Do you understand your workout?

Everytime i set out a training workout, i bound to get the results that made me upset. Sometime i asked myself do they understand what i want? Or is it my explaination very poor; of course i understand my command of English is "pte ltd". Or maybe they (athletes) like to do that they want to do?

I never believe everyday is hard training, everyday your foot got to slam on this "concrete" track a thousand times. I gave out light training, a training easily to achieve the end result but seem no one understand its effect.
I let my 4 groups doing different distances at different pacing, ranging from 1'40 to 2'30 per lap. I understand this can easily achieved by most of them, yet they don't seem to understand what is it for. If i don't explain over and over again, i probably get a much faster end results and most of them come back with their max. effort. Just for an example, group 1 doing 3.5km @ 1'40/lap; very easy workout, just maintain around 1'35 to 1'40, that it, you end the workout smiling. Then from 3.5km, we progress to a longer distances. If every slow steady run training without much effort to end it, you'll be doing a 41'40 for 10km coming home smiling. How many of you PB is 41 minutes? Probably, you fighting very hard to achieve it, right?
If you can progress to 10km running @ 41'40 without much effort, so what will be your 10km timing be if you fight on a faster pace?

How many of you understand what i'm doing? SIGH!

Robin