Series elastic element stiffness was studied during isometric muscle contraction in cylindrical segments of dog common carotid artery. These vessel segments were mounted in vitro and restored to in situ length. Vessel diameter was constantly monitored with a linear displacement transducer. The arteries were subjected to isometric contraction by adding norepinephrine to the bath and elevating th...

The purpose of this study was to examine the effectiveness of an electronic muscle stimulator in strengthening normal quadriceps femoris muscle without the assistance of simultaneous isometric muscle contraction. The sample consisted of 58 subjects who were randomly divided into three independent groups. One group (n = 19) served as controls; one group (n = 20) underwent daily stimulation of th...

BACKGROUND Peripheral muscle dysfunction is a common finding in patients with COPD; however, the structural adaptation and functional impairment of the upper and lower limb muscles do not seem to be homogenous. We compared muscle fatigue and recovery time between 2 representative muscles: the middle deltoid and the quadriceps femoris. METHODS Twenty-one subjects with COPD (FEV1 46.1 ± 10.3% o...

• The strength of myocardial contraction is influenced directly and strongly by the intervals separating individual beats. The large number of studies on this phenomenon during the 95 years since its original recognition have recently been reviewed. Interval-dependent changes in the strength and time course of contraction result both from alterations in the duration of the active state and from...

Background: Muscle Energy Technique (MET) has been advocated for the treatment of restricted range of motion in the upper neck. There is little evidence, however, to support the effectiveness of MET to increase motion in the cervical spine, or determine the optimal duration of isometric contraction during the technique. Objectives: The aim of this study was to investigate the effect of various ...

25 Introduction: Diabetic retinopathy is accompanied by disturbances in retinal blood flow 26 which is assumed to be related to the diabetic metabolic dysregulation. It has previously 27 been shown that normoinsulinemic hyperglycemia has no effect on the diameter of retinal 28 arterioles at rest and during an increase in the arterial blood pressure induced by isometric 29 exercise. However, the...

This study was designed to investigate the modulations of H-reflex and V-wave responses during passive and maximal active dynamic actions. Experiments were performed on 16 healthy males [age: 24 +/- 4 (SD) yr]. Maximal H-reflexes (Hmax) and M-waves (MmaxR) were evoked at the same muscle length during passive isometric, shortening and lengthening actions and during maximal voluntary isometric, c...

Introduction Changes in muscle geometry such as muscle thickness, pennation angle and fascicle length occur with muscle contraction (Herbert and Gandevia, 1995; Fukunaga et al., 1997; Ito et al., 1998; Kawakami et al., 1998; Maganaris and Baltzopoulos, 1999). These changes can be measured using computerised sonography and could potentially provide a measure of muscle 'activity'. This study inve...

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...

A conventional five-step chemo-mechanical cycle of the myosin-actin ATPase reaction, which implies myosin detachment from actin upon release of hydrolysis products (ADP and phosphate, Pi) and binding of a new ATP molecule, is able to fit the [Pi] dependence of the force and number of myosin motors during isometric contraction of skeletal muscle. However, this scheme is not able to explain why t...