This is the central risk in the whole subject, and it deserves stating plainly rather than as a caveat.
The mechanism
Rate pressure changes method. Under time pressure people take shortcuts that are individually rational and cumulatively harmful.
They skip preparation: fetching a ladder, adjusting a platform, getting help for a heavy item.
They adopt worse posture: twisting rather than stepping, reaching rather than repositioning, lifting from the floor rather than from a raised surface.
They stop taking micro-pauses, which are how the body recovers during repetitive work.
They work through minor discomfort, which is how minor strains become injuries.
None of this is carelessness. It is what happens when the achievable rate and the safe method are in conflict.
What the evidence supports
Manual handling injury risk rises with pace, repetition and duration. This is long established.
Force, posture and frequency interact. A load that is safe once an hour is not safe once a minute.
Recovery time matters, and continuous work without variation removes it.
Musculoskeletal disorders develop cumulatively, which means the harm from a rate change appears months later and is not attributed to it.
The test for any standard
If meeting the target requires abandoning the safe method, the target is wrong.
Not "the worker should manage both". Not "the method is a guideline". The target is wrong, and it should be changed.
Apply the test deliberately, by observing the work as performed at the target rate and asking whether the safe method survives.
Ask the people doing it, who will answer accurately if asked in a setting where the answer has no consequence for them.
Practices to avoid
Targets set from the fastest observed performance, which nobody sustains including the person who produced it.
Continuous automated tracking with escalating warnings, which is the arrangement most associated with harm and is under regulatory attention in several jurisdictions.
Ratcheting, where the standard tightens as performance improves, teaching people to conceal improvement.
Uniform targets across people with different roles, experience, physical capability and equipment.
Targets without allowances for rest, personal needs and unavoidable delay.
Penalising time away from the workstation without distinguishing why.
What a defensible arrangement looks like
Standards used for planning and costing, at team level.
Allowances included and stated.
Derived from observed data across many instances, segmented by work content.
Validated with workers and with a route to challenge.
Reviewed whenever layout, mix or equipment changes.
No automated discipline from rate data. A human decision, with context, and a route to contest it.
The measure that should be watched alongside
Injury and near-miss rates, plotted against any change in rate expectations.
Reported turnover, which responds faster than injury data.
Absence, particularly short-term.
Discomfort reporting, which is the earliest indicator and only exists if reporting is safe.
If a productivity improvement coincides with a rise in any of these, it is not an improvement. It has moved a cost from the operations budget to the people doing the work, and it will return with interest.
Watching the indicators alongside
Any change in rate expectation should be accompanied by a set of measures that would show harm.
Discomfort reports, the earliest indicator and only present if reporting is safe.
Short-term absence frequency.
Turnover, particularly among experienced staff, which moves faster than injury data.
Near-miss reporting rate.
Injury rate, which lags by months and should not be the only measure watched.
If productivity rises while any of these moves the wrong way, it is not an improvement. A cost has moved from the operation to the people, and it returns later with interest.
Observing the work at the target rate
The practical form of the safe-method test, and it takes an afternoon.
Watch the task performed at the target rate, by someone experienced.
Note every deviation from the safe method: the lift assist not fetched, the twist instead of the step, the reach instead of the reposition.
Ask whether the deviations are necessary to meet the rate.
Ask the worker, who will answer honestly if the answer has no consequence for them.
Where the safe method does not survive, the target is wrong, and that conclusion should be recorded rather than negotiated.