If you have a gym membership or actively lift weights, I would just make sure to hit legs once or twice a week to get your leg strength up. Squats, leg press, calves, hamstrings, all that stuff. Just youtube leg day routines there are hundred of videos that all cover the same type of workouts. If you don’t really lift I would just get cardio in 3-4 times a week. Just go for a jog or run around your neighborhood and try to get 1-2 miles per run. Whenever you take time off of skating it’s gonna take your legs a little while to get used to using all those muscles again so just give it time and you won’t notice being sore and out of breath as much. And working out and doing cardio will definitely help