Johnson Amanda, Doherty Patrick Joseph, Freemont Anthony
Manchester United Football Club, Trafford Training Centre, Carrington, Manchester M31 4BH.
BMJ. 2009 Feb 26;338:b490. doi: 10.1136/bmj.b490.
To investigate the differences between skeletal and chronological age and to assess the role of maturity status, anthropometric data, and football related variables in explaining injury statistics in elite schoolboy footballers.
Prospective study of injuries in schoolboy footballers according to skeletal age.
Premier league football club in England.
292 schoolboy players (age 9-16) registered at the club
Annual x ray film of hand or wrist.
Data on injury 2001-7. Skeletal age determined with the Fels method. Skeletal age of more than one year above chronological age was classified as an early maturer, within one year as a normal maturer, and more than one year below normal as a late maturer. Injury and hours of training and rates of exposure to match play.
Over six years 476 injuries were reported. The mean chronological age (11.74 (SD 2.35) years) and skeletal age defined by x ray picture (12.08 (SD 3.14) years) showed a significant mean difference of -0.344 (95% confidence interval -0.490 to -0.198; t=-4.64, df=280). Analysis of covariance showed that injury incidents did not differ significantly with maturity status after adjusting for training time, playing time, height, and position played (F=0.3(2,160), P=0.73). General log linear analysis with a Poisson model showed that difference in maturity, playing hours, and training hours collectively explained 48% of the variance in injury incidents. Injury exposure rates differed considerably, with 1.44/1000 hours for training and 10.5/1000 hours for match play.
Maturity, defined by the difference between chronological age and skeletal age, plus training and playing hours together predict injury in schoolboy footballers. Injury exposure rates were higher for match play than training, which could have implications for targeting preventative interventions by academy staff. The use of skeletal age measurements to establish accurate "windows of opportunity" for training is more appropriate than the commonly used chronological age. Caution is needed when interpreting differences in injury occurrence as the factors that contribute are often complex.
研究骨骼年龄与实际年龄之间的差异，并评估成熟状态、人体测量数据以及与足球相关的变量在解释精英男学生足球运动员损伤统计数据方面的作用。
根据骨骼年龄对男学生足球运动员的损伤进行前瞻性研究。
英格兰超级联赛足球俱乐部。
该俱乐部注册的292名男学生球员（年龄9 - 16岁）
每年拍摄手部或腕部的X光片。
2001 - 2007年的损伤数据。采用费尔斯方法确定骨骼年龄。骨骼年龄比实际年龄大一岁以上被归类为早熟者，在一岁以内为正常成熟者，比正常年龄小一岁以上为晚熟者。损伤情况、训练时长以及比赛出场率。
在六年期间共报告了476例损伤。平均实际年龄（11.74（标准差2.35）岁）和X光片确定的骨骼年龄（12.08（标准差3.14）岁）显示出显著的平均差异 -0.344（95%置信区间 -0.490至 -0.198；t = -4.64，自由度 = 280）。协方差分析表明，在调整训练时间、比赛时间、身高和比赛位置后，损伤事件在成熟状态方面没有显著差异（F = 0.3(2,160)，P = 0.73）。采用泊松模型的一般对数线性分析表明，成熟度、比赛时长和训练时长的差异共同解释了损伤事件中48%的方差。损伤发生率差异很大，训练时为1.44/1000小时，比赛时为10.5/1000小时。
由实际年龄与骨骼年龄差异所定义的成熟度，加上训练和比赛时长，共同可预测男学生足球运动员的损伤情况。比赛的损伤发生率高于训练，这可能对青训营工作人员确定预防性干预措施的目标有影响。使用骨骼年龄测量来确定准确的训练“机会窗口”比常用的实际年龄更为合适。在解释损伤发生差异时需要谨慎，因为造成损伤的因素往往很复杂。
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