Yes, I remember the episode very well. I saw it not too long ago on a station where Emergency was in syndication.
I remember seeing the episode when it first aired back in the 70's, and I thought I remembered it being a great fight. But it wasn't.
Squad 51 was called for a rescue at a school. No further details were relayed by the dispatcher. When Roy and Johnny got there, there were two female field hockey teams battling it out all over the field. But it really didn't show much of anything. There was one promising part, where two rival women were standing right behind the paramedics where they were working on another girl. The two women smashed at each other with their sticks, and before they even started to fight, a sheriff's deputy broke them up.
If you check the IMDB you may be able to find which episode it was. And youtube may have the fight as well, but I wouldn't waste my time.