Extending 1/2 marathon training plan to include more x-training days?

So... Runner's World magazine (August 09) has a nice beginner half marathon training schedule. *Nice* for me because it includes two x-training workouts per week. I am very injury prone, so have switched to triathlons, so this would work nearly perfectly as an off-season goal.

Except... I'd really like three days of running and three days of x-training (2 bike, 1 swim, and then 2 swim, 1 bike the next week). It's a 10 week schedule. Would there be any disadvantage to extending the schedule to 13 weeks and doing the 3 run/3 x-train? It would be nearly the same number of workouts with less weekly mileage.

The only issue I can think of is that a 13-week training plan might be a tad long... but the lower running frequency should balance that, no? I should add that I haven't been able to run over 6 miles without pain since 1990. But I think if I build up gradually it should be able to do it.

Probably over analyzing... need outside perspective...

Zia - I'd like to comment on this but I'm shooting in the dark without seeing the training plan. I tried to pull it up on-line but several are available. Would you be able to find a link to the plan you're looking at?

Ah, buried, but here:

http://www.runnersworld.com/article/...X5X6-7,00.html

Consistency in running is super important and this program has 3 days running built in on some weeks and 4 on others. I would say that you don't want to do less than 3 days per week running. On the 4 days running weeks I would switch out the short easy run on Friday for another cross training day. You might even want to switch the longer run to Friday and do your extra cross training day on Saturday. The big thing would be to not have a long or hard bike workout the day before your long run. Swimming would be fine though.

A program like that would get you to your goal and you wouldn't have to extend the length of the program. Especially if you're getting in a ride every week that is a little longer than the total time that you would expect the half marathon to take you.

Hope that helps.