nerve cooling increased the delay of the medium latency component to a greater extent than that of the short latency component (P < 0.005). 5. Ischaemia strongly decreased the short latency component (P = 0.004), whereas the medium latency component was unchanged (P = 0.437). 6. Two hours after the ingestion of tizanidine, an alpha(2)-adrenergic receptor agonist known to selectively depress the transmission in the group II afferent pathway, the medium latency reflex was strongly depressed (P = 0.007), whereas the short latency component was unchanged (P = 0.653). 7. An ankle block with lidocaine hydrochloride was performed to suppress the cutaneous afferents of the foot and ankle. Neither the short (P = 0.453) nor medium (P = 0.310) latency reflexes were changed. 8. Our results support the hypothesis that, during walking the medium latency component of the stretch reflex resulting from an unexpected perturbation is contributed to by group II muscle afferents.
M3 - Journal article
C2 - 11483721
VL - 534
SP - 925
EP - 933
JO - The Journal of Physiology
JF - The Journal of Physiology
SN - 0022-3751
IS - 3
ER -
ID: 5961110