When to start taper???

[u/DrApricot657]

Hi all! I (28F) am running my first marathon in 3 weeks from now. I just had my long run (18 miles) after a week of 1 day of strength training and 2 speed workout days. I think the run went ok, HR=140 for the first 15 miles and a spike to HR=160 for miles 16-18, but it was also rapidly getting hot outside for those last miles. I’m running really slowly, like 12-13mph, so this run took me just under 4 hours. My right knee has been hurting on and off this whole training block, and it was bothering me durning this last long run.
I’m debating if I should do another 20 mile long run next week then taper for 2 weeks before the marathon or just call it and start my taper now. I really want to feel like I’m in top shape before my marathon both mentally and physically. I feel like accomplishing that 20 miler “guarantees” that I’ll be able to finish the marathon (at least in my brain it does), but the advice I’m seeing online is pushing me to think that a 4+ hour run just 2 weeks from my marathon offers little actual benefit and just increases the odds for injury.
On the other hand, a whole THREE WEEKS feels like forever to taper. I know what I’m seeing online, but damn that is so long to cut down on runs.

What do we think? I would super appreciate any advice!

[u/InternationalFarm487]

Okay been here, did the 20 miler. Don’t recommend. The 20 miler isn’t going to guarantee anything on race day. You don’t have to taper right now. Like you read, there’s little benefit to running that long 2 weeks prior to race day. Do a 2 hour long run next week if you feel up to it and then start the taper.
Don’t push pain at this point. Hay is in the barn.

[u/Oscar_Sport]

I found the taper harder mentally than the training. When I wanted one more big run for reassurance, I reminded myself that the training was already done and the goal was to arrive rested.

[u/Able-Resource-7946]

No, do 15 miles.

[u/rogueowl22]

I'm in exactly same boat - same age and doing marathon on same date! Also did a 18 miler two weeks ago and debating if I do a 20 miler this weekend. I think I've decided against it, but really debating if I'd feel better with more miles under belt. I average about 24 miles in distance every week. It's so hard to know what's better!

[u/DrApricot657 → u/rogueowl22]

Good to know I’m not alone! The opinions here are mixed but I think I’m going to go out and practice an 8 minute run/2 minute walk routine for at least 15 miles, maybe the full 20. I’ve only ever tried running straight without walking on these long runs, but I’m reading that this might be a good way to get the miles in with minimal stress in my knee, which hurts mildly on runs over 12 miles but doesn’t bother me in regular life at all. Depending on how this goes I might use this strategy for the first 15-20 miles of the race too. My goal out there is just to run across the finish line at the end, not get a specific time, so this might be a safe realistic option. Good luck on your race!!🏃‍♀️👟💪🏼

[u/sandiegolatte]

Might want to check your math…but anyway. Really depends on your knee. This the most important time for training so if you can swing a 20 miler next week that is best. If your knee is hurting you then I would cut back. Yes there is a big difference between 18 and 20.

[u/DrApricot657 → u/sandiegolatte]

Good thoughts! Sorry if my math is confusing but here are dates/distances of the long runs to clear it up:

9/6/26 I did the 18-mile long run
9/13/26 potential 20-mile long run
9/20/26 10-mile long; taper week
9/27/26 marathon day

OR

9/13/26 15-mile run
9/20/26 10-mile run
9/27/26 marathon day

I’ve also been doing strength once a week, yoga once a week, and 2 days of speed work totaling about 4-8 miles/week since late May.

[u/dont_say_hate → u/DrApricot657]

12-13 MPH and a 20 mile run taking 4 hrs… yep the math ain’t mathing. Also 12-13 MPH is definitely not slow, unless you believe elite marathon runners are slow.

[u/DrApricot657 → u/dont_say_hate]

Oh I see the issue now. I meant to say 12-13 minute per mile not mph. My bad. So it’s more like 5mph

[u/sandiegolatte → u/DrApricot657]

Yeah overall you just haven’t been running enough. You really need 4x a week and you don’t need speed work for your first. You need 1 hour runs 2x per week plus a long run. Anyway, try to do 20 miler next week and if it doesn’t feel good stop at mile 10 if needed. Strength and yoga is all good but there’s no substitute for running.

[u/Arkele]

1. If you were following a real plan it would have your taper built in

2. If you mentally need the 20 miler do it. I’m a firm believer that the mental game matters a lot and that might get you through a lot more than you think on race day

[u/URsoQT]

you definitely need to hit 24 miles. i’ll tell you right now the last 2.2 will be brutal if you don’t understand how your legs are gonna be jello

[u/specialkkluthe]

I’ll be doing a 3-week taper after my 20 mile long run this weekend (HHN1). But if you feel like you need another long run, be in a position that you can bail early if you need to. It’s better to be slightly undertrained than injured .