Too slow for me. But also havenÂ’t done an all out 25 in a while. Put in 16 seconds and it came out with 63 minutes for me. Last IM I did I swam a 59 and I better be faster than that now!

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I predict a 15 flat 25 yard sprint.

My PB for a 50 free (masters) is 25.9 (SCM) That equates to about a 13.7s 25m free from the push (add .75 seconds to compensate for the a 1.5 second benefit off the start)

Converted to yards, that's about a 12.45 25 yard time, which, according to your calculator, means I should be in the range of 47:35 to 50:30 for an IM swim.

I haven't done an IM yet. Give you a half IM time next year....

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Sounds reasonable. I was a little faster than that in my swimming days, about 25.5 LCM (low 22 SCY), and literally loafed to a 52 minute swim on the IM Lake Pllacid course with about that same fitness. I backstroked a lot of it, waiting for others. I 'think' I could have swam it in 45 or so, and I also think I could have went about 11.5 for 25 from a push.

Can I divide by 2 for my 70.3 split?

I can do a 25 with 1 or no breaths to hit a fast time. But if I do the 25 breathing every right stroke (like I would in a 70.3), my 25 time is slower. Is the latter the better predictor?

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Alex Arman

Strava

My 50m free time is almost the same as Jason - 26.02 (*shakes fist at Jason*). My IM time is 54:03 (albeit 5 years ago in somewhat less swim form but not massively so). Going sub 50 for an IM seems out of reach to me. Maybe I'm under estimating what I could have done on that 26.0 fitness.

Close only counts in horseshoes and hand grenades.... ;-P

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100 free is even worse (if the masters canada site is right). 0.01 difference there

A couple points:

1. I'd estimate you need 20k weekly yardage to get close to the prediction. Wide range there, but more swimming than most are doing.

2. While my equation is linear, the relationship of 25 yard sprint to IM swim spits is probably not linear, when we consider a wide range of sprint speeds. It definitely underestimates IM Splits for very fast sprinters.

Something like Slowman's quadratic equation for predicted armrest drop is what is needed. That equation is C=.005D² - .2D (C = drop and D = seat height) But that is only good at 77.5° of seat tube angle. At steeper angles we need to predict greater drop, and shallower angles generally result in less drop. So that .2 before the final D gets bigger (for shallower) or smaller (for steeper) by .0075 for every degree we deviate from 77.5°

I likely need to anchor my formula at perhaps a :15 / 25 yard sprint predicting a low 59 IM swim, and then modify the calculations slightly for faster and slower sprint speeds. Or maybe a :16 / 25 yard predicting a 1:03 swim is the right starting point? It was just something I whipped up while basting a turkey, so any math majors want to take a shot at this, feel free.

It does seem to work well in the 14 - 24 second range

That's OK, you've got me in the breaststroke events. Not that anyone cares about breaststroke, the red headed stepchild of swimming.....

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Like zenmaster, I "think" that's an overly aggressive estimate of what I could actually do. My most recent 1500 swim was a 19:36, granted I'm not in really good swim shape right now, only getting in 3000-6000m per week, but I'm guessing that if I was in the same shape I was when I swam a 2:04 and 4:32 for my 200 and 400 (both SCM) then I'd be able to do the 1500 in 18:30-18:45 or so... If I could continue at that same pace, that's a 47:30 for 2400m in the pool, with a lot of turns....

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I guess a difference is do you calculate this with a push off or off the blocks? IÂ’m sure that makes a difference too. Either way kind of a cool tool. I remember someone saying a 17 flat 25 meant you had the technique for an hour IM swim so the calculator matches with that at least!

My 70.3 swims range from 26-30 the last few seasons depending on conditions and course accuracy so IÂ’d hope next IM IÂ’m closer to mid 50s. But still have work to do!

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I'm assuming its with a push. If we were to use my (estimated) 25 yard time off the blocks to my feet, then the model has me at 43:41 for an IM swim, and slightly faster than that if it's to a hand touch.

I don't think I'm that good.....

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We're just having some fun here. At least I am. I've got a bunch of coaches telling me it's way off, worthless, ridiculous, whatever.

I think a lot of you guys are missing the point. I am not trying to predict Cesar Cielo's IM split. I AM trying to help the average age grouper who might sprint at :19.0 / 25 yards, but then lays down a 1:30.00 IM split. There are plenty of those swimmers, and they would do well to question that 25 yard to 3800m relationship. Maybe they find out that a properly structured swim program of 15-20k weekly is NOT such a waste of time as they have been led to believe. Or their navigation sucks. Or there is some low hanging fruit somewhere and they should try to find it.

Same as 220 minus age is max HR...

No I get that. I'm really not a sprinter, either. My sprint sucks compared to middle d.

just giving you a bit of data that you might be able to use to tweak the model, whether it's the coefficient, the error boundaries, or what have you...

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pk wrote:

Same as 220 minus age is max HR...

World class coaches are a fragile group.

I didn't mean you Jason. You're a helpful dude.

Oh I totally get it! ANY predictor is just an educated guess assuming proper training. I love these calculators because they give a range/idea of what might be possible. This is similar to using a 1 mile/5k race to predict a marathon. It might do a good job in an ideal work but, like you said, poor sighting, poorly measure course, not finding feet, etc. can dramatically change the race. It is just another fun tool everyone can use to drive themselves crazy with more data points!

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You're hired!

More like trying to predict a half marathon time from somebody's 100 meter dash time.

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The funny thing is, it's proving to be pretty accurate, whereas the same would probably not hold true for your 100 meter dash / marathon metaphor. Why do you think that might be?

 

IMMT swim this year was 1:05:xx

Did a sprint set the other day(SCM) and was trying to keep them all at 16s, fastest one was 15.7

So would that put an all out sprint around 14.5? I'm just guessing. I have no swim expertise.

That puts the equation time at 57:xx, that's with no handicap for SCY/M

Do I think I could do that, yeah. I think I could do that. But when looking at a race scenario, not a chance am I going to push that pace. I would be so bagged after that, no sense in even getting on the bike.

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For a 25 yd sprint (yards being the key here), you need a 15.2 for the 25 yd sprint to go 59:59. Or were you thinking 25 m with the 17???

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