Flexor muscles

Bugyi, G. J., The effects of moderate doses of caffeine on fatigue parameters of the forearm flexor muscles, American Corrective Therapy Journal, 34, 49, 1980. 

Figure 7.4 The withdrawal reflex coupled with the crossed-extensor reflex. A painful stimulus will elicit the withdrawal reflex, which causes flexor muscles to contract and move the affected body part away from the stimulus. At the same time, the crossed-extensor reflex causes extensor muscles in the opposite limb to contract. The straightening of the opposite limb provides support for the body.

The excitatory intemeuron then synapses with the alpha motor neuron that innervates Hie flexor muscles of the right leg. Consequently, stimulation of the excitatory intemeuron leads to stimulation of the alpha motor neuron, which then stimulates the flexor muscles to contract and pick up or withdraw the foot from the painful stimulus. The inhibitory intemeuron synapses with the alpha motor neuron that innervates the extensor muscles of the right leg. Therefore, stimulation of the inhibitory intemeuron leads to inhibition of the alpha motor neuron. As a result, the extensor muscles relax. 

The flexor muscles and the extensor muscles are antagonistic — they cause opposite effects. Therefore, when one of these groups of muscles is activated, the other group must be inhibited. This is referred to as reciprocal... 

Taylor et which found no significant difference in Pi/PCr between resting finger flexor muscles of 7 PD subjects and 11 age-matched controls. Methodological differences, unknown pharmacological effects of medication, and the low statistical power of the Taylor et al. study could attribute to the discrepancies between the findings of these studies. 

Figure 19-22 Phosphorus-31 magnetic resonance spectra of wrist flexor muscles of the forearm of a trained long-distance runner at rest and during contraction at three different levels of exercise. Ergometer measurements indicating the percent of initial maximum strength (% max) were recorded over each 6-min period. Spectra were obtained during the last 3 min of each period. Times of spectral data collection A, resting B, 4—6 min C, 10-12 min and D, 16-18 min. The pH ranged from 6.9 to 7.0. From Park et al.288...

Wand, P., Sontag, K-H., Cremer, H. (1977). Effects of 1,3-dimethyl-5-aminoadamantane hydrochloride (DMAA) on the stretch-induced reflex tension of flexor muscles and the... 

A network model of ATP free energy metabolism in muscle consisting of actomyosin ATPase, sarcoplasmic reticulum Ca -ATPase and mitochondria has been developed. The model was used to analyse ATP metabolic flux and cytosolic ATP/ADP steady state at six contraction frequencies between 0 and 2 Hz measured in the forearm flexor muscle using P NMR. ... 

Comparison of results of scanning electron microscopy and MRI was done before and after administration of a radiographic contrast agent in the tendon of the deep digital flexor muscle obtained from horse cadavers. 

Myoclonic seizures consist of sudden, very brief, jerking contractions that may involve the entire body or be confined to limited areas, such as the face and neck. The contractions may affect Individual muscles or groups, with simultaneous contraction of both extensor and flexor muscles. These seizures occur In all age groups, with symptoms ranging from rapid tremors to falling down. No loss of consciousness Is detectable because of the brief duration of the seizure. Myoclonic seizures often occur In combination with other seizure types. Valproate and clonazepam are used most often to treat myoclonic seizures lamotrigine and topiramate also have shown some efficacy. 

Cromarty SI, Kass-Simon G (1998) Differential effects of a molting hormone, 20-hydroxyecdysone, on the neuromuscular junctions of the claw opener and abdominal flexor muscles of the American lobster. Comp Biochem Physiol A 120 289-300... 

Flexion of a joint is defined to be the positive direction for angular changes hence, the flexor torque is assumed to be positive. Index/ is for the equivalent flexor muscle, and index e for the equivalent extensor muscle. The contribution of passive tissue crossing the joints is included by a resistive torque (index r), which will be described below. 

In addition to cortical motor neurons, control of the musculosketal system also relies on afferent receptors or sensory neurons that carry information from the periphery to the brain or spinal cord. The simplest nerve pathways lead directly from sensory neurons to motor neurons, and are known as reflex arcs. One such example is the withdrawal reflex. When skin receptors sense something is hot or sharp (a pin prick, for example), a sensory impulse is sent to the spinal cord, where an intemeuron integrates the information and relays it to a motor neuron. The motor neuron in turn transmits a signal to the appropriate flexor muscle, which contracts and thus completes the reflex loop. 

FIGURE 6.26 Resultant force in the ACL for isometric (thick line) and isokinetic (30, 90, 180, and 300 deg/sec) knee-extension exercises. The results were obtained from a two-dimensional model of the knee joint, assuming the quadriceps are fully activated and there is no cocontraction in the flexor muscles of the knee (Serpas et al in press). The model results show that exercises in the studied speed range can reduce the force in the ACL by as much as one-half. [Modified from Serpas et at. (in press. ]... 

The relationship between the Gibbs energy of ATP hydrolysis and the performance of muscle is sigmoidal, and the normal operating domain is in the quasilinear region of the curve. This corresponds with the magnetic resonance spectroscopy results obtained from studies of the finger-flexor muscle. Chemiosmotic potentials... 

Third phase The worker complains of symptoms of peripheral neuritis, initially of hands and feet, which is essentially sensory. In more severe cases, motor paralyses occur the first muscles affected are usually the toe extensors and the peronei. In only the most severe cases will paralysis of flexor muscles of the feet or of the extensor muscles of hands occur. 

In the supine position, the concentric (shortening) contraction of the flexor muscles lifts the tead off the floor. These muscles are exercised. 

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