Different Training improvement?

[mint]

When I lunge my horses (same time, gait and place), some of them improve their stamina by 7 and some only by 1. I have noticed this happening with other stats too. Why does this happen?

[Nate]

As a horse gets more fit, you get diminishing returns on your training. Early in a horse's training, it's common to get 10+ points in one session. Much later, even 0.1% can be a big accomplishment.

[mint]

Ok, that makes sense. The horses with the most improvement were the young/new ones. Thanks