One of the most efficient ways to generate power in all of your strokes is to use more of your body than your arms.
By “body,” I refer mainly to the trunk/torso area which normally contains most of your body mass.
If we can engage this body mass more as we hit a very light tennis ball, we’ll make that little ball fly off our racquets effortlessly.
We’ll need to veer off to the field of physics for a minute, but no worries – we’ll be back very soon!
The physics of hitting a tennis ball is very complex if we want to get to the bottom of it as it includes friction, ball deformation, angles of the racquet path, angle of the racquet face, angular momentum and so on.
But, in the most basic way, we are dealing with the transfer and conservation of momentum.
Momentum is defined as mass times speed, and the laws of physics say that if there is a collision between two objects (in an isolated system – no other forces are in play), the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision.
When the racquet and the ball collide, the racquet transfers some of its momentum to the ball.
And since momentum is a product of mass and speed, that tells us that if we increase either or both, we will increase the total momentum.
In tennis, we use both principles, especially when it comes to groundstrokes.
This article focuses mostly on the first principle, which is adding body weight to the stroke in both neutral and open stance, meaning we want to step into the ball or rotate through the stroke continuously.
Those are both the foundations of weight transfer upon which we build the more advanced technique which uses body acceleration and deceleration to transfer the momentum from the body into the arm, which then makes the arm accelerate.
We’re then using the second principle, which is speeding up the arm and the racquet in order to increase the momentum transferred into the ball.
The foundation that most recreational and junior tennis players are missing is to engage their body in the first place and put more body weight into the stroke.
So, let’s continue with this topic for the remainder of this article….
The first principle of adding more power (momentum) to our strokes is to increase the mass of the object going towards the tennis ball.
If we swing with the same speed but increase the mass of the racquet, the speed of the outgoing ball will increase since its mass is constant.
The graph above shows how the speed of the outgoing ball increases with the mass of the racquet. (Image credit and more on the physics of hitting a tennis ball.)
But, heavy racquets are difficult to maneuver, require a lot of strength and almost perfect technique as their greater momentum can cause injuries to a recreational tennis player.
So, instead of increasing the mass of the racquet, we must try to “add” our mass to the racquet so that we can increase the total momentum and therefore make that small ball fly faster off our racquet.
“Put your weight behind the ball!” and “Lean into the shot!” are some instructions you might have heard from coaches here and there.
What they want is to have the player transfer weight into the ball.
When we transfer weight into the shot, we basically connect the arm and the racquet to our body and therefore put more weight behind the racquet and increase its momentum.
If we do not transfer weight into the shot and do not engage the body much, the mass going against the ball is basically the mass of our arm plus the racquet, so the total momentum is not that big.
There is a distinct difference when I hit a stroke while my body is static and I engage solely my arm to hit the ball compared to the stroke when I engage more of my body, either with linear weight transfer or by adding more rotation of the trunk.
I feel exactly what the physics explain mathematically: I am transferring greater momentum into the ball; therefore, the little, light ball has to fly off faster off the racquet.
And not only that, I feel that my arm doesn’t have to contract and “work” so much, so I gain much more feel and the ability to adjust to each ball.
In fact, weight transfer makes especially groundstrokes so effortless and comfortable that I have been looking to hit the ball almost every time with the weight transfer if only I have enough time to set up early for the shot.
And that brings us to…
If we don’t transfer the weight into the ball and we simply imagine that we need to reach the ball and then swing the racquet, we can do that fairly quickly.
Swinging the racquet forward takes very little time, so we don’t need to be at the right place very early.
But, if we want to transfer our body weight into the ball, it will take much more time to get the body going into the ball as it’s much heavier and takes time to get going.
Of course, the better athlete you are, the faster you can do it, but there’s still a big difference in how much time it takes to move your arm and the racquet two feet forward, for example, compared to how much time it takes to move your trunk two feet forward.
That’s why we need to be at the right place much earlier if we want to transfer weight into the ball as our whole stroke will take more time.
That means we must be able to judge the ball flight faster and be able to move faster to the proper hitting position if we want to buy ourselves some time so that we can use it for weight transfer.
That’s why tennis beginners who judge the ball very poorly and don’t know where it’s going to land can’t get into the position early enough to have enough time for weight transfer.
If they play for a long time with someone playing too fast for their judging and movement ability, they will develop a habit of NOT putting weight transfer into the ball and will stick to it even when their judgment and movement abilities improve and they could transfer weight into the ball!
Just something to keep in mind if you’re playing with beginners. The danger of developing bad habits in tennis when you attempt to play much better tennis than you’re currently capable of is very very big.
The first step to using weight transfer more often is becoming aware of how it feels different when we hit without and with weight transfer.
Once you’re aware of the difference and you feel how much more comfortable and powerful your strokes are when you transfer weight into the ball, you should attempt to do that when you can.
Everything, of course, depends on the situation you’re in and whether linear weight transfer, meaning hitting in neutral stance, is more adequate for that situation than open stance.
I know that many tennis players want to KNOW with certainty what is correct and what isn’t. That is impossible to answer in theory as there are infinite possible situations on the court.
