I have obtained digital pictures of students throwing a shot put which I will try and comment on what they are doing wrong and describe the type of muscles they are using. During a shot put the following joints are used, foot, knee, elbow, and shoulder. Antagonistic muscles used attached joints, contract and relax. Agonist muscles used biceps and triceps. To obtain this maximum contribution to speed, the stronger, larger, but slower muscles must be used first (thighs, trunk); followed by the weaker, smaller, but faster muscles of the arms, hands, feet, and lower legs.
Although there is a sequence involved, it is imperative that all the forces be applied as simultaneously as possible. Before describing the students let me describe a professional attempt at shot putting to make it easier to compare. To describe the above pictures as you can see the person starts with a relaxed low posture and has his elbow high, while the shot put is just about touching his neck. 1. Then you can see his hips start off balancing. 2. He slowly starts extending his rear leg.
3. When the rear leg is fully extended the glide is low and fast. 4. The shot putter gets into the power position with his hips open and his shoulders closed 5. The chin, knee and toe are now in line. 6. The right hip pushes horizontally to the front 7. The shot is detained back 8. The weight is then pushed over the front foot. 9. While the hips are square the putting arm exerts force 10. The arm pushes the shot away Now I will describe the student’s mistakes Image one:
The student is in a good position but he doesn’t have his elbow high. His feet are almost in a good position if he had them a bit closer together. His knee is crouched down well but not a very good startup position it seems more like the second sequence described above (his hips start off balancing). This is meant to make his knees drop lower. Image two: This picture is meant to show the 9th step described above “while the hips are square the putting arm exerts force”.
As you can see in his image his hips are not totally square, his rear foot is too far back, and his knee is too curved. At this point his arm should be high but in this case it’s aligned with his face. His non-putting arm is too relaxed. His elbow is too low it needs to be high enough to release the shot at a high distance. Image three: This shows a picture of a more experienced thrower at you can see his starting position is almost perfect, if he just had his knees lower.
He doesn’t start with a low posture. The shot put touches his neck, and his elbows are high. Image four: Of the same student, he is performing step 10 described above (The arm pushes the shot away). His knees are pushing upwards to give him the last bit of energy. Unfortunately he is too unbalanced and this is an important part in shot putting, the shot putter needs good balance to complete the throw successfully.
His shoulder needs to deliver the final force exert but it is released too early without much power. He doesn’t jump far leap far enough with his front leg because he was struggling to get his balance. Image five: As you can see a faint white line which the student has not left throughout the throw. He finally gets back into a comfortable position to make sure he doesn’t fall out of the circle so he needs to get his balance. An example of why this happens see what I have written about Newton’s first law.