BACKGROUND the magnitude of cardiovascular responses is dependent on the static and dynamic components as well as the duration and intensity of the contraction performed. OBJECTIVE to evaluate the heart rate responses to different percentages of isometric contractions in 12 patients (63 ± 11.6 years) with coronary artery disease and/or risk factors for coronary artery disease that were partic...

Although skeletal muscle perfusion is fundamental to proper muscle function, in vivo measurements are typically limited to those of limb or arterial blood flow, rather than flow within the muscle bed itself. We present a noninvasive functional MRI (fMRI) technique for measuring perfusion-related signal intensity (SI) changes in human skeletal muscle during and after contractions and demonstrate...

INTRODUCTION Hypertension is a major risk factor contributing to cardiovascular disease, which is the number one cause of deaths worldwide. Although antihypertensive medications are effective at controlling blood pressure, current first-line treatment for hypertension is nonpharmacological lifestyle modifications. Recent studies indicate that isometric resistance training (IRT) may also be effe...

Del Balso C, Cafarelli E. Adaptations in the activation of human skeletal muscle induced by short-term isometric resistance training. J Appl Physiol 103: 402–411, 2007. First published 19 April 2007; doi:10.1152/japplphysiol.00477.2006.—This study employed longitudinal measures of evoked spinal reflex responses (Hoffman reflex, V wave) to investigate changes in the activation of muscle and to d...

Background: Based on previously reported changes in muscle metabolism that could increase susceptibility to fatigue, we speculated that patients with chronic obstructive pulmonary disease (COPD) have reduced quadriceps endurance and that this will be correlated with the proportion of type I muscle fibres and with the activity of oxidative enzymes. Methods: The endurance of the quadriceps was ev...

BACKGROUND While total knee arthroplasty reduces pain and provides a functional range of motion of the knee, quadriceps weakness and reduced functional capacity typically are still present one year after surgery. The purpose of the present investigation was to determine the role of failure of voluntary muscle activation and muscle atrophy in the early loss of quadriceps strength after surgery. ...

This study compared alternating current and pulsed current electrical muscle stimulation (EMS) for torque output, skin temperature (Tsk), blood lactate and hormonal responses, and skeletal muscle damage markers. Twelve healthy men (23-48 yr) received alternating current EMS (2.5 kHz delivered at 75 Hz, 400 micros) for the knee extensors of one leg and pulsed current (75 Hz, 400 micros) for the ...

Effect of contraction intensity [100%, 75%, 50%, and 25% maximum voluntary contraction (MVC)] and movement velocity [0 degrees (isometric)], 50 degrees, 100 degrees, 200 degrees, and 400 degrees/sec. [isovelocities]) on root mean square amplitude (SEMG-RMS) and median frequency power spectrum (SEMG-MNF) of vastus lateralis (VL) surface electromyography was investigated with ten healthy female u...

Background: PNF stretching is a reputed exercise for the development of physical and sports performance. However, there was no review study on fitness. Aim: The aim to identify effect fitness in perspective positive effect, negative effect. Method: 28 articles fulfilling criteria made this after inclusion exclusion were done. All collected through online scientific data sources. Discussion: Int...

The purpose of this study was to investigate the asymmetry of force fluctuation in the leg muscles during isometric knee extension and flexion. Twenty healthy males (21±2 years) performed the maximal voluntary isometric contraction (MVC) in knee extensor and flexor. On the basis of MVC measurement, the subjects performed sustained isometric knee extension and flexion for 15s at levels correspon...