The growth of lung volumes affected by physical performance capacity in boys and girls during childhood and adolescence.

The paper concerns a longitudinal study of the relationship between growth in lung functions in terms of forced vital capacity and forced expiratory volume in 1 s, and the development of maximal aerobic power during the age span from 8-18 years of age. The growth curves of anatomical dimensions for boys and girls were similar to those previously established for Northern European children. The growth in lung volume ended later than the growth in body height. It was found that the growth in lung volume was entirely due to growth in body dimensions, with no additional effect of changes in the development of physical performance capacity.

Maximal aerobic power affected by maturation and body growth during childhood and adolescence.

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 VO2-max, reached at the end of adolescence, averaged 3.2 1/min with a coefficient of variation of about 12% for the boys, and 2.5 1/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.

Health standards in terms of exercise fitness of school children in urban and rural areas in various European countries.

Health standard in terms of maximal aerobic power has been assessed in representative samples of school children in four European countries, with the object of testing the hypothesis that factors associated with the present days urbanization hamper the developmental process. In Norway and Iceland the exercise fitness of urban living children was stronger than that of children living in scarcely populated areas. In West Germany and Czechoslovakia there appeared a tendency in the same direction though the health standard in some ages was similar for urban and rural living children. The conclusion is consequently clear in as much as no evidence was found that supports the widespread concept that urbanization affects the exercise fitness during growth. On the contrary, urban living seems to enhance the developmental process most likely because the urbanized society stimulates children to vigorous play and sport, thus increasing habitual physical activity. Children living in rural environment become socially isolated, adopt sedentary living habits which subsequently hamper the development of functional characteristics. The maximal aerobic power of the boys and girls in these four European countries was similar when compared on basis on where they are living (urban/rural) except for the Norwegian boys who were considerably superior to the others.

Maximum aerobic power and body composition during the puberty growth period: similarities and differences between children of two European countries.

This report gives results of a longitudinal study of two cohorts of school children in Norway and West-Germany. The rate of growth in body size and composition is identical for the two samples, but different for the two sexes, and follows closely the trend of growth which has been found for North-Europeans in general. Despite of this similarity in growth of anatomical variables the Norwegian children appeared to be superior in their maximum aerobic power at all comparable ages and in both sexes. The differences between means in maximal oxygen uptake varies somewhat with age and sex and are in the range of 5-10%. It is suggested that the mean differences between Norwegian and German children in their exercise and cardio-vascular fitness are brought about by a more physically active behavioural pattern of living in Norway.

Excercise ventilation during the growth spurt period: comparison between two European countries.

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.

Physical performance capacity of children in Norway. V. The influence of social isolation on the rate of growth in body size and composition and on the achievement in lung function and maximal aerobic power of children in a rural community.

This paper tested the hypothesis that social isolation of children brings about a reduced pattern of habitual physical activity, influences body composition during growth, and hampers development of physical performance capacity. Two cohorts of children were studied, one living at or close to the center, the other living in the periphery of the community of Lom in Southern Norway. The two cohorts of children differed in their patterns of physical behavior, but were otherwise similar in genetic traits, nutrition, and environmental conditions. During a 4-year period the two cohorts of children were tested annually. The center children were leaner, and their maximal oxygen uptake and forced expiratory volume were greater in all years of growth when related to body size.

A dynamometric comparison of maximum eccentric, concentric, and isometric contractions using emg and energy expenditure measurements.

In fourteen subjects we compared maximum voluntary eccentric, concentric, and isometric contractions. The maximum voluntary forces by the subjects on a weight-lifting rod when changing from standing to squatting and from squatting to standing, and during a halfway knee-bend, were measured. The rod was placed on a special stand and moved up and down at a constant speed of 8.5 m/s by a motor. Energy expenditure was measured by the indirect method and EMG activity was measured in the quadriceps femoris. It was found that the force which the muscles generated was greatest during eccentric contraction, lower during isometric and lowest during concentric contraction. Energy expenditure was slightly greater during concentric than eccentric contraction. The level of difference in EMG activity of the quadriceps femoris was statistically insignificant. An energy comparison with isometric contractions was not undertaken in view of the very complex nature of these relationships.

Backward extrapolation of VO2max values from the O2 recovery curve.

