Search results for "Reflex response"
showing 4 items of 4 documents
Significance of passively induced stretch reflexes on achilles tendon force enhancement
1998
An in vivo buckle transducer technique was applied to study the reflex contribution to ATF enhancement during passive dorsiflexion stretches. Single stretches led to a linear ATF increase in the absence of an EMG reflex response, whereas clear ATF enhancement over the passive component occurred 13-15 ms after the onset of EMG responses. To quantify the reflexly induced increase in ATF, the stretched position was maintained. The mean reflex effect was two to four times greater than the passive stretch effect.
Pain-evoked blink reflex
1997
The electrically evoked blink reflex (BR) consists of an ipsilateral R1 component (R1) at 11 ms and two bilateral components R2 at 33 ms and R3 at 83 ms. It is still unclear whether the R2 is mediated by activation of tactile or nociceptive afferents. For testing the nociceptive hypothesis, nociceptors of the supraorbital nerve were selectively activated by infrared laser stimuli in 10 subjects. Only painful laser stimuli evoked a bilateral early polyphasic BR response (LR2) at 71 ms. Stimulation of infraorbital and mental nerve dermatomes was equally effective. A late bilateral reflex response at 130 ms was occasionally observed. Regarding the nociceptor activation time of about 40 ms, ons…
Masseter reflex in childhood and adolescence.
2003
We report normative data of masseter reflex from a group of 54 children 2-16 years of age. For statistical analysis, the patients were divided into five age groups: 2-4, 5-7, 8-10, 11-13, and 14-16 years of age. A tap to the chin, using a hammer with a trigger device, elicited the masseter reflex. The response was recorded by surface electrodes. The onset latency and peak-to-peak amplitude of the averaged curve of eight reflex responses were measured. The reflex response could be recorded in all children and adolescents of all groups. The mean latency shortened from age 2 to 7 and was stable at the age of 8 years. As a sign of maturation, the increase of amplitude corresponded to the shorte…
Soleus and lateral gastrocnemius H-reflexes during standing with unstable footwear
2015
Introduction: Unstable footwear has been shown to increase lower extremity muscle activity, but the reflex response to perturbations induced by this intervention is unknown. Methods: Twenty healthy subjects stood in stable and unstable footwear conditions (presented randomly) while H-reflex amplitude and background muscle activity were measured in the soleus and lateral gastrocnemius (LG) muscles. Results: Wearing unstable footwear resulted in larger H-reflexes (normalized to the maximal M-wave) for the LG (+12%; P = 0.025), but not for the soleus (+4%; P > 0.05). Background activity of both muscles was significantly higher in the unstable condition. Conclusions: The H-reflex facilitation o…