Ciao Stefano – a major objective when focusing on your SPM while running, is to progress it as you go through your run workouts. Any type of run, easy, tempo, hills, long, ect.
Trying to maintain a certain SPM from the get go, can be challenging and over whelming for most age groupers. So starting at a lower rate, then increasing it, you will be able to get the most out of yourself. All the while touching on a range of SPM’s and being able to find suitable range.
In my experience, of observing SPM data on Garmin Connect almost daily, is that tall athletes naturally have a lower SPM and shorter athletes naturally have a higher SPM. It only makes sense. So knowing yourself, then working with what you have, will be key to finding an optimal range!