You need to put some aspects of your running into “maintenance mode,” where you're just doing enough on that physiological feature to maintain the attribute that you've developed while we progress in another area. That could be your endurance and top speed–or, if you're going into a race with a lot of vert, it's hard to try and increase your speed on the flat, improve your ability to run in the steep mountains, and stretch your endurance all at the same time. It all depends on what the goal is and where that's placed. You should choose to keep some things in maintenance, which means you can cut down on the time that you focus on that aspect of your training, and put other things into focus progression mode.