Faculty of Health and Sport Sciences, University of Agder, Kristiansand, Norway.
Med Sci Sports Exerc. 2012 May;44(5):949-57. doi: 10.1249/MSS.0b013e31823fe4ef.
The study's purpose was to relate body mass index (BMI) to body fat percentage as measured by dual-energy x-ray absorptiometry in female elite athletes from different sports and nonathletic controls and to investigate what characterizes the athletes with unhealthy low and high body fat values.
This study was conducted in three phases: 1) screening with a detailed questionnaire, 2) body composition measurement (dual-energy x-ray absorptiometry), and 3) clinical interview. All female elite athletes representing national teams at the junior or senior level age 13-39 yr (n = 938) and an age group-matched randomly selected population-based control group (n = 900) were invited to participate. A stratified random sample was invited to participate in parts 2 and 3. A total of 186 athletes (62%) and 145 controls (48%) participated in all three phases.
Of those athletes with normal BMI values (18.5-24.9 kg·m⁻²) (n = 150), 2.0% were classified with low body fat levels (<12%), and 6.7% were classified with obese body fat levels (≥ 33%). The median value for the entire group was 24.3% body fat. For the controls with normal BMI values (n = 96), none was classified with low body fat levels, and 50% were classified with obese body fat levels (median = 33.1%). The correlation between BMI and body fat percentage was 0.671 (P < 0.01) (SEE = 5.3%) for the athletes and 0.813 (P < 0.01) (SEE = 4.1%) for the controls. Both under- and overfat athletes self-reported menstrual dysfunction, stress fractures, history of weight fluctuation, and use of pathogenic weight control methods and were diagnosed with clinical eating disorders and/or low bone density.
Our data show that BMI is not a valid measure for assessing or monitoring body composition in female elite athletes, and it should be used carefully in female nonathletes.
本研究旨在通过双能 X 射线吸收法（DXA）测量不同运动项目的女性精英运动员和非运动员对照者的体重指数（BMI）与体脂百分比，并探讨具有不健康低体脂和高体脂值的运动员的特征。
本研究分为三个阶段进行：1）使用详细问卷进行筛查，2）身体成分测量（DXA），3）临床访谈。所有年龄在 13-39 岁的代表国家队参加青少年或高级别比赛的女性精英运动员（n=938）和年龄匹配的随机选择的基于人群的对照组（n=900）都被邀请参加。分层随机抽样邀请参加第 2 部分和第 3 部分。共有 186 名运动员（62%）和 145 名对照者（48%）参加了所有三个阶段。
在 BMI 值正常（18.5-24.9kg·m⁻²）的运动员中（n=150），有 2.0%的人被归类为低体脂水平（<12%），6.7%的人被归类为肥胖体脂水平（≥33%）。整个组的中位数为 24.3%体脂。对于 BMI 值正常的对照组（n=96），没有一人被归类为低体脂水平，50%的人被归类为肥胖体脂水平（中位数=33.1%）。运动员的 BMI 和体脂百分比之间的相关性为 0.671（P<0.01）（SEE=5.3%），对照组为 0.813（P<0.01）（SEE=4.1%）。低体脂和高体脂的运动员都自述出现月经功能障碍、应力性骨折、体重波动史、使用致病的体重控制方法，并被诊断为临床饮食失调和/或低骨密度。
我们的数据表明，BMI 不是评估或监测女性精英运动员身体成分的有效指标，在女性非运动员中应谨慎使用。
