Improving your strength and endurance requires techniques where you can incorporate weighted pull-ups in preparation for a PT test. Stew Smith suggests the ‘pull-up push’ where it requires you daily pull-ups for ten straight days then a three days’ rest and recovery. You will see results on the 14th day where you can increase your normal weekly volume by 200% or more. This will help you quickly add repetitions to pull-up and push-up tests with no additional weight by using bodyweight calisthenics.
Source: https://www.military.com/military-fitness/ask-stew-improving-weighted-pull-ups