Destabilizing and stabilizing forces to assess equilibrium during everyday activities

Duclos, Cyril; Desjardins, P.; Nadeau, Sylvie; Delisle, Alain; Gravel, Denis; Brouwer, Brenda; Corriveau, Hélène

doi:10.1016/j.jbiomech.2008.11.007

Cited by 37 publications

(40 citation statements)

References 14 publications

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“…Duclos et al [174] introduced the concept of stabilizing and destabilizing forces. It may be viewed as an extension of the method adopted by Delisle et al [175] to assess stability during lifting.…”

Section: Stabilizing and Destabilizing Forces 2231 General Descrimentioning

confidence: 99%

Assessing the stability of human locomotion: a review of current measures

Bruijn

Meijer

Beek³

et al. 2013

J. R. Soc. Interface.

512

365

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Falling poses a major threat to the steadily growing population of the elderly in modern-day society. A major challenge in the prevention of falls is the identification of individuals who are at risk of falling owing to an unstable gait. At present, several methods are available for estimating gait stability, each with its own advantages and disadvantages. In this paper, we review the currently available measures: the maximum Lyapunov exponent (l S and l L ), the maximum Floquet multiplier, variability measures, long-range correlations, extrapolated centre of mass, stabilizing and destabilizing forces, foot placement estimator, gait sensitivity norm and maximum allowableperturbation. We explain what these measures represent and how they are calculated, and we assess their validity, divided up into construct validity, predictive validity in simple models, convergent validity in experimental studies, and predictive validity in observational studies. We conclude that (i) the validity of variability measures and l S is best supported across all levels, (ii) the maximum Floquet multiplier and l L have good construct validity, but negative predictive validity in models, negative convergent validity and (for l L ) negative predictive validity in observational studies, (iii) long-range correlations lack construct validity and predictive validity in models and have negative convergent validity, and (iv) measures derived from perturbation experiments have good construct validity, but data are lacking on convergent validity in experimental studies and predictive validity in observational studies. In closing, directions for future research on dynamic gait stability are discussed.

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Section: Stabilizing and Destabilizing Forces 2231 General Descrimentioning

confidence: 99%

Assessing the stability of human locomotion: a review of current measures

Bruijn

Meijer

Beek³

et al. 2013

J. R. Soc. Interface.

512

365

View full text Add to dashboard Cite

show abstract

“…From a motor control perspective, an increased VCOP challenges the postural control system to respond rapidly and accurately to COP perturbations in order to maintain stability [21]. In contrast, slower VCOP enables more graded responses as the destabilization forces are lower [21].…”

Section: Discussionmentioning

confidence: 99%

Relationship between stair ambulation with and without a handrail and centre of pressure velocities during stair ascent and descent

et al. 2011

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“…To quantify the state of balance during bipedal gait, multiple definitions have been proposed in literature, both for human locomotion (Hof et al, 2005;Herr and Popovic, 2008;Duclos et al, 2009) and bipedal robots (Goswami and Kallem, 2004;Popovic and Herr, 2005;Pratt and Tedrake, 2006;Wight et al, 2007). What most definitions have in common is that they require at least the position and velocity of the body's center of mass (CoM) with respect to the center of pressure (CoP), the point of application of the net ground reaction force.…”

Section: Introductionmentioning

confidence: 99%

Observing the State of Balance with a Single Upper-Body Sensor

2016

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The occurrence of falls is an urgent challenge in our aging society. For wearable devices that actively prevent falls or mitigate their consequences, a critical prerequisite is knowledge on the user's current state of balance. To keep such wearable systems practical and to achieve high acceptance, only very limited sensor instrumentation is possible, often restricted to inertial measurement units at waist level. We propose to augment this limited sensor information by combining it with additional knowledge on human gait, in the form of an observer concept. The observer contains a combination of validated concepts to model human gait: a spring-loaded inverted pendulum model with articulated upper body, where foot placement and stance leg are controlled via the extrapolated center of mass (XCoM) and the virtual pivot point (VPP), respectively. State estimation is performed via an Additive Unscented Kalman Filter (Additive UKF). We investigated sensitivity of the proposed concept to model uncertainties, and we evaluated observer performance with real data from human subjects walking on a treadmill. Data were collected from an Inertial Measurement Unit (IMU) placed near the subject's center of mass (CoM), and observer estimates were compared to the ground truth as obtained via infrared motion capture. We found that the root mean squared deviation did not exceed 13 cm on position, 22 cm/s on velocity (0.56-1.35 m/s), 1.2°on orientation, and 17°/s on angular velocity.Keywords: human gait and balance, wearable sensors, state estimation, virtual pivot point, extrapolated center of mass, capture point, additive unscented kalman filter, fall detection

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Destabilizing and stabilizing forces to assess equilibrium during everyday activities

Cited by 37 publications

References 14 publications

Assessing the stability of human locomotion: a review of current measures

Assessing the stability of human locomotion: a review of current measures

Relationship between stair ambulation with and without a handrail and centre of pressure velocities during stair ascent and descent

Observing the State of Balance with a Single Upper-Body Sensor

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