t’s a valid question as there is a level of Fitness (fitness for purpose) for everything we do.
The two variables are the purpose and required fitness level.
Andy Murray had to opt for a metal hip to keep playing and other pros work hard to maintain or improve their level to compete at the top of the game. That’s their purpose and the consequent level of fitness they need to attain. No new information so far, but let’s consider a question that’s becoming increasingly difficult to duck without consequences. What’s your level and what do you do, or need to do to achieve it? Do you do this? https://www.youtube.com/watch?v=F_9Bmag3ee0
No, nor do I although it might work for her to achieve her goals at her level.  Do you lift weights and/or sit at one of the many shiny muscle workout machines at the gym? https://www.youtube.com/watch?v=wdew6wIkX0M Look out for my vlog on muscles as reactors.
You might want that sort of muscle definition, but these types of workouts won’t help your tennis. The Gray institute has a saying penned by Gary Gray ” If your golf workout doesn’t look like golf or smell like golf, it probably won’t help your golf a lot’. The same applies to any activity, in this case tennis.

As a recreational player do you, as I used to, consider the walk from the car enough of a warm up? Honestly… it’s what a lot of club tennis players do, with some doing a couple of static stretches which help but are really inadequate to prepare for the rigours and stresses of playing, whatever your level. Being fit to play tennis has taken on a whole new resonance at the top of the game over the last few years. Murray’s metal hip, Nadal’s litany of injuries which regularly interrupt his progress, Federer’s knees forcing retirement and even Djokovic now having more injury time outs in matches. I hear you say yes but they are mature players who should expect physical decline. But then, what about the so called ‘Next Gen’ and the prominence of injury interrupting their fledgling careers, Alcaraz, Draper and Radacanu to name some of the many in recent headlines.

Has something changed? Could it be that racket and string technology have made the game faster and more physically demanding at the top level? Do their training regimes, which also add to the speed of the game, now need to address the ability of their bodies to withstand the physical stresses and strains of today’s professional game.

But I hear you say, and you can perm anyone of following; I play for fun, I don’t play very often, I only play doubles, I’ve never been injured before and a whole host of other reasons why I don’t train or have any warm up routines. It’s achingly clear that you need a level of fitness to play this game, whatever your standard, to get the most out of it, to achieve your goals and to play on for as long as you want without injury constantly interrupting your play.

If what’s happening at the top of the game at the moment convinces you of your need to know your level of fitness for purpose and how to improve it sustainably then you need to read on.

But the question remains, what sustainable level of fitness do you need for your level of tennis (or desired level), which begs the question how do I measure my level and consequently how do I develop it. (I mean Fitness for Function, not some arbitrary measure of muscle strength or cardio capacity.)

There is no silver bullet, it’s 3D MAPS: Three-dimensional Movement Analysis and Performance System which can answer these questions for you and help you achieve your goals whether through a trained coach, therapist, or home workout program. 3D MAPS will allow your coach/trainer to assess your movement capability, both mobility, and stability, in both directions of all three planes of motion. These aren’t measurements against some arbitrary standard, they are a record of your range of motion at the start of a process of sustainable improvements you can make. The analysis allows us to assess your ability for skill acquisition and more fluid movement patterns, and which by applying selected exercise matrices enables you to develop your biomechanical function for your function, tennis. It is an integral part of my sustainability coaching that will enable you to play the best tennis you can and dramatically reduce the risk of the types of acute or chronic injury that keep a lot of recreational tennis players off the court for long periods of time. Injuries like tennis elbow, tennis leg, rotator cuff impingements and a variety of other complaints which are mostly not normal, not necessarily the result of aging, and more likely to be avoidable with tennis sustainability coaching with me.

You only have one body, work with it and it will work for you, for longer. See these functional exercise matrices and see the Chain Reaction vlogs.