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The paper provides reference values with regard to pulmonary ventilation responses o progressively increasing bicycling up to the maximal level during the period of growth spurt. Data are based on longitudinal studies or rural Norwegian and German school children. A cluster sampling technique was used, starting with the total pupil-population at Lom in Norway at an age of 8 years, and annual tests were performed until the age of 15 years. In germany a similar pupil-population was tested from age 12 until age 17 years. Functional growth curves giving means and dispersions for ventilation rates, tidal volume, respiratory frequency, ventilatory equivalent and respiratory gas exchange ratio are constructed. Norwegian and German children's developmental processes with regard to the exercise ventilation variables were compared, and revealed no significant differences.

In order to analyse the relationship between maximal aerobic power (VO2max) and height, body mass and lean body mass a multi-longitudinal survey was conducted on three different age groups of randomly selected children from a small Czech community. Beginning at the initial ages of 8, 12 and 16 years subjects were subsequently retested three times at 2-year intervals. At overlapping ages there were no differences in the various age groups between height and VO2max. By utilizing mean values for the various parameters at specific calendar ages a growth curve was constructed for each sex for the age range 8-20 years. The values were compared with longitudinal studies in various countries and no substantial differences were found. When VO2max was then compared to height, body mass and lean body mass it was apparent that the almost linear relationship with height was the most precise. In addition the children remained, generally speaking, in their same rank order for VO2max for the three different age groupings.

Abstract. This paper examines the development of maximal aerobic power as a function of maturation by a longitudinal study with annual examinations of representative samples of 56 boys and 56 girls in Norway and Western Germany. The age at which occurred peak height velocity (PHV) (i.e. the age at which the greatest height velocity was observed) was used as a reference of biological age and maturation.Before the PHV the mean maximal aerobic power was the same in two cohorts of children both in absolute values as well as in values relative to total and lean body mass. At and after PHV the boys were similar in their absolute values, but the German girls decreased their exercise fitness and became inferior to the Norwegian girls during later adolescence. When related to age of PHV the maximal aerobic power increased during the prepubertal years, mainly as an effect of growth in body size with little or no additional effect of other factors and approached a ceiling level at the end of adolescence.The boys exhibited clearly superior exercise fitness during all years of childhood and adolescence, this being in contrast to the widely accepted concept that no sex difference exists in exercise fitness before puberty.The maximum level for I2o2-max, reached at the end of adolescence, averaged 3.2 l/rain with a coefficient of variation of about 12% for the boys, and 2.51/min for the Norwegian girls and a similar coefficient of variation.As these ceiling values of maximal oxygen uptake agree with published averages for normal young adults representative for the normal population in these two countries, it is suggested that they represent optimal values brought about mainly by normal growth in body size with no or little additional effects of other factors.

The maximal aerobic power of six highly trained young cyclist, mean age 16.3 years and mean VO2max 4.9 l/min, was directly measured at intervals of 4 hrs. A Latin square design was used for the test order. At submaximal work of O2-consumption 2.4 to 4.4 l/min no circadian variation of any single function was found. However, at maximal work load the differences between the maxima and minima values were 12.4% for maximal work output (W max), 7.8% for expiratory minute volume (V Emax), 5.7% for maximal aerobic power (VO2max) and 3.4% for maximal heart rate (H Rmax). All the functions--with the exception of VO2max-had their minima at 0300 hrs; the minima of VO2max was reached already at 2300 hours. The maxima-values of V Emax and VO2max were measured at 1500 hrs, of W max and H Rmax at 0700 and of H Rrest at 1900 hrs correspondingly. A one-tailed test showed significant differences between the maxima and minima values of all variables (P less than 0.05). The results suggest a decreased cardiopulmonary working capacity at night. However, this impairment is only of practical importance if the work will be done near the limit of endurance capacity. Besides it will suggest, that the indirect methods for assessing the cardiopulmonary capacity based on VO2max and W170 are not useful at nighttime, because the presuppositions for these methods are limited of the time of day.