visual3d:documentation:pipeline:metric_commands:temporal_distance_calculations_for_gait
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visual3d:documentation:pipeline:metric_commands:temporal_distance_calculations_for_gait [2025/05/20 16:55] – Started the clean-up. wikisysop | visual3d:documentation:pipeline:metric_commands:temporal_distance_calculations_for_gait [2025/05/20 18:23] (current) – Linked to Metric_Compute_Temporal_Distance commmand page. wikisysop | ||
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====== Temporal Distance Calculations for Gait ====== | ====== Temporal Distance Calculations for Gait ====== | ||
- | Visual3D calculates a set of for temporal and distance information based on a set of 4 gait events (Right and Left Heel Strike and Toe Off). These spatiotemporal metrics are part of the common cohort of [[https:// | + | Visual3D calculates a set of for temporal and distance information based on a set of 4 gait events (Right and Left Heel Strike and Toe Off). These spatiotemporal metrics are part of the common cohort of [[https:// |
**Notes**: | **Notes**: | ||
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* If a Right and Left foot segment do not exist, stride length and stride width cannot be computed. | * If a Right and Left foot segment do not exist, stride length and stride width cannot be computed. | ||
* The treadmill unit vector refers to the Anterior Direction of walking. | * The treadmill unit vector refers to the Anterior Direction of walking. | ||
- | |||
- | ===== Metric_Compute_Temporal_Distance ===== | ||
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- | Metric_Compute_Temporal_Distance | ||
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- | </ | ||
===== Temporal Distance Dialog ===== | ===== Temporal Distance Dialog ===== | ||
+ | ^ Dialog ^ Description ^ | ||
|{{: | |{{: | ||
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- | \\ | + | ===== Reporting Temporal Distance Metrics ===== |
+ | Two chart styles exist for reporting temporal distance metrics: horizontal and vertical. The latter allows the metrics to be compared against control data. | ||
- | ===== Report TD Horizontal Chart ===== | + | ==== Report TD Horizontal Chart ==== |
- | {{:TemporalDistance.gif}}\\ | + | Temporal distance metrics can be reported graphically in the [[visual3d:documentation: |
+ | {{: | ||
==== Report TD Vertical Chart ==== | ==== Report TD Vertical Chart ==== | ||
- | This chart has the option of linking | + | Temporal distance metrics can also be reported vertically, which allows |
- | The name of the metric is the same as the Temporal Distance metric signal names created automatically for the report (only the suffix MEAN is removed) | + | {{: |
- | + | ||
- | There are many ways to create these GLOBAL METRIC signals, but many labs have numbers hard coded. | + | |
- | The following example | + | The name of the metric is the same as the Temporal Distance metric signal names created automatically for the report (only the suffix MEAN is removed). There are many ways to create these GLOBAL METRIC signals, but many labs have numbers hard coded. |
< | < | ||
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</ | </ | ||
- | {{: | + | ^ Dialog ^ Description ^ |
- | + | | {{: | |
- | **Note** the selection of the Global Control Data Folder near the top of the dialog\\ | + | |
- | **Note** the selection of the vertical bars at the bottom right of the dialog. | + | |
- | + | ||
- | {{: | + | |
===== Metrics Computed ===== | ===== Metrics Computed ===== | ||
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The stance time for a given side of the body is the portion of the gait cycle when that side's leg is in contact with the ground. It is calculated as the time from that foot's heel strike event to its toe off event. | The stance time for a given side of the body is the portion of the gait cycle when that side's leg is in contact with the ground. It is calculated as the time from that foot's heel strike event to its toe off event. | ||
+ | < | ||
Right Stance Time = RHS-RTO | Right Stance Time = RHS-RTO | ||
- | |||
Left Stance Time= LHS-LTO | Left Stance Time= LHS-LTO | ||
+ | </ | ||
==== Swing Time ==== | ==== Swing Time ==== | ||
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The swing time for a given side of the body is the portion of the gait cycle when that side's leg is not contacting the ground. It is calculated as the time from that foot's toe off event to its heel strike event. | The swing time for a given side of the body is the portion of the gait cycle when that side's leg is not contacting the ground. It is calculated as the time from that foot's toe off event to its heel strike event. | ||
+ | < | ||
Right Swing Time= RTO-RHS | Right Swing Time= RTO-RHS | ||
- | |||
Left Swing Time= LTO-LHS | Left Swing Time= LTO-LHS | ||
+ | </ | ||
==== Step Time ==== | ==== Step Time ==== | ||
