So let me start off by saying that for the past few years I've incorporated weight training during the winter months. I have done the traditional Friel plan a couple of years and last year I tried a more overall body/core plan focused on building functional strength. I would say that last year's workouts where I used a balance ball and incorporated my core was way better than the traditional weight approach.
But even still, the only benefit I felt was from the core/upper-body exercises. I definitely felt much stronger through my back and my ability to support myself on the bike was great. But I've never really felt there has been a benefit to the lower body exercises. Let me also say that I already have a fair amount of muscle mass in my lower body.
So what I'm wondering is if this year I would be just as well off swimming instead of doing upper body exercises. I'll still do a bit of core work after the swim, but it seems that 40 minutes of continually stressing my upper body is way better than a bunch of 60 second sets. Plus the added benefit of getting a bit more cardio in.
If you are prone to build or have a lot of muscle mass already, swimming would be your best bet. Tons of functional muscle (long and lean) and a alot of core work done during your swim. The added benefit of cardio especially deep breathing exercises and lung capacity. Add some pure kick exercises during your sessions and you have a nice total body workout.
