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，影响60岁以上的男性和女性。虽然骨质疏松症会影响老年人，但预防骨质疏松症的最佳时机可能是在儿童时期。身体活动是一种生活方式因素，已知会影响骨骼的强度。骨密度通常用作骨强度的量度，因为它易于测量并且与骨的断裂强度有关。然而，骨骼形状的变化也会影响骨强度，无论是否增加骨密度。很少有人研究儿童或成人运动对骨骼形状的变化，而且对不同生长阶段运动对骨骼形状的影响知之甚少。这项研究是第一次调查儿童时期的运动如何通过改变骨骼形状来影响骨骼强度。45名年龄在6至18岁之间的优秀女子网球运动员完成了为期两年的研究。90名年龄在6 - 20岁之间的新手和有竞争力的男子网球运动员和60名健康年龄匹配的对照将被要求参加这项研究。每年测量一次，为期三年。运动员的优势臂和非优势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。这项研究的发现是重要的，因为今天的儿童的生活方式可能使他们在晚年患骨质疏松症的风险更大。体力活动可能是最重要的可改变的保护因素，防止老年人骨质疏松。这项研究的结果将首次提供洞察力，以了解在生长过程中是否有一个独特的时间，运动将通过改变骨骼形状来最大限度地增加骨骼强度。

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.