I made an observation back in August 2013 when I was on my circuit of US collegiate volleyball team trainings. It was the way jump float serves changed in recent years. The main idea of the jump float serve remains the same. The player strikes the ball at a higher contact point. That creates a more favorable serve trajectory than could be achieved while standing. A standing float requires the ball to first rise to be able to clear the net. That is not the case for the jump float – at least for taller players. What is evolving is the approach.
Over the years, we have seen a number of different types of jump float serve approaches. One of the most popular for a while was a slide type of approach where the server jumps off one foot (rather like a lay-up in basketball). This sort of approach is often parallel to the end line, similar to how a slide approach is parallel to the net. You can still see some players using it today.
What seems to have become the dominant technique these days, though, is what Brian Gimmillaro at Long Beach State referred to as a poor spike approach. It features the standard 3-step footwork of Left-Right-Left (Right-Left-Right for lefties), but in a much subdued fashion. It’s kind of like a step-shuffle, rather than being something explosive. The toss is usually with the non-hitting hand. Some players use a 2-hand toss, though.
Clearly, the idea of this new approach technique is to execute serves more consistently. It doesn’t offer the same type of reach potential as the slide type of approach, but also reduces the variability. Basically, it trades height for consistency. The fact that things have worked in this direction suggests that while coaches certainly see the value of aggressive serving, they also understand that at a certain point getting a little more height (and maybe power) may be more than offset by the decrease in accuracy.