Ergonomics | A1.1

Ergonomics (also called human factors engineering) is the study of how people interact with the products, systems and environments they use. When designers apply ergonomic thinking, the result is products that are safer, more comfortable and more efficient to use.

The field is built on three interlocking disciplines:

• Anthropometrics — the measurement of human body dimensions. Knowing how large or small a user's body is allows designers to set appropriate dimensions for a chair, a control panel or a doorway.
• Physiology — how the body's systems (muscles, nervous system, cardiovascular system) function, respond and reach their limits. Relevant when designing for force, fatigue, posture or sensory capability.
• Psychology — how the mind perceives and interprets information from the senses. Relevant when designing interfaces, environments, warnings or anything that communicates through sight, sound, smell, taste or touch.

A product designed without ergonomic consideration may still function technically — but it will be harder to use, more tiring, riskier or inaccessible to some users. Good ergonomic design removes the mismatch between the product and the person.

人体工程学（也称为人因工程）是研究人与产品、系统和环境之间互动关系的学科。当设计师将人体工程学思维应用于设计时，产品将变得更安全、更舒适、更高效。

该领域建立在三个相互关联的分支学科上：

• 人体测量学——测量人体各部位的尺寸。了解用户身体的大小，帮助设计师确定椅子、控制面板或门口的正确尺寸。
• 生理学——研究人体系统（肌肉、神经系统、心血管系统）的功能、反应及其极限。在设计需要施力、抵抗疲劳、保持姿势或感知能力的产品时尤为重要。
• 心理学——研究人脑如何感知和解读感官信息。在设计界面、环境、警告标志或任何通过视觉、听觉、嗅觉、味觉或触觉传达信息的产品时至关重要。

未经人体工程学考量的产品在技术上或许仍能正常运行，但使用起来会更费力、更易疲劳、风险更高，或对某些用户不友好。优秀的人体工程学设计能消除产品与使用者之间的不匹配。

Anthropometric data is the systematic collection of human body measurements — height, reach, grip diameter, shoulder width, eye height and hundreds of other dimensions. Designers use this data to set critical product dimensions.

Two types of data are collected:

• Static anthropometrics — measurements taken with the body still: standing height, seated eye height, shoulder breadth, hand length. Used when designing furniture, clothing, vehicle interiors and equipment that must fit a stationary body.
• Dynamic anthropometrics — measurements taken during movement: reach envelope, step length, grip force, range of motion. Used when designing controls, handles, tools and spaces where the user must move to operate the product.

A critical principle is that no two bodies are the same. A person tall enough to fit clothing size L may have arms that fit a size S. Designing for a single "standard human" always excludes many real users. Anthropometric data must therefore account for variation across:

• Age — children and older adults differ significantly from young adults in reach, grip strength and mobility.
• Gender — male and female bodies differ on average in many dimensions; mixed-gender products must accommodate both.
• Ethnicity — body proportions vary across populations; data collected from one ethnic group cannot be applied globally without adjustment.
• Disability — users with physical disabilities may have different reach ranges, grip capabilities or postures that change every dimension a designer must consider.

人体测量数据是对人体各部位尺寸的系统性收集——包括身高、伸展范围、握持直径、肩宽、眼睛高度等数百个维度。设计师利用这些数据来确定产品的关键尺寸。

人体测量数据分为两类：

• 静态人体测量——在静止状态下测量：站立身高、坐姿眼睛高度、肩宽、手长等。用于设计家具、服装、车辆内饰及需要适应静止人体的设备。
• 动态人体测量——在运动状态下测量：伸展范围、步幅、握力、活动范围等。用于设计控件、手柄、工具及需要用户在操作时移动的空间。

一个关键原则是：没有两个人体是完全相同的。一个身高适合L码服装的人，手臂长度可能只适合S码。针对单一"标准人"进行设计必然会排除许多真实用户。因此，人体测量数据必须考虑以下方面的差异：

• 年龄——儿童和老年人在伸展范围、握力和运动能力方面与年轻人有显著差异。
• 性别——男女体型在许多尺寸上存在平均差异；面向混合性别的产品必须同时兼顾两者。
• 种族——不同人群的体型比例各不相同；从某一种族群体收集的数据不能在未经调整的情况下应用于全球。
• 残障——身体残障用户可能有不同的伸展范围、握持能力或姿势，这会改变设计师需要考量的每一个维度。

Anthropometric data for any dimension — such as standing height — follows a normal distribution (bell curve). Most people cluster near the middle; fewer people are at the extremes. Percentiles tell you what percentage of the measured population falls at or below a given measurement.

