Rowlands Alex V, Orme Mark W, Maylor Ben, Kingsnorth Andrew, Herring Louisa, Khunti Kamlesh, Davies Melanie, Yates Tom
Assessment of Movement Behaviours (AMBer) Group, Diabetes Research Centre, University of Leicester, Leicester, UK
National Institute for Health Research (NIHR) Leicester Biomedical Research Centre (BRC), University Hospitals of Leicester NHS Trust and the University of Leicester, Leicester, UK.
Br J Sports Med. 2023 Nov;57(22):1428-1434. doi: 10.1136/bjsports-2023-106953. Epub 2023 Aug 16.
To determine whether quantifying both the absolute and relative intensity of accelerometer-assessed physical activity (PA) can inform PA interventions. We hypothesised that individuals whose free-living PA is at a low relative intensity are more likely to increase PA in response to an intervention, as they have spare physical capacity.
We conducted a secondary data analysis of a 12-month randomised controlled trial, Physical Activity after Cardiac EventS, which was designed to increase PA but showed no improvement. Participants (N=239, 86% male; age 66.4 (9.7); control N=126, intervention N=113) wore accelerometers for 7 days and performed the incremental shuttle walk test (ISWT) at baseline and 12 months. PA intensity was expressed in absolute terms (intensity gradient) and relative to acceleration at maximal physical capacity (predicted from an individual's maximal ISWT walking speed). PA outcomes were volume and absolute intensity gradient.
At baseline, ISWT performance was positively correlated with PA volume (r=0.50, p<0.001) and absolute intensity (r=0.50, p<0.001), but negatively correlated with relative intensity (r=-0.13, p=0.025). Relative intensity of PA at baseline moderated the change in absolute intensity (p=0.017), but not volume, of PA postintervention. Low relative intensity at baseline was associated with increased absolute intensity gradient (+0.5 SD), while high relative intensity at baseline was associated with decreased absolute intensity gradient (-0.5 SD).
Those with low relative intensity of PA were more likely to increase their absolute PA intensity gradient in response to an intervention. Quantifying absolute and relative PA intensity of PA could improve enables personalisation of interventions.
确定对加速度计评估的身体活动（PA）的绝对强度和相对强度进行量化是否能为PA干预提供信息。我们假设，自由生活状态下PA相对强度较低的个体更有可能因干预而增加PA，因为他们有额外的身体能力。
我们对一项为期12个月的随机对照试验“心脏事件后的身体活动”进行了二次数据分析，该试验旨在增加PA，但未显示出改善效果。参与者（N = 239，86%为男性；年龄66.4（9.7）岁；对照组N = 126，干预组N = 113）佩戴加速度计7天，并在基线和12个月时进行递增穿梭步行试验（ISWT）。PA强度用绝对值（强度梯度）表示，并相对于最大身体能力时的加速度（根据个体的最大ISWT步行速度预测）。PA结果是运动量和绝对强度梯度。
在基线时，ISWT表现与PA运动量（r = 0.50，p < 0.001）和绝对强度（r = 0.50，p < 0.001）呈正相关，但与相对强度呈负相关（r = -0.13，p = 0.025）。基线时PA的相对强度调节了干预后PA绝对强度的变化（p = 0.017），但未调节运动量的变化。基线时相对强度较低与绝对强度梯度增加（+0.5标准差）相关，而基线时相对强度较高与绝对强度梯度降低（-0.5标准差）相关。
PA相对强度较低的个体更有可能因干预而增加其绝对PA强度梯度。对PA的绝对强度和相对强度进行量化可以改善干预的个性化。
