The effect of loading on the size, shape and strength of cortical bone during different stages of maturation

骨质疏松症是骨骼变得脆弱和容易骨折的一种情况。这是一个公共卫生问题，对60岁以上的男性和女性都有影响。虽然骨质疏松症影响老年人，但预防骨质疏松症的最好时机可能是在儿童时期。体力活动是已知的影响骨骼力量的生活方式因素。骨密度通常被用来衡量骨骼的强度，因为它很容易测量，而且与骨骼的断裂强度有关。然而，骨骼形状的变化也会在骨密度增加或不增加的情况下影响骨骼强度。在儿童或成人中，很少有人研究运动对骨骼形状的影响，对运动对不同发育阶段骨骼形状的影响也知之甚少。这项研究首次调查了童年时期的锻炼如何通过改变骨骼形状来影响骨骼强度。45名年龄在6岁到18岁之间的优秀女子网球运动员完成了为期两年的研究。年龄在6-20岁之间的90名新手和竞技男子网球运动员和60名年龄匹配的健康对照组将被要求参加这项研究。测量将在三年内每年进行一次。运动员的优势和非优势手臂的骨骼形状和密度将与不打网球的儿童进行比较--也将在i)青春期的不同阶段和ii)女孩和男孩之间进行比较。这项研究的发现很重要，因为今天儿童的生活方式可能会使他们在晚年更容易患上骨质疏松症。体力活动可能是防止老年骨骼脆弱的最重要的可改变的保护因素。这项研究的发现将首次提供关于在生长过程中是否存在一个独特的时间段，当锻炼通过改变骨骼形状导致骨骼强度最大增长的洞察。

Osteoporosis is a condition in which the skeleton becomes fragile and susceptible to fractures. It is a public health problem that affects both men and women over the age of sixty. Although osteoporosis affects the elderly, the most opportune time to prevent osteoporosis may be during childhood. Physical activity is a lifestyle factor known to affect the strength of the skeleton. Bone density is commonly used as a measure of bone strength because it is easily measured and is related to the breaking strength of bones. However changes in the shape of bones can also affect bone strength with or without an increase in bone density. Changes in bone shape in response to exercise in children or adults have rarely been investigated, and little is known about the effects of exercise on bone shape during different stages of growth. This study is the first to investigate how exercise during childhood may affect bone strength by changing bone shape. 45 elite female tennis players aged between 6 to 18 years have completed two years of this study. 90 novice and competitive male tennis players aged between 6 to 20 years and 60 healthy age matched controls will be asked to participate in this study. Measurements will be made annually for three years. The bone shape and density of the dominant and non-dominant arms of the players will be compared with the children who don't play tennis - comparisons will also be made between i) different stages of puberty and ii) girls and boys. The findings of this study are important because the lifestyle of children today may predispose them to a greater risk of osteoporosis late in life. Physical activity may be the most important modifiable protective factor against fragile bones in old age. The findings of this study will be the first to provide insight into whether there is a unique time during growth when exercise will result in the greatest increase in bone strength by changing bone shape.