How long to get to sub 16 from 17:35 5k?

Also, 5k splits by km: 3:13, 3:30, 3:34, 3:42, 3:36 (went out a bit too fast to start)

if you actually got to mid 17s in a couple months on 20mpw, yeah

just don't build too quickly and get hurt

Congrats, that’s a great achievement and improvement in a short time. I ran my 5K PR’s years ago sub 16:15 I was running 60-70MPW. It’s definitely doable and maybe within 12 months. If you want to run marathons anyways try and get up to 70-80MPW in the next year and see where that gets you on your 5K time, after that you can take a short break and take that experience of high mileage into a marathon build.

I ran in high school then picked it up again mid-20s. Similar baseline to you, sub-20-ish
"off-the-couch". Based on old logs:

Several months of 30-45 km/week got me => down to sub-18:00.

Another year of up to 50-70 km/week => down to sub-17:00.

Another six months of 70-80 km/week => down to sub 16:30.

PBs 16:23 / 34:01

Of course, we all respond differently to training and have different injury propensities.

By comparison, after several idle years I took up running again two years ago in my mid-30s. Last two years I trained significantly more than I ever did in my 20s (lots of 90-100K weeks) and recently ran....16:55 at age 37, and was super pleased to do so. If I had progressed my training load to this level when I was younger, I have no doubt I would have dropped to sub-16:00. But the marginal gains getting costlier and costlier.

So to answer your question, I think you should be able to break 16:00 in the next two years if you can continue training consistently in the 80-100 km/week range. Just know that the drop from 20:00 to 17:30 is considerably easier than the drop from 17:30 to 16:00.

How can I avoid getting hurt? Just stepback weeks every so often when building milage right?

Sounds like a great plan and is what I was thinking of doing! Good to hear the external confirmation.

and of course, congrats on your own running times and progressions, that’s quite respectable. I’m just surprised how much mileage makes a difference.

approximately 1 minute and 36 seconds

Yeah, a down week every 3-4 weeks is a good idea. The other biggest risk factor is increasing volume too quickly. In general, learn to listen to your body and have the discipline to back off when you're pushing it too hard. Learning the difference between "good pain" (i.e. normal soreness from pushing yourself) and bad pain (the start of an injury) can be tricky and take a while but it's an important skill.

There’s a lot of good stuff in this playlist from Bowerman TC, especially the mobility with Heath..

get resistance bands and do activation & strengthening stuff with them, I started doing this stuff before runs and during my at home workouts it helps alot. Stretching and foam rolling are obvious ones as well, get a lacrosse or trigger point ball too those are great for attacking specific spots that flare up. Other than that sleep is also really important for recovery.

To answer the question in the title: How long's a piece of string?

Also, you likely would've run 20 seconds faster if you went 10 seconds slower in the first km. Add in some competition, and there's more time gains.

My advice would be to not up the mileage so quickly. If you're only used to running 30-35km a week, it's quite risky to step up to 80kms in one block.

A better approach would be to hold at 60kms a week for a few months. You're obviously quite inexperienced at 5,000m, so there's plenty of gains to be made simply by learning the event. If you put a couple of months of consistent training together, you may well have the talent to get close to sub-16 without overdoing the mileage (and then you can up the mileage once the gains plateau).

It took about 1 year to go from 17:30 to sub16. Sounds like you could maybe do it in shorter time, but you'll need to temper your exuberance in just the right way so that you consistently run well, but don't get injured, etc.

This is great advice thanks, especially on the splitting and how it could have improved my time further (though I’m curious how you estimate these kinds of improvements). Was my first time running a 5k on the track at all, so after warming up a bit I had a lot of adrenaline starting out and it got the better of me.

I’m definitely new to the world of increasing mileage and I want to see gains in my times as fast as possible for my own enjoyment, but it’s good to hear how to run smart, though I plan on following 80/20 running (heard something about that somewhere either on this site or Reddit I think…) to not strain things too much.

Perhaps I could go up to 60-65 kms a week by end of September and hold there until December, then ramp up again to 80 by say February/March? I’d like to run a half marathon in May in Toronto, so I might follow one of those 12 week training plans then instead.

Good to know thanks. Not in a rush or anything per se - just trying to be the best I can be as fast as possible for personal fulfillment

I’ll try and use these too!

Your improvement quickness depends on your speed base.

So what are your PRs 800/1000/1500?

Not sure for 800 or 1500 but 1k is close to 3:05 per km I think, if not slightly over **

Obviously you are lack of speed base, your endurance is very good relatively.

Thus just increase weekly mileage will not help you.

In my opinion, more focus on speed workouts would be more helpful for you.

Good to know thanks, will see if I can incorporate more speed workouts then

Though as my goal is more inclined towards half marathons and marathons inclined, I was thinking of doing Fartleks except say 2 months before races where I would hammer out intervals (6x800, 6x1000, etc) or if I’m following a specific training plan (heard Pfitz and Daniels suggested here on this forum?)

Update: 2-3 weeks ago I ran 16:08 on the track (solo time trial, third one ever) after sorta following an 8 week McMillan Running plan ("The Best 5K Workout"). Splits (by km) were
3:10, 3:13, 3:17, 3:18, 3:10.

This was done after my half-marathon in October 2023 where I was trying to get to a point I could consistently run 40 mpw from week to week. Training consisted of tempo runs, intervals and a long run each week. Sometimes I skipped one of the workouts if I wasn't feeling great. As a result I peaked at 50 mpw but again the training still seemed very disorganized and my mileage oscillated a bit too much for my liking from week to week. Biggest issue is consistency, though fortunately no injuries so far. Solidly on track for sub 16 in less than 1.5 years!

Heart rate was 200 bpm average according to the Apple Watch so I'd like to think I squeezed out everything I could. Not quite sub 16 but I think I can hit it the next time I try it out say end of August (maybe even 15:45). However, I want to do it after a higher mileage summer first where my base is 50-60 mpw for at least a few months (now that I have more time from grad school and I know mentally that 50 mpw is achievable for me). Plan for me is to try to do more intervals and maybe some more hill training this time around.

Will keep updating as I can, though the long term plan is still longer distance running like half and full marathons.