Shifting is not a question of hand strength!

A shifter that requires any sizeable amount of effort when correctly set up, tensioned and sized for the user is a badly designed shifter. Shifting is not completely effortless, but it should be nowhere near a question of having enough hand strength. That's just absurd. I'm rarely this absolute about things, but this I truely believe.

I have struggled with many shifters, but I've fixed just about all of them by taking them apart, lubing them, tweaking position and/or rerouting cables. I have big strong hands, but shortish fingers, and easy shifting has a lot to do with correct positioning and proper reach. It's a limited range you're working with, and the shifter should be designed for easy use within that range.