The purpose of this study was to validate a method for measuring Vo2max in field conditions. In order to do so, Vo2max obtained by backward extrapolation of the O2 recovery curve at time zero of recovery (BE), was compared to the Vo2max measured directly at the end of a continuous multistage test (Exercise). The optimal way to determine Vo2max was by using a single component exponential least-squares regression on the first three or four 20 x recovery values. When a three-way valve was used to collect expired air immediately at the start of recovery (n=20), BE Vo2max (X- +/- SD=56.5 +/- 7.4 ML KG-1 MIN-1) WAS NOT SIGNIFICANTLY DIFFERENT FROM Exercise Vo2max (56.1 +/- 7.6). When subjects (n=16) connected themselves to another breathing valve immediately at the end of the test to simulate field conditions BE and Exercise Vo2max were similar (63.9 +/- 6.7 and 63.1 +/- 7.0, respectively) as long as a 3 s correction was made for the delay caused by this procedure. BE and Exercise Vo2max were 59.8 +/- 8 and 59.2 +/- 8.1 for the 36 subjects; the Pearson's correlation coefficient was 0.92. BE Vo2max measured on 11 additional runners tested on a track (62.6 +/- 13) yielded similar results as Exercise Vo2max measured on the treadmill using the same protocol (61.2 +/- 13.3). The backward extrapolation method appears to be valid to measure Vo2max when the air collecting equipment might otherwise be cumubersome during actual sport and/or laboratory conditions.

Comparsions among VO2 max values for hockey players and runners.

This study was designed to investigate the specificity of the VO2 max response of runners and hockey players for multistage tests done on the treadmill (RUN) or on the ice, skating a shuttle 20m course with (20m+) or without equipment (20m-) and a 140m oval course (140m-). Hockey players VO2 max in ml.kg-1.min-1 (n=10) were similar for the 4 tests (RUN: X +/- SD = 61.4 +/- 6.3; 140m-: 62.1 +/- 9.4; 20m-: 58.6 +/- 6.4; and 20m+: 59.9 +/- 7.4). VO2 max of runners (n = 10) were superior on the treadmill (68.6 +/- 4.5) as compared to the ice (140m-: 65.6 +/- 5.4). Hockey players as compared to runners, were 15% more efficient on the ice and 7.9% less efficient on the treadmill. The equipment increased the energy cost of skating by 4.8% and decreased the multistage test time by 20.3%. The low temperature arena as compared to the standard temperature laboratory, yielded lower heart rate response with multistage tests. Blood lactates (mg%) were similar for all tests done with hockey players (RUN: 128.3 +/- 19.3; 140m-: 126.8 +/- 14.7; 20m-: 133.0 +/- 17.5; and 20m+: 131.4 +/- 18.5), but lower on the ice (140m-: 87.7 +/- 15.9) as compared to the treadmill (127.2 +/- 26.4) for the runners. Maximal skating speed disclosed a relatively homogenous group of hockey players but their VO2 max scores were more widely distributed.

Physical fitness of Czechoslovak population between the ages of 12 and 55 years. Pulse rate and blood pressure.

In loading test of a representative sample of the Czechoslovak population aged 12--55 years, the authors, examined the reaction of the pulse rate and blood pressure (in watts--W) to loading on a bicycle ergometer. On increasing the submaximal load, the pulse rate rose linearly with age--more gradually in the phase of growth and along an approximately the same trend from the age of 18. The course in adult women corresponded to the course in boys aged about 13. The maximum pulse rate fell linearly in correlation to age, by about 4--5 beats for every 10 years, from 195/min in 12-year-old boys and 198/min in girls. The working capacity at pulse rate 170 (W 170) attained the maximum at 25 years (men 198, women 112 W). The systolic pressure rose non-linearly with loading. It increased more rapidly at lower loads. Children had the smallest pressure reaction and the oldest subjects the greatest. Diastolic pressure fell gradually and non-linearly with loading. The maximum blood pressure values, according to age, rose from 138/56 torr in the oldest males and from 139/57 to 182/84 torr in females.

Physical fitness of the Czechoslovak population between the ages of 12 and 55 years. Oxygen consumption and pulse oxygen.

