looking for advice on changing a toddlers diaper

Hey guys! So I have a 21 month old girl and she's honestly a really good toddler. Minimal tantrums, sleeps well, eats well, she's smart and affectionate and plays well with other children. I have been having trouble changing her diaper. Its like a 30 minute ordeal with screaming and kicking and naked poop bum trying to run everywhere. Any advice on how to keep her calm for those diaper changes? We are planning to start potty training in November when shes 2. I should also mention she's very tall and heavy for her age. I. Not 100% sure of her height (she won't stand still to be meaured) but she weights about 40 lbs.Thanks :) via /r/Parenting http://ift.tt/2a9JGJO