Agiovlasitis S, Ballenger B K, Choi P, Haider M, Du Q, Motl R W
Department of Kinesiology, Mississippi State University, Starkville, USA.
Health and Exercise Science, Transylvania University, Lexington, USA.
J Intellect Disabil Res. 2025 Aug;69(8):693-702. doi: 10.1111/jir.13253. Epub 2025 May 20.
The estimation of physical activity (PA) and sedentary behaviour with accelerometers is typically based on the relationship between accelerometer output and metabolic equivalents (METs)-an index of PA intensity. But for adults with Down syndrome (DS), PA intensity may be better reflected in the percent oxygen uptake reserve (%VO), as it accounts for their lower aerobic fitness. This study examined if the relationship between accelerometer output and METs or %VO across various PAs and sedentary behaviours differs between adults with and without DS.
Forty-one adults with DS (age 35 ± 9 years; 18 women) and 41 adults without DS (age 24 ± 5 years; 18 women) performed 17 tasks of varying intensity. We estimated aerobic fitness with a submaximal treadmill test. We measured oxygen uptake with portable calorimetry and expressed it as METs and %VO. Output from triaxial accelerometers on the nondominant hip and wrist was determined as Vector Magnitude (VM). We used multilevel modelling to evaluate the relationships of METs or %VO with VM, controlling for body mass index (BMI) and age.
For the hip accelerometer, VM and the group-by-VM interaction significantly predicted METs (p < 0.001; conditional R = 0.82), but between-group differences were small. For the wrist accelerometer, VM and age significantly predicted METs (p < 0.035; conditional R = 0.76). For both the hip and the wrist accelerometer, VM, the group-by-VM interaction and BMI significantly predicted %VO (p ≤ 0.047; conditional R = 0.82 and 0.74, respectively). Between-group differences in the response to VM were larger for VO than METs models.
The relationship between accelerometer output and %VO across PAs and sedentary behaviours is different between adults with and without DS. Calibrating accelerometer output against %VO may be preferable to METs.
使用加速度计估计身体活动（PA）和久坐行为通常基于加速度计输出与代谢当量（METs）之间的关系——PA强度的一个指标。但对于唐氏综合征（DS）成年人，PA强度可能在摄氧量储备百分比（%VO）中得到更好反映，因为它考虑到了他们较低的有氧适能。本研究考察了有和没有DS的成年人在各种PA和久坐行为中加速度计输出与METs或%VO之间的关系是否不同。
41名DS成年人（年龄35±9岁；18名女性）和41名非DS成年人（年龄24±5岁；18名女性）进行了17项强度各异的任务。我们通过次极量跑步机测试估计有氧适能。我们用便携式量热法测量摄氧量，并将其表示为METs和%VO。非优势髋部和腕部的三轴加速度计输出被确定为矢量大小（VM）。我们使用多水平模型评估METs或%VO与VM之间的关系，并控制体重指数（BMI）和年龄。
对于髋部加速度计，VM和组×VM交互作用显著预测METs（p<0.001；条件R=0.82），但组间差异较小。对于腕部加速度计，VM和年龄显著预测METs（p<0.035；条件R=0.76）。对于髋部和腕部加速度计，VM、组×VM交互作用和BMI均显著预测%VO（p≤0.047；条件R分别为0.82和0.74）。与METs模型相比，VO模型中组间对VM反应的差异更大。
有和没有DS的成年人在PA和久坐行为中加速度计输出与%VO之间的关系不同。根据%VO校准加速度计输出可能比根据METs更可取。