The authors measured oxygen consumption in a Czechoslovak population aged from 12 to 55 years. An abrupt increase was found between 12 and 18 years, when the maximum was reached (males 3.28, females 2.17 l/min), followed by a slower decrease to 55 years. Relative O2 consumption (per kg body weight) showed a continuous decrease from 12 years, when maximum values were recorded (49 ml/min . kg for boys, 46 ml/min . kg for girls), to 55 (33 ml/min . kg for males, 27 ml/min . kg for females). In the adult population (18--55 years), no differences were observed in the values at the various levels of submaximal loading. The pulse oxygen attained the maximum at 18 (males 16.8, females 11 ml).

Physical fitness of the Czechoslovak population between the ages of 12 and 55 years. Pulmonary ventilation.

Examination of ventilation function in an average population showed that maximum minute ventilation in adults fell with advancing age. Males had higher values than females, the highest values being attained, in both sexes, at 18 (117 and 83 1/min respectively). Tidal volume during loading, expressed as a percentage of vital capacity, rose with advancing age in all groups of males and females (from 53% at 18 to 64% at 55 in males and from 51% to 59% in females). The ventilation equivalents for O2 and CO2 attained optimum values at a load of 100 W in males and at 50 W in females. On increasing the load they rose in both sexes--in females more than in males. Percentual utilization of O2 from the inspired air was greatest in males at a load of about 100 W (4.8--5%) and in females at about 50 W (4.3--4.8%). At higher loads it fell faster in females than in males. In males, the respiratory quocient attained the value 1 at a load of about 2 W/kg body weight and in females at 1.5 W/kg. At maximum loading it was over 1 in all the age categories. No differences between males and females were observed, but males, in maximum loading, gave the greatest absolute and the greatest relative performance.

Activity pattern, smoking habits, and somatometric variables of the Czechoslovakian population.

A total of 3762 subjects of both sexes, natives of Czechoslovakia, ranging in age from 12--55 years, were examined. Both anamnestic data and selected anthropometric variables were evaluated. The proportion of non-smokers for adult males was 47--56%, and for adult females was 54--74% of the population. The proportion of subjects not engaged in any type of physical activity decreases in boys between 12 and 18 years from 28 to 16%, in girls between 12 and 15 years from 25 to 22%; from then on the trend reverses and the percentages rises up to 42% in men and 65% in women. The number of subjects participating in competitive sporting activity reaches its peak at 18 years, when 46% of boys annd 43% of girls compete, but then decreases quickly. 12 year old girls are taller and heavier than boys but at 15 years the relationship is reversed. The LBM at the age of 12 is equal in boys and girls, but from then till 18 years the increase is larger in boys. The LBM weight in adults remains steady, women attaining 77% of the value found in men. The skinfold increases with age similarly in both sexes, except for an interval between 12 and 18 years, when girls show a steeper increase. Adult women attain 121--160% of the values characteristic for men. The grip strength of the right hand equals about 50 kp in adult men and 30 kp in adult women. Within the age range followed, it remains unaffected by age.

[Experiences with a cardiorecorder system for continuous 24-hour registration of heart rate]. / Erfahrungen mit einem transportablem Gerät zur kontinuierlichen registrierung der Herzfrequenz für Zeiten bis zu 24 Stunden

Studies regarding to the continuous registration of the heart frequency by a transportable instrument, which can store the data of the heart frequency per minute up to 24h, are presented. It is a tape recorder the speed of which is geared down. Thus a normal tape cassette C 60 is sufficient for a registration of the heart frequency during 2 X 24h. The R-wave of the ECG is registered on the first channel of the tape as a biological signal. Moreover every minute an impulse of a clock is recorded on the second channel of the tape. With help of a second instrument the play back procedure for the 24-h-recording can be performed in about 15 min. The signals of both channels of the tape are transformed in digital rectangle impulses by an installed impulse-converter. The serial impulses are counted per minute with help of the time-mark by an interface in a counter. These data are at disposal in BCD-code. They can be passed on the following peripherals: digital printer, computer, pen-recorder and so on. A parallel standardized recording of the physical activity observed by the subject or by an experimenter allows a statistical evaluation and comparison of the physical activity with the corresponding heart frequency data. Some examples of the aread of occupational health, epidemiology and exercise physiology are discussed.