Electromyographic Activity of Rat Ankle Extensors During Treadmill Locomotion after Hindlimb Unloading
نویسندگان
چکیده
The aim of this work was to study the electromyographic characteristics of two ankle extensors during treadmill locomotion after hindlimb unloading. The studied muscles were the soleus which contains mainly slow fibres, and three parts (red, mixed and white) of the heterogeneous gastrocnemius. Our results showed that the cycle duration was significantly increased (+26%) after 14 days of unloading; the burst duration was increased in the soleus (+18%) and in the red gastrocnemius (+20%). The mean EMG (burst area divided by burst duration) was decreased when treadmill speed was increased in the soleus (-11%) and the red part (-5%) of the gastrocnemius after unloading; in contrast, it was greatly increased in the white part (+46%). These data suggest that hindlimb unloading shifts the normal speedrelated increase in muscle effort from the red to the white compartment of the muscle.
منابع مشابه
Plasticity of reflexes from the foot during locomotion after denervating ankle extensors in intact cats.
Although sensory feedback is important in regulating the timing and magnitude of muscle activity during locomotion few studies have evaluated how it changes after peripheral nerve lesions. To assess this, reflexes evoked by stimulating a nerve before and after denervating other nerves can be quantified to determine changes. The aim of this study was to investigate consequences of denervating an...
متن کاملContribution of Social Isolation, Restraint, and Hindlimb Unloading to Changes in Hemodynamic Parameters and Motion Activity in Rats
The most accepted animal model for simulation of the physiological and morphological consequences of microgravity on the cardiovascular system is one of head-down hindlimb unloading. Experimental conditions surrounding this model include not only head-down tilting of rats, but also social and restraint stresses that have their own influences on cardiovascular system function. Here, we studied l...
متن کاملShort-term motor compensations to denervation of feline soleus and lateral gastrocnemius result in preservation of ankle mechanical output during locomotion.
Denervation of selected ankle extensors in animals results in locomotor changes. These changes have been suggested to permit preservation of global kinematic characteristics of the hindlimb during stance. The peak ankle joint moment is also preserved immediately after denervation of several ankle extensors in the cat, suggesting that the animal's response to peripheral nerve injury may also be ...
متن کاملContribution of cutaneous inputs from the hindpaw to the control of locomotion. II. Spinal cats.
The goal of these experiments was to define the contribution of hindpaw cutaneous inputs in the expression of spinal locomotion in cats. In 3 cats, some (n = 1) or all (n = 2) cutaneous nerves were cut bilaterally at ankle level before spinalization. This denervation caused small deficits that were gradually compensated as reported in the companion study. After spinalization, the completely den...
متن کاملContribution of cutaneous inputs from the hindpaw to the control of locomotion : 2 . Spinal cats
The goal of these experiments was to define the contribution of hindpaw cutaneous inputs in the expression of spinal locomotion in cats. In 3 cats, some (n=1) or all (n=2) cutaneous nerves were cut bilaterally at ankle level before spinalisation. This denervation caused small deficits that were gradually compensated as reported in the companion paper (Bouyer and Rossignol, 2003a). After spinali...
متن کامل