Laing Emma M, Wilson Alissa R, Modlesky Christopher M, O'Connor Patrick J, Hall Daniel B, Lewis Richard D
Department of Foods and Nutrition, The University of Georgia, Athens, Georgia 30602, USA.
J Bone Miner Res. 2005 Mar;20(3):509-19. doi: 10.1359/JBMR.041127. Epub 2004 Nov 29.
Gymnasts' bone mineral characteristics are generally not known before starting their sport. Prepubertal females who enrolled in beginning artistic gymnastics (n = 65) had lower bone mineral than controls (n = 78). However, 2 years of gymnastics participation versus no participation led to a significantly greater accrual of forearm bone area and lumbar spine areal BMD.
The skeletal response to exercise in children compared with adults is heightened because of the high bone turnover rate and the ability of bone to change its size and shape. Whereas child gymnasts generally have greater rates of bone mineral accrual compared with nongymnasts, it is unknown if some of these skeletal advantages are present before the onset of training or are caused entirely by training.
Changes in bone area (BA; cm2), BMC (g), and areal BMD (aBMD; g/cm2) over 24 months were examined in prepubertal females, 4-8 years of age, who selected to perform recreational gymnastics (GYM; n = 65), nongymnastic activities, or no organized activity (CON; n = 78). Participants had essentially no lifetime history of organized athletic participation (< 12 weeks). Pubertal maturation was assessed annually by a physician. Total body, lumbar spine, total proximal femur, and forearm BA, BMC, and aBMD were measured every 6 months using DXA (Hologic QDR-1000W). Independent samples t-tests determined baseline group differences. Nonlinear mixed effects models were used to model 24-month changes in bone data. In subset analyses, high-level gymnasts advancing to competition (HLG; n = 9) were compared with low-level nonadvancing gymnasts (LLG; n = 56).
At baseline, GYM were shorter, lighter, and had lower BA, BMC, and aBMD compared with CON (p < 0.05), whereas HLG did not differ significantly in these measurements compared with LLG (p > 0.05). Controlling for differences in race, baseline measures of body mass, height, and calcium intake, and change in breast development beyond stage II at 24 months, GYM had greater long-term (asymptotic) mean responses for total body aBMD and forearm BMC (p < 0.04) and greater rates of increase in the mean responses of lumbar spine aBMD and forearm BA compared with CON over 24 months. Over time, forearm BA increased to a greater extent in HLG compared with LLG (p < 0.01).
Females participating in recreational gymnastics initiated during childhood have enhanced bone mineral gains at the total body, lumbar spine, and forearm over 24 months. Higher-level training promotes additional gains in forearm BA.
体操运动员开始从事这项运动之前，其骨矿物质特征通常并不为人所知。开始参加艺术体操的青春期前女性（n = 65）的骨矿物质含量低于对照组（n = 78）。然而，参与两年体操运动与未参与相比，前臂骨面积和腰椎骨面积骨密度（aBMD）的增加显著更大。
由于儿童的骨转换率高以及骨骼改变其大小和形状的能力，与成年人相比，儿童对运动的骨骼反应更为强烈。虽然儿童体操运动员与非体操运动员相比，通常骨矿物质积累率更高，但尚不清楚这些骨骼优势是在训练开始之前就已存在，还是完全由训练引起。
对4至8岁选择进行娱乐性体操（GYM；n = 65）、非体操活动或无有组织活动（CON；n = 78）的青春期前女性，在24个月内检查其骨面积（BA；cm²）、骨矿物质含量（BMC；g）和骨面积骨密度（aBMD；g/cm²）的变化。参与者基本上没有有组织体育参与的终身史（< 12周）。每年由医生评估青春期成熟情况。每6个月使用双能X线吸收仪（Hologic QDR - 1000W）测量全身、腰椎、股骨近端和前臂的BA、BMC和aBMD。独立样本t检验确定基线组差异。使用非线性混合效应模型对骨数据的24个月变化进行建模。在亚组分析中，将晋级比赛的高水平体操运动员（HLG；n = 9）与未晋级的低水平体操运动员（LLG；n = 56）进行比较。
在基线时，与CON相比，GYM身高更矮、体重更轻，BA、BMC和aBMD更低（p < 0.05），而与LLG相比，HLG在这些测量值上无显著差异（p > 0.05）。在控制种族、体重、身高和钙摄入量的基线测量值以及24个月时超过II期的乳房发育变化的差异后，与CON相比，GYM在全身aBMD和前臂BMC方面具有更大的长期（渐近）平均反应（p < 0.04），并且在24个月内腰椎aBMD和前臂BA的平均反应增加率更大。随着时间的推移，与LLG相比，HLG的前臂BA增加幅度更大（p < 0.01）。
儿童期开始参加娱乐性体操的女性在24个月内全身、腰椎和前臂的骨矿物质增加有所增强。更高水平的训练促进前臂BA的进一步增加。
