I recently saw a video on Facebook (see it here on YouTube) that involved a young boy, approximately 18 months old, that literally dived into a pool, was fully submerged for at least 7 seconds, and kicked/swam his way to the surface of the water. At this point, he spends another 2 full minutes on his back, staying afloat and keeping his face out of the water. (A parent was in the pool, off-camera, the whole time. This was an educational/informational video.)
It also appeared to me that while the child was underwater he was covering his nose and/or mouth with one of his hands, and so returned to the surface using only his legs and one arm to swim.
I'd heard of babies being train to keep there heads afloat, and I know there's a reflex that causes them to hold there breaths when submerged. But, I'd never been under the impression that diving (practically head first!) was part of that training?
What are the safe techniques used to train such a young child in that way?
What type of background or certifications should you look for in an infant swim instruct to achieve this?
How much in-the-water time does it take to teach young ones this particular skill?
Here are some stills from the video, which illustrate the type of techniques I'm asking about: