Found out my own answer! Good article:
Is Nadal Sending Out The Wrong Message
With the modern tennis focus on power and the physique of Rafael Nadal, players are hitting the gym in the quest to become stronger and, hopefully, more powerful on court.
Increasing strength can improve the intensities at which players can perform (as well as reducing the potential for injury), but can you be too strong?
For example, there have been many past players who were acknowledged as being very fit, but I think you would agree were not visually brimming with strength and power like Nadal.
Would those former stars have been more “talented” than a Nadal if they had been stronger?
Would they have been that much better if they had been training today?
There is no question that strength without skill, or even good skill levels with low strength, will produce less than optimum results. But does it really matter if a player can squat 440+ lbs (200+ kg)? Is a squat of 220 lbs (100 kg) along with great stability, power, body control, and skill, etc. a better combination?
I can hear some of you saying, “Why not have all these and a 440+ lbs) 200+ kg squat”?
The main problem I see is that many coaches and fitness trainers are getting their players to weight train using “old” non-sports specific bodybuilding principles focusing on building size in isolated muscles using exercises that focus primarily on one plane of motion.
Is this the fault of the players like Nadal – is Nadal sending out the wrong message?
Let’s get back to that 440+ lbs (200+ kg) squat.
To work on the squat in this way means at best that the player loads up the bar to the point where they need a “spotter” for safety reasons or they use a cage that is safer, but because the bar is fixed it does not allow them to work in a multi-planer environment – which after all is how the game is played.
The big problem with both of these scenarios is that the excessive loading that must occur to the spine and joints on an ongoing basis must impact on the risk/safety ratio over time. The greater the loads we use in this way surely increase the chance of injury and in my experience players often "fail" because of the physical and mental pressure of the bar on their backs rather than because of fatigue in the legs.
While I completely understand the push for greater loads to improve absolute strength levels, I feel that there is a different way to improve performance and reduce injuries. There is no doubt that for a player to improve strength they must train at intensities high enough to elicit a strength response (principle of overload).
Nevertheless, I feel that there is a better way to increase muscular and nervous system loading, yet lessening the strain on the spine and joints. To achieve this I recommend the use of single leg exercises that not only produce great strength gains, but also increased stability and balance without the risk of back and joint injury.
If we think about it the game is played predominantly on a single leg basis anyway. You can still do maximal lifts just as one would with double leg squatting, without the excessive loads on the spine and joints.
NOTE - You can also use this type of training on the upper body with the use of dumbbells. This again forces a greater nervous system response.
I also believe that training in this way improves tennis specific strength in a way that provides an added skill component to a players’ physical training, which will reap rewards they can transfer directly to the court.
Ultimately, it's not that Nadal is sending out the wrong message; it's that the message being sent is being wrongly interpreted by much of the coaching and playing community.
Let's not forget that Nadal is a very talented player, who was born with innate tennis skills that he has honed over the years. The physique he has and the physicality of his game enhance his considerable racket skills without which he would not be the same player.
Don’t misunderstand me; the physical side of his game is very important just as it is to many of the top tour players, but to train the nervous system (by adding balance and stabilizing challenges) alongside the muscular system is a superior form of training from both a skill enhancement and functional basis as well as being a safer environment for the players.
After all in a multi-skilled sport like tennis the objective is to improve sport performance and reduce injury potential, not build entrants for body-building competitions. So do your strength work wisely, which means as a sportsperson not a bodybuilder (there is a difference), which will leave you more time to enhance your skill development.