Hormonal factors in the development of differences in strength between boys and girls during adolescence: a longitudinal study

Abstract

The development of elbow flexor (biceps) and knee extensor (quadriceps) strength has been followed in a mixed longitudinal study of 50 boys and 50 girls from the age of 8 to 17 years. Sex differences in strength emerged at the time of peak height velocity and were especially marked for the biceps. Data for individual children were aligned to the time of peak height velocity and associations between strength, height, weight and circulating testosterone were investigated using multi-level modelling. The results show that, for girls, quadriceps strength is proportional to height and weight while for boys there is an additional factor which can be fully attributed to increasing levels of testosterone. Testosterone is important in explaining differences in biceps strength between the sexes but an additional factor is also required. It is suggested that, in addition to a direct effect on muscle, testosterone could have a second indirect action on biceps strength by promoting growth in length of the humerus as part of the general development of the male upper limb girdle.

Muscle Analysis by Measurement of Maximal Isometric Grip Force: New Reference Data and Clinical Applications in Pediatrics

“…It is well known that height-and thereby the lengths of muscles, bones, and lever arms-is the main determinant of upper extremity muscle force (7)(8)(9), and this was confirmed by the present results. Although it is also possible to compute reference values as a function of weight, these data are not presented in tabular form, because there is little logic in relating the force of non-weight-bearing muscles to weight.…”

“…From a functional perspective the muscle system needs to be adapted to body size rather than to age. Indeed, muscle force is largely determined by body size (7)(8)(9). However, many children and adolescents undergoing muscle performance tests in the clinical setting suffer from growth retardation secondary to a chronic disorder.…”

Limb bone bilateral asymmetry: variability and commonality among modern humans

“…Females also have lower correlations among all asymmetries compared with males, both within and between elements. The greater male asymmetry in humeral diaphyseal breadths could be a result of generally greater mechanical loadings on the upper limb bones in males, related to greater muscular development during adolescence (Parker et al, 1990;Round et al, 1999) or possibly to more marked asymmetry in upper-limb-use among males (on average). Behavioral evidence for sex differences in upper limb preference are mixed, and potentially confounded by cultural factors (Perelle and Ehrman, 1994;Raymond and Pontier, 2004).…”

Energy Metabolism in Children and Adolescents

“…Orchotomy has the opposite results (Musaeva, 1986;Son'kin & Tambovtseva, 2011). Probably, male sex hormones play a role that is not less significant in formation of a morphological-functional status of human skeletal muscles (Boisseau & Delamarche, 2000;Ferretti et al, 1994;Jansson, 1996;Round et al, 1999;Tambovtseva & Kornienko, 1986;Van Praagh & Dore, 2002). It is remarkable that for girls the same effects of pubescence processes on the structure and function of their skeletal muscles are not revealed (Petersen et al, 1999;Tambovtseva, 2003;Treuth et al, 2001), which can be explained by various structuralmetabolic consequences of androgen and estrogen effects.…”