The speed of electrical impulses is constant. What is not constant is the path that these impulses travel.
1 – Your brain has to determine the correct route for each finger command.
2 – Your brain has to determine the shortest route to send commands.
3 – Some of the routes must be improved for the increased electrical traffic. This means your body must grow your nerve pathways thicker to handle the increased load.
The path for increased speed is always slow. Why? Slower means accurate. Therefore, your brain has an easier time figuring out the shortest correct route to send commands. Your body responds by improving your neural highways.
It take 120 days for your body to renew itself. Therefore, you should track your improvements in these cycles.
Many players just don’t get that its requires a physiological change (along with mental) that brings improvement. Even though your mental capability may be there, your body has to catch up. Ramming 10 hours of practice a day will bring improvement. However, you do not have to practice that much to trigger the physiological changes that bring about the speed improvements you desire. There is a reason why Tom advocates practicing a maximum of 3 hours a day.
（来自Lee Gattenby，forum.tomhess.net）
根据这个理论，
1，每天的练习时间最多不应该超过3小时（技术/速度练习，不包括其他方面）。超时练习，不但是浪费时间，而且从精神上到身体上，有害无益。
2，练习，尤其是刚开始练习一项新技术，开始要练的极端慢，要克制快弹的冲动（极端慢指，以大概两秒一个音的速度开始）；用最正确最放松的方式练习，然后根据一些速度练习的系统方法逐步进行，可能整个进程会持续数月。（刚开始也许会非常枯燥。）
3，速度练习是一个身心同步提高的过程。并且涉及到神经元（实际身体上构造）的改变。身体的更新周期是120天。（这也可以解释为什么有时候较长时间不练习之后，重新拿起吉他会发现自己能解决之前不能解决的一些问题。有时候你的心里准备和练习已经够了，需要的是等待你的身体赶上意识的进度。）
4，最后一点，持续少量并且正确的练习，比大量粗糙的练习有效的多。真正建立一些速度练习的方法，并记录自己的成长。不要急躁、不要气馁。只要认真正确的练习，也许短时候的挫折只是技术突破的前夜。
另附两篇系统练习速度的文章。来自Rhapsody of Fire现任吉他手Tom Hess，转载请注明出处。
http://tomhess.net/Articles/HowToPracticeForMaximumSpeedPart1.aspx
http://tomhess.net/Articles/HowToPracticeForMaximumSpeedPart2.aspx
