Anabolic effects of androgens on skeletal muscle are well documented, but the physiological and biochemical bases of these effects are poorly understood. Skeletal muscles that differ in their androgen responsiveness can be used to examine these mechanisms. We compared androgen receptor mRNA and protein levels of the rat levator ani, a perineal skeletal muscle that depends on androgens for its n...

Free grafts were performed on the rat extensor digitorum longus muscle after no pretreatment, 14-day predenervation, or two or one preinjections of Marcaine. Numbers of surviving muscle fibers were counted in 4-day grafts, and the total number of muscle fibers was counted in 60-day grafts. Mean numbers of surviving muscle fibers in 4-day grafts were 132 for untreated muscles, 1166 for predenerv...

The regenerating levator ani muscle of the rat is known to retain its sensitivity to the effects of testosterone. To determine whether hormonal sensitivity of the regenerating muscle is purely myogenic or requires some interaction with the pudendal nerve or the local humoral environment, levator ani muscles were freely grafted in place of the soleus or extensor digitorum longus muscles in norma...

INTRODUCTION In this study, we analyzed the crosstalk in mechanomyographic (MMG) signals generated by the extensor digitorum (ED), extensor carpi ulnaris (ECU), and flexor carpi ulnaris (FCU) muscles of the forearm during wrist flexion (WF) and extension (WE) and radial (RD) and ulnar (UD) deviations. METHODS Twenty right-handed men (mean ± SD age=26.7 ± 3.83 years) performed the wrist postur...

OBJECTIVE To investigate the influence of fatigue on phasic muscle-activation patterns during dynamic trunk extension exercise. DESIGN Fifteen healthy volunteers performed dynamic trunk-extension exercise through a 30-degree range-of-motion (ROM) exercise to task failure at an intensity of 50% of maximum. Electromyography (EMG) signals were recorded unilaterally from the lumbar extensor, glut...

PURPOSE To quantify the gain in muscle mobility with progressive release of surrounding connective-tissue structures and to compare this property with the known architecture of each muscle. METHODS Each of 5 different muscle tendon units (extensor carpi radialis brevis, extensor carpi radialis longus, flexor carpi ulnaris, flexor digitorum superficialis, pronator teres) was released from its ...

This study assessed muscle inhibition in patients with chronic anterior cruciate ligament (ACL) deficiency or ACL reconstruction. A series of protocols were tested for their effectiveness in increasing activity of the individual knee extensor muscles and decreasing muscle inhibition of the whole quadriceps group. Quadriceps muscle inhibition was measured by superimposing an electrical twitch on...

Many patients with upper limb defects desire myoelectric prosthetic hands, but they are still not used for some reasons. One of the most significant reasons is its external appearance, which has discomfort caused by structural difference between a human hand and robotic link. The structure must be based on anatomy to create more natural-looking prosthesis. This study designed biomimetic bones, ...

A detailed electrophysiological study has been made of the extensor digitorum brevis, thenar, hypothenar and soleus muscles in one patient with myotubular or centronuclear myopathy. The main finding was a noticeable reduction in the population of active motor units in all the investigated muscles. The remainer units showed normal sizes. The experimental observations have been interpreted in ter...

In many species of frog, the forelimb muscles important in amplexus are known to be much larger in males than in females. We studied this dimorphism in three forelimb muscles in the bullfrog [abductor indicus longus (AIL), flexor carpi radialis (FCR) and extensor carpi radialis (ECR)] by testing their isometric contractile properties. One muscle that is not dimorphic, the extensor carpi ulnaris...