tenis-maniak.pl - What is the "pronation and supination" and why it matters?

What is the "pronation and supination" and why it matters?

At the very beginning I would like to explain what is the pronation and suplination of the forearm and arm and why it matters for us - people after medical or sport studies can skip the introduction part ;)

Pronation is rotating movement of forearm in the wrist and elbow joint but we need to underline that elbow is making more work – some analyses say it’s 75% to 15 %. Supination is movement against the pronation – other direction. Shoulder have 3 degrees of movement and combined with other joints we can achieve big range of movement.

To illustrate this movement I will use simple exercise. Please rise your hand shoulder high and look at your palm. Put your elbow for an example on the table to lock the shoulder movement. Than turn your palm to see back of it. It’s isolated pronation movement but we don’t find isolated movement’s like this while playing tennis. We are going to use another exercise. Please rise your arm shoulder high again. Bend your arm this way that your forearm is pointing up and your thumb is pointing back. Than you need to straighten your arm but this way that your thumb is pointing up. This is simple straightening of forearm. Now repeat the same exercise but after straightening your thumb should point down. Try which movement is faster? This type of forearm rotation we call pronation and we can observe it during service. Player when pulling racquet from his back is using forearm straightening to reach as high as possible and at the very last moment (starting from about 90 degrees of forearm and arm bend angle) he is starting the forearm pronation to give as much acceleration to the racquet and to the ball as possible.

Pronation of forearm during service is combined with arm pronation. It’s easy to illustrate this movement when rising arm to the side and pointing forearm and your fingers up. Than you need to keep your elbow at the same level(you will need a help to do that from other joints because it’s not well separated movement) but you need to drop forearm down to point with your fingers down. Putting this two pronation movements will give best results to accelerate the ball while hitting serve.

Why pronation is so important? This movement cause giving to the racquet bigger acceleration. Researches says that pronation of arm is responsible for about 40 % of racquet acceleration and the forearm in about 10-20 %. Making this movement in the proper serve sequence will pay off with higher ball speed. Very often with amateurs I find difficulties with a grip. It’s hard to switch to the continental grip for them and they use forehand one which require only the forearm straightening but is not allowing to really smash the ball because movement of wrist and forearm is blocked. Changes in the grip at the very beginning causes problems with proper ball contact – movement around the ball, slice serve, hitting with a frame. It’s all because while using continental grip there is no pronation of the forearm, which would let to show head of the racquet to the ball and than smash it down. Lack of understanding the pronation movement is one of the problem for amateurs to switch to continental grip.

What we can do to practice the pronation movement and put it into our serve? There is no simple answer to that question because we find different problems- grips , position, movement. It takes some time to change our habits and the core of movement. Some exercise that I use:
- Throw the ball or the flying toys- kids loves bombs- to the other side of the net, to each other or play games. Practice the throws from the sharp angle – from the Ad side , moving all the way to the double alley. We can repeat this in different positions and directions. It’s important to underline that we should throw high not flat because we need to reach high to the ball while serve.
- Throw in the ground to accelerate the arm pronation. Try to smash the ball and let it bounce as high as possible. You can try to smash the ball with your racquet as well but keep safe distance in the group. AND OTHERS ;)

For a good serve it’s important to practice throws from the very begging as soon as kid comes on court because serve is nothing but “throwing the racquet”. If you practice that with a kid, few years later you won’t have this kind of a problems with a player :D

I would like to use a photo of Venus Williams serve to show some parts of the movement I wrote about in this article.

I have marked on the photo key elements of good use of arm and forearm pronation
1. Head of the racquet is dropped down behind the back and away from the body( this angle and moment on the photo doesn’t show perfect possible range of movement, she's got more room for that) using the forearm pronation.
2. Hitting the ball as high as possible with use of pronation.
3. I have marked extreme position of pronation.
4. Dropping racquet to the left with relaxed shoulder muscles and with a good body balance with landing on the left foot and the “back kick” of the right one.