But, in practice, we can answer in a very simple way: which stance – neutral or open – feels better?
In which stance did you feel better energy transfer into the ball, and in which were you better balanced?
As you experiment thousands of times while playing different balls in different situations, you’ll feel which stance is better suited for each situation.
I firmly believe that there is no need for a theoretical explanation which says: “In situation A, it’s better to use neutral stance, and in situation B it’s better to use open stance.”
There is no need to tell that to the player ever.
All that is needed is to have the player EXPERIENCE and be aware of how it feels to hit a stroke with a certain stance in a certain situation, and they will very quickly feel which one is better.
After all, we do not think about stances when we play tennis.
We simply operate with energy transfer based on feel and our brain unconsciously chooses a certain stance and body movement based on the situation we’re in.
While we do consciously repeat footwork patterns with players in training so that they improve their foot speed and balance in these specific situations, we do not have to tell them when to use which one. Again, they will not think when they play so this “theoretical” knowledge is pointless.
If one player uses an open stance, for example, when moving forward to a short ball and is afterward approaching the net, that means that the player is simply not aware of how better that would feel with a neutral stance. And how much more ball control he would have…
No one chooses uncomfortable stances and strokes on purpose. The only reason they do is because they are not aware of the more comfortable ones.
But, I digress. So, let’s get back to how we can add more effortless power to our strokes.
To conclude, laws of physics and practical experience tell us that there will be much more momentum transferred into the ball if we add body weight into the stroke, in this case stepping into the ball in a neutral stance.
Your goal is to feel the difference at first of how it feels when you hit the ball only with your arm compared to hitting the ball when you’re able to step in.
Once you’re aware of how much more effortless and powerful your stroke is, look for that when you can.
Most players that have trouble with the weight transfer and don’t really use it are those who play very close to the baseline.
When you’re close to the baseline, you don’t have the space or the time to move against the ball.
So, what you can do is have your starting position further behind the baseline and move towards the ball in a diagonal way, therefore automatically transferring some weight into it.
Just remember to always recover slightly further back behind the baseline than you’re used to.
This is also very useful when you’re practicing volleys and, of course, when you’re playing them.
Again, always use common sense and not just rules.
You don’t have to step into the volley if there’s no time for that.
You can simply lean against the ball slightly if it’s fast or use your arms only to play it back if that is better in a certain situation.
I like to use the term “engaging the body” when talking about open stance forehands and backhands because it immediately tells to the player what to look for.
Open stance can be executed incorrectly, too, where the player typically doesn’t really rotate the shoulders much in the preparation phase nor does he rotate the body through the hitting zone, and that’s typically because they are preoccupied with what to do with their arms.
As mentioned above, we can increase the momentum of our racquet in two ways:
I find that the second approach simply develops in time unconsciously if the first one is in place.
The players are actually rarely aware when each happens in the same way as they are not aware of which stance they use for each stroke. They simply want to hit the ball in a certain way, and the brain and body find the most efficient way to do it.
You can use this simple arm-dangling exercise shown in the video above where you can feel very distinctly what it means to engage and rotate your body instead of your arms.
Then try to apply the same feel when you’re hitting an easy ball and try to feel if there’s any difference in how much effort you need to hit the ball and how much your arm is straining as you’re hitting the ball.
The same principles of adding more weight to your shots apply also to the one-handed backhand where the linear weight transfer is the key to getting more power.
We often get lost in the technique of the strokes as we observe all the time only the arm movement and the racquet path.
Whenever we pay so much attention to the arm, we will unconsciously disengage the body.
That’s also one of the biggest problems with the serve technique.
There’s much to observe when it comes to the racquet drop, pronation, racquet path and so on that, as we try to move our arm correctly, we stop using the trunk and hips and therefore cut the energy transfer from the body.
The linear weight transfer and engaging your body more in open stance and other strokes in tennis will relieve your arms of a lot of work and help you regain that fine feel and control of the racquet face you need to play the ball very accurately.
Your long-term goal is to bring as much work as possible as close as possible to the center of your body and away from your arms.
Our eyes always spot the moving objects first. Whether you want it or not, the first thing you’ll observe in a tennis stroke is the racquet and its path.
You’ll also see that the racquet is held in the arm, and you’ll assume that we move the racquet with the arm, so you’ll try to copy that.
That’s where you’ll go wrong as ALL of the tennis strokes are initiated (unless in emergency situations) from the core and from the center of the body.
The core and the shoulder axis are the parts of the body that generate the most power, and they transfer that power to the arms.
Next time you observe the pros on YouTube, consciously focus on the trunk and try to note how they transfer weight into shots and how they engage the body in open stance. Stop paying attention to the racquet for once!
This time look only in the area between the knees and the shoulders and try to notice how Federer uses his core to initiate all other movements.
So, as you hit your strokes in easy conditions, at first rallying with your partner nicely, focus on transferring as much work as possible towards the center of the body and relieve your arms of work.
It’s a long term process with which in time you’ll get better and better and learn to hit with more power, more control and less overall effort.