purpose: low back pain is one of the most common musculoskeletal disorders, and lifting is one of its risk factors. the activities of lumbar muscles as the main muscles involved in lifting are important with regard to identification of the allowable limits and the injury mechanisms as well as the motor control aspects. this study aimed to investigate the effects of the lifting speed on the lumb...

The aim of this study was to explore the cellular mechanisms underlying the impaired contractile response to beta adrenoceptor stimulation in diabetic hearts. Chronic diabetes was induced in rats by a streptozotocin injection. Four to six weeks later, papillary muscles isolated from diabetic hearts exhibited marked reductions in the positive inotropic responses to isoproterenol, norepinephrine ...

BACKGROUND Recent reports suggest that activation of adenosine monophosphate (AMP)-activated protein kinase (AMPK), in response to acute changes in cellular energy status in cardiac and skeletal muscles, results in altered substrate utilization. We hypothesized that chronic alterations in myocardial energetics in hypertrophied hearts (left ventricular hypertrophy, LVH) will lead to elevated AMP...

In this study, the bandwidth of the filter-based fatigue index was determined by the comparison of optimized cut-off frequencies in different inter-electrode distances. Sixty-one subjects participated in isometric knee extension, isotonic ankle dorsiflexion, and isotonic elbow extension exercises. Electromyography (EMG) signals were obtained from right rectus femoris, triceps brachii, and tibia...

1 Parque Tecnológico de Belo Horizonte, Rua Professor José Vieira de Mendonça N 770, Salas 406 e 407, Engenho Nogueira, 31310-260 Belo Horizonte, MG, Brazil 2 Departamento Regional da Bahia, Centro Integrado de Manufatura e Tecnologia, SENAI, Avenida Orlando Gomes N 1845, Piatã, 41650-010 Salvador, BA, Brazil 3 Departamento de Electromagnetismo y Fı́sica de la Materia Facultad de Ciencias, Unive...

Isolated rat papillary muscles of the right ventricle were used to discover the origin of reduced myocardial efficiency in chronic heart failure. Right ventricular hypertrophy was induced by monocrotaline injection, causing pulmonary hypertension. Control (n = 7) and hypertrophied (n = 11) papillary muscles were subjected to sinusoidal length changes at 37 degrees C and 5 Hz with a peak-to-peak...

The present study was designed to determine whether myocardial atrophy is necessarily associated with changes in cardiac contractility. Myocardial unloading of normal hearts was produced via heterotopic transplantation in rats. Contractions of isolated myocytes (1.2 mM Ca2+; 37 degrees C) were assessed during field stimulation (0.5, 1.0, and 2.0 Hz), and papillary muscle contractions were asses...

BACKGROUND The localization of dystrophin at the sarcolemma of cardiac skeletal fibers and cardiac Purkinje fibers has been described. Dystrophin deficiency produces clinical manifestations of disease in skeletal muscles and hearts of patients with Duchenne and Becker muscular dystrophy. Utrophin (or dystrophin-related protein), a dystrophin homologous protein, was found to be expressed in feta...

Stimulation of beta-adrenergic receptors activates type I and II cyclic AMP-dependent protein kinase A, resulting in phosphorylation of various proteins in the heart. It has been proposed that PKA II compartmentalization by A-kinase-anchoring proteins (AKAPs) regulates cyclic AMP-dependent signaling in the cell. We investigated the expression and localization of AKAP100 in adult hearts. By immu...

This paper investigates the approximation behaviour of the K1 oczy–Hirota (KH) interpolative fuzzy controllers. First, in accordance with the remarks in (Fuzzy Sets and Systems 125(1) (2002) 105), it is pointed out that it is a fuzzy generalization of the Shepard operator. Shepard operator has thoroughly studied by approximation theorist since the mid-1970s. Exploiting the aforementioned relati...