Health app iPhone 5S

Hello,

iPhone 5S iOS 11.2.5

Health app

Problem:

I have a 3.7 km walk to work every day. The Health app is tracking and reporting the number of steps correctly. Roughly 5000 steps. But the distance is not correct. The app is only reporting 2.8 km. The length of my step is not 56 cm (2800/5000). More like 74 cm (3700/5000).

I tried another app (called Stepz). I get the same number of steps - roughly 5000. And the correct distance - 3.7 km. This app is using a much better value for the length of ones step.

So something is wrong with the iOS Health app. How can I fix this? How can I set my step length to 74 cm?

Thanks, Richard