Search results for "Exertion"
showing 10 items of 258 documents
Mechanical jumping power in young athletes.
1987
Mechanical jumping power was determined for 286 young male athletes representing six sports events and ranging in calendar and skeletal ages from 8.8 to 17.1 and from 7.8 to 18.1 years, respectively. The subjects performed successive maximal vertical jumps on a contact mat for 30 s. The number of jumps and their cumulative flight time after 15 and 30 s were used for calculations of mechanical power. The jumping performances of the young athletes were found to be reproducible from the age of 10-12 years in respect to the angular displacement of the knee and duration of contact. Absolute mechanical power, as well as power related to body weight, increased with calendar and skeletal ages. Of t…
Effect of isometric strength training of mechanical, electrical, and metabolic aspects of muscle function.
1978
Monozygous twin pairs (two female and four male) were used in a strength training study so that one member of each pair served as training subject (TS) and the other members as nonexercising controls (CS). TS trained four times a week for 12 weeks with maximal isometric knee extensions of the right leg. The parameters studied included muscle strength, endurance time, electromyographic activity, and activities of several key enzymes in nonoxidative and oxidative muscle metabolism. The results disclosed that in addition to a 20% increase in isometric knee extension strength in the trained leg of TS, an average increase of 11% was observed in strength of TS untrained leg. CS did not demonstrat…
Kayaking performance is altered in mentally fatigued young elite athletes
2019
Background The present study aimed to assess the impact of 60 min of a cognitive demanding task inducing mental fatigue (Stroop) on kayaking performance in young elite athletes. The second objective was to elucidate the effect of mental fatigue on performance in a population of young under-17 elite athletes of national. Methods Thirteen under-17 elite kayakers completed 60 min of an incongruent Stroop color-word test, or the equivalent time in a control condition in a cross-over study design. Afterwards, participants completed a 2000 m kayaking time trial in which power output, stroke rate and time at the end of 400, 800, 1200, 1600 and 2000 m were recorded. Physiological and perceptual mea…
Effects of aging and life-long physical training on collagen in slow and fast skeletal muscle in rats. A morphometric and immuno-histochemical study.
1987
Intramuscular collagen in a slow (m. soleus) and a fast (m. rectus femoris) skeletal muscle was studied by biochemical, morphometric, and immunohistochemical methods. Wistar white rats of 1, 4, 10, and 24 months were used as experimental animals. Our aim was to evaluate the effects of life-long physical training (treadmill running, 5 days a week for 1, 3, 9, and 23 months depending on the age attained). The biochemical concentration of collagen was higher in m. soleus than in m. rectus femoris and it increased in youth and in old age in m. soleus. The trained rats had higher concentrations of collagen than the untrained rats at 10 and 24 months. The morphometrically measured area-fractions …
Effects of age and prolonged running on proteolytic capacity in mouse cardiac and skeletal muscles.
1981
Male NMRI-mice, aged 3, 6, 9, and 12 months, were made to run for a period of 4 4 at a speed of 13.5 m/min on a motor-driven treadmill, 5 days after exertion, selected enzymatic estimates of acid and alkaline proteolytic as well as energy metabolic capacities were analyzed from the cardiac muscle and from the red and white parts of m. quadriceps femoris (MQF). The activities of alkaline and myofibrillar proteases increased most considerably in skeletal muscles with age. Cathepsin D and beta-glucuronidase activities were less affected in both muscles. Prolonged running increased the activities of cathepsin D, dipeptidyl aminopeptidase I and beta-glucuronidase in the white and, especially in …
Lysosomal changes related to ageing and physical exercise in mouse cardiac and skeletal muscles.
1982
Physical exercise increased the activities of arylsulphatase, cathepsin D and β-glucuronidase in mouse skeletal muscle but not in cardiac muscle. Exercise-induced lysosomal response was more prominent in young adult than in senescent mice. The lipofuscin content of cardiac and skeletal muscles increased markedly during ageing and was also found to increase slightly after exertion in young mice, but not in senescent ones.
Concurrent validation of the OMNI-Resistance Exercise Scale of perceived exertion with elastic bands in the elderly.
2018
Purpose:\ud To examine the concurrent validity of the OMNI-Resistance Exercise Scale of perceived exertion using elastic bands in elder population.\ud \ud Methods:\ud Twenty-six participants performed three separate sets of 15 repetitions (low- medium- and high-intensity) for 4 different exercises (2 for the upper-limb and 2 for the lower limb), over two different testing sessions. The criterion variables were heart rate and applied force (average and maximum). In addition to these dependent variables, the active muscle and overall body OMNI-RES for elastic bands scores were collected at the end of each repetition.\ud \ud Results:\ud Significant differences in heart rate, applied force and …
Decreased level of cardiac antioxidants in endurance-trained rats.
1989
Han-Wistar rats were exposed to a 194-200 h swimming protocol which caused a significant increase in the cardiac weight. The levels of various tissue antioxidants were assayed from the myocardium of the right ventricle and from the left ventricle (subendo- and subepimyocardium). This endurance training decreased the activities of catalase in the right ventricle and in the subendo- and subepimyocardium and Cu,Zn-superoxide dismutase in the subendomyocardium as well as the concentration of vitamin E in the right ventricle and in the subendomyocardium. Also, the activity of thioredoxin reductase decreased in each part of myocardium and that of glutathione reductase in the right ventricle and i…
Exhaustive physical exercise causes oxidation of glutathione status in blood: Prevention by antioxidant administration
1992
We have studied the effect of exhaustive concentric physical exercise on glutathione redox status and the possible relationship between blood glutathione oxidation and blood lactate and pyruvate levels. Levels of oxidized glutathione (GSSG) in blood increase after exhaustive concentric physical exercise in trained humans. GSSG levels were 72% higher immediately after exercise than at rest. They returned to normal values 1 h after exercise. Blood reduced glutathione (GSH) levels did not change significantly after the exercise. We have found a linear relationship between GSSG-to-GSH and lactate-to-pyruvate ratios in human blood before, during, and after exhaustive exercise. In rats, physical…
Effects of high-intensity circuit training, low-intensity circuit training and endurance training on blood pressure and lipoproteins in middle-aged o…
2013
Background The aim of this study was to determine the physiological effects of an high-intensity circuit training (HICT) on several cardiovascular disease risk factors in healthy, overweight middle-aged subjects, and to compare the effects of HICT to traditional endurance training (ET) and low-intensity circuit training (LICT). Methods Fifty-eight participants (ages 61±3.3 yrs, BMI 29.8±0.9) were randomly assigned to one of the three exercise treatment groups: HICT, LICT and ET. The three groups exercised three times per week, 50 min per session for 12 weeks. Baseline and after intervention anthropometric characteristics: body weight (BW), fat mass (FM); blood pressure: diastolic (DBP) and …