Q: reply to 1258, im 15 kinda with manboobs you said dont worry about it though and just try to get much muscle as possible. im the guy a couple days ago that asked about my training routine if its overtraining and you referred me to your 4 day routine

A: OK, now I know who you are. With your existing routine as you gain strength and muscle and as you lose fat your muscular endurance will automatically improve too. Because you train quite a bit already I would recommend doing little additional endurance-specific training. Alternatively you can decrease your current weights training to 2-3 sets per exercise and then do some more endurance-specific training.

But if your primary goal is building muscle and burning fat, focus more on the heavier weight training that you do now than on endurance-specific stuff. Like maybe spend 4 hours/week on heavier weights and 1-2 hours/week on endurance stuff at most.

And don't forget about good diet as you train -- even if you are not trying to actively lose weight healthy eating will still make a huge difference in building new muscle and burning existing fat.