One of the elucidating practices in laboratory work is the comparison of correct and incorrect technique in track and field. The athletic techniques which have been codified for each of the track and field events were refined by athletes, but the logic of using those techniques is not always obvious to the public.
For instance, consider the hammer throw. A traditional hammer throw involves a weighted ball on a long metal rod, with a handle for easy grasp. First, the hammer is swung upwards several times, gaining momentum. This may be in pendulum motion, or in circles at an angle to the ground. Then, the hammer is swung around in horizontal circles above the head, as the thrower takes three circular steps. Finally, the hammer is released, resulting in a forwards trajectory into the field.
The graphs below, excerpted from The Science of Track and Field: Volume 1 from Schottenbauer Publishing show differences between two types of hammer throws, contrasting and comparing incorrect and correct techniques in laboratory conditions.
Discussion Questions:
- As measured by the accelerometer, in which direction is the centripetal force?
- What is the average centripetal acceleration during the motion?
- As measured by the accelerometer, which direction is vertical?
- What is the average acceleration in the vertical direction during the motion? Is this acceleration equal to the acceleration due to gravity? Why or why not?
- Draw a horizontal sketch of the wireless device in relation to the hammer motion. Label the axes on the device.
- Draw a vertical sketch of the wireless device in relation to the hammer motion. Label the axes on the device.
- Is the motion of the hammer entirely horizontal to the ground? How can this be determined?
- In this graph, does the the arm move in relation to the torso? How can this be determined?
Discussion Questions:
- Separate the graph into four sections, based on type of movement present. Label each section with one of the following: (a) Release, (b) Pendulum Motion, (c) At Rest, (d) Stepping Rotation.
- Which of the four sections above is most similar to the first graph? How are these motions similar? How are they different?
- For each section of the graph, what are the maximum and minimum forces? The maximum and minimum accelerations? Make a table, listing the four sections sequentially.
- How many times is the hammer swung in pendulum motion? How is this indicated on the graph?
- Are the pendulum swings only in one plane? Describe the motion.
- Are the three circular steps shown in the graph? If so, how? Are any steps evident in the first graph above?
- Are the circles perfectly horizontal to the ground? If not, what is the maximum variation in the vertical direction during the three steps?
- Is the hammer released in a horizontal or vertical direction, or a combination of the two directions? What data from the graph indicate direction of the release?
- What is the time of release of the hammer?
- What is the height of the measurement device at release?
- What occurs after release of the hammer?
- Using data from the two graphs above, describe several potential benefits of correct hammer throw technique.
- Using the graphs above, suggest potential results of using incorrect technique, such as: (a) Pendulum Motion Alone, (b) Circles Alone, or (c) Overhand Throw Style.
- Compare and contrast the laboratory conditions used in the graphs above with real, Olympic hammer conditions. Do these conditions change any answers to the questions above?
Now, consider the theory of correct and incorrect hammer technique.
Discussion Questions:
- What forces affect the hammer during the thrower's preparatory motions?
- What forces affect the hammer at release?
- What forces affect the hammer during its free trajectory?
- Why are circular steps used when throwing hammer? Why not throw hammer from pendulum swings alone?
- Why are repetitive motions used when throwing hammer? Why not throw hammer after one swing or circle?
- If speed were equal, which release direction results in the longest throw distance? Several options to consider include: (a) horizontal, (b) vertical, (c) mostly horizontal, (d) mostly vertical, (e) equally horizontal and vertical.
- What environmental conditions affect release of the hammer? Are these substantial?
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