Physical Performance and Growth in Children. Influence of Sex, Age and Intelligence

Abstract

Influence of sex, age and intelligence on the development of physical capacities in growing children, aged 7-17 years, was studied. By referring all the test results to body height it was attempted to separate qualitative differences from quantitative. It was found that girls in some tests (e.g. respiratory strength, handgrip) were inferior to boys, but in others (vertical jump, strength of leg extensors) were practically equal to the boys. The sex differences found were most pronounced in the youngest children. The onset of puberty seemed to put an end to the increase of some physical capacities with height. Age, beside influencing anatomical dimensions, seems to have a positive influence on physical capacities, mostly so in tests that require the highest degree of neuromuscular coordination. The age of puberty seems further to increase physical capacities as related to body height in boys, whereas in girls it tends to decelerate the development of certain motor performances. Intelligence, as expressed by the intelligence quotient (I.Q.), seems to play no statistically significant role as long as the I.Q. lies above 95. Boys with a lower I.Q. (average 83) on the whole performed less well than "normal" boys.