I have a case now for several weeks in use and use it on average every am every other day. In addition to the normal jogging it is also used in the sprint training and keeps very well here on the arm when it is worn on the skin. Once a thin windbreaker or other training jacket is worn under it, it starts easy to slide, but does not interfere great.
I can only Bemengeln quality. I know that I may need earlier to buy a new case against the end of the year. That is partly a bit frustrating, but should not in principle be shied away now.
The iPhone 5s is operated by the protective film on the screen and it also keeps sweat and light rain was. Only things like the tab on the side of the cable or some seams suffer but very fast. Especially here, the tab for the cable.
Who wants to test whether a sports case for him is right and who is willing to replace it in less than 6 months who can access. For 'occasional sports' is definitely well suited the Case! It is well located, holds the iPhone securely in place and protects it from sweat and rain showers.