Car tests surfer’s nasty pressure injuries (6,9)

I believe the answer is:

stress fractures

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'pressure injuries' is the definition.
I know nothing about this answer so I can't tell whether this works.

'car tests surfer's nasty' is the wordplay.
'nasty' is an anagram indicator.
'car'+'tests'+'surfers'='cartestssurfers'
'cartestssurfers' with letters rearranged gives 'STRESS FRACTURES'.

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(Another definition for stress fractures that I've seen is " Results of marathon perhaps".)

I've seen this clue in the Sydney Morning Herald.

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