Related Experiment Video
Updated: Feb 12, 2026
09:04
Leaf Area Index Estimation Using Three Distinct Methods in Pure Deciduous Stands
Published on: August 29, 2019
14.2K
Stability basin estimates fall risk from observed kinematics, demonstrated on the Sit-to-Stand task
Victor Shia1, Talia Yuki Moore2, Patrick Holmes3
1Electrical Engineering and Computer Sciences, University of California, Berkeley, United States.
Journal of Biomechanics
|March 25, 2018
Summary
Researchers developed a new method to measure human motion stability without risky physical tests. This technique uses dynamical systems theory to analyze movement and accurately predict stability, improving safety assessments for locomotion.
Area of Science:
- Biomechanics and Dynamical Systems Theory
- Human Locomotion and Stability Analysis
Background:
- Quantitatively measuring the stability of locomoting systems is crucial for safety.
- Perturbation-based stability assessment is effective but poses risks to human subjects.
- Existing indirect methods for estimating stability from unperturbed motion lack predictive power.
Purpose of the Study:
- To develop an accurate, non-perturbation-based method for estimating human motion stability.
- To leverage dynamical systems theory for a more reliable assessment of movement stability.
- To differentiate between stable and less stable Sit-to-Stand (STS) strategies.
Main Methods:
- Utilized kinematic observations of nominal Sit-to-Stand (STS) motions.
- Constructed individual-specific dynamic models, input bounds, and feedback control.
- Computed the 'stability basin'—the set of perturbations from which the model can recover.
Main Results:
- The stability basin was successfully computed for 14 individuals.
- The method accurately differentiated between less and more stable STS strategies for each individual.
- Achieved greater accuracy in stability differentiation compared to existing indirect methods.
Conclusions:
- Advances in dynamical systems theory enable accurate stability estimation without perturbation.
- The 'stability basin' provides a robust measure for assessing individual human motion stability.
- This non-invasive approach enhances the safety and accuracy of stability assessments in locomotion.
More Related Videos
Related Concept Videos
01:05Free-falling Bodies: Example
32.9K
An object falling without any air resistance under the influence of gravitational force is said to be in free-fall. For free-falling bodies, the acceleration due to gravity is constant, irrespective of their mass. Free-fall is experienced not only by objects falling downward, but also by all objects whose motion is influenced by gravitational force alone. The dynamics of free-fall motion can be calculated using kinematic equations of motion, since free-fall acceleration is constant.
The...
The...
32.9K
01:17Standing Waves
5.5K
Sometimes waves do not seem to move; rather, they just vibrate in place. Unmoving waves can be seen on the surface of a glass of milk kept in a refrigerator, which is one example of standing waves. Vibrations from the refrigerator motor create waves on the milk that oscillate up and down but do not seem to move across the surface. These waves are formed or created by the superposition of two or more identical moving waves in opposite directions. The waves move through each other, with their...
5.5K
01:26Kinematic Equations - I
16.3K
When an object moves with constant acceleration, the velocity of the object changes at a constant rate throughout the motion. The kinematic equations of motions are derived for such cases where the acceleration of the object is constant. The first kinematic equation gives an insight into the relationship between velocity, acceleration, and time. We can see, for example:
16.3K
01:07Free-falling Bodies: Introduction
13.3K
All objects, neglecting air resistance, fall with the same acceleration towards the Earth's center due to the force exerted by the Earth's gravity. This experimentally determined fact is unexpected because we are so accustomed to the effects of air resistance and friction that we expect light objects to fall slower than heavier ones. People believed that a heavier object had a greater acceleration when falling until Galileo Galilei (1564–1642) proved otherwise. We now know this is...
13.3K
03:18Nuclear Stability
23.4K
Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10−15 meters, a nucleus is quite small compared to the radius of the entire atom, which is about 10−10 meters. Nuclei are extremely dense compared to bulk matter, averaging 1.8 × 1014 grams per cubic centimeter. If the earth’s density were equal to the average nuclear density, the earth’s radius would be only about 200 meters.
To hold positively charged protons together...
To hold positively charged protons together...
23.4K
01:17Kinematic Equations - II
14.8K
The second kinematic equation expresses the final position of an object in terms of its initial position, the distance traveled with the initial constant velocity, and the distance traveled due to a change in velocity. Similar to the first kinematic equation, this equation is also only valid when the acceleration is constant throughout the motion of an object.
Suppose a car merges into freeway traffic on a 200 m long ramp. If its initial velocity is 10 m/s and it accelerates at 2 m/s2, then the...
Suppose a car merges into freeway traffic on a 200 m long ramp. If its initial velocity is 10 m/s and it accelerates at 2 m/s2, then the...
14.8K