Department of Physical Education, GALENO Research Group, School of Education Sciences, University of Cádiz, Avenida República Saharaui s/n, 11519, Puerto Real, Cádiz, Spain.
Biomedical Research and Innovation Institute of Cádiz (INiBICA) Research Unit, Puerta del Mar University Hospital University of Cádiz, Cádiz, Spain.
Int J Behav Nutr Phys Act. 2020 Mar 10;17(1):37. doi: 10.1186/s12966-020-00940-9.
Longitudinal changes in child and adolescent active school transport (AST), and the mediating role of different intensities of daily physical activity (PA) levels in relation to AST and physical fitness and adiposity indicators is unclear. This study aimed to: 1) describe longitudinal changes in AST, light PA (LPA), moderate- to vigorous-intensity PA (MVPA), physical fitness and adiposity indicators over three time-points; and 2) investigate the mediating role of LPA and MVPA levels on associations between AST and physical fitness and adiposity indicators over three time-points among children and adolescents.
This longitudinal study comprised 1646 Spanish children and adolescents (48.8% girls, mean age 12.5 years ±2.5) at baseline, recruited from schools in Cádiz and Madrid. Mode of commuting to school was self-reported at baseline (T0, 2011-12), 1-year (T1) and 2-year follow-up (T2). PA was assessed using accelerometers. Handgrip strength, standing long jump and cardiorespiratory fitness (CRF) assessed physical fitness. Height, weight, body mass index, waist circumference, and triceps and subscapular skinfold thickness were measured. Multilevel linear regression analyses assessed changes in AST, PA levels, physical fitness and adiposity indicators over three time-points (T0-T1-T2). Additionally, longitudinal path analysis (n = 453; mean age [years] 12.6 ± 2.4) was used to test the mediating effects of LPA and MVPA levels on the association between AST and physical fitness and adiposity indicators.
Multilevel analyses observed decreases in LPA between T0-T1 (β = - 11.27; p < 0.001) and T0-T2 (β = - 16.27; p < 0.001) and decreases in MVPA between T0-T2 (β = - 4.51; p = 0.011). Moreover, changes over time showed increases in handgrip between T0-T1 (β = 0.78; p = 0.028) and T0-T2 (β = 0.81; p = 0.046). Path analyses showed that AST was directly positively associated with MVPA at T1 (all, β ≈ 0.33; p < 0.001). MVPA at T1 mediated associations between AST and CRF at T2 (β = 0.20; p = 0.040), but not the other outcomes. LPA did not mediate any associations.
Results from longitudinal path analysis suggest that participation in more AST may help attenuate declines in MVPA that typically occur with age and improve CRF. Therefore, we encourage health authorities to promote AST, as a way to increase MVPA levels and CRF among youth.
儿童和青少年主动上学交通方式（AST）的纵向变化，以及与 AST 和身体成分指标相关的不同日常体力活动（PA）水平的轻 PA（LPA）和中高强度 PA（MVPA）的中介作用尚不清楚。本研究旨在：1）描述 AST、LPA、MVPA、身体成分和身体成分指标在三个时间点的纵向变化；2）调查 LPA 和 MVPA 水平在三个时间点之间 AST 与身体成分和身体成分指标之间的关联中的中介作用。
本纵向研究包括 1646 名西班牙儿童和青少年（48.8%为女孩，平均年龄 12.5±2.5 岁），于基线（T0，2011-12 年）、1 年（T1）和 2 年随访（T2）时分别从卡迪斯和马德里的学校招募。采用加速度计评估交通方式。使用握力计、站立跳远和心肺适能（CRF）评估身体适能。测量身高、体重、体重指数、腰围、三头肌和肩胛下皮褶厚度。多水平线性回归分析评估了三个时间点（T0-T1-T2）AST、PA 水平、身体适能和身体成分指标的变化。此外，还使用纵向路径分析（n=453；平均年龄[岁]12.6±2.4）测试了 LPA 和 MVPA 水平在 AST 与身体成分和身体成分指标之间的关联中的中介作用。
多水平分析观察到 LPA 在 T0-T1（β=-11.27；p<0.001）和 T0-T2（β=-16.27；p<0.001）之间减少，MVPA 在 T0-T2 之间减少（β=-4.51；p=0.011）。此外，随着时间的推移，T0-T1（β=0.78；p=0.028）和 T0-T2（β=0.81；p=0.046）之间的握力增加。路径分析显示，T1 时 AST 与 MVPA 呈直接正相关（所有，β≈0.33；p<0.001）。T1 时的 MVPA 介导了 T2 时 AST 与 CRF 之间的关联（β=0.20；p=0.040），但其他结果没有。LPA 不介导任何关联。
纵向路径分析的结果表明，更多地参与 AST 可能有助于减轻随着年龄增长而出现的 MVPA 下降，并提高 CRF。因此，我们鼓励卫生当局促进 AST，作为增加青少年中 MVPA 水平和 CRF 的一种方式。
