As an ex-triathlete of 15 yrs ago, I raced as a Clydesdale, so you’re about the same size as I am. First, congratulations on embarking on first marathon and your weight loss. My suggestion as a big guy is to save your body as mush as possible, running on a big frame is murder on the joints. I would recommend cross-training as mush as possible, run & biking, swimming if you can, and core training.
Sense my last race I would bet there has been new and better training programs out there, internet has many ideas out there, just have to search them, and they are free. But I would say for a big guy, an interval training program would be best to save your body and lessen injuries. I forget what was the numbers were, but I would trained on a 20/60/40% and 30/40/30% program (recovery/core/high impact). The main goal was to increase lactate build up and aerobic conditioning, which will give you power and speed. Also, I see you are running 3-5 miles a day, don’t run blind just to put in miles, find a program that will help you in the long run like a light day (recovery day), core day (strength & endurance), high impact day (speed and power), by implementing the 20/60/40% rule and over time you will increase mileage and speed. As to the treadmill, it is a great avenue to train, but I would run on it with at least 2-3% incline to stimulate road conditions (resistance). A little about 20/60/40% program (after warm up), say you’re running a mile, 4x400mm=1,200mm (200mm slow/600mm pace/400mm fast), your pace, 8 min mile, would look something like this (10 min mile(200mm)/8 min mile (600mm)/6 min mile (400mm))=8min mile average over a mile run. You can use this formula in biking, swimming or what ever, and mix up your %’s like 10/30/30/20/10 (slow/pace/fast/pace/recovery) this is good for race simulations.
Last, before you run your first marathon, which I bet the Marine Corps marathon will be a big event lots of runners, I would run a couple 5k and maybe a 10K race just to run it, don’t worry about time, just run it for the feel and experience of a real race. My first triathlon race was an eye opener to what happens in the race, after it I made a note to all future races is to watch my pace with my time watch and heart monitor as in my first race, I over did it and hit the wall before the run was half over. So, remember set your pace and stick to it all through the race, and at the end you should feel a lot better then trying to keep up with some one else who may be faster or not knowing what lays ahead like a big wall.
