# How to film a workstation for an ergonomic assessment: the rules that make the score reliable > A video-based assessment is only as good as the video. Film the wrong operator, a partial cycle or only the worst condition and the score comes back precise and wrong. This guide sets out what to record, for how long and how, and what to settle before the first take. - Type: free guide · 5 chapters - Topics: Video analysis, OCRA, Methods - Author: Postura Ergonomics team - Published: 2026-11-10 · Updated: 2026-11-10 - Overview: https://postura.vision/resources/guides/video-recording-ergonomic-assessment/ - Read online: https://postura.vision/resources/guides/video-recording-ergonomic-assessment/read/ ## Why the video decides the score The arithmetic of a risk method does not check what it is fed. A clip that covers two pieces instead of one, or only the heaviest variant of a job, produces a score that looks exactly like a legitimate one and will be defended as one. Most disputed results trace back to the recording, not to the method. - **3 in 5** workers in the EU report musculoskeletal complaints, the most common work-related health problem in Europe. (Source: [EU-OSHA, Work-related MSDs, facts and figures (2019)](https://osha.europa.eu/en/publications/msds-facts-and-figures-overview-prevalence-costs-and-demographics-msds-europe)) - **2–3 cycles** the minimum to film for a task with a defined takt time, so the variability between cycles can be checked. (Source: [Postura field practice (guide 02, chapter 3)](https://postura.vision/resources/guides/video-recording-ergonomic-assessment/read/)) - **Art. 35** of the GDPR: an impact assessment is required before processing likely to result in a high risk; supervisory authorities, Italy's Garante included, list systematic monitoring of employees among such cases. (Source: [Regulation (EU) 2016/679, Article 35](https://eur-lex.europa.eu/eli/reg/2016/679/oj)) - **Art. 4** of the Italian Workers' Statute: audiovisual equipment from which remote monitoring of workers may derive needs a collective agreement with the union representatives or, failing that, an authorisation from the Labour Inspectorate. (Source: [Law 300/1970, Article 4 (Normattiva)](https://www.normattiva.it/uri-res/N2Ls?urn:nir:stato:legge:1970-05-20;300~art4)) ## How long should your video be? Answer up to four questions about the task you are about to film. You get the recording length the guide recommends, with the reason behind it. 1. Does the workstation combine several phases or tasks in one cycle? If yes → **every phase**: For a multitask workstation the video has to be long enough to cover every relevant phase, not just the busiest one. 2. Does the task repeat in cycles with a defined takt time? If yes → **2–3 full cycles**: At least two or three complete consecutive cycles let you check the variability between cycles and confirm the pattern of actions. 3. Is the work repetitive but without a fixed takt time? If yes → **1–4 minutes**: Without a takt time the video is the observation window. One to four minutes of typical actions is usually enough to capture the pattern. 4. Does the operator wait for a machine cycle, such as a press, during the task? If yes → **the machine wait**: Keep the waiting time in the video, with the operator still. It lowers the action frequency and, when it lasts at least 10 seconds in every cycle, counts as recovery; cutting it inflates the score. If none applies: Film at least one complete cycle, from the first action on a piece to the first action on the next, and read chapter 3 before you record. ## Who it is for - **HSE:** HSE managers organising a video campaign across a plant and the paperwork that comes with it. - **Ergonomics:** Ergonomists and assessors who need videos they can defend when a score is challenged. - **Line leaders:** Supervisors and line leaders who choose the operator, the shift and the moment to record. ## Contents 1. **Before you film** — The impact assessment, the worker notice, the union agreement and the message that keeps operators on board. 2. **Who and what to film** — The typical trained operator, the standard cycle, normal production and the condition that represents the station. 3. **How long to record** — Recording length by type of task, machine waiting time and why lengths should match across a batch. 4. **Framing and camera handling** — How the AI finds and follows the operator, when moving the phone is fine and what breaks the tracking. 5. **Checks before you upload** — The recorded segment versus the real cycle, setup time, fragments and the worst-condition trap. ## FAQ **How long should a video for an ergonomic assessment be?** It depends on the task. For work with a defined takt time, film at least two or three complete consecutive cycles. For repetitive work without a takt time, one to four minutes of typical actions is usually enough. For a workstation with several phases, the video has to cover every relevant phase. Very short videos can fail processing; very long ones add noise. **Which operator should I film?