[quote=@Lucius Cypher]
It's a good thing they speed up him playing it instead of making him actually try to play it at 4x the speed. When I was younger and tried my hand at the viola I thought I was hot shit and tried to play a song as fast as I can. Broke a string that whipped me in the across the face very, very badly. Not bad enough to leave a badass scar, but certainly enough to give an awkward gap on my eyebrow where my skin was torn off.
[/quote]

Playing fast takes skills and an extreme level of precision. Once you can play a violin song flawlessly at one speed you try to speed it up and its almost like having to learn the song over again to get it sounding right. Speaking as an amateur violin player (been at it for about two months, I can play a Scottish harvest dance song and a Newfoundland drinking song).