That would depend upon where your interest lies. Are you interested in the science, then perhaps you should take out membership from the NSCA as well as the ACSM.
If you are interested in what is happening in the industry in a general way a subscription to IDEA might be a good place to start.
Hi Demarques. I like the NSCA’s Essentials of Strength Training and Conditioning. This is a really thorough text book. However, I must say that in my opinion, the best way to “stay up to date” as your question asks, is to read and follow some of the research (articles), journals and blogs from reputable fitness organizations such as NSCA, ASCM and ACE.
Because of the long lead time to get a book published and released, I do not think that reading books is the best way to be ‘ahead’ of the training and fitness curve. The newest, most up-to-date information is found in the journals, not the books.
My two cents 🙂