Either Kim or miles

Can you elaborate why this is confusing or difficult?

I've used a few of the Garmin training plans, and have never seen this as an issue. The watch tells you what the distance target is, and it counts down until you reach that distance. All of the values on your watch show up in using the distance units that are selected on the device... i.e., if you're using Statue distances, and the workout on Garmin Connect says to run 1km, the watch says run for .62mi.

So this is kind of a US thing. For short running distances (e.g. less than 1 mile/km, e.g. track events), metres are used as a standard. e.g. Everyone talks about running 100m/200m/400m/800m on a track. For longer distances they use miles.

Canada is kinda similar -- even though we're supposed to be fully metric, we use feet/inches for people's heights and pounds for weight. But we use km for distances.

As a Canadian who consumes a lot of American media, I just try to remember that 1 mile is about 1.6 km.

I'm sure this isn't helpful, but:

Great reply mate thank you, and pretty funny too really. In Australia there are a few things that are still clinging to Imperial measure but in the main it is all the same.

The mixing up of the two forms of measurement is pretty crazy IMHO.

I grew up during a time where they were trying to get the US to go metric.  They put road signs up with both, things had sizes in both ml and fluid oz's etc.

As of right now the only thing that really stuck is you can by things like soft drinks in 2 liter bottles.