** The typical trained operator of the station, working at normal pace. Not a trainee, whose cycle is slow and uncertain, and not a veteran with decades on the same job, whose personal shortcuts are not standard. If the station is usually worked by right-handed operators, film a right-handed execution. **Can I move the phone to follow the operator?** Yes. Moving the camera, even quickly, does not penalise the analysis: the system is designed for dynamic recording. The only requirement is that the operator stays visible. The tracking locks on to the subject at the start of the video and is lost only if the operator leaves the frame completely. **Do I need the workers' consent to film them?** Every worker filmed should receive a notice on how their image and the biomechanical data extracted from it are processed. Whether an impact assessment under GDPR Article 35 is required depends on the processing; in Italy, systems from which remote monitoring of employees may derive are on the Garante's list of processing that requires one, together with an agreement with worker representatives. Settle all of it before the first recording, ideally one to two weeks ahead. **Are the operators' faces stored?** Not unobscured. During processing Postura recognises the people in the frame and covers their heads irreversibly, and no unobscured original is kept. The obscuring errs on the side of covering too much; if a face is ever visible in a frame, report it to support. Videos are kept for ten years on a dedicated server in Italy. **Should I cut the time the operator waits for a machine?** No. Keep the waiting time in the video and ask the operator to stay still rather than gesture. The system then recognises it as time without technical actions, which lowers the action frequency and, when it lasts at least 10 consecutive seconds in every cycle, counts as recovery. Cutting it makes the work look denser than it is and pushes the score up. --- ## Introduction A video-based ergonomic assessment is only as reliable as the video behind it. The risk methods (OCRA, NIOSH, REBA) do not check what they are fed: a clip that shows the wrong operator, half a cycle or only the heaviest variant of a job produces a score that looks exactly like a legitimate one. This guide collects the field rules that decide whether a recording can be trusted. They come from the assessments Postura runs every week on production lines, and from the questions customers ask most often when they start filming. It is written for the people who organise and record the videos: HSE managers, ergonomists, line leaders and the colleague holding the phone. You do not need to know the risk methods to follow it. ### What the guide covers - **Before you film**: the documents to prepare and how to explain the recording to operators. - **Who and what to film**: the operator, the cycle and the conditions the video has to represent. - **How long to record**: the recommended length for each kind of task. - **Framing and camera handling**: what the analysis needs to see and what breaks it. - **Checks before you upload**: the mistakes that are invisible in the result and how to catch them. ### The one rule behind all the others The assessment describes **the workstation as it normally runs**. Every choice in this guide, from the operator you film to the minute you stop recording, follows from that. ## 1. Before you film Settle the paperwork and the communication before the first recording, not after: plan for one to two weeks of lead time. Filming people at work involves data protection rules and, in many plants, the worker representatives. ### The documents to prepare - **Data protection impact assessment (DPIA)**: under Article 35 of the GDPR, an impact assessment is required before processing that is likely to result in a high risk to people; supervisory authorities, Italy's Garante included, list systematic monitoring of employees among such cases. Share the vendor's documentation with your Data Protection Officer at the start, so they can adapt it to your context. - **Notice to each worker filmed**: every operator who is recorded receives a notice explaining how their image and the biomechanical parameters extracted from it are processed. - **Agreement with worker representatives**: where the law or the plant's industrial relations require it, agree the recording campaign with the unions before it starts. In Italy, for example, Article 4 of the Workers' Statute (Law 300/1970) allows audiovisual equipment from which remote monitoring of workers may derive only for organisational and production needs, workplace safety or the protection of company assets, and after a collective agreement with the union representatives or, failing that, an authorisation from the Labour Inspectorate. Requirements differ by country and by company. Treat this list as the starting point for your DPO and HR, not as legal advice. ### The message for operators The key sentence is simple: **we are analysing the workstation, not the worker.