Swim/Bike VS Swim/Run Bricks

Hi to all you experienced Triathloners!!

I'm in the throes of training for my very first triathlon season.. a mini in August and an Olympic in September. So far the training has gone pretty well. Its quite different from me in that my previous exercise life consisted of much more weight training/shorter cardio sessions. I've been lurking for a few weeks and have enjoyed reading all of the helpful info.. its a great forum!

My question is in regard to the Brick schedule. Most of the training plans that I have seen always pair up swim/bike together as opposed to bike/run.. Why is that? In my world of strength training, it seems to me that bike/run should go together one day , than swimming the next day. My reason being that if you are exhausting your legs on the bike/run day, than you should swim the next day to let your legs recover a bit before doing it again.

Also, because that bike/run transistion is challenging, would it make sense to train that way to get used to that feeling of the switch?

I'd love to get a better understanding of why alot of the plans do it this way.. Thanks so much in advance to anybody who can give me some enlightenment!

Take care, Lynn