Guide
OCRA vs NIOSH vs REBA: the complete guide
What each method measures, when it is the right choice, the data it needs and how to read its results — side by side.
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.
EU-OSHA, Work-related MSDs, facts and figures (2019)2–3 cycles
the minimum to film for a task with a defined takt time, so the variability between cycles can be checked.
Postura field practice (guide 02, chapter 3)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.
Regulation (EU) 2016/679, Article 35Art. 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.
Law 300/1970, Article 4 (Normattiva)From chapter 3
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.
Question 1 of 4
Does the workstation combine several phases or tasks in one cycle?
Question 2 of 4
Does the task repeat in cycles with a defined takt time?
Question 3 of 4
Is the work repetitive but without a fixed takt time?
Question 4 of 4
Does the operator wait for a machine cycle, such as a press, during the task?
Your result
Your video should cover
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.
Inside the guide
Before you film
The impact assessment, the worker notice, the union agreement and the message that keeps operators on board.
Who and what to film
The typical trained operator, the standard cycle, normal production and the condition that represents the station.
How long to record
Recording length by type of task, machine waiting time and why lengths should match across a batch.
Framing and camera handling
How the AI finds and follows the operator, when moving the phone is fine and what breaks the tracking.
Checks before you upload
The recorded segment versus the real cycle, setup time, fragments and the worst-condition trap.
Excerpt · Chapter 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.
Written for the people who film the stations
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.
Frequently asked questions about filming workstations
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.