Rationale: Standing from a sitting position is an important activity of daily living. The five-repetition sit-to-stand test (5STS) is a simple physical performance test that measures the fastest time taken to stand five times from a chair with arms folded. It can be measured in most healthcare settings and at home, where traditional field walking tests may not be possible. The 5STS has been validated in community-dwelling older adults and people with chronic obstructive pulmonary disease, but data in idiopathic pulmonary fibrosis (IPF) are limited.

Objectives: The aims of this cohort study were to establish the construct validity, responsiveness to pulmonary rehabilitation (PR), and minimal important difference (MID) of the 5STS in IPF.

Methods: In 149 people with IPF, we compared the 5STS with measures of lung function, exercise capacity, quadriceps strength, breathlessness, and health-related quality of life. Responsiveness and effect sizes were determined by measuring the 5STS before and after PR. The MID was estimated using anchor- and distribution-based methods.

Results: The 5STS correlated significantly with incremental shuttle walk test (ISW) (r = −0.55), isometric quadriceps maximum voluntary contraction (QMVC) (r = −0.45), Medical Research Council dyspnea scale score (r = 0.40), Chronic Respiratory Questionnaire–Total (r = −0.21), and King’s Brief Interstitial Lung Disease Questionnaire–Total (r = −0.21) but not forced vital capacity percentage predicted or quadriceps one-repetition maximum (1RM). There was a significant but very weak correlation between change in 5STS and changes in Medical Research Council (r = 0.18), ISW (r = −0.21), and Chronic Respiratory Questionnaire–Total (r = −0.26) but no significant correlation with change in 1RM (r = −0.12) or QMVC (r = −0.18). 5STS time improved with PR (median [25th percentile, 75th percentile] change, −1.97 [−3.47, −0.62] s; P < 0.001). The effect size for the 5STS was 0.66 and higher than quadriceps 1RM, QMVC, and ISW. The mean (range) MID estimate was −1.93 (−1.85 to −2.10) seconds.

Conclusions: In people with IPF, the 5STS is a valid physical performance measure that is responsive to exercise-based interventions and suitable for use in most healthcare settings.

理由：从坐姿站立是日常生活中的一项重要活动。五次重复坐站测试 (5STS) 是一项简单的身体表现测试，测量双臂交叉从椅子上站立五次所需的最快时间。它可以在大多数医疗机构和家里进行测量，而传统的野外步行测试可能无法进行。 5STS 已在社区老年人和慢性阻塞性肺病患者中得到验证，但特发性肺纤维化 (IPF) 的数据有限。

目的：本队列研究的目的是确定 IPF 中 5STS 的结构有效性、对肺康复 (PR) 的反应性和最小重要差异 (MID)。

方法：在 149 名 IPF 患者中，我们将 5STS 与肺功能、运动能力、股四头肌力量、呼吸困难和健康相关生活质量的测量结果进行了比较。通过测量 PR 前后的 5STS 来确定反应性和效应大小。 MID 使用基于锚点和分布的方法进行估计。

结果： 5STS 与增量穿梭步行测试 (ISW) ( r  = -0.55)、等长股四头肌最大自主收缩 (QMVC) ( r  = -0.45)、医学研究委员会呼吸困难量表评分 ( r  = 0.40)、慢性呼吸系统显着相关问卷 – 总计 ( r  = -0.21) 和 King 简短间质性肺疾病问卷 – 总计 ( r  = -0.21)，但不预测用力肺活量百分比或股四头肌单次重复最大值 (1RM)。 5STS 的变化与医学研究委员会 ( r  = 0.18)、ISW ( r  = -0.21) 和慢性呼吸问卷总计 ( r  = -0.26) 的变化之间存在显着但非常弱的相关性，但与变化没有显着相关性在 1RM ( r  = −0.12) 或 QMVC ( r  = −0.18) 中。 PR 改善了 5STS 时间（中位数 [25%，75%] 变化，−1.97 [−3.47，−0.62] s；P  < 0.001）。 5STS 的效应大小为 0.66，高于股四头肌 1RM、QMVC 和 ISW。平均（范围）MID 估计值为−1.93（−1.85 至−2.10）秒。

结论：对于 IPF 患者，5STS 是一种有效的身体机能测量方法，对基于运动的干预措施有反应，适合在大多数医疗机构中使用。