The effects of repetitive muscle contraction on energy state and tension production were studied in rabbit tibialis anterior/extensor digitorum longus muscles that had been subjected to 90 days of continuous indirect electrical stimulation at 10 Hz. Anesthetized chronically stimulated and control rabbits were challenged with 15 min of stimulation at 4 and 15 tetani/min. Pi-to-phosphocreatine (P...

Even when the muscles surrounding a joint are inactive, they still exert a damping effect on joint mobility, because of the passive elastic tension exerted by the stretched muscle fibres and their connective tissue (Clemmesen, 1951). For example, if the forearm muscles are allowed to relax and the forearm is then shaken violently, the hand will swing loosely at the wrist; however, if the experi...

Effects of venom from black scorpion Androctonus crasicuda (AC) were determined on isolated chick biventer cervices nerve-muscle and mouse hemidiaphragm preparations using twitch tension method. The isolated nerves were stimulated by electrical stimulator and response to each stimulus was recorded. The venom mainly acted prejunctionally to facilitate neuromuscular activity due to an increase in...

In skeletal muscle, oxygen (O(2)) delivery to appropriately meet metabolic need requires mechanisms for detection of the magnitude of O(2) demand and the regulation of O(2) delivery. Erythrocytes, when exposed to a decrease in O(2) tension, release both O(2) and the vasodilator adenosine triphosphate (ATP). The aims of this study were to establish that erythrocytes release ATP in response to re...

Background: The prevalence of pediatric dysphonia ranges from 6-23%. Chronic dysphonia can negatively affect the lives of children physically, socially, and emotionally. The body of literature continues to grow regarding the pathophysiology and management of dysphonic children. Methods: This article presents a relevant literature review of vocal fold pathology leading to hoarseness and recent a...

Spasmodic dysphonia (SD) is a voice disorder characterized by abnormal intermittent spasms of intralaryngeal muscles that result in voice breaks during speech. In the adductor variant of spasmodic dysphonia (ADSD), spasms of the adductor muscles cause strangled voice breaks and a strained-strangled voice quality. In the abductor variant (ABSD), spasms of the posterior cricoarytenoid muscle (PCA...

INTRODUCTION Hyperkinetic (hyperfunctional) dysphonia is a common pathology. The disorder is often found in vocal professionals faced with high vocal requirements. OBJECTIVE The objective of this study was to evaluate the effects of vocal therapy on voice condition characterized by hyperkinetic dysphonia with prenodular lesions and soft nodules. METHODS The study included 100 adult patients...

The study of loading in the muscle is essential to better understanding the adaptation and plasticity of the muscle under pathologic or surgically-altered conditions. Muscle recruitment and muscle force are determined by the muscle's mechanical function as a joint mover and a joint stabilizer. The coordination of muscle contraction affects joint stability. However, the conditions of the joint p...