五次坐站测试：方法学、测力台指标与社区健康应用 The Five Times Sit-to-Stand: Methodology, Force-Plate Metrics, and Community Health Application

两种版本及其区别Two versions of the test

两个版本之间没有换算关系。同一个人在两项测试中的表现由不同能力主导：5STS 更多反映力量与功率，30CST 的后半程则掺入耐力成分。报告成绩时应注明所用的版本。 There is no conversion between the two. Different capacities dominate: the 5STS leans more on strength and power, while the second half of a 30CST brings in endurance. Reported results should name the version used.

标准化流程Standardised protocol

器材要求Equipment

• 椅子：直背、无扶手，座面高度 43–45 cm，部分研究采用 48 cm。应靠墙放置或以其他方式固定，以防测试过程中后移。 Chair: straight-backed and armless, with a seat height of 43–45 cm; some studies employ 48 cm. It should be placed against a wall or otherwise braced to prevent displacement during the test.
• 秒表：精度 0.1 秒。 Stopwatch: resolution of 0.1 s.

座面高度是这项测试最主要的混杂因素，而且各研究之间有差异。记录所用座位高度，复测同样高度，否则纵向比较不成立。 Seat height is the largest confounder in this test, and it varies between studies. Record the seat height used and re-test at the same height; otherwise comparison over time does not hold.

操作步骤Administration

1. 受试者就坐，背部贴靠椅背，双脚平放于地面，双臂交叉置于胸前。 The participant is seated with the back against the backrest, feet flat on the floor, and arms crossed over the chest.
2. 指导语为：「尽可能快地站起、坐下，共五次。」 The instruction is: "Stand up and sit down five times, as fast as you can."
3. 计时始于发出「开始」口令，止于第五次臀部接触座面。 Timing begins on the command to start and ends when the buttocks contact the seat on the fifth repetition.
4. 全程双臂不得离开胸前，不得借助椅子或大腿推撑；每次起身须完全直立，每次回坐须完全接触座面。 The arms remain crossed throughout, and the participant may not push off the chair or thighs. Each rise must reach full extension and each descent must achieve full seat contact.
5. 正式计时前应先行示范并允许试做一次。两次正式测试之间至少休息 1 分钟，取较好成绩。 A demonstration and one practice rise precede the scored trials. At least 1 min of rest separates scored trials, and the better result is taken.

四阶段模型The four-phase model

Schenkman 等提出的四阶段模型是描述坐站动作的标准框架。 The four-phase model of Schenkman et al. is the standard framework for describing the chair rise.

第一阶段的躯干前摆并非多余动作，而是一项省力机制：上身所建立的动量在离座瞬间传递至下肢。躯干活动受限者，或因恐惧跌倒而不敢前倾者，须以单纯的下肢力量完成起身。这一机制可以解释为何在下肢力量并未明显下降的情况下，起身动作仍可能变得困难。 The trunk swing of the first phase is not extraneous motion but an energy-conserving mechanism: momentum generated by the upper body is transferred to the lower limbs at the moment of seat-off. Individuals with restricted trunk mobility, or who avoid forward lean owing to fear of falling, must complete the rise through lower-limb strength alone. This mechanism accounts for the observation that rising may become difficult even where lower-limb strength has not appreciably declined.

需要说明的是，躯干前摆的幅度是一个角度量，测力台无法测量，需借助动作捕捉或惯性测量单元。测力台记录的是它的效果与时长：躯干前倾时体重由椅面转移至双脚，垂直力随之上升。 The amplitude of the trunk swing is an angle, which a force plate cannot measure; motion capture or an inertial sensor is needed for that. What the plate records is its effect and duration: as the trunk leans forward, load transfers from the seat to the feet and vertical force rises with it.

测力台可识别的关键时刻Landmarks identifiable on a force plate

当椅子置于测力台之外、仅双足承载于台面时，垂直力曲线在两个水平之间往复： When the chair is positioned off the plate and only the feet are supported on it, the vertical force trace alternates between two levels:

• 坐姿平台：由下肢承担的体重份额，通常为体重的 15–25%，其余由椅子承担。 the seated plateau, being the share of body weight borne by the lower limbs, typically 15–25% of body weight, with the remainder borne by the chair; and
• 站立水平：等于体重。 the standing level, equal to body weight.

