Advice on processing raw gait data

Question

jennifer aniston 2016-10-1

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/305313-advice-on-processing-raw-gait-data

编辑： Star Strider 2016-10-2

Gait Data.xls

Hi,

I collected gait data using a force plate several years ago as a part of an experiment. The data is raw data, a sample of which I am attaching in an excel file. As I have very limited experience in MAT LAB, (however I would really really like to learn) i would appreciate any insights into this data and on how to proceed with it so that I can extract parameters such as step length, stride length and cadence etc to come to some conclusive results and findings.

i hope i am not being too ambitious, but i would really appreciate any help on how to proceed further.

Thanks a lot! Jen

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Star Strider 2016-10-1

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/305313-advice-on-processing-raw-gait-data#answer_236863

在 MATLAB Online 中打开

Getting the data and variable names is straightforward:

[d,s,r] = xlsread('jennifer aniston Gait Data.xls');
var_names = s(11,:);

What am I looking at? What experiment did you do?

What are the data? (Force is obvious.) What are x and y? They seem to be displacements, but how to they factor into all this?

15 个评论
显示 13更早的评论隐藏 13更早的评论

Star Strider 2016-10-1

编辑：Star Strider 2016-10-1

在 MATLAB Online 中打开

Thank you for the information (that seems to be duplicates of the .xls file, so it unfortunately adds nothing).

So far, we have someone standing on a force plate bearing a load.

Is there any other information you’d like to share that might put this into some context?

EDIT — (01 October 2016 at 21:25 UTC)

This is as far as I can get with ‘Gait data sample.txt’:

fidi = fopen('jennifer aniston Gait data sample.txt','rt');
d{1} = textscan(fidi, '%f%f', 'HeaderLines',67, 'CollectOutput',1, 'Delimiter','\t', 'EndOfLine','\r\n');
right_foot = cell2mat(d{1});
figure(1)
plot(right_foot(:,1), right_foot(:,2))
grid
xlabel('Time (sec)')
ylabel('Force (N)')

There is no valid end-of-file statement, and the data are extremely difficult to parse because the content and format vary. Some of the data are derived, statistical or other summaries of other data, and some are raw.

This appears to have been produced with other software. If you can save only the raw data to a text or Excel file, without the intermediate analysis summaries, that would be preferable. I have no idea what else to suggest.

jennifer aniston 2016-10-2

编辑：jennifer aniston 2016-10-2

gait data modified.xls

Thank you for taking out time to study my data.

I have pasted the alternate right foot and left foot force data starting with the right foot contact with force plate in the 2nd column in the excel 'gait data modified'. Had to do a bit of back and forth to pick right foot data from the bottom and left foot data from the top part of the notepad file. The first column has the corresponding time of contact with the force plate.

the notepad is confusing since the force exerted by the left foot is listed together and not alternatively with the right foot. First left foot heel strikes at time=950, 2nd left foot @ t=5300, 4th @ t=8570, 5th @t=13010.

Similarly right foot heel strikes @t=1550, 2nd right foot @t=4710, 3rd @t=7980, 4th @t=9170 and so on. The force plate was just long enough for the subject to step on it twice or thrice. the subject then had to turn around and walk back.

The left foot data is in the first half of the sheet and right foot data in the latter half. A break in time for example between time 3690 and 3700 shows the end of one gait cycle and beginning of the next. one gait cycle may contain 2 heel strikes or 3.

Star Strider 2016-10-2

编辑：Star Strider 2016-10-2

My pleasure!

O.K. Without knowing the walking speeds, subject-specific distances aren’t possible to calculate.

Data without gaps are important. It’s not possible to interpolate missing data here.

Probably. Anthony’s data have a clearly defined single peak. Yours do not, making that slightly more difficult. If you’re willing to accept a ‘peak’ as either of the two peaks in each stride in your data, then you can use the code I wrote for Anthony without modification. The 50 N threshold will also apply to your data. You may have to make certain modifications if the format of your data are different than his, (his are very consistent, and that helps significantly) but you should be able to adapt the analysis with minimal changes.

EDIT — Added to address Jen’s added edits:

‘the time between gait cycles will not be even’

I’m not certain how to deal with that. It’s an instrumentation problem you have to decide how to work with in your experiment design. Perhaps putting lasers and detectors on both ends of your force plate (perpendicular to the walking direction) to use as event detectors would allow you to approximate walking speed.

With the gaps filled, you should have no problem using the code I wrote for Anthony. One change you may want to make is to increase the 50 N threshold to 100 N. In the data I plotted, I noticed that the 50 N point may be obscured in some strides by a sampling irregularity. The threshold change should not make a significant difference, since the slopes are nearly vertical in that region.

jennifer aniston 2016-10-2

Well, you have been most helpful to tolerate my silly questions!

The gaps are not an issue anymore since it was copy pasting job gone wrong.

Yeah I am curious as to why Anthony's data has a single peak since gait data would give 2 peaks, where the 1st peak would show heel strike and the 2nd toe strike.

Is there any way and need to connect these fragmented gaits into one continuous gait cycle? or would that distort our data and purpose?

请先登录，再进行评论。