Ок, нашел на англоязычном форуме TI мнение самого Лафлина. Привожу ниже, может кому пригодится:
Shinji and some other TI coaches use a snorkel in teaching. They do so to allow students to
Have more time to examine and refine elements of Skate position - i.e. experiment with X/Y coordinates of hand position, or slightly tweak rotation - and then to imprint. (As you do this, avoid turning Skate into a kicking exercise; stop for a breather any time your kick feels labored.)
Refine and imprint aspects of SpearSwitch - such as hitting the X/Y targets or arcing the hand to the targets via VW Bug focal point, or getting the overlap of spearing hand with Patient Lead Hand just right, etc.
Work on Mail Slot timing or observe whether hands are relaxed as they complete extension in Whole Stroke,
Etc.
Any aspect of technique which may be examined more closely or imprinted more quickly if you can continue longer without interrupting your focus for a breath -- especially if your breathing skill is still not great -- is a candidate for snorkel practice.
__________________
Terry Laughlin
Head Coach & Chief Executive Optimist
И еще одно:
I think the best use for a swimmer's snorkel in TI Practice is to allow longer practice reps of Skating and Switch drills.
Here's one example of how:
In Skating practice, being able to go as much as 25y/m without having to interrupt for breathing allows you much opportunity to experiment with different hand positions and discover the 'optimal geometry' of your leading edge in freestyle.
A slightly deeper lead hand can often make the legs feel much more 'weightless' but there's a fine line between deep enough and too deep.
A slightly wider lead hand can greatly improve lateral stability. But the benefits are maximized when the hand is directly forward, or millimeters outside, the shoulder. Wider than that brings no greater stability and can reduce 'effortless' power for the stroke.
With a snorkel, you can discover just the right position - and begin to imprint that position in muscle memory.
If you progress to SpearSwitch, practicing with the snorkel allows you to repeat many repetitions with a keen focus on spearing your hand to the exact position - or target - you imprinted in Skating. This turns a basic skill into a dynamic skill and deepens the muscle memory.
__________________
Terry Laughlin
Head Coach & Chief Executive Optimist