Three percentiles are used routinely in design:

• 5th percentile — 5% of the population is at or below this measurement. A 5th percentile adult is among the smallest in the population. When designing for reach — how far a person must stretch to operate something — design for the 5th percentile: if the smallest person can reach it, everyone can.
• 50th percentile — the median value; half the population is above and half below. Rarely the right choice on its own — a product sized only for the median excludes people at both extremes.
• 95th percentile — 95% of the population is at or below this measurement. A 95th percentile adult is among the largest. When designing for clearance — how much space a person needs to fit through or under something — design for the 95th percentile: if the largest person fits, almost everyone fits.

Most products should be designed for the 5th–95th percentile range, covering 90% of the population. The extreme 5% at each end are excluded — a deliberate design compromise when the cost of accommodating them is too high.

Case study: Early crash test dummies (e.g., Hybrid I, 1971) were modelled on the 50th percentile male. Female anthropometric data was not included. As a result, vehicle safety features — seatbelts, airbag placement — were optimised for a male body. Studies later showed women were significantly more likely to be injured in crashes. The THOR 5th ATD (Anthropomorphic Test Device), representing a 5th percentile female, was developed to address this. The case illustrates the real harm that follows when designers fail to represent the full range of users in their data.

任何一项人体测量数据（如站立身高）都遵循正态分布（钟形曲线）。大多数人集中在中间值附近，极端值处的人数较少。百分位数表示被测人群中有多少比例的人达到或低于某一特定测量值。

设计中常用以下三个百分位数：

• 第5百分位数——5%的人口处于或低于此测量值，即人群中体型最小的一类人。在设计触及范围——用户必须伸展多远才能操作某物——时，应针对第5百分位设计：如果最矮小的人能够触及，那么所有人都能。
• 第50百分位数——中位值，一半人口在其上，一半在其下。单独使用该数值进行设计通常并不合适——只适合中间值的产品会同时排除两端的用户。
• 第95百分位数——95%的人口处于或低于此测量值，即人群中体型最大的一类人。在设计间隙——用户需要多少空间才能通过或穿过某物——时，应针对第95百分位设计：如果最高大的人能通过，几乎所有人都能。

大多数产品应针对第5至第95百分位范围进行设计，覆盖90%的人口。两端各5%的极端用户被排除在外——当满足他们的成本过高时，这是一种有意为之的设计权衡。

案例研究：早期碰撞测试假人（如1971年的Hybrid I）以第50百分位男性为模型，未纳入女性人体测量数据。因此，车辆安全装置——安全带、气囊位置——均针对男性体型进行了优化。后来的研究显示，女性在碰撞中受伤的概率显著更高。代表第5百分位女性的THOR 5th ATD（拟人化测试装置）因此被开发出来。这一案例充分说明，当设计师未能在数据中体现用户群体的完整范围时，会带来真实的伤害。

Because no single fixed dimension suits the full 5th–95th percentile range, designers have two core strategies for accommodating different body sizes:

Strategy 1 — Adjustability
The product has components that can be moved, extended or set by the user to suit their own body. Examples:

• An office chair with adjustable seat height, lumbar support and armrests allows a 5th percentile small user and a 95th percentile tall user to both sit comfortably at the same workstation.
• A car's steering column and seat position both adjust, accommodating drivers across a wide height range.
• A bicycle saddle slides up and down its post to match the rider's leg length.

Adjustability is preferred when users share a product and need it to fit their specific body. Its main cost is added mechanical complexity and the need for users to correctly set it up.

Strategy 2 — Range of sizes
The product is manufactured in multiple fixed sizes. Users select the size closest to their body. Examples:

• Clothing sold in XS, S, M, L and XL.
• Crash test dummies: the Hybrid III family includes a 50th percentile male, a 5th percentile female and three child dummies — five sizes to cover a wider population range.
• Bicycle helmets offered in S, M and L to fit different head circumferences.

A range of sizes is appropriate when adjustability is mechanically impractical, too costly, or when the product is consumed or worn and cannot be shared. Some products use both strategies — adjustable components within each size — to maximise fit.