每一次起身构成两个水平之间的一次往复，其中包含三个时刻： Each rise constitutes one excursion between these levels and contains three instants:

1. 起始：力值离开坐姿平台，对应躯干开始前倾。 Onset, at which force departs the seated plateau, corresponding to the beginning of trunk flexion.
2. 离座：力值上穿体重线。臀部此时离开座面，下肢自该时刻起承担全部体重。 Seat-off, at which force crosses body weight. The buttocks leave the seat, and from this instant the lower limbs bear the entire body weight.
3. 峰值力：全程最大值，健康成人通常介于 1.1–1.4 倍体重之间。 Peak ground reaction force, the maximum of the trace, typically between 1.1 and 1.4 times body weight in healthy adults.

Chang 等采用两块测力台（分别置于椅下与足下）分别测量臀部与下肢的地面反作用力，确认上述时刻依次出现而非同时发生：全身最大合力、下肢最大受力与离座三者存在先后顺序。在仅使用单块测力台时，离座时刻由下肢力曲线上穿体重线推断。 Chang et al. employed two force platforms, one beneath the chair and one beneath the feet, to measure the buttock and leg ground reaction forces separately, and established that these landmarks occur in sequence rather than simultaneously: maximum whole-body force, maximum leg force, and seat-off arise successively. Where a single plate is used, seat-off is inferred from the crossing of body weight by the leg-force trace.

测力台提供的附加指标Additional metrics provided by a force plate

无测力台条件下的功率估算Estimation of power without a force plate

Alcazar 等提出的坐站功率测试仅依据秒表成绩与身高即可估算功率，并已与测力台测得的功率进行过对照验证。其假设为：上升阶段被加速的质量取体重的 90%，重心位移由身高的 50%（作为腿长）减去座高得到，向心阶段占单次坐站总时间的 50%。该方法适用于流行病学调查与大样本筛查；但其性质为估算，上述三项假设在个体层面均存在偏差。 The sit-to-stand muscle power test proposed by Alcazar et al. estimates power from the stopwatch score and body height alone, and has been validated against force-plate-derived power. Its assumptions are that 90% of body mass is accelerated during the ascending phase, that centre-of-mass displacement equals 50% of body height (taken as leg length) minus chair height, and that the concentric phase occupies 50% of the total time per repetition. The method is appropriate for epidemiological surveys and large-scale screening; it remains, however, an estimate, and each of these assumptions varies at the individual level.

便携测力台在社区与现场筛查中的应用Portable force plates in community and field screening

在便携测力台普及前，成本低廉、操作简单的秒表是这项测试的默认器材。对老年筛查而言，器材能否走出实验室不止关乎便利，更关乎样本的代表性：最需要评估的人，往往也是最难前往实验室的人。能够自行前往并完成测试的老年人，事实上已在功能能力上经过了一次筛选。便携测力台改变的正是这一环节，使测量得以在人群所在之处进行。 Before portable force plates, the stopwatch — inexpensive and simple to operate — was the default instrument for this test. For screening in older adults, whether the instrument can leave the laboratory concerns more than convenience: it shapes who ends up in the sample. Those who most need assessing are often the least able to reach a laboratory, and an older adult who can travel there and complete the protocol has already been filtered on the very capacity under measurement. Portable instruments change that, allowing the measurement to take place where the population already is.

