Huh, interesting. I try to lunge (I spell it lunge instead of longe) our heavier mini every day in the summer to lose weight, and our younger energetic mini for exercise ever day as well.
I used to use a round pen when I was training my own riding horses. I did round pen DJ (Jaci's sire) some as he wouldn't let me touch him when I first got him and showed no signs of coming around even after months of living here. But I use it for training, not exercising. I never cared for longeing, but it has uses.
I use to round pen my riding horses and boy did they need it! LOL! I don’t round pen my little ones because I don’t have a round pen anymore. I mostly ground drive and then i will do a circle or two if needed.