Journal of Biomechanics dataset

This tutorial covers the basic usage of the dataset from A comprehensive, open-source dataset of lower limb biomechanics in multiple conditions of stairs, ramps, and level-ground ambulation and transitions

For this example, let’s focus on obtaining the average ankle moment profiles during walking on a treadmill at different speeds. We will do that in 5 steps.

Step 1. Check the paper

If you haven’t read the paper, I recommend to look at the methods to see what this is all about. Also, the supplemental material contains some instructions on how to use the dataset and the scripts. We will cover those instructions step by step in this post.

Here is the bibtex reference if you want to cite:

@article{CAMARGO2021110320,
title = {A comprehensive, open-source dataset of lower limb biomechanics in multiple conditions of stairs, ramps, and level-ground ambulation and transitions},
journal = {Journal of Biomechanics},
volume = {119},
pages = {110320},
year = {2021},
issn = {0021-9290},
doi = {https://doi.org/10.1016/j.jbiomech.2021.110320},
url = {https://www.sciencedirect.com/science/article/pii/S0021929021001007},
author = {Jonathan Camargo and Aditya Ramanathan and Will Flanagan and Aaron Young},
keywords = {Locomotion biomechanics, Stairs, Ramps, Level-ground, Treadmill, Wearable sensors, Open dataset},

Step 2. Download the dataset and scripts

The subject information is in SubjectInfo.mat, you will need it too, since we want to normalize the moment by subject weight.

Step 3. Setup EpicToolbox dependency

On your Matlab command window, go in the EpicToolbox folder and run install.m. That’s it!

Step 4. Split the time series in strides

So, we are going to use the STRIDES.m script to split the time series steps based on the gait cycle (heel contact to heel contact). On STRIDES.m edit line 7 with the ambulation mode you want to process. In this case I will only do treadmill.

ambulationModes={'treadmill'};

The STRIDES.m script will process one subject at a time. Thus, I need to define the variable SUBJECT for each subject I want to process, and then run STRIDES.m.

On the command window:

>> SUBJECT='AB06';
>> STRIDES
Processing strides for subject AB06
>> SUBJECT='AB07';
>> STRIDES
Processing strides for subject AB07
>> SUBJECT='AB08';
>> STRIDES
Processing strides for subject AB08
>> SUBJECT='AB09';
>> STRIDES
Processing strides for subject AB09
>>% I will stop here and process only 4 subjects

Alternatively, use the BATCHRUN.m script to process multiple subjects in sequence using a for loop.

Step 5. Use the data

Now you should have a STRIDES/ folder containing the individual stride data for each subject.

You can use PLOTS.m to read from the strides folder and create the plots or script you own analysis.

Let’s look at the PLOTS.m script to see what you can do. On lines 3-8 you can select the ambulation mode and the dependent variable of interest (sensor table, channel column). In our case, we want to observe the inverse dynamics id and from that, the channel ankle_angle_r_moment. You can reuse this script for any other variables. The commented lines are other examples.

% Select an ambulation mode and a sensor/channel of interest
AMBULATION='treadmill';
%sensor='ik'; channel='hip_flexion_r';
%sensor='emg'; channel='gastrocmed';
%sensor='imu'; channel='thigh_Gyro_Z'; 
sensor='id'; channel='ankle_angle_r_moment';

After running this script you will have plots showing the individual stride data per subject, the average across strides per subject, and the average across subjects. All the plots are color coded with respect to the condition (in this case, the condition is treadmill speed).

All strides

Subject Average

Mode Average

That’s all for this post. Feel free to reach out @jcamargo_co if you need more information!