Sprint Training, 5K Training, and Strength Training
In real-world scenarios, endurance, power, explosive are all very important. People usually think that explosive power, such as 100m time is very hard to improve, but endurance ability and strength are much easier. However, actually the truth is that explosive power are sometimes the easiest to improve compared to endurance for long run like 5K. 5K is very hard to improve beyond some point. It requires a long of weekly mileage and supreme VO2Max and aerobic ability, which are mostly from natural talents. Take me as an example, when I increase my weekly mileage from 15 miles to 25 miles, I did not see a significant change in 5K (at that time PB was 19:37). I ran several bad races after high mileage week. However, I discovered that sprinting is just merely something that is far more technical than endurance training, it requires very careful designed postures and mechanisms. However, once you got all the things correct, you can see very fast improvement in sprinting. For me it was like in one year for 100m from 14.6s to 13.5s, and then in two month to 12.9s. You just get the right posture and consistent training, it will improve. I also see my 5K time improving even though I did not train it specifically.
This is one of the most subtle part that people miss, endurance training is actually beneficial to sprint training. Endurance training helps you recover faster, which is super important after hard sprints. However, the endurance training must be real low intensity Z2 training. No 800m pace. No VO2max. No threshold Z2 slow running will do the trick. You can add threshold, vo2max later once you are satisfied with your sprinting time, but not during your sprint trainign block.