Assuming that they are all new to badminton, why not start them off without the relatively heavy racket (unless you have a modified version), but just using their arms initially.
1. Line them up in a straight line with ample room for them to move their arms and body.
2. Since you have to start the clear with a "throwing action" as in throwing a ball, let them have a number of used shuttles in their "non-racket" hand or on the floor beside them.
3. To demonstrate first, with a shuttle in your "racket" hand (most will likely be right handed), throw it forward as far as you can, as though you are hitting the shuttle with a racket to do the attacking clear. Do not use the net yet.
Points to note:
a) Hold the shuttle at the cork (base).
b) Bring your arm up and behind your head and make sure your elbow is not pointing down.
c) Turn your body at the trunk/waist with head looking up front at imaginary target as you bring the shuttle backwards.
d) Your lower limbs, feet about shoulder width apart, left leg forward (opposite racket hand) for good balance, should move accordingly when you bring your hand behind your head (or thereabouts).
e) Then release the shuttle by throwing your hand forward as fast as possible. Your elbow should be as straight as possible (not bent) when your arm is about slightly forward your body. (Imagine you are hitting the shuttle with your racket as high as possible.)
Your arm should be closer to your body not away from it. When it comes down it should be across your body, ie from right to left. The other non-shuttle hand should be used to act as a balancer to steady both the backward and foreward movement actions.
f) Weight Transfer: The lower limbs, especially the legs, must provide the "transfer" of the body weight from backwards to forewards as the swing is completed. The right leg can go forward to complete the follow through.
The above could take 5 min.
Then introduce the
net as the barrier.
The kids will do the same routine of throwing the shuttle in proper movements, but this time they have to throw it across the net as far as possible. You may make it more enjoyable by dividing them into 3 groups of 2 players each (you form one of the groups) with the groups facing each other on the opposite side of the net. The distance between them could be adjusted accordingly, the more difficult being placing the groups farther apart to induce them to throw at each other as target.
The above could take another 5 min.
Playing with the Racket
*Acquaint the kids with the racket by teaching them the common grip.
*Allow them to hit the shuttle by boucing it on the strings, just to get the feel first.
*Then allow them to hit the shuttle harder towards the ceiling.
*Once they are quite confident, allow them to hit to their partners without the net yet, with the throwing/clearing action.
*Then bring the net into play.
This should take another 10 min. Lesson completed.
Good Luck