现场应用的具体收益Specific benefits in field application

现场部署的前提条件Prerequisites for field deployment

• 场地：椅子需放在台面之外，因此要有一块能同时容纳测力台与椅子的连续平整地面。社区卫生服务中心的普通房间通常足够，但宜事先确认。 Space. The chair stands off the plate, so a continuous level floor area large enough for both is required. An ordinary room in a community health centre is usually sufficient, though this is worth confirming in advance.
• 供电与连接：现场往往既无稳定市电也无网络，设备需支持电池供电与本地采集，测试结束后再行上传。 Power and connectivity. Field sites often have neither reliable mains power nor network access, so the device must run on battery, capture locally, and upload afterwards.
• 架设时间：筛查现场的节奏由排队人数决定，架设过慢会明显压缩实际受测人数。 Setup time. Throughput at a screening site is set by the queue, and a slow setup noticeably reduces the number of people actually measured.
• 采集窗口：虚弱人群完成五次起坐常需 20–30 秒，SPPB 允许至 60 秒。窗口若设为 20 秒，便只能记录动作最快的一部分人，而他们恰恰不是这项测试要识别的对象。 Capture window. Frail participants often need 20–30 s for five rises, and the SPPB allows up to 60 s. A 20 s window records only the fastest, who are precisely the people the test is not meant to identify.
• 采样率不应为便携性让步：冲量法计算功率需对力做时间积分，丢失的样本即为丢失的贡献。设备若在现场表现正常而实际存在数据丢失，产出的将是一个难以察觉的错误数值，危害甚于明确的失败。便携性应来自电池、无线传输与结构设计，而非降低采样率。 Sampling rate should not be traded for portability. Impulse-based power integrates force over time, so every missing sample is a missing contribution. A device that appears to work in the field while losing data produces a wrong number that reads as real, which is more damaging than an outright failure. Portability should come from the battery, the wireless link and the mechanical design, not from a lower sampling rate.

社区场景中最直接的两项应用是跌倒风险筛查（CDC STEADI 采用 30 秒坐站）与肌少症筛查（EWGSOP2 将 SPPB ≤ 8 列为严重程度标准之一）。两者均已有成熟的秒表流程。测力台的价值在于：在不改变流程的前提下，把「慢」分解为力量不足、发力过慢或不敢负荷患侧，而干预方向正取决于这一区分。 The two most direct community applications are falls-risk screening, in which CDC STEADI uses the 30-second chair stand, and sarcopenia screening, in which EWGSOP2 treats an SPPB score of 8 or below as one criterion of severity. Both already have established stopwatch procedures. What a force plate adds is the ability to separate slowness into its causes without altering the procedure: insufficient strength, slow force development, or reluctance to load the involved side. That distinction determines the intervention.

参考值Reference values

Bohannon（2006）针对 60 岁以上人群的描述性 meta 分析给出了按年龄分层的参考值。超过下列时间者，可视为表现低于同龄平均水平。 The descriptive meta-analysis of Bohannon (2006) provides age-stratified reference values for adults aged 60 years and over. Times exceeding those below may be regarded as worse than average for the age band.

该研究的结论本身即强调，对「正常」的判断必须按年龄分层进行。以单一界值评价全部老年人群缺乏依据。 The conclusion of that analysis is itself that judgements concerning normal performance must be made on an age-specific basis. Application of a single cutoff across the whole older population lacks support.

在 SPPB 中的位置Position within the SPPB

简易体能状况量表（Short Physical Performance Battery，SPPB；Guralnik 等，1994）由三个部分组成，按平衡、步速、坐站的顺序实施，每部分计 0–4 分，总分 0–12 分。其中坐站部分所采用的即为五次坐站测试。 The Short Physical Performance Battery (SPPB; Guralnik et al., 1994) comprises three components administered in the order of balance, gait speed, and chair stands, each scored from 0 to 4 for a total of 0 to 12. The chair-stand component is the Five Times Sit-to-Stand.

• 平衡（0–4 分）：并足站立保持 10 秒计 1 分；半前后足站立保持 10 秒计 1 分；前后足站立保持 10 秒计 2 分，保持 3–9.99 秒计 1 分，不足 3 秒计 0 分。 Balance (0–4). Side-by-side stance held for 10 s scores 1 point; semi-tandem stance held for 10 s scores 1 point; tandem stance held for 10 s scores 2 points, for 3–9.99 s scores 1 point, and for less than 3 s scores 0.
• 步速（0–4 分）：4 米常速步行，取两次中较快者。 Gait speed (0–4). A 4 m walk at usual pace, the faster of two trials being taken.
• 坐站（0–4 分）：界值见下表。 Chair stands (0–4). Cutoffs are given below.

坐站部分须先行预筛：受试者双臂抱胸，自椅上站起一次。若无法在不借助上肢的情况下完成，该部分直接计 0 分，不再实施五次测试。 The chair-stand component is preceded by a screening trial in which the participant, with arms crossed, rises once from the chair. Where this cannot be accomplished without the use of the upper limbs, the component is scored 0 and the five-repetition test is not attempted.

