The throwing arm should be kept at approximately 90 deg from the torso at all times. Lowering the to much, ie the discus in the body, leads to the dreaded scooping. Scooping is when the athlete throws at an angle much to high (closer to 90 than 40-45 degrees).
This can be caused by dropping the left shoulder during the turn across the circle which leads to a loss of balance which can cause the athlete to look up and away from the discus quickly. Make sure the thrower's shoulders are square during the throw.
2) Whiplash turning of the head.
The head of the thrower and the discus must turn at exactly the same speed. If the head turns faster than the disc, it will cause a loss of control. This results in foul throws, throws into the cage and generally unsafe throws - plus 0m of distance.
3) Improper flight of the discus
This is when a discus wobbles and is often the result of the thrower tilting the hand during the throw and not getting a smooth, relatively flat hand on release. Ephasise a smooth steady hand while throwing. THe flight of the discus tells us many things about the throw.
4) "Gopher Hunting"
This is a popular phrase in my group refering to low throws. It could happen if the athlete doesn't "throw thru the point". By this I mean their arm is moving at the correct angle for release but then the thrower's follow thru doesn't continue on the same upward path. If the follow through is downward then the discus will not achieve its desired height. It is possible that the athlete isn't achieving the proper throwing angle (~45 deg.).
5) Narrow base in power position
In the power position feet should be wider than shoulder width, back leg bent and front leg straight. Having a narrow base can lead to scooping, premature jumping and even fouling. It also results in a loss of leg drive or "hip whip", as their is less time for the leg to generate force for the throw.
6) Too many preliminary swings
This just wastes power and time and it costs distance, need I say more.
7) Athlete dips left shoulder during the drive across the circle
This often puts the athlete off balance and leads to problems like scooping. Have the athlete keep up tall during the drive.
8) Blocked / in the bucket
blocked --> the block leg prevents the power leg from fully rotating to the front - this lowers your power
bucket --> prevents you from achivening max. distance by taking force away from the direction of the throw
Do plenty of phantom (throwing without the implement) throws/jump-turns until they hit it right and then do some more.
9) Late left foot
During the jump-turn, it is important to get the left foot down ASAP. You can't leave the power position with any amount of force until the block leg is down. Work on the quickness of your jump-turns (esp. phantoms!) and put the empahasis getting the left leg around and down. While the goal is to turn with the left leg fully extended begginners will need to kep it bent, then slowly extend as they are able to rotate faster.
10) Not finishing up tall
Athletes sometimes have a problem bending over excessively at release. This is due to a poor left side blocking action. (contract the abs hard!!!)
11) Weight shifts forward
Sometimes the thrower will shift their weight forward and off his right leg, thus reducing the amount of force they can generate. Here I recommend stop and go throwing. Have the athlete jump-turn into the power position and stop. Adjust if necessary. Then do a standing throw.
BEGINNER
Releases - bowling the discus (5-10 or make a game for accuracy/distance)
5-10 Shoulder tosses
5-10 Standing throws
Clock drills
Phantom step-ins and south africans
5-10 step-ins
5-10 South Africans
NOTE: Beginners need to master the stand throw before step-ins and step-ins before the South Africans. 3/4 and Full turns can wait until the athletes 2nd or even third year of discus training.
ADVANCED
While walking around the throwing area, they can do 10 or so shoulder tosses and stand throws to warm themselves up.
Advanced trowers can do drills while they are waiting to throw as you won't have to watch them as closely.
1 set of 4 step-ins
2 sets of 4 South Africans
2 sets of 4 3/4 throws
4-5 sets of full throws
(might also add other advanced drills/throws)