Why does my kitten like to play rough with my brother, but not me?

I've noticed that my Kitten tends to get more wild and playful when my older brother comes over, but with me she likes to sleep on my lap, play with her toys, and snuggle. While with my brother, she perks up, bites playfully, and runs around the house like a crazy cat. Its not like I want her to play rough with me (it hurts ) but I was thinking, does she ociate him with play and me with relaxation?