Week level aggregation

Not sure if this really makes sense, but I’m looking to get a weekly/monthly understanding of work rate (ie. kj/hrs). I have created a custom calculation at an activity level, so I can see per activity kjs/hours - however I would like to be able to see for example (Total weekly work / total hours for week). I can display those two metrics on the fitness page, but wondered if there was a way to do a calculation at that level?