According to the Urban Dictionary, "HIP CHECKING" means:
"to physically impact someone at the hip by using the hip. It is a versatile action but can especially be used as a greeting or to show playful aggression or disagreement.She hip checked him when he told her that chicks were weak."
In the context of derby, it is an unfortunate effect of a hit turning bad. Tested. I will not display a picture of my hip because there is nothing to see, not even an itsy bitsy tiny bruise. It's been one week and I suspect I may have stretched/torn an ab. Time will tell.
In the meantime I have searched the Internet and asked information around about crashpads. I was looking for a light one that would just cover the hips and I stumbled upon volleyball items. I am impatiently waiting for the McDavid 9230 hexpad shorts. I am counting on them to cushion the repeated shocks during the everlasting hit sessions at training! FML.