Search results for "MUSCLES"

Alterations of mechanical characteristics of human skeletal muscle during strength training

1983

To investigate the influence of strength training on the mechanical characteristics of human skeletal muscle, 14 male subjects went through training of combined heavy concentric and eccentric contractions three times a week for 16 weeks. The strength training program consisted mainly of dynamic exercises for leg extensors with loads of 80 to 120% of one maximum repetition. The force-time curves produced during various vertical jumps were the basis for calculation of various mechanical parameters. In addition to a great increase (p less than 0.001) in maximal isometric force, heavy resistance strength training also caused significant (p less than 0.05-0.01) increases in heights and in variou…

Store and recoil of elastic energy in slow and fast types of human skeletal muscles.

1982

Stretch-shortening cycle refers to the mechanical condition in which store and recoil of elastic energy occur in the skeletal muscle. This leads to a greater work output when compared to a simple shortening contraction. The subjects performed vertical jumps with and without preliminary counter-movement and with small and large knee angular displacement. The results indicated that those subjects who had more fast twitch (FT) fibers benefited more from the stretching phase performed with high speed and short angular displacement. The amounts of elastic energy stored in this phase were 30 and 26 N X kgBW-1, respectively, for FT and slow twitch (ST) type subjects. The recoil of elastic energy w…

A comparison of the triceps surae and residual muscle moments at the ankle during cycling.

1991

The rigid linked system model and principles of inverse dynamics have been widely used to calculate residual muscle moments during various activities. EMG driven models and optimization algorithms have also been presented in the literature in efforts to estimate skeletal muscle forces and evaluate their possible contribution to the residual muscle moment. Additionally, skeletal muscle-tendon forces have been measured, directly, in both animals and humans. The purpose of this investigation was to calculate the moment produced by the triceps surae muscles and compare it to the residual muscle moment at the ankle during cycling at three power outputs (90, 180 and 270 W). Inferences were made r…

Conduction times of cortical projections to paravertebral muscles in controls and in patients with multiple sclerosis

1994

Interrelationships between electromyographic, mechanical, muscle structure and reflex time measurements in man.

1981

Reaction time (TRT) with its premotor (PMT) and motor time (MT) components, patellar reflex time (TRfT) with its latency (LAT) and motor time (RfMT) were studied together with isometric force production and relaxation time variables in one leg isometric knee extension. These variables were intercorrelated together with muscle biopsy variables taken from m. vastus lateralis. From these computations MT proved to demonstrate significant correlations to rate of isometric force development (RFD) (P less than 0.001), maximum force (P0) (P less than 0.001) and per cent distribution of ST fibers (P less than 0.001). It is speculated that these relationships are determined by the pattern of the moto…

Bilateral and Unilateral Neuromuscular Function and Muscle Cross-Sectional Area in Middle-Aged and Elderly Men and Women

1996

Forty-eight healthy men (M) and women (W), divided into two different age groups, i.e., M50 yrs (range 44-57; n = 12), W50 yrs (range 43-57; n = 12), M70 yrs (range 59-75; n = 12), and W70 yrs (range 62-75; n = 12), volunteered as subjects for examination of muscle cross-sectional area (CSA), maximal voluntary forces, force-time curves, and electromyographic activity of the knee extensor muscles during bilateral and unilateral isometric contractions. The maximal bilateral knee extension force and the average CSA values in M50 were greater (p < .05) than in M70 and in W50 were greater (p < .05-.001) than those recorded for W70. The early forces in the force-time curve were greater (p < .05) …

Muscle cross-sectional area and voluntary force production characteristics in elite strength- and endurance-trained athletes and sprinters

1989

Seven male elite strength-trained athletes (SA) from different weight categories, six elite sprinters (SPA) and seven elite endurance-trained athletes (EA) volunteered as subjects for examination of their muscle cross-sectional area (CSA), maximal voluntary isometric force, force-time and relaxation-time characteristics of the leg extensor muscles. The SA group demonstrated slightly greater CSA and maximal absolute strength than the SPA group, while the EA group demonstrated the smallest values both in CSA and especially in maximal strength (p<0.05). When the maximal forces were related to CSA of the muscles, the mean value for the SA group of 60.8±10.0 N·cm−2 remained slightly greater than…

End-plate dysfunction in acute organophosphate intoxication.

1989

Acute organophosphate intoxication resulting from suicide attempts in 14 patients produced a series of electrophysiologic abnormalities that correlated with the clinical course. Spontaneous repetitive firing of single evoked compound muscle action potentials (CMAP) was the earliest and most sensitive indicator of the acetylcholinesterase inhibition. A decrement of evoked CMAP following repetitive nerve stimulation was the most severe abnormality. At the height of the intoxication no CMAP was evoked after the first few stimuli. The decrement-increment phenomenon occurred only at milder stages of intoxication and its features are characteristic of acetylcholinesterase inhibition. These electr…

Reliability of measuring the fat content of the lumbar vertebral marrow and paraspinal muscles using MRI mDIXON-quant sequence

2018

PURPOSE We aimed to assess the reliability of measuring the fat content of the lumbar vertebral marrow and the paraspinal muscles using magnetic resonance imaging (MRI) mDIXON-Quant sequence. METHODS Thirty-one healthy volunteers were included. All participants underwent liver mDIXON-Quant imaging on a 3.0 T Philips MRI scanner by observer A. Within two weeks, observer B repeated the scan. After the examination, each observer independently measured the fat content of the third lumbar vertebra (L3), and the psoas (PS), erector spinae (ES), and multifidus (MF) muscles on central L3 axial images. After two weeks, each observer repeated the same measurements. They were blinded to their previous…

Short-term effects of kinesio taping in the treatment of latent and active upper trapezius trigger points : two prospective, randomized, sham-control…

2019

Este es el artículo que se ha publicado de forma definitiva en: https://www.nature.com/articles/s41598-019-51146-4 The presence of myofascial trigger points (MTrPs) is one of the most common causes of musculoskeletal problems and may lead to limited professional activity. Among the various treatment methods proposed for MTrPs, Kinesio Taping (KT) is a non-invasive, painless, and less time-consuming method with fewer side efects that has become widely used as a therapeutic tool in a variety of prevention and rehabilitation protocols. The aim of the study was to evaluate the immediate and short-term efcacy of the space correction KT technique in patients with latent or active MTrPs in the upp…