Ask Augustin 49: How to keep your left hand relaxed during fast passages

It's been forever since I uploaded an Ask Augustin episode!
I'm very happy to announce that I've collaborated with Tonebase to produce a number of new episodes. There will be more in the next few weeks, so stay tuned!
Also, be sure to check out everything else they have to offer at http://www.tonebase.co/violin

In this episode, I talk about reducing tension while playing very fast passages. When you practice a fast piece (in this example, Paganini caprice 5, but it applies to any very fast piece really, particularly an extended one) it's important to keep your hand relaxed enough, to prevent fatigue in the hand and injury. Over the past 10 years, I've gradually optimized my left hand technique, decreasing tension considerably.
While it's inevitable that your hand will tense up sometimes, here are the things I like to focus on to decrease tension:
__ moving the first and second fingers as little as possible (often leaving them on the string if I will return to them, and only lifting them when necessary -- and not lifting them too high); -- you often don't need to press down on the string very much, when you are just tapping the note and then lifting again -- this applies particularly to the third and fourth finger.
Basically, the faster you are playing, the less you need to press on the string. And, the higher you are playing, the less you need to press on the string. Pressing less = less tension.
This will not only prevent injury, it can also help with playing more accurately- not least because it enables you to practice more before the hand gets tired.
Don't forget that, in any case, it takes time to build stamina-- remember to take enough breaks during your practice!