The Apple Buruma Project (aka Apple Bloomers) is a parody project poking fun at the traditional mahou shoujo (magical girl) genre. That's why Apple Bloom is a Magical Girl, Sweetie Belle is a mechanic that rarely opens her eyes (which is an anime trope again), and Scootaloo is a farmer but also an over-powered fighter. Most of the times the adventures they partake in is a result of Apple Bloom messing around with magic.
Hope I managed to explain it, if you have more questions let me know. ^^
(Btw Buruma is a type of running shorts, exactly what Apple Bloom is wearing)
The Apple Buruma Project (aka Apple Bloomers) is a parody project poking fun at the traditional maho