Sprint mainly defines the length and style of course. The park and urban series in Brisbane are normally a bit longer in distance than a typical sprint course. Don't worry about whether you can run or can't, all the events cater for runners or walkers, and you won't get in the way of anyone serious. Jump on
www.oq.asn.au and have a look at the upcoming events. There is a new urban street series starting in May that you would probably enjoy. There are two sprint races on tomorrow which I think you can enter on the day. They are part of the national league series, go along to one of them if you're interested in seeing the elite side of competition