Are kids able to copy the biomechanics of modern tennis? Is it a problem body and focus wise? What about many repetitions of a movement in young age? Let me give you my view on it.

Nothing speaks against the copying elements of the pro`s strokes, if bio-mechanical principles are respected. With the right material (proper racket size, proper balls, proper number of repetition) even in very young age it is no problem. The most important aspect when training with young kids between 5 and ten years is the danger of too early specialization. Jelena (5/on the pic above) is practicing two hours tennis a week but additionally goes one time to athletics and one time to ballet. It is important that kids have also days where they can only play and can stay kids. The fun is of highest priority. If it feels for them like a “must do”, fun can disappear very fast. Let the kids do as many as possible different movement solutions from different sports so a wide range of coordination skills can develop. It is also important that they get the chance to decide on their own when playing and that they have to deal with conflicts. Playing (not in the sense of doing sports) is important to develop the “executive functions” of the frontal brain lobe.

Learning the different techniques of tennis should not be only on the basis of “try and error”. It is normal that kids start hitting with huge loops on back swing, braking the plane (crossing the shoulder axis) because they think it is the best way to give the ball speed. And it is definitely the most natural way to hit the ball. But “natural” does not mean it is suitable for the geometry, ball physics and biomechanics needed to play “modern tennis” on a tennis court. Despite of this, non optimal strokes are difficult to correct later on when having done thousands of repetitions that way. Let us take an example on the “modern forehand” in tennis. What are the requirements that make a great biomechanics of a pro`s shot possible?

A compact back swing (unit turn) with no early separation of both hands
The elbow having a at least 45 degrees angle from the body and having enough free space between upper body and elbow
A drop of the racket with not going the long way breaking the plane (crossing shoulder axis)
A proper “lag drive position ( with maximum extension of the wrist)
a contact point diagonally in front of the body with an almost stretched arm (depending on grip eastern/semi western/western)
A long phase of the racket strings facing the net for a maximum spin impact on the ball (depending on shot selection and intention)
a not to early rotation of the shoulder axis
A dynamic whip of the racket which starts during contact and ends with the racket tip showing to the ground on the left side of the body. The elbow facing the target.
a sound kinetic chain release

These are a lot of points that have to go together and if neglected can lead to limited technique. Do not forget that technique is a LIMITATION FACTOR in tennis.

For me the player must be able to produce all kind of ball trajectories (flat, spin, heavy spin) to be able to not let the opponent play too many balls in row in his comfort zone.

In the picture above you can see a great example of four different back swings but all of them having the requirements needed for a proper use of ball physics, biomechanics due to individual body measurements and intention in relation to target (court geometry).

None of them has the elbow very near to the body so enough racket acceleration swing way is guaranteed, maintaining a compact back swing. Here we get to a first crucial point of sound biomechanics on the forehand. If the elbow is not away from the body on the back swing, it keeps staying near or on the body and it is natural that the arm keeps bend on contact with the ball, with the result that the arm will cross the body far too early. That means that the ball gets less spin, less curved trajectory and no depth.

Common examples that result in poor biomechanics

In the picture above you can see the most common examples resulting in poor biomechanics. The early separation of both hands (kids do this very often when running to short balls) results in a big loop and in a late contact point. The risk of playing the ball into the net or with almost no spin out of the lines of the court is high. As mentioned before the elbow near the body or on body at back swing and as a result also at contact point with low acceleration only using the forearm. Another often seen example is a late contact on return or ground strokes because of a loopy backswing breaking the plane. Here often the contact point is just next to the body with a high strain onto the shoulder. All that examples lead to no variation of contact points for the opponent (meaning that the opponent has always time to get to the ball and the ball keeps jumping into the comfort zone between hip and shoulder height).

In modern tennis the two arm positions on contact point are an “almost straight arm” or a “bend arm” on contact. The bending of the arm is a result of the extremeness of the grip. Roger Federer for example with a not extreme grip contacts the ball with a almost stretched arm.

Brushing the ball vertical and diagonal (both goes together)

Depending on the racket swing path during impact of the ball he creates more or less spin and ball trajectories on his shots. As longer the racket stays parallel to net during the contact, what means that the strings brush vertically upwards, as more spin is produced onto the ball. On flat shots the horizontal wrist snap is taking place very early, on spin and heavy spin shots the parallel to net string position is longer, before the wrist snaps in. We are talking here about fractions of time and very little differences.

Different ball trajectories depending on RPM.

Different ball penetration according to RPM.

We mentioned before that as more extreme are the grips, as more the arm is bend on contact point. The best pro`s still manage to have the elbow away from the body on contact point because they have it in a distance to the upper body when doing the unit turn. See here an example of Novak on contact point (picture below).

Another result of the contact point very much in front of the body is the capability to hit the ball “nearer” to the net to be able to produce better angles.

Angle play from angle bisector positions

The difference between cross and down the line on racket head position

Due to a tiny difference of the angle at contact point the hit ball goes down the line or cross court. This is the most challenging factor for young kids developing sound biomechanics. A modern forehand shot is depending on a sound kinetic chain from lower body, over core to upper body. Here the position of the legs on stance and the resulting range of hip and shoulder axis rotation have an impact of the right angle of the racket head on contact of the ball. While the range of hip and shoulder rotation is high, the range of the racket head position is just about 3 degrees difference to place the shot cross court or down the line. The geometry of the court does not allow higher ranges on that angle. Our young students and also very good Juniors struggle with timing the hip and shoulder rotation with the optimal racket head position on contact point. In my eyes this is the most difficult task for the whole career of a player. How often do we have too early hip rotation resulting in too early shoulder rotation with having the contact point in a position so the ball goes wide cross court out, or the ball is hit with frame? I lost count ;-) The same when the players have a loopy back swing, two back swings or even too long stop of the racket on loading phase. In that case, often the ball is hit a bit too late and goes more middle court or out when supposed to strike down the line.

So when knowing all of these important factors we need to have a red line according to develop a sound biomechanics for our players in their development as young tennis playing kids. Giving them too many corrections and trying to press them into a kind of “form” that we try to apply for every player is not the best solution the same as giving them too much freedom in finding their shots. From my experience the young kids do well in shadowing with proper technique and quite well when balls are fed from low distance. When they have to play from bigger distances, playing rallies or points, the quality of the shots goes down. Here it is important to understand that the kids need to develop plenty of different neuronal pathways to be able to relay on them under stress. Nothing blocks movement patterns more than stress. We must understand as coaches that playing the shot isolated is not the same as in a rally, with serve and return, in practice match or in official match (or with parents watching nervous from outside the court ;-)

The stress factor increases from rally to official match. If we do not work on multiple neuronal pathway building under stress, the development will be poor.

HERE ARE MY TOP 4 ADVICES

Always implement coordination exercises at beginning or in between technique sessions
Teach technique match orientated if possible always combined with a game and with a proper target
Implement exercises where they have to work their decision making (developing the frontal lobe of brain and the executive functions)
fun is the most important aspect for very young kids and also for developed players

A red line for kids development to orientate on

We as coaches are responsible for how many tools we give our students to be geared up for the up and downs of a official match.

All the best COACH DIMI