|
3 Mar
10:11pm, 3 Mar 2025
1,471 posts
|
monki
Must be HR based. My Garmin has been predicting me a 5k PB for nearly 9 months now based on some fantasy of how fast I’d run if a bear was chasing me. Literally 5 minutes faster than any training I’ve done in the past 12 months and 45s faster than the PB I raced 15 years ago. I train (ish) 60+% in Z2.
|
|
4 Mar
11:59am, 4 Mar 2025
1,472 posts
|
monki
Actually, no. Says it’s VO2 and training load. Swings and roundabouts I guess
|
|
4 Mar
2:05pm, 4 Mar 2025
4,765 posts
|
tipsku
That's my problem with the 5k predictions as well. They are a lot faster what I can do right now because I'm in marathon training and the watch doesn't take that into account. It predicts 19:44 (3:57 min/km, 6:21 m/m) when my actual capacity is probably around 21:45, based on the 10k race in January in 44:30. It seems to ignore my actual race results for calculating its predictions.
Now I did something to confuse it further: nearly 3 weeks ago, I ran a paarlauf event where I exchanged the baton 40 times with my running partner on a 200 m indoor track to run 80 laps, 16,000 m or nearly 10 miles together.
My laps were mostly around 45 s, that's 3:45 pace (6:00 m/m) so I did a session of 40x 200 m at 6 m/m pace. I was surprised that I could run that fast and maintain the lap speed for the entire hour, 45 s on, 45 s off.
What I found was that I did not really feel the same burning in the legs that I would feel when doing the same thing but with 400s on an outdoor track. 45 seconds is too short to really make the lactate shoot up. I was just horribly out of breath each time I finished the lap, spent 20 seconds just gasping for air, had a quick sip from my bottle and then I was ready to go again. I still don't fully understand where that came from. My legs just felt more like jelly the longer I did that so I needed to focus more on not to trip over my own legs, if that makes sense.
So I think that Garmin now thinks that, because I did that massive interval session at 6 m/m, I should be able to run a 5k at 6:20 when the fitness required for this is different. I would definitely feel the lactate hitting me hard after the first km at that pace and I would fade badly. It doesn't appreciate that the interval length is way too short for me to have to deal with the effects of prolonged running at paces faster than 7 m/m.
Apologies for the almost essay-length comment. Maybe I should blog about it after reading a bit more on fuelling, energy systems, etc. I'm just stunned that I pulled this off in the middle of marathon training and now my Garmin is more confused than ever.
|
|
4 Mar
2:33pm, 4 Mar 2025
26,803 posts
|
larkim
That does feel like an interesting gulf between your speed and your speed endurance. If I could do 40x200m at that pace I'd definitely be telling myself I was in good shape for a 3k or 5k race and most likely sub 20 for 5k.
|
|
4 Mar
2:44pm, 4 Mar 2025
47,205 posts
|
SPR
My first thought was what Larkim said. I can get the marathon Vs 5k speed thing and as I said earlier, McMillan backs you on that but this is different as you're showing you have the leg speed so it doesn't really fit that you can't run the 5k time. Certainly a slower pace for 1km shouldn't feel like you don't have much left.
Have you ever done 5 x 1000 with 60-120 recovery? Not a session to do now as you're training for a marathon but probably one to try in the future (starting at 120 and possibly not doing 60, I did 75 last year) as I get the feeling it may be a confidence/ practice thing.
|
|
4 Mar
3:25pm, 4 Mar 2025
21,407 posts
|
flanker
I always view the Garmin race predictions as my potential best time for my current level of fitness if I focussed my training on that specific event. I'm never going to hit any of the times if I focus on some other distance, or just sit on my arse, and that makes them pretty reasonable IMO.
To put it another way, you're never going to be able to reach your max potential for 5k, 10k, HM and marathon at the same time as the training to optimise for each is different. Therefore it's only worth paying attention to the prediction that aligns with your current training regime.
|
|
4 Mar
3:27pm, 4 Mar 2025
17,970 posts
|
chunkywizard
What I'm hearing a lot of people say is the predictors really bad and way off, but then showing they are actually fit enough to run the time just not focused on it/ training for it. As I've said before, as long as your max heart rate is set correctly I think the Garmin is a pretty good estimator of potential as long as you have one of the newer watch released in the last 3 years or so.
|
|
4 Mar
3:28pm, 4 Mar 2025
17,971 posts
|
chunkywizard
x-post with flanker but we are basically saying the same thing
|
|
4 Mar
3:50pm, 4 Mar 2025
44,800 posts
|
Nellers
I think that's exactly what I've found after only a month or 2 with a watch that does the race predictions, CW. I'm fairly fit (compared to gen pop at my age because I do a lot of non-running stuff) but I'm not "running fit" yet so I'm limited. I don't even think I'd finish a 10k at the moment unless there was a really strong incentive! But the 5k isn't far off and if I'm able to build the distance and not have anything go ping or pop the 10k prediction (51:38) probably isn't unrealistic.
(This against an all-time PB of 44:06 and 5k of 21 dead but that was pre-Achilles issue and about 15-20lbs lighter!)
|
|
4 Mar
3:58pm, 4 Mar 2025
18,545 posts
|
jda
In the past my garmin race predictors have come out with all sorts of guff, from well under my lifetime PB to completely pedestrian. Currently probably about right however.
|
Garmin 735xt problem
Jan 2021