由于没有任何单一固定尺寸能够适合第5至第95百分位的全部用户，设计师有两种核心策略来适应不同体型：

策略一——可调节性
产品具有可由用户移动、延伸或调整的部件，以适应自身体型。例如：

• 配有可调节座椅高度、腰部支撑和扶手的办公椅，能让第5百分位的矮小用户和第95百分位的高大用户都能在同一工作站舒适就座。
• 汽车的方向盘柱和座椅位置均可调节，可适应较大身高范围的驾驶者。
• 自行车座垫可沿座杆上下滑动，以匹配骑手的腿长。

当多个用户共用同一产品且需要根据各自体型进行适配时，可调节性是首选方案。其主要代价是增加了机械复杂性，以及用户需要正确地进行调节。

策略二——尺寸范围
产品以多种固定尺寸生产，用户选择最接近自身体型的尺寸。例如：

• 按XS、S、M、L、XL出售的服装。
• 碰撞测试假人：Hybrid III系列包括第50百分位男性、第5百分位女性及三个儿童假人——通过五种尺寸覆盖更广泛的人群范围。
• 提供S、M、L码以适应不同头围的自行车头盔。

当可调节性在机械上不可行、成本过高，或产品为消耗品或穿戴品而无法共用时，尺寸范围策略更为适合。部分产品同时采用两种策略——在每个尺寸内提供可调节部件——以最大化适配性。

When designing a workspace — whether a cockpit, a kitchen or a production line — a designer needs to map not just body size, but the space in which the body moves and operates. This is captured by a set of related concepts:

Work envelope (workspace envelope) — the three-dimensional space that a person can comfortably reach and operate within from a fixed position. Imagine a sphere of reachable space around a seated operator. All critical controls must fall within this envelope; otherwise the user must stretch, lean or shift in ways that increase fatigue and error rate. The size of the work envelope changes with body size, so it must be defined using percentile data.

Reach — the maximum distance a person can extend their arm to contact or operate something. Reach is a 5th percentile design concern: if the smallest user can reach every control, everyone can. Place the most frequently used controls in the nearest zone of the work envelope.

Clearance — the minimum space needed to fit part of the body without obstruction: head clearance in a doorway, knee clearance under a desk, shoulder width in a corridor. Clearance is a 95th percentile concern: design so the largest user fits through or into the space, and everyone else will too.

Applying these correctly means using different percentiles for different problems: reach calls for 5th percentile data; clearance calls for 95th percentile data. A single percentile cannot solve both simultaneously — which is one reason adjustable workstations exist.

在设计工作空间时——无论是驾驶舱、厨房还是生产线——设计师不仅需要考虑人体尺寸，还需要规划人体活动和操作所占据的空间。这由一组相关概念来描述：

工作包络（工作空间包络）——一个人从固定位置可以舒适地伸够和操作的三维空间。想象坐姿操作者周围可触及的空间球体。所有关键控件必须位于此包络内；否则用户将不得不拉伸、弯腰或移动，从而增加疲劳感和操作失误率。工作包络的大小随体型而变化，因此必须使用百分位数据进行界定。

触及范围——一个人伸展手臂可以接触或操作某物的最大距离。触及范围是第5百分位设计问题：如果最矮小的用户能够触及所有控件，那么所有人都可以。应将使用最频繁的控件放置在工作包络最近的区域内。

间隙——身体某部位通过而不受阻挡所需的最小空间：门洞的头部间隙、桌子下方的膝盖间隙、走廊的肩宽。间隙是第95百分位问题：设计应确保最高大的用户能够通过或进入该空间，其他所有人也能。

正确应用这些概念需要针对不同问题使用不同的百分位数：触及范围使用第5百分位数据；间隙使用第95百分位数据。单一百分位无法同时解决两个问题——这也是可调节工作站存在的主要原因之一。

Physiology is the study of how the body's systems function, respond and break down under use. For designers, the relevant question is: what are the limits of what the human body can do, and how does the product stay within those limits?

Visual accuracy and colour perception — The eye can distinguish fine detail only at the centre of the visual field (the fovea). Peripheral vision picks up motion but not detail. Approximately 8% of males have some form of colour vision deficiency. Designs that rely on colour alone to convey critical information (red = danger, green = safe) exclude these users. Good design uses colour as one channel among several — shape, symbol and position reinforce the message.

Muscle strength and fatigue — The force a person can exert — gripping, lifting, pushing — varies widely by age, gender, hand size and physical condition. Biomechanics is the study of mechanical forces acting in the body: levers, joints and load paths. Designing a product that requires excessive force can cause injury over time. A rubber jar opener with a serrated strip works by increasing friction and mechanical advantage, allowing the same torque to be produced with far less hand force — preventing fatigue and injury for users with reduced grip strength.

Muscle control — Fine motor control (precise finger and hand movements) decreases with age, fatigue, cold and certain medical conditions. Products requiring precise input — small buttons, fine-tuned controls — can exclude users with reduced motor control.

Hearing thresholds — Human hearing is most sensitive in the 1,000–4,000 Hz range. High-frequency hearing loss is common with age. Auditory warnings must be designed to reach users with reduced hearing and must not be masked by background noise in the environment where the product is used.