** The movements an operator makes depend on how the work is designed, not on personal choices. Saying it clearly, before the camera comes out, removes most of the nervousness. Two more points help: - The analysis protects the operator as well as the company: an up-to-date risk assessment is the basis for fixing the stations that hurt. - The videos can be used for training, to share the way of working that loads the body least. ### Privacy by design In Postura, faces are **obscured irreversibly** during processing: people in the frame are recognised and their heads covered, and no unobscured original is kept. The obscuring is calibrated to cover too much rather than too little; if you spot a frame where a face is visible, report it to support. Videos are kept for ten years on a dedicated server in Italy. Say so when you present the campaign: it answers the first question most operators ask. ## 2. Who and what to film Film the typical trained operator doing the standard cycle during normal production. A video that departs from any of the three gives a score for a job that does not really exist, too high or too low. ### Who to film | Operator | Film? | Why | | --- | --- | --- | | **Trained operator at normal pace** | Yes | Knows the standard cycle and runs it with realistic efficiency. | | **Trainee** | No | Uncertain movements, slow pace and errors are not the station's real load. | | **Veteran with decades on the same job** | No | Personal shortcuts lower their effort but cannot be standardised. | The same logic applies to **handedness**. If the station is normally worked by right-handed operators and the person available on the day is left-handed, the recorded cycle is not the one the station usually runs. Reschedule the recording rather than noting the mismatch afterwards: it is invisible in the result. Individual cases belong to health surveillance and the occupational physician. ### What to film - **The standard cycle**, as written in the procedure. Ask the operator not to speed up for the camera. - **No out-of-standard gestures.** If the operator plays with the screwdriver between pieces or adds steps that are not in the procedure, that is not the cycle. Flag it to the supervisor as a training point instead of scoring it. - **Normal production**, not end of shift, product changeover or extraordinary maintenance. ### Film the condition that represents the station A cycle can be non-standard in a less obvious way: the **condition** filmed. If a station also runs lighter variants and the video shows only the heaviest one, the analysis treats that variant as the whole job and overstates the risk. The calculation is right; the sample is wrong. And a high band is read as a station to fix urgently, so nobody goes back to ask which condition the video showed. Decide which conditions are relevant **before** recording, with the people who run the station. ### The supervisor's role The line supervisor is the person who keeps the standard cycle in place. Plan the recording with the supervisor and the operator in advance. If the analysis reveals gestures outside the procedure, the fix is to brief the supervisor, otherwise every later assessment will be based on the same non-representative cycle. If you can, film the same task with **more than one operator**: it confirms the pattern is stable and shows individual variants worth aligning. ## 3. How long to record Record at least two or three complete cycles for a task with a takt time, one to four minutes for repetitive work without one, and every phase for a multitask workstation. Videos that are too short or too long both degrade the result. | Type of task | Recommended length | | --- | --- | | **Cycles with a defined takt time** | At least 2–3 complete consecutive cycles | | **Repetitive work without a takt time** | 1–4 minutes of typical actions | | **Multitask workstation (several phases)** | Long enough to cover every relevant phase | ### Why length matters - **Too short**: processing can fail or give an imprecise analysis. Short videos often need a manual quality review before the result is released. - **Too long**: processing takes longer and the video fills with noise, such as actions that are not representative, meaningless pauses and setup. - **Two or three cycles** let you check the variability between cycles and confirm that the pattern of actions is stable. - **Without a takt time**, the video length is the observation window. One to four minutes usually captures the pattern; use judgement for more complex tasks. ### Keep the machine waiting time On tasks with a machine cycle, such as a press, **do not cut the time the operator waits** for the machine to finish. Keep it in the video and ask the operator to stay still rather than gesture. The system then recognises it as time without technical actions: it lowers the action frequency and, when it lasts at least 10 consecutive seconds in every cycle, counts as recovery inside the cycle. Cutting it makes the work look denser than it is. ### Keep lengths consistent When you record several videos of the same station, keep their lengths similar. Very uneven lengths in the same batch cause comparison and processing errors. The simplest fix is an internal standard, written down and shared