Why do I suck at 5ks?

are you doing any indicator workouts?

eg 3x1 mile @ 5k pace +10s/mi or thereabouts, on 60s rest

The workout is supposed to hurt really bad and you dont do it very often. But it helps get work in @ pace

also 800s @ 5k pace on similar rest is beneficial

You have the fitness IMHO, just not that special 5k pain tolerance yet

[FWIW our mile times are similar, (I'm a handful of seconds under 6] your half PR is like 5 mins better than mine, and I sneak under 20 in a 5k if the weather is perfect else end up around 20:30]

my humble opinion is you havent spent enough time at that race pace/particular pain cave

Icouldbeyourmom wrote:

I don’t understand why I am so bad at the 5k distance. My mile time trial from a month ago is 6 min flat. A recent half marathon was 1:37. I’m a female with young kids, run about 30 miles a week.

I raced a 5k a week ago expecting to be capable of around 20:30 based on my mile time and I ran a 22:04. It was a hot day and I was completely out of breath mile 3. I don’t feel like I could have run it much faster.

How is it that I can run a 7:20s pace for a half and then struggle to run 7 min miles for a 5k?

You need more long reps and tempo work.

Icouldbeyourmom wrote:

I don’t understand why I am so bad at the 5k distance. My mile time trial from a month ago is 6 min flat. A recent half marathon was 1:37. I’m a female with young kids, run about 30 miles a week.

I raced a 5k a week ago expecting to be capable of around 20:30 based on my mile time and I ran a 22:04. It was a hot day and I was completely out of breath mile 3. I don’t feel like I could have run it much faster.

How is it that I can run a 7:20s pace for a half and then struggle to run 7 min miles for a 5k?

You need to do more intervals to run well at 5k. It's a "short" distance compared to a half marathon.

You may have:

- a genetically high anaerobic capacity, making you decent at the mile and down

- a fair amount of slow twitch fibres making you decent at the half marathon

- a genetically average VO2max, making you mediocre at 2k to 5k distances.

Or:

- you do not have the correct 5k specific endurance training

- you weren’t mentally or physically your best that day

Without knowing any details I bet you start out way too hard. Most people run 5Ks like morons

Biggest problem is pain. Accepting the pain and pushing through it.

Nine days before the race I did 3x1 mile at around 6:35-6:45 pace each mile...but I had more like 90 seconds rest....maybe 120 seconds after mile 2 which should have been a red flag. The workout smoked me and the third mile was painful and the slowest but It was still under 6:45. I’m thinking I either did that workout too hard and wasn’t recovered from it by the race, or it was just too much rest between repeats to be a proper indicator.

Two months ago I ran a 21:30 in cooler weather conditions but I still feel like that is less than my potential.

I'm older and slower than you (also female) and I have similar issues. Last month I ran a 1:46 half-marathon (8:06/mile) and a 23:51 5K (7:41/mile). Both races were under good conditions, flat and not hot. I feel I ran as well as I could in both races. The difference is that I'm very sure I could not run anywhere near a 6:41 mile, while you say you can run a 6-min mile but only about 7-min pace for 5K. That does seem a bit odd, and suggests some deficiency in the way you're training.

sit and kick wrote:

are you doing any indicator workouts?

eg 3x1 mile @ 5k pace +10s/mi or thereabouts, on 60s rest

The workout is supposed to hurt really bad and you dont do it very often. But it helps get work in @ pace

also 800s @ 5k pace on similar rest is beneficial

You have the fitness IMHO, just not that special 5k pain tolerance yet

[FWIW our mile times are similar, (I'm a handful of seconds under 6] your half PR is like 5 mins better than mine, and I sneak under 20 in a 5k if the weather is perfect else end up around 20:30]

my humble opinion is you havent spent enough time at that race pace/particular pain cave

If that's the case maybe you need to actually try during a half. You need no fitness gains to just run closer to 1:30.

You got the end points so just fill in the middle

6 months focus on building your LT and I bet ALL of your times improve probably sub 20.

Checkout this article:

http://www.traininkenya.com/2018/07/08/coaches-blog-lactate-threshold-training-for-5km-races/

Lactic Acid is back, Baby!