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  #1  
Old 08-24-2016
ScoopUK
 
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Default Maintaining pace over time

Hi,

Weather here in UK has finally been good enough for me to enjoy non-wetsuit swimming in the local lakes. I have a route I can swim regularly to compare efforts so today I thought I'd have a go with tempo trainer set at 1.3 (46 SPM). I put my GPS watch on a tow buoy so it's super accurate and I have clear wrists.

What is really clear is my pace gets progressively slower the longer I go on. I can feel elements in my stroke getting sloppier as I get more tired/colder too and my concentration breaks.

What tips are there for overcoming this breakdown? In the pool I tend to do sets which allow me to reset and start fresh meaning my avg pace over the session stays high(er). Right now I'm having a hard time understanding how people do these marathon swims.

On the plus side at a nice steady 46 strokes/minute my avg HR was a sedate 133 BPM.

Pic attached to show pace drop off.

PS: In a wetsuit my avg pace over the same course and distance is 2:00/100m. It's also far more consistent. Pace doesn't really drop off (so maybe it's body position faltering as get tired?)

Thanks, look forward to some solutions!
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  #2  
Old 08-25-2016
s.sciame s.sciame is offline
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s.sciame
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Good topic ScoopUK, you're not alone

The more I swim the more I understand how much more difficult open water swimming (w/o wetsuit, ie the way pure ow swimmers do) is comparing to pool swimming. Even in perfect conditions, even when the water is completely flat and there's a cable assisting your trajectory.

To my experience, the main difference is that in the pool you're lucky enough to find every 25m a wall which solves any problem:

1) it boosts your speed: with a decent flip turn (no uw dolphin) my times improve by around 10% over no-wall swimming. Note that the faster your pace the less the walls boost your overall speed and viceversa (at 2:00/100m the difference is huge, at 1:20/100m less)

2) it resets your stroke: every time you start a length your strokes are (probably) a bit longer than the last ones before the wall. The wall saves your stroke by resetting it before it gets shorter. So, if you think your stroke length is 1m because in a 25m pool you can hold 19-20SPL all day with a 5m pushoff, perhaps in open water this is not true anymore: without resetting walls your SL maybe settles down to 0.95m for a while and, as fatigue builds up, 0.9m and less.

Another problem is the lack of reference points in ow. In the pool you have the pace clock, can count SPL etc. You always know your current pace and this is a big advantage. In open water you're kind of blind: you can use a tempo trainer but you can't count SPL. If your stroke gets shorter you may not realize it until you get to the far buoy and check your time, which is too late

And I didn't mention all the other open water issues than can contribute to pace drop off (eg wind can change during the swim).

Now you ask about tips for overcoming this breakdown. I think it depends on the individual. Personally in open water I try to focus mainly on keeping stroke length because I know that when my pace gets slower it's usually not because of lack of stroke rate but it's my DPS which shortens. I swim in the 60-70SPM range. Perhaps at higher rates (eg toward 80SPM) DPS settles down to a short but stable value, so the pace drop off becomes a matter of holding stroke rate.

Salvo
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  #3  
Old 08-26-2016
CoachBobM CoachBobM is offline
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Quote:
Originally Posted by ScoopUK View Post
What is really clear is my pace gets progressively slower the longer I go on. I can feel elements in my stroke getting sloppier as I get more tired/colder too and my concentration breaks.

What tips are there for overcoming this breakdown? In the pool I tend to do sets which allow me to reset and start fresh meaning my avg pace over the session stays high(er). Right now I'm having a hard time understanding how people do these marathon swims.
It sounds like you are overpacing the event. All swimmers, regardless of their swimming level, need to swim at a slower pace as the distance they have to swim increases. If you look at the world records for freestyle, for example, you'll find that the world record times for 100m freestyle are more than twice the world record times for 50m freestyle, the world record times for 200m freestyle are more than twice the world record times for 100m freestyle, etc. And you'll find that the swimmers are swimming at the slower pace throughout the race - not just getting slower as the race proceeds.

