McMaster University, Hamilton, ON L8N 3Z5, Canada.
Appl Physiol Nutr Metab. 2011 Dec;36(6):939-45. doi: 10.1139/h11-118. Epub 2011 Nov 16.
The purpose of this study was to examine the tracking of short-term muscle power, speed, and physical activity over a 15-month period in a sample of healthy Canadian preschool-aged children. Seventeen preschoolers (age, 4.4 ± 0.8 years) completed exercise testing and physical activity monitoring at baseline and follow-up separated by 14.6 ± 4.1 months. Short-term muscle power was measured using a modified 10-s Wingate test with peak power and mean power normalized to body mass. Speed was assessed with a 25-m dash. Physical activity was measured by accelerometry (Actigraph GT1M) using a 3-s epoch over 7 consecutive days. Total physical activity and moderate-to-vigorous physical activity, expressed as a percentage of accelerometer wear time, were examined. Tracking of the variables between year 1 and year 2 was analyzed using Spearman rank order correlations and Kappa statistics. Paired t-tests were used to assess differences in performance and physical activity between year 1 and year 2. Total physical activity was not significantly different at year 2 (p > 0.05) and showed fair tracking (r = 0.51, p = 0.05; ĸ = 0.30). Moderate-to-vigorous physical activity was increased at year 2 (p = 0.03) and exhibited poor tracking (r = 0.29, p = 0.28; ĸ = 0.00). Short-term muscle power and speed was increased at year 2 (p < 0.0001) and exhibited significant tracking: peak power (r = 0.72, p = 0.001; ĸ = 0.46), mean power (r = 0.83, p = 0.00004; ĸ = 0.82), and 25-m dash (r = 0.82, p = 0.0001; ĸ = 0.47). Moderate-to-vigorous physical activity increased in this sample of boys and girls during the preschool years, and short-term muscle power and speed exhibited stronger tracking than physical activity.
本研究旨在考察 17 名健康的加拿大学龄前儿童在 15 个月的时间内短期肌肉力量、速度和身体活动的跟踪情况。这些儿童的年龄为 4.4±0.8 岁，分别在基线和随访时（间隔 14.6±4.1 个月）完成了运动测试和身体活动监测。使用改良的 10 秒 Wingate 测试测量短期肌肉力量，峰值功率和平均功率均按体重标准化。速度通过 25 米短跑评估。身体活动通过加速度计（Actigraph GT1M）以 3 秒为一个时段，在连续 7 天内进行监测。总身体活动量和中等到剧烈的身体活动量，以加速度计佩戴时间的百分比表示，作为考察指标。使用 Spearman 等级相关系数和 Kappa 统计分析第 1 年和第 2 年之间变量的跟踪情况。使用配对 t 检验评估第 1 年和第 2 年之间表现和身体活动的差异。第 2 年的总身体活动量没有显著差异（p>0.05），显示出适度的跟踪（r=0.51，p=0.05；Kappa=0.30）。第 2 年的中等到剧烈的身体活动量增加（p=0.03），跟踪效果不佳（r=0.29，p=0.28；Kappa=0.00）。第 2 年的短期肌肉力量和速度增加（p<0.0001），且具有显著的跟踪效果：峰值功率（r=0.72，p=0.001；Kappa=0.46）、平均功率（r=0.83，p=0.00004；Kappa=0.82）和 25 米短跑（r=0.82，p=0.0001；Kappa=0.47）。在这个男孩和女孩的样本中，中等到剧烈的身体活动在学龄前期间增加，而短期肌肉力量和速度的跟踪效果强于身体活动。
