Posted: 18/02/2014 at 21:11
Tim, you may get injured if you long run every week as your not yet hardened to it like many here. If you only do two more really long runs and the rest are cut back long runs and or taper then make them run by time instead. Eg the next one at 3hrs 30 and the last one at 3hrs 45min (Ish)
a rule of thumb is to run 22 Miles in the time you expect to run the marathon at. So if you run 22 miles in 3:50 you will run at 10:30 pace average and get real benefit from time on your feet. It won't be easy but you will feel better at 17.5miles
remember this too. Your better only to have done 3x20mile plus runs and turn up at the start line in good health rather than do 4-5x 20 miles and be at the start line injured as you have forced too many long runs in your plan and over done it...
good luck !!