I’m looking to gain speed and be able to jump higher. I’ve tried to look this up on the internet but, all the websites i go to are wanting me to pay money. All i want is some simple exercises. I don’t want to have to pay to get them. So if you could help me that would be awesome.

Does anyone know of any exercises or anything that will build the amount of fast twitch muscle fibres in my arm and/or fingers, i feel i’ve hit a speed wall on guitar and would desperately like to be faster.
(I’m from the UK hence ‘fibres’ not ‘fibers’)