Physical activity in childhood may be the key to optimizing lifespan skeletal health

Abstract

Physical activities undertaken in childhood, particularly activities, which apply large forces quickly convey optimal benefits to bone mass, size, and structure. Evidence is accumulating that benefits persist well beyond activity cessation. This review examines the potential for early childhood activity to improve bone mineralization and structure and explores childhood activity as prevention for osteoporosis in later life.

Figure 1

Ground reaction forces (measured in portions of bodyweight (BW)) and loading rates experienced by a pre-pubertal female child during quite standing, walking, running and a drop landing from a 61 cm height. All recorded values are from a single leg. Values for the drop jump were derived from a two-foot drop landing on dual force plates. Values for quiet standing reflect 0.5 BW per leg while standing on two feet; one foot on each plate.

Figure 2

Bone structural changes attributed to growth and aging (A) contrasted with the additive effects of exercise during growth and the subsequent benefits to lifelong skeletal health if effects persist into older adulthood (B). (Reprinted from (36). Copyright © 2009 BMJ Publishing Group Ltd.. Used with permission.

Figure 3

Mixed model least square means of Iowa Bone Development Study cohort contrasting the hip bone mineral content (BMC) (g) at ages 8 and 11 in the most active and least physically active quartiles of boys and girls at age 5 with adjustment for age, weight (wt), height (ht), maturity, and current physical activity (at age 8 and 11). N = 333 children. Findings published in (18).

Figure 4

The effect of a jumping intervention on Δtotal hip bone mineral content (BMC) after 8 years showing percent change in total hip BMC from baseline in jumpers above that of controls. Data points are displayed after 7 mo of exercise training, 1 yr of detraining (19 mo), and 4–8 yr of detraining (43–91 mo). The intervention participants had 3.6% greater bone mass at the total hip than controls immediately after the intervention and 1.4% greater bone mass 8 yrs later. *Results are significant at each of the seven measurement intervals (p < 0.05) and are adjusted for baseline age, ΔHt, ΔWt, maturity, and sports participation. [Adapted from (9). Copyright © 2008 John Wiley and Sons. Used with permission.]