Testo Boost X Pre-exhaust is a useful strategy you can use if a certain muscle group is giving up on you early and reducing the effectiveness of subsequent exercises. For example, your biceps may tire faster than your lats when you are doing row exercises. The way to get around this is to isolate the problem by doing an exercise that targets the problem muscle group. In this case, you can isolate the lats by doing lat pulldowns. If your lats are pre-exhausted, your biceps won't be limiting you when you go to do your rows.