So i have finally been gaining some mass and putting on some weight. But now i have a problem. Lately, i have been lifting heavy with low reps, but now i need to get my endurance. Mainly to increase overall strength and endurance, getting ready for the navy. I need to get in the best condition of my life, but i still wouldnt mind putting on some more size. So i was thinking of doing like ever week or every other to switch workouts. Lets say one week to do low rep, high weight. Then the following week to do high rep, low weight. Some variation of that. What would be best?