There is a fairly simple scientific reason for all of this: All other things being equal, drag in the water varies roughly with the square of the speed. So if you double your speed, you will be covering twice as much distance per second but consuming 4 times as much energy per second. Consequently, you will travel only half as far before you run out of energy.

In a swim meet held in a pool, things get very complicated because you have to take into account block starts, turns, and streamlines. But if you are swimming in open water and want to swim twice the distance using the same amount of energy, then (all other things being equal), you will need to cut your speed by about 29%. But let's say that you overpace it, swimming, e.g., the first 50m of a 200m swim at the pace you use for a 100m swim. You will then have only half your energy left to swim the remaining 150m. And to do this, you will need to cut your speed by about 42%, leaving you with an overall speed that is about 32% slower than your 100m speed.

Of course, the key qualifier is "all other things being equal." When our muscles begin to tire, our brains instinctively try to shift the effort to other muscles, which in swimming almost invariably means becoming less efficient, which makes our muscles tire even faster, thereby compounding the problem.

The best remedy for overpacing, in my experience, is to approach the problem from the other end by deliberately underpacing the distance, finding a TT setting at which you can easily complete the distance while maintaining good technique and finish feeling that you still have plenty of energy left in your tank. Then gradually increase the pace on your TT until you find the stroke rate at which you can finish the distance with good technique and feel like your tank is empty right at the end.


Bob

Last edited by CoachBobM : 08-26-2016 at 03:28 AM.
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  #4  
Old 08-26-2016
ScoopUK
 
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Thanks for your input so far.

I've been at the pool today and swam with TT set at 46 SPM (1.3s/stroke) again. Obviously there are push offs and rest but I was consistently swimming 25s/25m & 50s/50m so a pace of 1:40/100m. I was typically swimming 16 SPL, occasionally 15.

I get frustrated that this doesn't translate to speed in open water although I admit I find open water more difficult as I don't have the visual feedback like the rate the tiles are moving past me while I'm gliding etc.

I have the CV fitness to thrash it out like a windmill and be faster and more consistent with my open water pace (in a wetsuit anyway) but I'm trying to be patient and develop a longer stroke and save some energy as well as be a good swimmer without a wetsuit.

By overpacing I'm not sure what you mean. I certainly didn't go out too hard. Heart rate barely ticking over. I know I can hold that distance per stroke but I need to understand why my distance per stroke is reducing as the event goes on. My suspicion is I start to reach forward rather than a deep spear and this causes more drag on my legs and a poorer catch. Not having instant feedback like I would in a pool I don't correct this and it's only afterwards I see how my pace dropped off. I suppose to overcome I need to effectively imprint the right technique so it is so instinctive it is resistant to fatigue and when I start to get cold.

I got to swim with the wave machine on today at the pool and I love the sense of balance I have swimming TI style. Big swell is no problem at all if your balanced. I just rise and fall with the rhythm of the waves. Pace drops off a bit but I've learned there is no need to get anxious or feel the need to swim harder anymore. Just go with the flow.

I have a race in December (half Ironman) which is quite likely to be a non-wetsuit sea swim so I want to be as good (and efficient) as I can be by then.

A somewhat rambling post but it's good to get my thoughts down for myself and for others to give their opinion.

Thanks again,

Sam
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  #5  
Old 08-27-2016
WFEGb WFEGb is offline
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Hello Sam,

just remembered. Once upon a time I assembled a 30min-mp3-file for Westyswood. Where the bongs continuesly changed from 1.40s down to 1.20s and back. Westy was thrilled about. Maybe you might give a similar one a choice to discover how your stroke will feel along this time. Although it might be, Terry would advocate the other way round from 1.20s up to 1.40s and back...

Best regards,
Werner
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  #6  
Old 08-28-2016
ScoopUK
 
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That's interesting, thanks. I suppose I need to work on my perception of length of stroke when I don't have the same visual cue as in a pool.
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