These times in carbon spring shoes? So it's like breaking 20 min and trying to go sub 19..
I've run 5k in a range of shoes from the reebok floatride to the saucony endorphin speed to the vaporfly 2 and 3. The vaporfly made very little difference over 5k, if any.
I recommend saving your money unless you're racing a half or full.
I have run 18:30-19:00 off nothing more than 20-30 miles a week of jogging at 8-10 min/mile.
But to run sub 18 I have to do hard workouts at sub 6 pace.
Why is that?
Well....the key is 1830 was your best, regardless of what your training was. So either inc miles or quality is the only way to drop. Some specificity was the only thing u changed. Makes sense. Now go run 30+.
Still all wrong. Slower isn't the answer. TWO MILE REPEATS? Who filled your head with so much junk? You need to be shorter/faster stuff, including hills. 150-600m. No long runs, no mile repeats.
600m hill repeats once a week so you are breathing really hard at the top walk down
one day of 150m repeats jog
one day 3 x 1 mile at 550 to 610 pace
between the above, other days cross country at a slow to medium pace if you feel good.
take a day off
reconsider
this is free
i am the author of the new zealand middle distance training method circa 1978 sold through runner's world.
which is based on quax, dixon, walker, lydiard, and most of all Arch Jelley,
The difference between 18:30 and 18:00 is about 3 percent. No two runners are the same but running 30 comfortable miles a week over a long period of time may get you to 85 percent of your max potential, that leaves room for 15 percent improvement, which is slightly over 2:30.
Adding a little hard speedwork for a month can easily get you 3 of the available 15 percent. To get the remaining 12 percent of your available potential will take years of very high mileage, lots of tempo runs, optimal weight, strength training......