Search results for "Exercise."
showing 10 items of 3068 documents
Behaviour of nitric oxide metabolites in unprofessional athletes before and after a cardiopulmonary test.
2010
Physical training causes an increase in nitric oxide (NO) production [2, 3, 8, 9] and this datum explains the link between exercise and endothelium and seems to demonstrate how regular training upregulates eNOS expression, although it is not sure if this upregulation is due to shear stress or metabolic factors [3]. However, it must be underlined that besides to be directly influenced by exogenous NO, erythrocytes express a functional NOS [5, 6, 11, 13] that raises the circulation NO pool. The literature data describe that an 8-week exercise training induced an increase in plasma levels of NO metabolites (NOx), that persisted four weeks after interruption of training [8]. A similar trend was…
Neck trouble in machine operating, dynamic physical work and sedentary work: a prospective study on occupational and individual risk factors.
1994
A prospective study on the effects of occupational and individual factors on neck trouble was carried out among 1832 men representing static work with whole-body vibration (machine operators), dynamic physical work (construction carpenters) and sedentary work (office workers). Neck trouble and occupational and individual factors were inquired about via postal questionnaires in 1984 and 1987. Machine operating was associated with an increased risk to contract severe neck trouble, and machine operating and dynamic physical work were associated with persistently severe neck trouble. Other predictors for contracting severe neck trouble were age and current smoking. Physical exercise decreased t…
Domains of Physical Activity in Relation to Stiffness Index in the General Population.
2021
Background Regular exercise training represents an important modifier of arterial stiffness (AS). Therefore, sex‐specific relations between domains of physical activity (PA; commuting, domestic, and leisure‐time PA, including active sport and occupational PA) with AS were investigated. Methods and Results Stiffness index by digital photoplethysmography was investigated in 12 650 subjects from the GHS (Gutenberg Health Study). Self‐reported PA was evaluated by the “Short Questionnaire to Assess Health‐Enhancing Physical Activity” and reported as activity score peer week, being a combined measure of duration, frequency, and intensity of PA. Multivariable linear regression analysis demonstrat…
Physical activity, morbidity and mortality in twins: a 24-year prospective follow-up.
2010
The aim of this study was to find out whether persistent leisure-time physical activity, adjusted for genetic liability and childhood experiences, protect against occurrence of specific chronic diseases and all-cause mortality. Study design was a 24-year prospective follow-up after 6-year physical activity discordance in twin pairs. From 5,663 healthy adult twin pairs, 146 pairs (including 29 mozygotic) discordant for both intensity and volume of leisure physical activity at baseline in both 1975 and 1981 were systematically identified. Mortality and occurrence of chronic diseases (diabetes, hypertension, coronary heart disease defined according to reimbursable medication status) were follo…
Plasma catecholamine responses and neural adaptation during short-term resistance training
2000
Low exercise-induced plasma adrenaline (A) responses have been reported in resistance-trained indi- viduals. In the study reported here, we investigated the interaction between strength gain and neural adaptation of the muscles, and the plasma A response in eight healthy men during a short-term resistance-training period. The subjects performed 5 resistance exercises (E1-E5), consisting of 6 sets of 12 bilateral leg exten- sions performed at a 50% load, and with 2 days rest in between. Average electromyographic (EMG) signal amplitude was recorded before and after the exercises, from the knee extensor muscles in isometric maximal voluntary contraction (MVC) as well as during the exercises (a…
Hormonal Responses to a Resistance Exercise Performed Under the Influence of Delayed Onset Muscle Soreness
2002
Hormonal responses to an unaccustomed knee-extension exercise (E1; 5 times 10 repetitions with 40% load of 1RM [1 repetition maximum] followed by 2 sets until exhaustion) were compared in 6 men with the corresponding responses to an identical exercise performed 2 days later under the influence of delayed onset muscle soreness (DOMS) (E2). Both exercises were performed with a variable-resistance machine causing exhaustion with significantly fewer repetitions than a normal constant-resistance knee-extension device does. The E1 induced DOMS as expected, but the 1RM, the total work done, and the repetition number and frequency were not different in the 2 exercises. In the 2 sets to failure, the…
Effects of oxygen fraction in inspired air on force production and electromyogram activity during ergometer rowing
1997
Six male rowers rowed maximally for 2500 m in ergometer tests during normoxia (fractional concentration of oxygen in inspired air, F IO2 0.209), in hyperoxia (F IO2 0.622) and in hypoxia (F IO2 0.158) in a randomized single-blind fashion. Oxygen consumption (V˙O2), force production of strokes as well as integrated electromyographs (iEMG) and mean power frequency (MPF) from seven muscles were measured in 500-m intervals. The iEMG signals from individual muscles were summed to represent overall electrical activity of these muscles (sum-iEMG). Maximal force of a stroke (F max) decreased from the 100% pre-exercise maximal value to 67 (SD 12)%, 63 (SD 15)% and 76 (SD 13)% (P<0.05 to normoxia, AN…
The Effects of a Prolonged Running Exercise on Strength Characteristics
2000
The aim of this study was to examine concentric, isometric, and eccentric strength reductions in the quadriceps muscle following a prolonged running exercise. Before and after a 2 h run (28.4+/-1.4 km) peak torque (PT) of the knee extensors at angular velocities of -120, -90, -60, 0, 60, 120, 180, 240 degrees x s(-1) using an isokinetic dynamometer, electromyographic (EMG) activity of the vastus lateralis (VL) and vastus medialis (VM) muscles and height of a counter movement jump were recorded in twelve well-trained triathletes. Counter movement jump performances decreased by 10% and PT values were all significantly lower (p < 0.01) at each angular velocity following the run. The torque los…
Effect of exercise training on in vitro LDL oxidation and free radical-induced hemolysis: the HERITAGE Family Study.
2006
Oxidant stress and overproduction of reactive oxygen species (ROS) contribute to the development of cardiovascular disease. Oxidative modifications of low-density lipoproteins (LDL) are thought to play an early and critical role in atherogenesis. LDL oxidation can be reproduced in vitro, but results usually show a large interindividual variation not entirely explained by the environment. Free radical-induced hemolysis is also proposed to reveal the overall antioxidant capacity. The roles of genetic factors and exercise on the variability of both measures were investigated. The study was conducted in 146 healthy individuals from 28 families participating in a 20-week exercise-training progra…
Neuromuscular efficiency of the triceps surae in induced and voluntary contractions: morning and evening evaluations.
2004
Variations in force and electromyographic (EMG) activities of skeletal muscles with the time-of-day have been previously described, but not for a postural muscle, submitted to daily postural and locomotor tasks. In this article, mechanical performances, EMGs, and the ratio between these parameters, i.e., the neuromuscular efficiency (NME), were measured on the triceps surae (TS) of eight subjects, two times each day, at 6:00 and 18:00 h. NME was evaluated under different experimental conditions (electrically induced contractions, reflex contractions, maximal and submaximal voluntary isometric contractions, and during a natural movement, a drop jump) to determine whether mechanisms, peripher…