I play tennis in the spring and want to start getting in shape for tennis soon.
I'm currently on 5/3/1 and eat at about a 700 calorie surplus per day. I also don't do any cardio. Come winter I'm gonna eat at a 500 calorie deficit with cardio, but I want to know the most efficient way to develop long term endurance.
A lot of times I'm playing outside in the heat for many hours, and I need the fitness to be able to do that. Currently I can barely get through a set without being exhausted, and as I've been bulking my conditioning is even worse now. I'm also not very flexible.
Ideas for the best way to get in shape, while keeping my strength gains (and possibly even seeing them go up, please?)?