Quite the bodacious day to go out in the park for a run or better yet just slowly trot behind, oh snap. ^O^
Man that's some awesome booty and even amongst the many MLP works its awesome to see some the more anthro horses around here, bravo to say the least juzztice. Especially like the way you present her in the image, seemingly tired from her run but just letting you take in that glorious backside, well done.
Fine work can say though on the way you manage her animal characteristics with her human style of anatomy. Making great stride to show off her curves but still appeal to her unique character of the appeal of the tail, the awesome tones for the skin and heck even the animal nature of the face is done very well to draw you right into her sass, whoa!
Fine work to what can say with your coloring. Most of what I mean with that refers to her skin again and how you add the spots but even more considering the way you show off the shadowing and the direction of the sun, good tone work to what I can say the least here. Same want to cheer you on for the angle itself, giving that environment some huge realism with the sun beating down to even showing the soft and fluffy nature of the trees in the distance.
Could go on but its already plain to see you know what your doing juzztice, keep it up and by the way epic grinface you on your avatar, well done. ^o^