The standard way of practicing fast passages is to start slowly with the metronome and then gradually bring the tempo up. Before we arrive at the desired speed, there usually is one tempo at which we begin to have trouble playing the passage through without stopping. This is because up to this point with this “gradual method,” we have only been practicing playing slowly. To play fast, one has to practice fast. The physiological reasons for this are simple. The body has two different kinds of muscles: fast-twitch and slow-twitch. Like athletes, as string players we must train both our fast-twitch and slow twitch muscles. A runner will tell you that the only way to train their fast-twitch muscles (i.e. increase speed) is to do interval training, or fartleks. In this kind of training, we practice activating our fast-twitch muscles by doing short bursts of speed (like sprints) with recovery in-between the bursts. The goal is to gradually increase the length (distance) of the fast bits (sprints) until you are able to complete your whole passage (distance) at top speed.
To get our fingers to remember tricky finger patterns in fast combinations, try the following exercise as a warm-up.
Daily Torture Exercise 1- An Oldie but a Goodie
Speedwork–This will train your fingers for fast combinations/muscle memory.
1) Play each group of 4 four times fast. Short pauses may be taken between groups, but it is crucial that the 4 fingers be played as rapidly as possible. For example:
1-2-3-4 *pause* 1-2-3-4 *pause* 1-2-3-4 *pause* 1-2-3-4 *pause*
1-2-4-3 *pause* 1-2-4-3 *pause* 1-2-4-3 *pause* 1-2-4-3 *pause*
etc, etc, ad nauseum, and I mean NAUS-E-UM.
2) Play the whole exercise all the way through 4X, one time on each string
3) You can change up the half and whole steps/change keys