Swim smooth has an interesting pair of videos that makes the argument that minimizing strokes per length isn't the same thing as maximizing efficiency. Janet Evans and Laure Manaudou are cited as examples of swimmers with high strokes per length and a faster turnover. Elite triathletes with shorter strokes are also cited. The idea is not to advocate everyone use a shorter stroke but just to say that if a shorter stroke works for you don't throw that away in pursuit of lower strokes per length.
I wonder if swimming with a shorter stroke and higher turnover is analogous to using a lower gear when cycling (spinning versus grinding). People generally acknowledge that the optimal gear to use will vary from individual to individual. Extrapolating from that line of reasoning, perhaps elite swimmers using longer strokes do so because they have greater strength/more power that allows them to use a longer stroke/higher gear rather than because they worked on lengthening their strokes (although the two are clearly related).
YouTube- Swim Smooth: What Is An Efficient Freestyle Stroke? Part 1
YouTube- Swim Smooth: What Is An Efficient Freestyle Stroke? Part 2
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one can get technical
efficiency = useful power output divided by total power input
ie, what are you getting for what you are putting in
question is, what's your measure.....strokes per length, distance per stroke, or speed or time to the finish?
hard to pin down things that are changing, particularly regarding input power/energy
perhaps time to get to finish with an all out swim may be the most meaningful estimate of efficiency
(power = work divided by time)
(work = force times distance traveled)
I think the point here is that, as you say, efficiency is measured in terms of energy expended, and none of strokes per length, distance per stroke, or time for distance measure energy expended directly.
The problem is that it is hard to measure energy output directly. I think your assumption is that in two all out swim of a given distance by a single person the total energy expended by an individual will be the same so the faster time will indicate greater efficiency. This would imply that instead of counting strokes in an effort to get more efficient that we should track our interval times instead.
Alternately one could test the duration for which one could maintain a given pace using two stroke variations, and the greater the duration the more efficient that stroke variation must be.
That brings up the question of the relative advantages of stroke counting versus monitoring speed or duration...
one can get technical
efficiency = useful power output divided by total power input
ie, what are you getting for what you are putting in
question is, what's your measure.....strokes per length, distance per stroke, or speed or time to the finish?
hard to pin down things that are changing, particularly regarding input power/energy
perhaps time to get to finish with an all out swim may be the most meaningful estimate of efficiency
(power = work divided by time)
(work = force times distance traveled)
I think the point here is that, as you say, efficiency is measured in terms of energy expended, and none of strokes per length, distance per stroke, or time for distance measure energy expended directly.
The problem is that it is hard to measure energy output directly. I think your assumption is that in two all out swim of a given distance by a single person the total energy expended by an individual will be the same so the faster time will indicate greater efficiency. This would imply that instead of counting strokes in an effort to get more efficient that we should track our interval times instead.
Alternately one could test the duration for which one could maintain a given pace using two stroke variations, and the greater the duration the more efficient that stroke variation must be.
That brings up the question of the relative advantages of stroke counting versus monitoring speed or duration...
