I noticed that your German translations are not really complete and ready. Some strings are translated (like HR = Puls, or Power = Leistung), but most aren’t and those which are translated, could be tweaked a little bit.
Many software developers - especially those with a community of devoted users - make their translation strings publicly available and allow users to translate them for them (Facebook being one example). I am a Product Manager in SaaS myself, and have always preferred relying on native speakers within the company - or customers if possible.
So, why not make your translation strings publicly available and let the community do the (better) job for you? Just highlighted some of the issues in red (the green ones are ok), but there is more non-translated text of course within the app of course:
Just a friendly offer, but I am sure those who are from outside the US would be happy to help you internationalize your product.