with everyone who films. ## 4. Framing and camera handling Keep the operator fully in frame for the whole video, from the first second. That is the one hard requirement: the camera can move, the background can be busy, but the operator must stay visible. ### How the AI finds and follows the operator - At the **start** of the video, the tracking locks on to the **largest person in the frame**. Start recording with the operator you want to assess close to the camera and clearly visible. - Once locked, the tracking **stays on that person** even when colleagues walk through the scene. - It is lost only if the operator **leaves the frame completely**. If the operator is not in the frame when the video starts, the analysis cannot pick the right subject. Start the recording on the operator, not on the workstation. ### Moving the phone is fine Moving the camera to follow the operator, even quickly, **does not penalise the analysis**. The system is designed for dynamic recording, which is how real workstations are filmed. Walk with the operator if the job moves along the line. What matters is continuous visibility. For OCRA, Postura asks for: - **Two videos per task**, one from the right side and one from the left side; a video of the hands is optional. - **Hips to head in frame** at all times, with the head and pelvis visible. - **720p to Full HD at 30 fps**, not 4K. - **The same length** for the right and left videos: very different durations block the upload. ### Practical tips - **Prepare the shot before you press record.** If unlocking the phone and placing the operator take up a large share of the clip, the video is mostly setup. A dedicated person filming, or a gimbal with tracking, solves it. - **Film in normal light**, without strong backlight from windows behind the operator. - **One task per video.** Record the right and left side as two separate videos rather than one that switches between them. ## 5. Checks before you upload Before uploading, check that the video contains exactly one complete cycle, or the number of cycles you declare, and that the declared cycle time matches it. A wrong cycle time silently changes everything computed from it. ### The recorded segment is not the cycle This mistake is invisible in the result, and it comes in two opposite forms. - **The clip contains more than one cycle.** On a station that handles pieces that are not identical, a clip covering two of them and declared as one cycle doubles the declared cycle time. Action frequency and the index follow it. - **The clip contains less than one cycle.** If the clip stops before the cycle closes and leaves out refills, packaging disposal or any step that happens once every few pieces, the analysis scores the dense part of the work as if it were the whole. The station comes out red for a reason that is in the recording, not in the job. The check is the same in both cases: find the **first and last frame of one complete repetition** and confirm that the declared cycle time is the duration of that repetition, not of the clip. Where pieces differ, agree with the people who run the station which one the cycle represents. A practical corollary: **when someone disputes a score, check the cycle time first.** They are often disputing a cycle time without knowing it. ### Checklist before upload | Check | Look for | | --- | --- | | **Operator** | Trained, normal pace, the station's usual handedness | | **Cycle** | Standard procedure, no out-of-standard gestures | | **Condition** | The one that represents how the station runs, not only the worst | | **Start** | The operator is in frame from the first second | | **Length** | 2–3 cycles, 1–4 minutes, or every phase, as in chapter 3 | | **Machine time** | Waiting time kept, operator still | | **Segment** | First and last frame of a complete repetition identified | | **Cycle time** | Matches one repetition, not the clip | | **Batch** | Similar lengths across videos of the same station | | **Paperwork** | Notice, DPIA and agreement in place before filming | ## Your next step Pick one workstation, apply the checklist in chapter 5 and film it this week. One good video teaches more than a campaign planned on paper: it shows you how long your cycles really are, which conditions the station runs and what your operators need to hear before the camera comes out. ### With Postura Upload the videos from your phone and you get both readings of the same recordings: the ergonomic risk score (OCRA from the video, REBA where enabled on your account, with NIOSH and push-pull from the measurements you enter) and the time and methods analysis of the cycle. The first videos you upload are reviewed by our team, with feedback on the recording itself. - **See it on your own footage**: [book a demo](https://calendar.google.com/calendar/u/0/appointments/schedules/AcZssZ1vaRyHk2DvHW84TDK4rpDfgwOFSYqkmYbXOn_17BZ2S8BvLTSLYXhy7wdXo_DlMxpu61AJvnxv). - **Choosing the method**: read [OCRA vs NIOSH vs REBA](/resources/guides/ocra-vs-niosh-vs-reba/). - **Reading the OCRA score**: read [OCRA High-Precision Checklist](/resources/guides/ocra-checklist-guide/).