Duolingo provides these sentences in a health related context:
Are the children powerful. (given translation)
My sister is more powerful than me. (given translation)
The English translation provided is appalling. It brings to mind images of superheroes and radioactive rats.
Are these natural and unambiguous Japanese sentences, and if so, what on earth does 力 actually mean in this context? I suspect it means that the person has a generally healthy constitution; someone who rarely gets ill. But I can think of lots of other potential meanings both health and non-health related.