"Are you Sure?" You bring up valid points and tough questions that I have to deal with, because the truth is, you are absolutely right. An attentive reader will know who I am based on my following reply, but so it goes. I've listed my training, I'm proud of what I've accomplished, I am confident in the program I have designed for myself, and I hope my insight helps others reach their goals as well. I'll start off with PRs:
1500: 3:49, 2010
5000: 14:10, 2010
10k: 29:50, 2011
1/2: 1:05:57, 2014
Full: 2:18:35, 2014
I have run 9 marathons with the following progression and notes on each one.
2:33, 4 weeks after college, ill advised from new coach
2:27, First real attempt, fueling issues threw up at 18
2:24, got a free entry so ran for fun started really slow (6:10) and moved up
2:24, second full attempt threw up at 23
2:20, 6 weeks after previous race, decided to redeem myself, perfect weather, great day
2:23, perfect weather day, went out in 1:07:30 for half, blew up. in reality in 2:19:00 shape
2:18:35 , perfect build up conditions, 26deg at start winds up to 22mph, thought in shape for 2:15:30, beat a few 2:13 guys
2:20, 40deg 15mph winds and rain shut it down last 5k when i knew i wouldnt get the time.
2:21, 2014 Boston weather needs no explaination, i thought I was in shape for 2:17:00
Outside of bad luck with weather during races there were a couple things that hindered my development post collegiately. Biggest thing is I moved to the south for 2 years(i have since moved back) and cut my mileage by 30% because of a new coach and group I joined. After that I started being coached by a former teammate, who got me back closer to college shape and coached me to the 2:20 using primarily Lydiard schedules. In Nov 2013 life got in the way of a coaching relationship so I began training myself. I still use him as an advisor and routinely bounce ideas off him, he helps rein me in at times and convinces me to rest.
The second hindrance was adjusting to work life after school. I went through bouts of depression and gained 20 lbs. As of fall 2014 I got back to college weight. I still work full time, but have a flexible, low stress job.
Now to directly answer your questions, 4x5k is a very hard workout, i think it is necessary to prepare for the last 10k. last buildup I averaged 16:09 5k at 5500feet altitude with a 11 second/mi conversion, that suggests 2:17:00. I think I was there at Boston without the headwind.
Maybe this sounds like a list of excuses, it probably is. It's what happened. I definitely have gone through bouts of overtraining and race results showed. I think I have avoided over training the past year and a half though. Sometimes, it takes a while for race results to catch up to training.
I have 3 more shots going forward at the standard. I have learned a lot throughout the process and thoroughly enjoy every bit of it.