Mimicking Slipping Responses Using a Novel Mechanical Perturbation Algorithm

Study Overview
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Brief Summary
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Healthy subjects will be invited to fill out a questionnaire regarding falls and balance skills followed by normal walking trials on a treadmill at 9 different speeds (0.28-1.4 m/s). Key gait parameters for the normative database will be collected. During the perturbation trials, the subjects will walk at a constant speed (1.2 m/s). The treadmill belts are ac, - or decelerated during the perturbations according to three different perturbation algorithms with varying perturbation onset. Movements will be analyzed by 3D motion capture, force plates, surface electromyography and IMU sensors. All methods are non-invasive and commonly used in the field of biomechanics.

Official Title
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Mimicking Slipping Responses Using a Novel Mechanical Perturbation Algorithm

Conditions
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Gait, Stumbling, Gait, Perturbation

Intervention / Treatment
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* Other: Mechanical pertubation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy subjects aged 18-40 years and 60-80 years Ability to walk at minimum 30 minutes at a regular pace without assistance or breaks Written informed consent as documented by signature (see informed consent form) Exclusion Criteria: Women who are pregnant or breast feeding Current neurological problems affecting walking function and balance Current orthopedic problems affecting upper and lower extremity movements History of alcohol abuse or the intake of psychotropic drugs History of major cardiac condition (e.g., infarction, insufficiency (NYHA II-IV)) History of major pulmonary condition (e.g., chronic obstructive pulmonary disease (GOLD II-IV)) Current major depression or psychosis Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia Fever of unknown origin

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Healthy participants between 18 and 40 years of age<br> | Other: Mechanical pertubation<br>* Acceleration or deacceleration of one treadmill gait belt.<br>|
| Healthy participants between 60 and 80 years of age<br> | Other: Mechanical pertubation<br>* Acceleration or deacceleration of one treadmill gait belt.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Calculation of Margins of Stability (MoS) in anterior-posterior direction at foot contact | Difference between base of support and interpolated center of mass (mm), based on 3D motion capture. | Once during visit 1 | 
| Step length at baseline, before (Pre) and after (Recovery step 1-10) perturbation |  | Once during visit 1 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Step width at foot contact of baseline, before (Pre) and Recovery steps 1-10 |  | Once during visit 1 | 
| Calculation of Margin of stability medial-lateral direction at foot contact of baseline, before (Pre) and Recovery steps 1-10 | Difference between base of support and interpolated center of mass (mm), based on 3D motion capture. | Once during visit 1 | 
| Maximal trunk velocity during gait cycle at of baseline, before (Pre) and Recovery steps 1-10 to detect fast trunk movement to gain balance | Optical markers are placed on the upper body of the subjects and will be used for calculation (distance over time) of the trunk velocity. | Once during visit 1 | 
| 3D kinematic gait profiles to analyze detailed movement patterns/strategies | The optical markers are placed according to the Plug-in gait marker set in Vicon Nexus (motion capture system). Hip, knee, ankle and trunk angles are calculated from this marker set. | Once during visit 1 | 
| EMG analysis to detect reaction time and activity patterns of different leg muscles |  | Once during visit 1 | 
| Questionnaire regarding the incidence of falls in the last six months | Contains questions how often und the reason why the subject falls | Once during visit 1 | 
| Activities specific Balance Confidence scale (ABC scale) | Contains 16 questions rating the balance confidence between 0-100%. 100% means absolutely confident in doing some activity | Once during visit 1 | 
| Questionnaire regarding the perceived intensities of the three perturbation algorithms | Judging the three pertubation algorithms according to their intensity, inconvenience and how realistic the slipping felt. Scale ranges from 0-10, whereas 10 is the most intense | Once during visit 1 | 
| Functional Gait Assessment (FGA) as a clinical balance test | Assess the dynamic stability during different walking tasks. In total, 30 points are possible, at 22 points is the cut off score to classify the fall risk in older adults in predicting falls. | Once during visit 1 | 
| A set of kinematic parameters | Measurement of hip, knee, ankle and spine angles during walking in degrees (°). | Once during visit 1 | 
| A set of kinetic parameters | Ground reaction forces measured by force plates in Newton (N). | Once during visit 1 | 
| A set of spatiotemporal parameters | Stance time, double stance time in seconds (s). | Once during visit 1 |