Uhmmm... I'm getting a bit confused here... Duolingo sometimes translates "(sie for example) laufen" as "(they) run", others
as "(they) walk"... and I'm getting really really confused here...
It actually
can mean both - and no, I'm not sure that there are
only two categories in the first place. "Laufen" can be applied to the hobble of a convalescent ("wenigstens kann ich jetzt wieder
laufen") as well as olympics-grade sports ("der Weltrekord im 100-Meter-
Lauf wurde gebrochen") - but nonetheless using it
everywhere will lead to misinterpretation sooner rather than later.
If you want to refer to a specific speed level, use another, equally specific verb (off the top of my brain: schleichen, humpeln, gehen, eilen, hasten, rennen, hetzen, rasen, in order of increasing speed but not necessarily with
well-defined differences).