I've got no experience on 3-AD quite yet, either. However, from reading the logs on the product, many did note that endurance did increase while taking it. That might definitely help you out.
The downside is that many also noticed a good deal of delayed-onset muscle soreness (DOMS). That would definitely hinder your type of training. It's a tough call as to whether or not this will help the exact way that you need. The pumps that many noticed were quite long lasting, and they definitely would not help.
If you are looking into a PH for use in your training, SuperdrolNG might be a better option. It may not have the muscle-building capacity that 3-AD does, but it is a lighter PH with a stimulant mixed in to keep you going. I'd say that it would be quite good for increased energy, leading to endurance. Take a peak into it a bit and let us know if you have any questions. We'll be glad to help you out!