The aim of the present study was to assess the spectral behavior of the erector spinae muscle during isometric contractions performed before and after a dynamic manual load-lifting test carried out by the trunk in order to determine the capacity of muscle to perform this task. Nine healthy female students participated in the experiment. Their average age, height, and body mass (+/- SD) were 20 ...

PURPOSE The objective of the following study is to observe the behavior of the six layers of the masseter during an isometric contraction at maximum exertion with the deformation pattern analysis method. MATERIALS AND METHODS This study has been conducted by use of an ultrasound machine (MicrUs ext-1H Telemed Medical Systems Milano) and a linear probe (L12-5l40S-3 5-12 MHz 40 mm) which allowe...

The effects of the beta2-adrenoceptor agonist salbutamol (Slb) on isometric and isotonic contractile properties of the rat diaphragm muscle (Diamus) were examined. A loading dose of 25 microg/kg Slb was administered intracardially before Diamus excision to ensure adequate diffusion. Studies were then performed with 0.05 microM Slb in the in vitro tissue chamber. cAMP levels were determined by r...

Myosin can be labeled with 1 -fluoro-2,4-dinitrobenzene in frog muscle. The incorporation into myosin is decreased during isotonic contraction. In contrast no difference is found in the incorporation into the sarcoplasmic proteins of contracting and resting muscle. Myosin also reacts with iodoacetate in frog muscle. However, this reaction does not depend on the functional state of the muscle. T...

We recorded fast extensor tibiae motor neuron activity during single-legged treadmill walking in the stick insect, Carausius morosus. We used this activity to stimulate the extensor muscle motor nerve, observed the resulting extensor muscle contractions under isotonic conditions, and quantified these contractions with a variety of measures. Extensor contractions induced in this manner were high...

Long-latency (40-80 ms) electromyographic (e.m.g.) responses of the contracting flexor pollicis longus to stretches applied at the thumb-tip, were studied in normal human subjects. Stretches were applied during four classes of contraction: (i) isometric 'hold', in which the subject held a steady isometric contraction; (ii) isometric tracking, in which the subject tracked a steadily rising force...

In this paper, we show that a pointwise symmetric pre-isotonic preclosure function is uniquely determined the pairs of sets it separates. We then show that when the preclosure function of the domain is pre-isotonic and the pre-closure function of the codomain is pre-isotonic and pointwise-pre-symmetric, functions which separate only those pairs of sets which are already separated are precontinu...

The isolation of the cortex of the sea urchin blastomere by detergent lysis was explored with the aim of analyzing components important in the structure and function of the cortical cytoskeleton, and their relationship to such phenomena as contraction. Buffered EGTA medium supplemented with isotonic glycerol and with magnesium, at a level close to the reported internal cellular concentration, y...

Introduction. ............................................................ 129 Fiber Types. ............................................................ 130 Historical introduction. ................................................. 130 Classification and terminology. ........................................... 131 Contractile properties of different types of fiber. ............................ ...