生理学研究人体系统在使用过程中的功能、反应与极限。对设计师而言，关键问题是：人体能做什么的极限在哪里，产品设计如何保持在这些极限之内？

视觉精度与色彩感知——眼睛只能在视野中心（中央凹）区分细节，周边视觉可感知运动但无法辨别细节。约8%的男性存在某种程度的色觉障碍。仅依赖颜色传达关键信息（红色=危险，绿色=安全）的设计会将这些用户排除在外。良好的设计将颜色作为多种传达渠道之一——形状、符号和位置共同强化信息传达。

肌肉力量与疲劳——一个人能够发出的力量——握持、提升、推压——因年龄、性别、手部大小和身体状况而存在很大差异。生物力学研究人体中的机械力：杠杆、关节和载荷路径。设计需要过大力量的产品可能随时间推移导致损伤。带有锯齿金属条的橡胶开瓶器通过增加摩擦力和机械优势发挥作用，让用户用更小的手部力量产生同样的扭矩——从而防止握力较弱用户出现疲劳和损伤。

肌肉控制——精细动作控制（精确的手指和手部运动）会随着年龄、疲劳、寒冷和某些医疗状况而下降。需要精确操作的产品——小按钮、精细控件——可能将动作控制能力减弱的用户排除在外。

听力阈值——人类听觉在1000至4000赫兹范围内最为敏感。随着年龄增长，高频听力损失较为常见。听觉警告信号的设计必须确保听力减退的用户能够听到，同时不能被产品使用环境中的背景噪音所掩盖。

Psychology, in the context of ergonomics, focuses on how the mind receives and interprets information from the environment through all five senses. Products communicate through sensory channels whether their designers intend it or not. Understanding how the brain processes sensory input allows designers to communicate more clearly, create safer products and shape user experience.

Sight (vision) — The most information-dense sense. Designers control colour, shape, size, contrast and motion to direct attention and communicate meaning. Orange is used for life rings, life vests and rescue equipment because it is the most easily detected colour against the sea surface and in low-light conditions — a decision grounded in visual psychology. Text contrast ratios must meet accessibility standards to remain readable for users with reduced vision.

Hearing (sound) — Auditory signals carry urgency: a car horn, a fire alarm, a hospital monitor. The tone, pitch, rhythm and volume of a sound communicate different levels of emergency. A warning tone that blends with background noise fails its purpose. Sound design must account for the acoustic environment where the product is used.

Touch (haptic feedback) — Textured surfaces, vibrations and physical resistance communicate information without vision or sound. Tactile paving at pedestrian crossings signals a safe crossing point to visually impaired users. Phone haptics confirm button presses in silent mode.

Smell (olfaction) — Natural gas is odourless; a sulphur compound is added to give it a distinctive smell because the brain responds rapidly to unfamiliar odours. Safety design sometimes uses smell as a warning channel when visual or auditory channels may be missed.

Taste — Less commonly a design consideration, but relevant in food products, medical devices (pill coatings designed to prevent accidental ingestion) and child safety (bitter coatings on hazardous household products).

在人体工程学的语境中，心理学关注人脑如何通过五种感官接收和解读来自环境的信息。无论设计师是否有意为之，产品都会通过感官渠道传递信息。了解大脑如何处理感官输入，使设计师能够更清晰地传达信息、创造更安全的产品，并塑造用户体验。

视觉——信息密度最高的感官。设计师通过控制颜色、形状、尺寸、对比度和运动来引导注意力、传达含义。救生圈、救生衣和救援设备使用橙色，因为它在海面和低光照条件下是最容易被探测到的颜色——这是一个基于视觉心理学的决策。文本对比度必须达到无障碍标准，以确保视力减退的用户也能清楚阅读。

听觉——听觉信号传达紧迫感：汽车喇叭声、火警警报、医院监护仪。声音的音调、音高、节奏和音量传达不同级别的紧急程度。与背景噪音融为一体的警告音无法实现其目的。声音设计必须考虑产品将被使用的声学环境。

触觉（触觉反馈）——纹理表面、振动和物理阻力无需视觉或声音即可传递信息。人行横道处的触觉铺装向视障用户发出安全过马路的信号。手机振动在静音模式下确认按键操作。

嗅觉——天然气本身无味；人们向其中添加含硫化合物，赋予其独特气味，因为大脑对陌生气味反应迅速。当视觉或听觉渠道可能被忽略时，安全设计有时会将嗅觉作为警告渠道。

味觉——较少作为设计考量，但与食品产品、医疗器械（防止意外服用的药片涂层）和儿童安全（危险家用产品上的苦味涂层）密切相关。