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The step time for a given side of the body is the portion of the gait cycle between the opposite side's heel strike event and the given side's heel strike event. | The step time for a given side of the body is the portion of the gait cycle between the opposite side's heel strike event and the given side's heel strike event. | ||
+ | < | ||
Right Step Time= LHS-RHS | Right Step Time= LHS-RHS | ||
- | |||
Left Step Time= RHS-LHS | Left Step Time= RHS-LHS | ||
+ | </ | ||
==== Double Limb Support Time ==== | ==== Double Limb Support Time ==== | ||
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The double limb support time for a gait cycle is the total time where both feet are in contact with the ground. This is the sum of an initial double limb support phase and a terminal double limb support phase. | The double limb support time for a gait cycle is the total time where both feet are in contact with the ground. This is the sum of an initial double limb support phase and a terminal double limb support phase. | ||
+ | < | ||
+ | Right Cycle Double Limb Support = Right Initial Double Limb + Right Terminal Double Limb | ||
Right Initial Double Limb= RHS to LTO | Right Initial Double Limb= RHS to LTO | ||
- | |||
Right Terminal Double Limb= LHS to RTO | Right Terminal Double Limb= LHS to RTO | ||
+ | </ | ||
The global mean double limb support time (stored in the global workspace as METRIC:: | The global mean double limb support time (stored in the global workspace as METRIC:: | ||
- | **Note:** | + | **Note**: the initial and terminal double limb support phases are inverted between the left and right sides of the body. |
+ | < | ||
Left Initial Double Limb Support (stance) = Right Terminal Double Limb Support (stance) | Left Initial Double Limb Support (stance) = Right Terminal Double Limb Support (stance) | ||
- | |||
Left Terminal Double Limb Support (stance) = Right Initial Double Limb Support (stance) | Left Terminal Double Limb Support (stance) = Right Initial Double Limb Support (stance) | ||
+ | </ | ||
==== Cycle Time ==== | ==== Cycle Time ==== | ||
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Flight time is the average time from LTO to RHS (ensuring no LHS or RTO events occur between LTO and RHS) and RTO to LHS (ensuring no RHS or LTO events occur between RTO and LHS). | Flight time is the average time from LTO to RHS (ensuring no LHS or RTO events occur between LTO and RHS) and RTO to LHS (ensuring no RHS or LTO events occur between RTO and LHS). | ||
- | + | * Left flight time is calculated from LTO to RHS. | |
- | Left flight time is calculated from LTO to RHS. | + | |
- | + | ||
- | Right flight time is calculated from RTO to LHS. | + | |
==== Stride Length ==== | ==== Stride Length ==== | ||
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=== Right Stride Length === | === Right Stride Length === | ||
- | Right Stride length is defined as the length of the Right Stride vector from the Proximal End of the Right Foot Segment at successive RHS events | + | Right Stride length is defined as the length of the Right Stride vector from the Proximal End of the Right Foot Segment at successive RHS events. Right Stride Length Count is the number of Right Strides. |
- | + | ||
- | Right Stride Length Count is the number of Right Strides. | + | |
=== Left Stride Length === | === Left Stride Length === | ||
- | Left Stride length is defined as the length of the Left Stride vector from the Proximal End of the Left Foot Segment at successive LHS events. | + | Left Stride length is defined as the length of the Left Stride vector from the Proximal End of the Left Foot Segment at successive LHS events. Left Stride Length Count is the number of Right Strides. |
- | + | ||
- | Left Stride Length Count is the number of Right Strides. | + | |
=== Stride Length Count === | === Stride Length Count === | ||
- | Stride Length Count is the sum of Right Stride | + | Stride Length Count is the sum of Right Stride |
=== Treadmill === | === Treadmill === | ||
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Stride width is the medio-lateral distance between proximal end position of the foot at ipsilateral heel strike to the proximal end position of the foot at the next contralateral heel strike. Calculated by taking a stride vector, and the step in between, and computing the cross product (distance between the stride vector and the opposing step (heel) position | Stride width is the medio-lateral distance between proximal end position of the foot at ipsilateral heel strike to the proximal end position of the foot at the next contralateral heel strike. Calculated by taking a stride vector, and the step in between, and computing the cross product (distance between the stride vector and the opposing step (heel) position | ||
- | Left Stride Width is the perpendicular distance from the proximal end of the Left foot segment to the Right Stride vector. | + | Left Stride Width is the perpendicular distance from the proximal end of the Left foot segment to the Right Stride vector |