总分判读如下：10–12 分为下肢功能良好；7–9 分为中度受限；6 分及以下为明显受限，是失能、住院与死亡的有力预测指标。最小临床重要差异约为 1 分。欧洲老年肌少症工作组（EWGSOP2）将 SPPB ≤ 8 分列为肌少症严重程度的判定标准之一。 Total scores are interpreted as follows: 10–12 indicates good lower-extremity function; 7–9 indicates moderate limitation; and 6 or below indicates marked limitation and constitutes a strong predictor of disability, institutionalisation, and mortality. The minimal clinically important difference is approximately 1 point. The European Working Group on Sarcopenia in Older People (EWGSOP2) adopts an SPPB score of 8 or below as one criterion of sarcopenia severity.

若需输出 SPPB 得分，应注意这组界值是按时间查表得到的。测力台的其他数据可以并列呈现，但不应改变该分项得分，因为临床认可的依据是完成五次所用的时间。 Where an SPPB score is reported, these cutoffs remain a lookup on time. Other force-plate data may be presented alongside it, but must not alter the component score, since what is clinically recognised is the number of seconds.

导致数据失效的常见操作问题Common procedural faults that invalidate the data

• 椅子置于测力台之上。此时所测为人与椅的合重，曲线不再回落至坐姿平台，起始、离座与回坐均无从判定。椅子必须置于台外，台面之上仅有双足。 The chair placed upon the plate. The combined weight of participant and chair is then measured, the trace no longer returns to a seated plateau, and onset, seat-off, and seat contact all become indeterminable. The chair must stand off the plate, with only the feet supported upon it.
• 未完全回坐。点触式的回坐会使相邻两次动作在曲线上相连，次数与时间均将出错。 Incomplete descent. A touch-and-go return merges adjacent repetitions within the trace, corrupting both the count and the time.
• 采集窗口过短。该测试的意义在于识别动作缓慢者：15 秒以上为常用的跌倒风险界值，虚弱人群常需 20–30 秒，SPPB 允许至 60 秒。窗口设为 20 秒，将使测试对象中最应被识别的部分无法完成记录。 An excessively short capture window. The purpose of the test is to identify slowness: 15 s is a commonly used falls-risk threshold, frail participants routinely require 20–30 s, and the SPPB permits 60 s. A 20 s window prevents the recording of precisely those participants whom the test is intended to identify.
• 未满五次仍报告时间。仅完成三次的成绩若填入同一字段，读者将其理解为一个较快的结果，与测试本意恰好相反。次数不足时应明确标注为无效，而非给出一个更小的秒数。 Reporting a time for fewer than five rises. A set of three repetitions entered in the same field will be read as a faster result, which inverts the meaning of the test. An incomplete set should be marked as invalid rather than assigned a smaller number of seconds.
• 更换椅子。座高改变后，成绩不再具有可比性。 Change of chair. Once seat height differs, results are no longer comparable.

第四阶段：站立之后的稳定过程The fourth phase: stabilisation after standing

已有研究发现，稳定阶段较起身阶段本身更能区分健康老年人与年轻受试者：站立之后恢复稳定所需的时间，其信息量高于起身本身所用的时间。该现象在术后与损伤人群中同样成立，并常伴随患侧负荷回避。 Research has found that the stabilisation phase discriminates healthy older adults from younger participants more effectively than the rise itself: the time required to regain stability after standing carries greater information than the duration of the rise. The same finding holds in post-surgical and injured populations, in whom it is commonly accompanied by avoidance of loading on the involved side.

但这一阶段能否测量，取决于受试人群。动作迅速的健康受试者，每次起身之后几乎没有静止站立的时间，稳定阶段被压缩到无法有效计算姿势摆动；而在这项测试真正服务的老年与术后人群中，它恰恰最值得测量。进行此类分析时，应先确认窗口是否足够长，再决定是否输出结果：窗口过短时算出的数值，价值低于不予报告。 Whether that phase can be measured at all depends on the population. In fast, healthy participants there is almost no quiet standing between repetitions, and the stabilisation phase is compressed to the point where postural sway cannot be computed meaningfully. In the older and post-surgical populations the test actually serves, it is the segment most worth measuring. Analyses of this kind should therefore confirm that the available window is long enough before any result is reported: a value computed from too short a window is worth less than no value at all.