During this assignment we will learn about using the electrogoniometer. This delicate little device can be used to measure absolute joint angles and changes in joint angles. We will obtain goniometer data during two different movements during classtime. You will take the data with you and complete the assignment during the week.

The two movements we will evaluate are natural walking and dart throwing. During walking we will measure from knee joint and during the dart throw we will measure from the elbow. We will obtain five trials (one block) of data from two people for each movement.

However before you get started on your data, answer the following two questions from this week's reading.

1. What was the main source of error for same day goniometer measurements. What was the source of error for between day measurements?

2. Given the results of the McDowell study and the information in the abstracts, what can be said about the goniometer as a device to measure human movement? Do you think the results would have been different if a video-based motion analysis system had been used? Explain your answer.

Representing your data

1. For each block of data, develop an Excel line graph that contains the 5 single trials for each block of trials (4 total graphs). Be sure you select a similar point in each waveform such that your waveforms "line-up" on your graph. You can do this by aligning the waveforms at Time 0. Another possibility is to select a consist point during the movement and align the waveforms relative to that point. For example, your could align your walking waveforms relative to peak knee flexion.

2. For each task, develop a graph that contains the mean waveform for each subject who completed that task. For example, your knee joint angle graph obtained during walking will contain the mean waveform for each of the two subjects. (2 total graphs).

3. For each task, develop a column graph that represents the mean duration of each movement for each subject (one stride and one throw). Include standard deviations in this graph. (2 total graphs).

4. Calculate the time to peak flexion (extension) from the starting position for each stride (throw) and represent the mean value for each subject in a column graph. (2 total graphs).

Describing your data

Answer the following questions.

1. What was the mean joint angle at peak knee flexion for each subject? Were these values different for the two subjects.

2. What was the mean joint angle at peak elbow extension for each subject? Were these values different for the two subjects.

3. What was the average time it took for each subject to complete a single stride. Were these values different for the two subjects?

4. What was the average time it took for each subject to complete a single dart throw. Were these values different for the two subjects?

5. What was the average time it took each subject to reach peak knee flexion during a single stride? Were these values different for the two subjects?

6. What was the average time it took each subject to reach peak elbow extension during a single stride? Were these values different for the two subjects?

Preparation for next week

Read

McGinnis, P.M., Newell, K.M. Topological dynamics: A framwork for describing movement and its constraints

Grasso, R., Bianchi, L., Lacquaniti, F. Motor patterns for human gait: Backward versus forward locomotion

Answer the following two questions.

1. What is a potential drawback of using configuation spaces to describe movement?

2. What measures indicate that forward and backward walking are very similar tasks? What measures indicate that forward and backward walking are quite different tasks?