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#11
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![]() Quote:
Last edited by descending : 04-10-2016 at 01:58 PM. |
#12
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Given the pace they're swimming at 1:22 100y pace (Suzanne I'm assuming yards - correct?). That around 14 spl, stroke length around 48" or 4'. That pace would put them at 59 min 2.4 mile swim. Given (and assuming) stroke length is a priority over stroke rate, to swim 52 mins in 2.4 miles at IMAZ, Darbi's turnover rate was between 60-63 strokes per min or 1.00 - 0.95 seconds per stroke and holding a slightly lower stroke length at 46" which puts her right at 52:00 for the 2.4 IM swim. Darbi certainly has a beautiful stroke, and clearly one that holds up for long distance swims with minimum effort. Haa! Well, we'll see about that Werner. I've already started lobbying for Tracey to LA! Stuart |
#13
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I could see the calculations transferring if someone swam in a perfectly straight line, had no slowing due to sighting, no slowing due to space/competitors, no slowing due to wind. If the swimmer deviates at all from a pool black line swim then they have to make up for that somehow. Does her stroke length get even longer in the open water? What would the stroke rate need to be to hit a 51 with 16 spl? |
#14
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![]() Hi Desc:
Sure - just math R=D/T, or in a swimming context Pace = SL/Tempo (seconds per stroke). SPL is a bit too broad and is based on true stroked yards excluding the glide off the wall. In the video, Darbi/Terry begin stroking at the 5y flags, so swimming a true (or very close to) 20 yards. SL = SPL/Dist, 20y/15spl = 1.33 yards or 4 ft. Roughly moving forward 70% of her height on each stroke - a very good "green zone". Using 16spl, given a 5y glide off the wall SL = 20y/16spl = 1.25y or 3.75 ft. To hit ~51 mins at a SL of 3.75 ft: Pace = 1.25y/.91 = 1.381 yards per second 100y pace = 100y/1.381=72.4 secs or 1:12.4 2.4 miles (4224y) = 4224y/1.381 = 3059 secs or 50.98 mins. Yes those that sight forward more frequently will swim slower since they step on the brakes more frequently. But good open water swimmers use lateral targets when breathing and sight forward less frequently, 30 maybe 40 strokes before picking the head up to sight forward. It is a skill to swim very straight without constant visual adjustment. Yes, my IM swimmers generally swim .1, .2 miles longer and that is a factor. Wind and currents absolutely. IMAZ little to no wind, it's in a man made lake, no current. Pros get the advantage of swimming in front the pack with no bottlenecks. There's also the wetsuit factor, stroke length will increase a bit. I use the math to get a good baseline then factor for each swimmer given their skill set and open water skill set when predicting/estimating swim times I think since Darbi hung on to another swimmers wheelhouse for most of the swim, she probably slowed tempo a bit and increased stroke length, saving even more energy. Being they're pros, elite swimmers, in front of the pack, they swam closer to 2.4 miles than the rest of the triathletes. Hope that helps a bit, but it's just using a little math. Stuart |
#15
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![]() Ok that makes sense thanks for that explanation.
Very impressive. Let me know if you ever come across any of her race footage at that pace please I'd love to digest some of that video! |
#16
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![]() She just did IM South Africa today/yesterday there may be women's pro start footage online
__________________
Suzanne Atkinson, MD Level 3 USAT Coach USA Paralympic Triathlon Coach Coach of 5 time USA Triathlon Triathlete of the Year, Kirsten Sass Steel City Endurance, LTD Fresh Freestyle |
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