- | + | ||
- | Right Stride Width is the perpendicular distance from the proximal end of the Right foot segment to the Left Stride vector. | + | |
- | + | ||
- | We don't actually report (or store) a left and right stride width, but rather an average stride width. | + | |
==== Step Length ==== | ==== Step Length ==== | ||
- | Step length is the distance between proximal end position of the contralateral foot at the previous contralateral heel strike to the proximal end position of the ipsilateral foot at the ipsilateral heel strike. This is calculated as the distance in the walking path direction. | + | Step length is the distance between proximal end position of the contralateral foot at the previous contralateral heel strike to the proximal end position of the ipsilateral foot at the ipsilateral heel strike. This is calculated as the distance in the walking path direction. If the person is walking on a treadmill, the distance |
- | + | ||
- | If the person is walking on a treadmill, the distance | + | |
==== Speed ==== | ==== Speed ==== | ||
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Cadence is the rate at which a person walks, expressed in steps per minute. | Cadence is the rate at which a person walks, expressed in steps per minute. | ||
- | In other words: | + | < |
Left Steps Per Minute = 60 / [[# | Left Steps Per Minute = 60 / [[# | ||
- | |||
Right Steps Per Minute = 60 / [[# | Right Steps Per Minute = 60 / [[# | ||
+ | </ | ||
===== Changing the text in the temporal distance chart ===== | ===== Changing the text in the temporal distance chart ===== | ||
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In the folder in which you have placed Visual3D.exe, | In the folder in which you have placed Visual3D.exe, | ||
- | The contents of this ini file containing a mapping from the text used internally in Visual3D to the text that appears in the report graph. | + | The contents of this ini file containing a mapping from the text used internally in Visual3D to the text that appears in the report graph. |
- | The text appearing to the right of the " | ||
- | |||
- | The default config file looks like this. | ||
- | |||
- | \\ | ||
**Temporal Distance**\\ | **Temporal Distance**\\ | ||
**Step Length Prompt=**Left Step Length / Right Step Length\\ | **Step Length Prompt=**Left Step Length / Right Step Length\\ | ||
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**Right Terminal Double Limb Support Time=**Right Terminal Double Limb Support Time\\ | **Right Terminal Double Limb Support Time=**Right Terminal Double Limb Support Time\\ | ||
**Flight Time=**Flight Time\\ | **Flight Time=**Flight Time\\ | ||
- | |||
===== Subject computation using subject name/prefix parameters ===== | ===== Subject computation using subject name/prefix parameters ===== | ||
- | Visual3D | + | Versions of Visual3D |
- | \\ | + | |
- | When using a version of Visual3D prior to implementing multisubject support, Visual3D treats each CMO/Z file as a single subject. In this way, the temporal and distance metrics are computed in the CMO/Z GLOBAL for the subject processed within that CMO. In the same manner, when computing the temporal and distance metrics across a library of subjects, each CMO/Z is treated as a single subject and then the subject averages are computed across CMO/Z files and placed into the workspace GLOBAL for the overall mean values across subjects.\\ | + | Older versions of Visual3D will not support the subject prefix extensions of this command and will treat each CMO/Z file as a single subject. In this way, the temporal and distance metrics are computed in the CMO/Z GLOBAL for the subject processed within that CMO. In the same manner, when computing the temporal and distance metrics across a library of subjects, each CMO/Z is treated as a single subject and then the subject averages are computed across CMO/Z files and placed into the workspace GLOBAL for the overall mean values across subjects. |
- | \\ | + | |
- | Visual3D with multisubject support extends these metric calculations to be computed for each subject that is identified in the .C3D parameters SUBJECT section. In this way, the a single CMO/Z GLOBAL will contain the computed metrics for each subject within the CMO/Z file, prefixed with the subject' | + | |
- | \\ | + | |
- | When working across CMO/Z files in the CMO/Z library, multisubject support for this command will treat each subject mean in each CMO/Z file as separate subject averages to be included for calculating the temporal and distance metric averages across all the subjects in the CMO/Z library. | + | |
===== Mimicking the Command ===== | ===== Mimicking the Command ===== | ||
- | [[Visual3D: | + | These calculations can be mimicked by implementing them manually using [[Visual3D: |
- | + | ||
- | + | ||
visual3d/documentation/pipeline/metric_commands/temporal_distance_calculations_for_gait.1747760138.txt.gz · Last modified: 2025/05/20 16:55 by wikisysop