Did my third long run today, because of a football match tomorrow. Finished the week with 48 kilometers, perfectly within the 10% per week increase. It was really cold, but at least that forced me to go pretty quick. Pfitzinger's long runs are far from the boring and slow ones I did in my training plan last year. They're a real workout and I dread the summer with longruns up to 26 kilometers. Next week is the last one without threshold work and I'm looking forward to getting some speed into my legs.
Also the brooks shoes have officially been relegated to gym duty, I keep getting knee pains after running with them. Maybe it'll get better with some more wear, but for now they're sidelined.
All depends on your fitness level and natural talent. 5k is long enough that it doesn't require a lot of specific skill work to improve your time. I did a sub 19 5k last year while halfway through my (free) half marathon plan from runnersworld on about 35-45 km weekly. I did some light interval work (800/1600m intervals), but nothing specific to the 5k.
How much do you run right now? What's the fastest you can run 1k/1mile? Have you struggled with injuries in the past?
I run 5 times per week, always over 5km but never more than 10. No injuries except for shin splints whenever I don't warm up properly but I learned to deal with it.
I noticed a gradual improvement since beginning (started at 35 min) but lately it seems like I keep hovering at the 25 min mark.