I am looking for a good iPhone 5 case for parkour. As I often climb up walls and something like this the iPhone should be protected well. I found the Griffin Survivor, which is actually perfekt but very very thick... Is there an alternative to Griffin Survivor, which is protecting well (also the screen) but smaller?
As you are aware, everything is a trade-off. Smaller case typically means less protection. Bigger usually equals more, obviously.
With that in mind, I have used an Otterbox, for rough going, and really like it:
It seems to be a solid build, and, although the rubber casing has gotten somewhat more loose over time, Otterbox does have a good warranty.
Now, this next thing is no match for a pocket, and likely as big as the Survivor, but perhaps you would like it:
If you desire an even more minimalistic approach and would consider carrying the phone in a pocket you could always go with my all-time case favorite:
This setup doesn't have a belt clip, but the case feels very natural in your hand - so you don't lose the iPhone feel, but also don't give up too much protection. Note that the back of the case does scratch some, but most of that is aesthetics. And the screen protector is terrific.
The ideal shell will be a custom molded, carbon fiber sleeve that you would drop the phone into (or similar thin case to totally enclose the device) and matching your desired level of bulk/strength ratio.
The larger a case, the more rigid it becomes, but at some point, it's too large for your preference.
That would be the smallest possibly package and you won't need to be looking at the device during parkour.
It would be the simplest to slide your phone into the case and you wouldn't have any trade off between clear case or one too large to fit in your pocket or backpack or wherever else you carry the phone. (I've seen runners tape the entire phone to their back or arm or leg and simply place the phone in a plastic bag for waterproofing.)