In Reply To:
I am coming off a an Ironman and 2 seasons of long distance triathlon and marathon training. I have now noticed my long runs (being shorter) are taking much less out of me and are feeling relatively easy.
Should I just enjoy this or is there an appropriate way to work some speed into my long runs. Should I just gradually increase the overall pace of my long runs, add some tempo efforts in the middle, something else? Any advice would be greatly appreciated.
Aside from intentionally running hills, the best approach is to add the intensity to the end of the long run. Why? If you force yourself to do 'tempo' in the middle of the long run after having done only easy long runs up to this point in your career, six weeks later you might find yourself over the edge. For you (with two years experience) there is too much of a risk that you might get to the weekend with tired bike legs and run tempo in the middle of the run during a week when your body needs to just put in the miles. Maybe in a few years and several thousand miles later you will be ready for weekly intense long runs, but not yet. However, if you feel good you could (and should) close the run with anything from 2 miles at 1/2marathon pace to 10 miles at marathon pace. Nothing wrong with letting it rip to close out the run on a good day. If you don't feel good and run steady you have still gotten your mileage in.
I would not increase the overall pace of your steady long runs unless your body is telling you the current pace is way too easy. Your steady pace 'is what it is' and it will change when you are ready (i.e., Don't go from 7:45s to 7:30s just for the sake of running 15 seconds faster).
For a multisport athlete with only two years experience who will come to the long run with biking miles in the legs, it would probably be a good idea to limit the 'intense' long runs to once every two or three weeks. Strides in the middle of the run or afterward are always good (I believe someone mentioned this above).
Another under-utilized option is to make sure you get in a long warm up and cool down during your mid-week faster session(s). Instead of the usual 10 minute warmup and cooldown, build up to a four mile warmup and six to eight mile cool down.