Weight-bearing bones are more sensitive to physical exercise in boys than in girls during pre- and early puberty: a cross-sectional study

Abstract

Summary We carried out a cross-section study of the sexspecific relationship between bone mineral content and physical activity at sites with different loading in pre-and early pubertal girls and boys. There was significant sensitivity of bone mineral content of the hip to physical exercise in boys, but not in girls. Background Since little is known whether there are sex differences in sensitivity of bone to loading, we investigated sex differences in the cross-sectional association between measures of physical activity (PA) and bone mass and size in pre-and early pubertal children of both sexes.Methods We measured bone mineral content/density (BMC/BMD) and fat-free mass (FFM) in 269 6-to 13-year-old children from randomly selected schools by dualenergy X-ray absorptiometry. Physical activity (PA) was measured by accelerometers and lower extremity strength by a jump-and-reach test. Results Boys (n=128) had higher hip and total body BMC and BMD, higher FFM, higher muscle strength and were more physically active than girls (n=141). Total hip BMC was positively associated with time spent in total and vigorous PA in boys (r=0.20-0.33, p<0.01), but not in girls (r=0.02-0.04, p = ns), even after adjusting for FFM and strength. While boys and girls in the lowest tertile of vigorous PA (22 min/day) did not differ in hip BMC (15.62 vs 15.52 g), boys in the highest tertile (72 min/day) had significantly higher values than the corresponding girls (16.84 vs 15.71 g, p<0.05). Conclusions Sex differences in BMC during pre-and early puberty may be related to a different sensitivity of bone to physical loading, irrespective of muscle mass.

Bone Mineral Density of Middle School Female Students with Three Level of Physical Activity in Rural Area

“…Until now, the most of study were focused on BMD of elite players in side-to-side effects, but a few investigations have been performed for normal people [30,31]. In this study, we observed that the non-dominant hand BMD of moderate and low physical activity groups were significantly lower than those in dominant hand, but did not in high activity group.…”

Determinants of Peak Bone Mass Acquisition

“…The magnitude of benefit in terms of bone strength will depend on the nature of the structural change, and possibly on the gender. Indeed, increasing levels of physical activity were associated with higher response weight-bearing BMD in boys than in girls before puberty (60). An effect consisting primarily of an increased periosteal apposition and consecutive diameter will confer greater mechanical resistance than a response limited to the endosteal apposition rate leading essentially to a reduction in the endocortical diameter.…”

Einfluss von körperlicher Aktivität und Sport auf die Knochengesundheit im Lebenslauf

“…Studien, die Kinder vor und zu Beginn der Pubertät einschlossen, zeigten, dass die KF durch MVPA und Sportprogramme vor der Pubertät stärker beeinflusst wurde als zu Beginn der Pubertät [11,12,30,43,44,45]. Besonders bei prä-pubertären Jungen wurde in einigen Beobachtungs-und Interventionsstudien ein bedeutender osteogener Effekt von KA und Sport beobachtet [10,11,45,46].…”

“…Besonders bei prä-pubertären Jungen wurde in einigen Beobachtungs-und Interventionsstudien ein bedeutender osteogener Effekt von KA und Sport beobachtet [10,11,45,46]. Dieser Effekt lässt sich durch eine stärke-re Beziehung zwischen KA und KF sowie durch die höhere KA/MVPA und Muskelstärke bei Jungen erklären [10,11,41,42,47].…”

“…Bone health · Osteoporosis · Physical activity · Exercise · Competence Network Obesity [9,10,11,41,42]. So wird bei Grundschulkindern, die 40 Minuten am Tag moderat bis stark körperlich aktiv sind, eine bis zu 3% bis 5% höhere KF erwartet als bei Kindern, die nur zehn Minuten MVPA am Tag durchführen [41].…”