General Fitness & Nutrition: endurance training

When you start increasing your mileage, switch back to doing intervals of walking and running. I usually do 3-5 minutes running, the 1-2 minutes walking, then repeat for the distance. When I do a longer run, especially if it's a long distance I've never done, I don't worry about my time, but just acomplishing the distance. Early on I found it took a lot of discipline to stop running after 4 minutes and take my 1 minute walking break. I thought, "If I can run 3 miles the whole way, why stop when I'm not exhausted?" But I found that I felt better after my first 5 mile run doing the intervals, than after pushing a 4 miler running the whole way. You will also decrease your chance for injury by giving your muscles time to recover in your runs.

Also, don't forget to stretch afterwards, drink lots of water, maybe a little sports drink, and eat something within half an hour after running. It will make the next day that much more compfortable. Also, don't push it too hard. If you do a long run on Sunday, take Monday off completely or do something gentle on your legs (swimming, maybe some yoga).  Rest days are just as important as running days, do not neglect them. 

 There are a couple of great books on indurance running that take a fairly laid back approach that I appricate. One is Marathoning for Mortals, by John Bingham and Jenny Hadfield. The other I'd recommend is Galloway's Book on Running by Jeff Galloway. He advocates running with walking recoveries; he developed a style of training called the Galloway Method. 

The most important thing is to keep at it. Figure out a schedule, know which days you'll be running (e.g. every mon, wed, fri) and which days you'll be resting. Drink some water before running (but not too much or it'll cause cramps). I know a lot of people who listen to music when running, it helps keep them motivated.

The best thing to do is keep strong. Every time you run, really try to improve over your last day's work. That might mean, taking less breaks, going longer without breaks. Stay motivated and good luck with your runs!

two words - interval training

I was in the same situation as you where my limit was around the 4-6 km mark - after reading a lot of research into building endurace i found that interval training was much much better at improving endurance than trying to work at lower intensity. This is not just my opinion it is proven by the american college of sports medicine - the most respected organisation for sports research in the world. Late last year after about 4km i was ready to die. Over the first 6 months of this year i interval ran (10 x 100m sprints at 95-100% intensity with 10 x 100m walks in between) with a 500m jog either side to warm up/cool down 2-3 times a week. I lost 10kg (i was not overweight before but my body fat is now 8%) And recently to test my theory i went for a long run - after 16km i decided to stop cos i was running late for an appointment. This was 10km further than i had ever run!!!.

i'll not solve your problem, but give you something to think about. i mainly run cross country marathons/fell runs and further, so a lot of my training runs before races are between 20-30miles and can  last 5 hours. i find that the thing that makes me get through without stopping is just me, telling me that i will not stop! hope it doesn't sound too pompous, but it's a state of mind worth developing. i don't know any books or techniques to help you attain it , but next time you feel like stopping, just get angry with yourself and keep those legs moving - doesn't matter how slowly, just not walking. eventually it'll be second nature...

This is an interesting conversation to me, because I just finished a 5k race.  I did well (for me).  I PRed.  Finished with a time of 27mins 10secs.  Prior to the race my PR was 28mins. 

 I'd trained for this race by running longer runs (4 and 6 mile routes) at a slower pace and doing shorter runs (2 and 3 mile routes) at a faster pace.  It seemed to work because I steadily improved.  (When I began I was running 3 miles in 35 minutes and by the time of the race was doing 3 miles in 28mins.)

 But, a strange thing has happened.  Now that the race is over, I'm having trouble completeing my long runs.  The last two times I tried running 6 miles, I ended up walking large portions of my run.  It's like my endurance base is shot after the race.  I don't get it.  It seems like, similar to alliyo, I'm stuck at three miles.

 I'm going to keep at it, but, I have to say, it's a little discouraging.

I'd say don't walk. It might be hard, but stopping during a run makes your heart rate drop pretty dramatically effectively losing a lot of the work you've done. I'm no professional, but thats what I think. The only other thing is not to increase your mileage too quickly. 10% increase a week is considered the max.