Cardiopulmonary and metabolic variables were investigated at maximal and submaximal bicycle ergometer exercises in 41 swimmers of both sexes, 8--18 years old. VO2 max and VO2 max . HR-1 were higher in boys than in girls and increased with maturity, while VO2 max. kg-1 and HVE were not influenced by this. The HV increased clearly during this growth period, the pubertal and postpubertal subjects showing 16 and 17% higher values for HV and HV . kg-1 than those reported in normal schoolchildren populations. During the submaximal exercise at 70% VO2 max the highest HR values were found in the prepubertal group, whilst the lowest were observed in the postpubertal subjects. These findings suggest that a given percentage of VO2 max as a reference unit, is more reliable than a certain HR to obtain comparable results in subjects with different ages. Blood samples were collected before, during, and after the submaximal exercise. Blood glucose and FFA did not differ in relation to the stages of maturity. During exercise, insulin decreased in prepubertal children, did not alter in pubertal adolescents, and increased in postpubertal subjects. The lactate concentration, during exercise, increased in relation to maturity. The same results were found for HGH, but no differences were found with regard to sex. Since the pattern of HGH secretion during exercise is similar to that found after arginine and insulin administration it is assumed that the same mechanism (i.e., sex hormones) triggers the HGH release.

A study was undertaken to evaluate and to examine the role of substrate supply in 50 healthy subjects after long distance events, such as 10 km, 25 km, and marathon races. The metabolic, variables of carbohydrate metabolism were greatest in 10-km runners, with the highest increase in glucose, lactate, and pyruvate, while in marathon runners only moderate changes were observed. Marathon competitors gave the greatest decrease in insulin concentration whereas glucagon and cortisol showed a contrary tendency. As for lipid concentrations, the most remarkable point was that after the marathon competition the best runners had the highest increase in free fatty acids; the longer the race, the higher were the beta-hydroxybutyrate and acetoacetate levels after the competition. It is important to emphasize that the limiting factor up to 90 min duration is the competitor's ability to deplete the stores of glycogen. Beyond 90 min (or 25 km) the decrease in insulin, the rise in cortisol and the higher concentration of ketnne bodies found indicate a change in metabnlic response.

The aim of this study was to evaluate the influence of the sports mechanic demands of competitive tennis on the thoracolumbar spinal profile. For that reason the spinal curvature (C7 - S2) of 123 male active gymnasts aged 23,8 +/- 4,5 years with a sporting exposure of 14,4 +/- 3,8 years and of 1347 age and gender matched non- and recreational sportsmen was recorded by means of the non-invasive ultrasonic-controlled contact rod. In the sagittal projection no differences between both groups were found. However, in control and sports group the dominant side of the arms induced statistically significant differences for all parameters describing spinal curvature in the frontal and transversal plane, data evaluated showed a relevant increase in the tennis group. Furthermore, the criterion both-handed hitting technique in fore and backhand caused an additional extension of lateral inclination, pelvic and pelvic-shoulder tilt as well as pelvic-shoulder rotation to the hitting side of the arms. After examining the sports-specific mechanic strain the measuring values are to interpret as a functional adaptation to the tennis-specific demands. But there is only a reduced correlation with the results of epidemiologic studies taking the incidence and prevalence of spinal injuries in competitive tennis into special account. So the tennis-specific modifications of spinal profile are not to characterise a priori as pathogen.

The effectiveness of the muscle strengthening program for patients with low back pain could be improved significantly by means of the elastic lumbar belt as an applicable therapy instrument in the functional rehabilitation of spinal injuries.

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