1. How Long Does It Take A Child To Run 2km
2. How Long It Take To Run 2k 2

Someone who can run an 18 min 5K and who is optimally trained for a marathon should be able to handily break 3 hours. I haven't run a 5K race in a long time, but since I have cranked up mileage and gotten more serious about structured workouts for half marathon and marathon training, my speed has gotten a lot faster.

If you upload a video that has a resolution of 3840 pixels wide by 2160 pixels high, YouTube will display the 2160p quality option in the settings (cog) for your video.
It may take several minutes or longer before it shows up after you've uploaded the video. This is because YouTube creates individual videos for each quality level based on your uploaded file. With 2160p, that means YouTube is creating 8 videos from your upload (this is why 'processing' takes so long).

The Test

How Long Does It Take A Child To Run 2km

How Long It Take To Run 2k 2

I created a short 3840x2160 test video using the mp4 format and H.264 codec (YouTube recommended). This is what the quality options look like. You can see that it functions in both the HTML5 player and Flash player.

Creating 2160p Video

Many free video editors are limited to exporting video in 1080p (1920x1080 pixels). You'll need something more robust to export to higher resolutions, such as Adobe Premiere. Unfortunately that program is not free, but you may be able to find a free alternative online. I recommend searching at AlternativeTo.net.