Do you have problems to handle the incoming spin?
If yes, then the following lines might help you to understand the rotation of a ball a little better which leads to a better ability to handle the spin. As a positive side effect your playing level with probably rise countless steps because by not eating the opponents spin, you also return most of his spin back to him and add your spin and speed on top of that.
As usual, if you already know everything about spin, feel free to spot and report mistakes as well as request additional information about certain points.
After reading this article you should be able to answer the following questions:
- Which spin types exists?
- How can I evade this particular spin and how do I choose the point of contact on the ball?
Do you need any prior knowledge from an other blog article to understand this?
No, but this might be helpful.
Part I – Types of spin
We roughly distinguish between three types of spin. We first recall that we need three coordinates to describe the position of an object, the length(x), width(y) and height(z). Table tennis wise we can imagine the x-y plane as the table surface and the height z as the height of the ball over the table.
Imagine the y line to be the end line of our table side and the x line to be the side line. We assume that we play in the direction of the x vector and call this direction v.
Now we need the definition of the axis of rotation, which shall be the line we get if we connect the two points of a ball with the smallest rotational velocity. But where are this points located? To illustrate this, we take a look at the “heat” map below.
The more the surface color moves into green the less the rotational speed. The heat map therefore tells us where we can hit the ball most safely regarding the spin we have to face.
The picture on the left displays the heat map of a sidespin ball.
In this case, the points with the smallest rotational velocity are the north and south pole and the axis of rotation connects these two points.
If we want to know which orbit on the sphere has the highest velocity, we imagine an usual oval race track. If we choose the inner orbit we have to run a smaller distance for one lap than a person on an outer orbit. Back to the ball we see that all points on it have to finish one rotation in the same time. If we want to run the greater distance on the outer orbit in the same time like the person on the inner one we have to run faster. The same applies to the ball.
Back to the spin types.
We use the concept of the heat map again to illustrate the imparted spin type. The axis of rotation is denoted with r. Where are aware that we slighty misuse the definitions of vector, line and the orientation of the rotation vector for an easier explanation.
To understand the pictures below a little better, we can prepare a little experiment. Grab two pens. Pen one (p1) is the stroke direction (v) while the other one (p2) represents the axis of rotation (r). Finally get a table tennis ball and use a desk surface as table tennis table (x-y surface). We pay attention that we sit at the y edge regarding the picture below.
We roll the ball away from us to simulate topspin.
The direction the ball rolls is v and we use p1 to illustrate this direction. We see that p1 is parallel to the table but could be pointing upwards in an certain angle in a real setting. The axis of rotation, which means our pen p2, is perpendicular to p1 and we connect p1 and p2 on their lower ends in an right angle. Surprisingly p2 is always parallel to our desk even if we lift p1 in a certain angle since they are connected on the end and just the tip of p1 is lifted.
Generally speaking, the axis of rotation (r) for an topspin / backspin ball is perpendicular to stroke direction (v) and parallel to the table surface (x-y plane).
We simulate corkscrewspin by brushing the ball on the left or right side in downward motion. The axis of rotation for our pen p2 obviously points away from us. The remaining properties are hardly doable and we have to use a little imagination here. By remembering that our desired stroke direction also points away from us, we see that we can lay pen 1 down next to pen 2. In this setup our pen p2 is complety connecting to pen 1 which means that if we lift the tip of p1 the position of p2 changes accordingly.
The fact that the axis of rotation (r) is parallel to the stroke direction (v) is the only general relation which can be made here. We conclude our collection of spin types with sidespin in the following picture.
We simulate sidespin by simply rotating our ball. By doing so we see that our pen p2 has to stand upwards and is connected to p1 at the lower end. Pen p1 points away from us as usual. If we try to lift our pen p1 on the tip we can see that we have to drag pen p2 towards us to maintain the right angle between them.
Back at our general setting we conclude that the axis of rotation is perpendicular to the stroke direction.
Part II – How to avoid the spin
We now know the different types of spin. The most common of the above three are topspin / backspin and sidespin. In the following lines we want to use our previously gained knowledge of the heat map to develop techniques for avoiding these two common spin types and understand the reasons behind our decisions.
The white rectangles illustrate a possible racket position to hit there.
To face the least amount of spin we could hit position 2 and 5. However it’s technically harder to hit the north and south pole exactly and the error chance for completely missing the ball is therefore bigger. The big advantage is the fact that we can slighty misjudge the amount of imparted topspin / backspin as seen in the pictures below.
As a rule of thumb, if we are sure about the sidespin to topspin / backspin ratio we use a location like 1,3,4 or 6 to compensate a possible technical inaccuracy in hitting the exact point.
If we are not sure about the ratio we have to take the greater technical risk and aim for position 2 or 5 to minimize our judgemental error.
If we are confident in our technique and spin judgement we also go for 2 or 5. The promised example can be found below:
The given stroke locations can be achieved by several techniques. The most common are given below.
- Position 1 : backhand loop / block
- Position 2 : backhand loop / block / forehand loop ( harder than backhand loop here)
- Position 3 : forehand loop / block
- Position 4 : push / chiquita
- Position 5 : push
- Position 6 : push / forehand hook loop
By chiquita we mean the backhand loop over the table which has its contact point on the lower hemisphere of the ball. Backhand loops with an contact point on or above the equator are called backhand loops. We remember that we use different grips between these two, backhand grip for the loop since the position of the racket favors contact points on or above the equator and the forehand grip for the chiquita because it favors contact points below the equator.
This paragraph made it pretty clear why the backhand techniques are dominant over the table. With the loop and chiquita we can increase the power of every ball and still have to advantage of the imparted topspin / sidespin arc which gives us a better consistency compared to flat trajectory shots.
Just consider the picture with the sidetopspin where most of the backhand side was red. By using the chiquita we can still play an optimal ball over the table. Compare this to vice versa forehand case. The only offensive stroke for contact point below the equator with an strong arc can’t be used because we are over the table.
Combine this results with the giving advantages of the position determination over the table by the left hand and the advantages due to our body anatomy and there are no questions left regarding the technical superiority of the backhand techniques over the table.
However, we recall that technical advantage isn’t the whole picture since the backhand techniques over the table require a big amount of footwork to come in position and close the wide backhand gap afterwards.
Topspin / Backspin
This knowledge can be applied during topspin rallies by hitting with more sidespin than trying to overpower the already strong topspin, by blocking more lateral than frontal or by hitting position 4 or 3 if we are defenders and try to chop heavy.
As said in the beginning lines, the beauty of the spin evasion lies in the fact, that we not only evade it, we also return it partially.
After the previous extensive explanation we should be able to find possible strokes for all given numbers.
- spin types: backspin,topspin,corkscrewspin,sidespin and all mixes of it
- evasion: hit where the rotation is the smallest, choose according to the given rule of thumb