Welk Gregory J, Wickel Eric, Peterson Marc, Heitzler Carrie D, Fulton Janet E, Potter Lance D
Iowa State University, Ames, IA 50011, USA.
Med Sci Sports Exerc. 2007 Apr;39(4):612-21. doi: 10.1249/mss.0b013e3180305c59.
The study evaluated the reliability and validity of the physical activity questions in the Youth Media Campaign Longitudinal Survey (YMCLS), a nationally representative survey of 9- to 13-yr-old youth.
The participants were 192 youth aged 9-13 yr (93 males and 99 females) in grades 4-8 from eight schools in a large, ethnically diverse school district. Participants completed two YMCLS phone interviews, which were administered 1 wk apart by trained interviewers. Reliability was examined by comparing data from two administrations of the survey. Validity was examined by comparing YMCLS measures from the second administration with temporally matched measures from an accelerometer and a detailed activity log.
Reliability coefficients were high for estimates of organized activity (intraclass correlation coefficient (ICC)=0.78) and moderate for estimates of free-time activity (ICC=0.60) and total weekly activity (ICC=0.60). Estimates of total weekly activity sessions were significantly correlated with the accelerometer (r=0.24) and the activity log (r=0.46). Estimates of activity time and activity sessions on the previous day were also significantly correlated with the accelerometer (r=0.53 and 0.37, respectively) and the activity log (r=0.37 and 0.47, respectively). Correlations between the YMCLS and the activity log were higher for organized activity (r=0.72) than for free-time activity (r=0.46). Reliability and validity coefficients were similar for boys and girls, but older youth (11-13 yr) had higher coefficients than younger students (9-10 yr).
The YMCLS has acceptable reliability and validity for estimating habitual physical activity in youth aged 9-13 yr.
本研究评估了青少年媒体宣传活动纵向调查（YMCLS）中身体活动问题的信度和效度，该调查是一项针对9至13岁青少年的全国代表性调查。
参与者为来自一个种族多元化的大校区八所学校4至8年级的192名9至13岁青少年（93名男性和99名女性）。参与者完成了两次YMCLS电话访谈，由经过培训的访谈员相隔1周进行。通过比较两次调查的数据来检验信度。通过将第二次调查的YMCLS测量结果与来自加速度计和详细活动日志的时间匹配测量结果进行比较来检验效度。
有组织活动估计值的信度系数较高（组内相关系数（ICC）=0.78），自由时间活动估计值的信度系数中等（ICC=0.60），每周总活动量估计值的信度系数中等（ICC=0.60）。每周总活动次数的估计值与加速度计（r=0.24）和活动日志（r=0.46）显著相关。前一天活动时间和活动次数的估计值也分别与加速度计（分别为r=0.53和0.37）和活动日志（分别为r=0.37和0.47）显著相关。YMCLS与活动日志之间的相关性，有组织活动（r=0.72）高于自由时间活动（r=0.46）。男孩和女孩的信度和效度系数相似，但年龄较大的青少年（11至13岁）的系数高于年龄较小的学生（9至10岁）。
YMCLS在估计9至13岁青少年的习惯性身体活动方面具有可接受的信度和效度。
