8x300, 90 second jogging rest averaged 55.6.

That workout alone does not give a definite answer on breaking 5. The best I can say is a 5 flat miler can certainly do that workout, but so could a 5:10 runner.

So, you are a decent sprinter then!?

Probably not quite there yet, but I'd love to be proven wrong.

I closed my last mile in 5:17 in a 5k for a 17:02 5k. I think I can run faster then 5:10. I’m not a sprinter lol that was just the workout. Sprinters just casually run mid 5s in our team.

If you closed a 17:02 5k in 5:17, yes, I think you can break 5min in a mile. Now go out and prove me right.

See, that is more useful than the workout you posted. I’d say this info indicates sub 5 mile.

Workout indicates 2:27.xx to 2:30.xx 800m fitness.

You can definitely break 5 and you are making good progress so far

Given these times you can defintely broke 5 (maybe not by much, but somewhere between 4'55" and 5'00" I'd say). The 8x300 workout per se could be made also by a 5'12" miler probably (but, given your 5k time and the 8x300, I'd guess that you are more suited to longer distances, or at least more trained on them, who knows).

The 5k looks great. Sub-5 should be doable if you're closing in 5:17. Would guess a lot of people can run ~30s/mile faster for a mile than their 5k pace. 17:02 is worth just under 5-flat. The 300s don't do it for me as a predictor workout. I would follow it up with some longer reps (400-800 range): 8 x 400 w./ 90s, 3 x (600-300) (600 @ mile, short rest, 300 faster, full rest), 3 x 800 w./ full rest.

Am I really the only person who sees 50m flies in lo/mid 6 as being rather significant?

I was a 3:57 1500m guy. I would have a hard time doing 50m flies at lo/mid 6.

Unless FAT there is a big margin for error.

Yeah idk maybe OP could knock out something fast 200-800 range but the 300s on their own just look like a normal workout for someone trying to run 5-flat & 17-flat. Definitely shows the potential for a strong close. Get someone to pace you through 1400 right @ 5-flat & then rip the last 200.

faster THAN 5:10 not faster then

have RUN not have ran

If that workout was very hard you probably cannot break 5. If you went 60s rest and averaged like 72s 400 pace for all the 300s, that would probably be around the barrier of indication. But I don't know where you're at in your periodization cycle so that's just a thought.

You're not a sprinter though, that doesn't exactly affect mile running. I see 1:50 800m guys struggle to run low 6 in 50 flies.

Do a 1200m TT. Hit around 3:40-3:45. Be honest with yourself about how it feels and that will let you know what kind of shape you are in.

Well, I suppose my point is this: OP may have a sprint background, and/or a sprinter build. That might inform how he/she approaches training for the mile.

You actually make my point! Even 1:50 guys find lo6 hard, but they (and me) would basically jog a 5min mile.