Wittich A, Mautalen C A, Oliveri M B, Bagur A, Somoza F, Rotemberg E
Centro de Osteopatías Médicas, Hospital de Clínicas, University of Buenos Aires, Medical Department of Ferro Carril Oeste, Argentina.
Calcif Tissue Int. 1998 Aug;63(2):112-7. doi: 10.1007/s002239900499.
The total skeletal bone mineral content (BMC), bone mineral density (BMD), bone size, and body composition were measured by dual-energy x-ray absorptiometry (DXA) in all professional male football players of a 1st division team (n = 24) and age- and BMI-matched (n = 22) controls (less than 3 hours of recreational sport activities per week). Average (+/- 1 SD) age of the athletes was 22.6 +/- 2.5 years. Intensive training is conducted during 48 weeks a year for 20-22 hours/week. The length of the registered playing career before the study was 8.2 +/- 2.7 years. Total skeleton BMC was 18.0% (P < 0.001) greater in the football players. The difference resulted from the sum of 5.2% (P < 0.02) increment of bone size and 12.3% (P < 0.001) increment of BMD. The analysis of skeletal subareas revealed that the difference of the BMC and BMD was greater at the level of the pelvis and legs compared with the arms or trunk. The BMC and BMD of the head was equal for both groups. Also, the bone size of the legs and pelvis was significantly greater for the players compared with controls; there was no difference at the level of the arms or head. Within the group of football players the increment of total skeleton BMD was similar in the young players, with less than 7 years of practice (age 20.6 +/- 0.9 years) compared with relative older players (age 24.6 +/- 1.9) with more than 7 years of practice. Lean body mass was significantly greater in the players (63.3 +/- 4.0 kg) compared with the controls (56.7 +/- 3.6, P < 0.001) whereas fat mass was markedly lower (9.4 +/- 2.9 kg versus 14.9 +/- 6.3 kg), P < 0.002). The BMD of the controls was significantly correlated to total weight, height, and lean mass whereas the BMD of the players was only correlated to muscle mass. The calcium intake from dairy products was similar in both groups. The range of calcium intake was wide among the players (184-2519 mg/day) but it was not significantly correlated to BMD (r = 0.03). In conclusion, male professional football players develop a significant increment of BMC as a result of increased bone size and density. This is already present at the end of the second decade and maintained at least to the end of the third decade in active players. As in other high impact loading sports, the effect on area is specific involving mainly the pelvis and legs. The increment was totally unrelated to the calcium intake from dairy products. The fate of the increased BMC after intensive training is discontinued should be assessed. However, if the findings of the present cross-sectional study are supported by detailed longitudinal investigations, the presently reported observations might be important for the prevention of future osteoporotic fractures.
通过双能X线吸收法（DXA）测量了一支甲级联赛球队所有职业男性足球运动员（n = 24）以及年龄和体重指数相匹配的对照组（n = 22，每周娱乐性体育活动少于3小时）的全身骨骼矿物质含量（BMC）、骨矿物质密度（BMD）、骨骼大小和身体成分。运动员的平均（±1标准差）年龄为22.6±2.5岁。每年进行48周、每周20 - 22小时的强化训练。研究前注册的运动生涯时长为8.2±2.7年。足球运动员的全身骨骼BMC比对照组高18.0%（P < 0.001）。这种差异源于骨骼大小增加5.2%（P < 0.02）和BMD增加12.3%（P < 0.001）。骨骼分区分析显示，与手臂或躯干相比，骨盆和腿部水平的BMC和BMD差异更大。两组的头部BMC和BMD相等。此外，与对照组相比，球员的腿部和骨盆骨骼大小明显更大；手臂或头部水平没有差异。在足球运动员组中，练习年限少于7年（年龄20.6±0.9岁）的年轻球员与练习年限超过7年（年龄24.6±1.9岁）的相对年长球员相比，全身骨骼BMD的增加相似。与对照组（56.7±3.6，P < 0.001）相比，球员的瘦体重明显更大（63.3±4.0 kg），而脂肪量明显更低（9.4±2.9 kg对14.9±6.3 kg），P < 0.002）。对照组的BMD与总体重、身高和瘦体重显著相关，而球员的BMD仅与肌肉量相关。两组从乳制品中摄入的钙相似。球员的钙摄入量范围较宽（184 - 2519毫克/天），但与BMD无显著相关性（r = 0.03）。总之，男性职业足球运动员由于骨骼大小和密度增加，BMC显著增加。这种情况在二十多岁末就已出现，并在活跃球员中至少维持到三十多岁末。与其他高冲击力运动一样，对骨骼区域的影响具有特异性，主要涉及骨盆和腿部。这种增加与从乳制品中摄入的钙完全无关。应评估强化训练停止后增加的BMC的走向。然而，如果本横断面研究的结果得到详细纵向调查的支持，目前报告的观察结果可能对预防未来骨质疏松性骨折很重要。
