It is going to depend somewhat on what your local PD requires for the initial fitness test and also what the training looks like once you have been hired. When I went through (keep in mind I’m in Canada and your process will likely differ somewhat) the initial fitness test consisted of an obstacle course (running, jumping over walls, dragging a 150 lb dummy for distance etc all of which was done wearing a weight belt to simulate the weight of a duty belt) followed by a shuttle run which added up to over 1 km to get a minimum passing grade.
Once hired, I did 4 months of recruit training - classroom stuff, scenarios, pursuit driving, firearms, and so on plus daily fitness. The daily fitness was mostly running based and we were doing up to 12 km runs by the end of the training. There was also some strength based stuff but this was not anything that your average, reasonably fit person couldn’t handle.
In my case I showed up at almost 210 lbs (at 5’6") and quite strong but this actually worked against me. While I did some running to prepare I didn’t do nearly enough and it showed. I lost 28 lbs during training (our training also consisted of sleep deprivation and frequently missed meals). The extra muscle mass that I was carrying at the time was a hinderance given the circumstances.
If your service has a heavy running component to their training do yourself a favor and prepare specifically for what is going to be required. Other types of conditioning work will help obviously but nothing prepares you for long, shitty, boring running like training the specific task itself. Keep in mind that these runs may also be done in boots or with a weight belt or vest.
Contact your PD’s recruitment office and gather as much information as you can about the preliminary fitness testing and the fitness component of recruit training and then train as specifically as possible for what is going to be required. Once recruit training is through you can then concentrate on strength and hypertrophy training again.