Search results for "centric"
showing 10 items of 389 documents
Time of day effects on isometric and isokinetic torque developed during elbow flexion in humans
2001
The aim of this study was, firstly, to confirm or refute the existence of circadian rhythms during several velocities of concentric action of the elbow flexor muscles and, secondly, to compare the characteristics of these circadian rhythms with those obtained during isometric actions. Eight volunteer subjects participated in this study. The circadian rhythms were obtained from six test sessions (TS) carried out at different times of day over 6 days with only one TS a day. During each TS, oral temperature and the torque of the muscle action were measured. The subjects made, on an isokinetic ergometer, two maximal isokinetic concentric elbow flexions at five angular velocities (60, 120, 180, …
The influence of electrostimulation on mechanical and morphological characteristics of the triceps surae.
1994
The present study assessed the effects of training using electrostimulation of muscle (EMS) on the torque-angular velocity and torque-angle relationships, and the cross-sectional area (CSA) of the triceps surae. Twelve physical education students, divided into two groups (6 controls, 6 experimental), participated in the experiment. The EMS sessions were undertaken using a 'Complex-type' stimulator. Flexible elastomer electrodes were used. The current used discharged pulses lasting for 200 microseconds at a frequency of 70 Hz. The durations of contraction and rest were 5 and 15 s, respectively. The session lasted for 10 min for each muscle. The training regimen was three sessions per week fo…
Exercise in waist-high warm water decreases pain and improves health-related quality of life and strength in the lower extremities in women with fibr…
2006
Objective To evaluate the short- and long-term efficacy of exercise therapy in a warm, waist-high pool in women with fibromyalgia. Methods Thirty-four women (mean ± SD tender points 17 ± 1) were randomly assigned to either an exercise group (n = 17) to perform 3 weekly sessions of training including aerobic, proprioceptive, and strengthening exercises during 12 weeks, or to a control group (n = 17). Maximal unilateral isokinetic strength was measured in the knee extensors and flexors in concentric and eccentric actions at 60°/second and 210°/second, and in the shoulder abductors and adductors in concentric contractions. Health-related quality of life (HRQOL) was assessed using the EQ-5D que…
Electrostimulation Training Effects on the Physical Performance of Ice Hockey Players
2005
BROCHERIE, F., N. BABAULT, G. COMETTI, N. MAFFIULETTI, and J.-C. CHATARD. Electrostimulation Training Effects on the Physical Performance of Ice Hockey Players. Med. Sci. Sports Exerc., Vol. 37, No. 3, pp. 455–460, 2005. Purpose: The aim of this study was to examine the influence of a short-term electromyostimulation (EMS) training program on the strength of knee extensors, skating, and vertical jump performance of a group of ice hockey players. Methods: Seventeen ice hockey players participated in this study, with nine in the electrostimulated group (ES) and the remaining height as controls (C). EMS sessions consisted of 30 contractions (4-s duration, 85 Hz) and were carried out 3 wk 1 for…
Combined effect of elastic energy and myoelectrical potentiation during stretch-shortening cycle exercise.
1982
In addition to the utilization of muscle's elastic energy enhancement of performance in exercise involving stretch-shortening cycle might be also due to simultaneous increase of myoelectrical activity. This hypothesis was tested by examining three athletes during jumping exercise on force-platform. Vertical jumps were performed with and without preliminary counter-movement, and the jumps were called counter-movement jump (CMJ) and squatting jump (SJ), respectively. In both conditions several jumps were performed also with extra loads on the shoulders (15–220% of b. wt.). Additional droppingjumps (DJ) were executed from different heights (20–100 cm). During jumping exercise myoelectrical act…
Effect of electrical stimulation training on the contractile characteristics of the triceps surae muscle.
1993
This study aimed to assess the effects of training using electrical stimulation (ES) on the contractile characteristics of the triceps surae muscle. A selection of 12 subjects was divided into two groups (6 control, 6 experimental). The ES sessions were carried out using a stimulator. Flexible elastomer electrodes were used. The current used discharged pulses lasting 200 microseconds at 70 Hz. Contraction time was 5 s and rest time 15 s. The session lasted 10 min for each muscle. Training sessions were three times a week for 4 weeks. Biomechanical tests were performed using an isokinetic ergometer. Subjects performed plantar flexions of the ankle over a concentric range of movement at diffe…
Short-term changes in the series elastic component after an acute eccentric exercise of the elbow flexors
2001
We have studied the effect of a unique eccentric exercise session on the series elastic component (SEC) properties of human elbow flexors. Ten active females performed five sets of ten maximal eccentric contractions on an isokinetic ergometer. Maximal isometric (MVC) torque, and the corresponding myoelectrical activity (RMS) of the biceps brachii and the triceps brachii muscles were recorded before, immediately after, 48 h after, and 1 week after the exercise session. SEC compliance was also measured, using the in situ quick-release technique. Maximal eccentric torque declined significantly among the five sets of the exercise session (P < 0.01). The exercise session induced a significant de…
Feasibility, safety and muscle activity during flywheel vs traditional strength training in adult patients with severe haemophilia
2021
INTRODUCTION: Eccentric training has been associated with several specific physiological adaptations. The flywheel machine is one of the easiest ways of performing eccentric overload training. However, no studies evaluated its feasibility, safety and muscle activity in patients with haemophilia (PWH).AIM: To evaluate feasibility and safety and compare muscle activity during flywheel vs weight machine knee extension exercise in severe PWH.METHODS: Eleven severe PWH [mean age of 33.5 (8.1) years] participated in this cross-sectional study after receiving prophylactic treatment. Surface electromyography (EMG) signals were recorded for the rectus femoris during the knee extension exercise perfo…
Eye position tunes the contribution of allocentric and egocentric information to target localization in human goal-directed arm movements.
1997
Subjects were required to point to the distant vertex of the closed and the open configurations of the Muller-Lyer illusion using either their right hand (experiment 1) or their left hand (experiment 2). In both experiments the Muller-Lyer figures were horizontally presented either in the left or in the right hemispace and movements were executed using either foveal or peripheral vision of the target. According to the illusion effect, subjects undershot and overshot the vertex location of the closed and the open configuration, respectively. The illusion effect decreased when the target was fixated and when the stimulus was positioned in the right hemispace. These results confirm the hypothe…
On Concentric Circles of Being Revisited: Friedrich Nietzsche and the Idea of Eternal Recurrence
2012
The circle, or ouroboros, is a perfect shape: within its depths lie both the beginning and the end. Things are repeated; people encounter the same situations again and again. Concentricity dwells in the spirit of a place, as it does in the ‘I’ of a person. A memory can bring to life the circular nature of existence, allowing the subject to travel recurrently through previously realised pasts. Photographs and literature are also capable of transferring the bygone into the freshness of the present moment. The aesthetics of inhabited space is articulated in architectural shapes. It is an essential part of the collective national narrative, a cultural philosophy narrated into the fabric of bein…