An intersegmental reflex initiated by flexing a crayfish leg at the merocarpal joint was examined by recording reflex response latencies of cephalic, thoracic and abdominal muscles. The first response was an intrasegmental resistance reflex in the extensor muscle of the stimulated leg. Spread of the intersegmental reflex occurred in both cephalic and caudal directions. Activation of the cephali...

K channels regulate action potential duration and thereby force of skeletal muscles. Diaphragm differs from limb muscles in the dependence of contraction on extracellular Ca. We hypothesized that diaphragm also differs from limb muscles in the regulation of contraction by membranous K conductances. This was tested in vitro by assessing changes in isometric twitch force and kinetics in response ...

We discovered that the contemporary procedure for assessing voluntary activation of knee extensor muscles with transcranial magnetic stimulation (TMS) is invalid. TMS activates too few agonist quadriceps motoneurons and many antagonist hamstrings to estimate resting twitch accurately. A modified procedure, in which TMS-evoked superimposed twitches are considered together from femoral nerve stim...

The storage and recovery of elastic strain energy in muscles and tendons increases the economy of locomotion in running vertebrates. In this investigation, we compared the negative and positive external work produced at individual limb joints of running dogs to evaluate which muscle-tendon systems contribute to elastic storage and to determine the extent to which the external work of locomotion...

the aim of the present study was to investigate the effect of hiit run on pgc-1α gene expression in fast & slow twitch muscles of healthy male  rats. for this purpose, 12 male wistar rats divided into two groups: contorol (n=6) and exercise (n=6) , respectively. intense interval training was consists of five days and a total of eight weeks,  that was formed the three frequencies ( 90 to 100% vo...

The choice of activity to improve finger extension of post-CVA patients is based on untested assumptions and hypotheses. In this study, using electromyography of the extrinsic finger muscles and electrogoniometry of wrist and finger joints, the effects of five types of exercise on the finger extension of post-CVA patients were documented. Results indicated that resisted and rapid exercises recr...

The three centrally located putative accessory neurons of the muscle receptor organ (MRO) of the isopod Ligia exotica were identified to the third segmental nerve (N3) of the thoracic ganglion by backfilling with Lucifer Yellow. These neurons were then studied intracellularly and extracellularly to determine whether they suppressed the stretch-activated responses of thoracic stretch receptors. ...

1. In this investigation, we tested the hypothesis that muscle spindle afferents signaling the length of hind-leg flexor muscles are involved in terminating extensor activity and initiating flexion during walking. The hip flexor muscle iliopsoas (IP) and the ankle flexors tibialis anterior (TA) and extensor digitorum longus (EDL) were stretched or vibrated at various phases of the step cycle in...

Duchenne muscular dystrophy is due to genetic abnormalities in the dystrophin gene and represents one of the most frequent genetic childhood diseases. In the X-linked muscular dystrophy (mdx) mouse model of dystrophinopathy, different subtypes of skeletal muscles are affected to a varying degree albeit the same single base substitution within exon 23 of the dystrophin gene. Thus, to determine p...

Numbers of functioning motor units have been estimated in 124 muscles of boys with Duchenne dystrophy; some of the patients were studied on several occasions. In the distal muscles examined (extensor digitorum brevis, thenar, and hypothenar muscles) the losses of units were probably present at birth and did not decrease with age. In contrast, the numbers of units and of excitable muscle fibres ...