I play a lot of tennis. I have often thought about the similarities found in the mindset and decision making between the tennis player and the improvising musician. On the surface an analogy can be made about the structure of the court (the lines within which the point must be played), and the structure of a song (the form and harmony which defines the particular song being played). For both the tennis player and the jazz musician, we must play within that fundamental structure, yet within those lines we have infinite freedom and room for creativity as to what kind of shot we hit or what notes we play. This isn't exactly an original thought, Jim Hall was also an avid tennis player and spoke about the similarities between jazz and tennis many times, but it's a connection I think about often both on the tennis court and on the bandstand.
In a couple of conversations I've had with students recently, one of the more interesting and perhaps instructive aspects of this analogy was highlighted for me. This is the notion of preparing and intending to do one thing but then reacting to the circumstances of the moment and perhaps choosing to do something else. Musicians and tennis players both train/practice in order to equip ourselves with tools and skills and options which we will use in match or performance situations. No matter what skill level one is at, the process is more or less the same, you draw from the tools you have and (mostly) play within your ability. This can probably be said of many endeavors, but where the close connection between tennis and improvising is really prominent is this: The intention to do one thing but the fluid flexibility to react in the moment and successfully execute something else.
When I'm soloing through a tune, my goal is to weave a compelling melodic thread through the form and harmony, my available tools are all of the devices I may draw from for phrasing (guide tones, target notes, motifs, tension/release, repetition, horizontal/vertical, inside/outside, contrast, space, dynamics, nuance, rhythmic variation, etc...). I might be playing a line through a passage following an idea taking shape in my head, it may seem clear to me where this line is going, where and how it's going to resolve. But along the way something may interfere, perhaps someone in the rhythm section plays something unexpected, or maybe I'm reaching for something and at that instant realize I'm not quite going to make it, in either scenario I have to be ready and able to react to the moment and play something else.
For a tennis player on the court something similar usually unfolds, I can be in a rally with a familiar opponent where the patterns are somewhat predictable, but then maybe a certain unexpected shot, or effect on the bounce from spin, or a let cord, or my foot slips, etc.. can make me have to react suddenly and decisively. Actually this kind of surprise probably happens much more frequently in tennis because you have someone working against you as opposed to music where hopefully all are collectively playing towards the same end goal. But all the same I feel that the process of decision making and creativity in tennis is beneficial companion to help nurture the musical improviser's mindset., and visa versa. This is just one of many analogies which stem from the similarities between tennis and improvising, I'll share more later.