been on many a manual handling course they only tell what anybody
generally with an ounce of common sense knows ,your more likely to wear
your joints with the repeated action of using the pole when scrubbing than
holding the brush slighly off the window to rinse which you do less often.
then again your just as likely to wear you leg joints out walking down
the street everyday, over time aging and fitness and genetics can also factor into
arthritis or rheumatism in fact i imagine you would be more likey to get in your hands from the daily gripping of the pole
most advice you get about these things are only general and not specific
to an individual.you are better off working to within your own limits whilst
also keeping yourself fit.
holding the brush slightly off the glass is well within my limits totally comfortable
with this and find im happiest working like this and highly unlikely i will
get an injury from this
i use an

sl brush