"just an fyi. i never said i was good. i don't ever expect to get any better, especially at 5K. I ran 2:23/22:30 in high school. guess what, three years later I run 2:10, and sub 5. I could care less about my 5K, i have raced it on the track like twice. and i run 50-60mpw, Quality not quanity. i never said i was going to be an all-american or win a major conference meet. but then, again, I am also 5"4 and weigh 120 so what do i know about being a good runner. sorry you are not a woman and withstand more pain. I have run with a broken foot and compartment syndrome, so now yes 10miles at 6:45 does feel easy."
I didn't mean for you to take my comments personally - I wasn't saying you weren't good - obviously 17:30 is more competitive at the college level for girls than 15:45 is for guys. 2:10 is good, but this is, again in comparison to the best in the world, like a guy running 1:57. Again, don't let the lack of depth in women's running fool you. I am simply saying that on a world-best scale they are equivalent and one reason why (and I have observed this running with many girls at your level and faster) is that girls UNIFORMLY run their easy days way harder than they need to and compensate for the fatigue by not making an effort to experiment with higher mileage to find their personal sweet spot AND by not running enough workouts at a properly challenging proper volume, pace, and shortness of recovery. And they also don't do AT pace tempo runs (or parts of runs). I would argue that speeding up one or two of your runs (or parts of runs) each week considerably while slowing the others (and making them longer) will be more effective than the training monotony of running medium hard daily. Someone needs to dredge up the interview with David Krummenacker where he talked about improving by adding mileage and more strictly delineating hard from easy runs.
For example, I am coming off a mild injury and haven't been able to work out for a few weeks. This morning, I did 12 miles on a hilly measured road course that has 10 miles that corresponds to a local certified race course. I ran the first 8 at just normal run pace and it was like 7:15 pace and that was just normal - didn't feel as slow as I know I sometimes run. Did the last 3 miles fairly hard in 5:20 each. Don't see how on earth you can call 6:45 easy if you can't just at random speed up 80+ seconds per mile. 6:45 for 10 miles is "easy" but 5:45's for 5k is race pace? Hogwash.
This "quality not quantity" s*** is just wrong as has been noted. Runs are either aerobic unless they are fast enough to be AT. High-end aerobic runs are no more "quality" than low-end aerobic runs (there are a few exceptions such as the second half of long runs where you can con your body into getting AT-type adaptations at high-end aerobic paces) and if higher mileage gets you injured, it is because you are running it too hard. I don't care if you are a miler, you would benefit by periods of higher mileage and some real AT work. It only appears not to make sense on the surface if you don't understand what is going on at the cellular level.
Next time you enter a base period and aren't going to be asked to race for a while, I challenge you to add about 20 miles/week to your regimen, slow 5 runs down to the 8:00 pace range and speed up two to the 6:10 pace range and see the difference.