How much friction should the zoom have?
That doesn't sound right. All my Canon zooms are very smooth and take almost no additional "break-out" force. What lens do you have? I would suspect there is a problem with the lens.
ps - there are a few zooms lenses that have a zoom lock - check to see that it isn't engaged (one example is the Canon 70-300 IS USM).
Jim 'Carnac' Carnahan