Mechanical work performed by individual limbs of transfemoral amputees during step-to-step transitions: Effect of walking velocity

Bonnet, Xavier; Villa, Coralie; Fodé, Pascale; Lavaste, F.; Pillet, Hélène

doi:10.1177/0954411913514036

Cited by 24 publications

(28 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Collectively, these findings demonstrate that soft robotic exosuits can assist the paretic ankle during walking in a manner that positively influences whole-body gait mechanics and energetics. Consistent with previous studies showing that post-stroke walking is energetically inefficient and mechanically asymmetric (Bonnet et al, 2014;Doets et al, 2009;Feng et al, 2014;Mahon et al, 2015), our participants expended 45% more metabolic power than healthy individuals to walk (Collins et al, 2015) and generated substantially less COM power from the paretic limb compared with the non-paretic limb during walking with the unpowered exosuit (Fig. 2).…”

Section: Discussionsupporting

confidence: 91%

“…Together, impaired paretic PF and DF contribute to slow walking speed, inter-limb gait asymmetry in spatiotemporal parameters (Lin et al, 2006) and reduced forward propulsion . Recent studies have shown a relationship between gait asymmetry and an increased metabolic cost of walking in healthy populations (Ellis et al, 2013;Shorter et al, 2017;Soo and Donelan, 2012) and also clinical populations with gait impairments Bonnet et al, 2014;Doets et al, 2009;Farris et al, 2015;Feng et al, 2014;Houdijk et al, 2009). Two of these studies, in particular, suggested that increased gait asymmetry in people post-stroke is correlated with the increased metabolic cost of walking Farris et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…Simulation and experimental studies have both shown that the COM power generated by the trailing limb during the step-to-step transition is correlated with metabolic power (Donelan et al, 2002;Geyer et al, 2006;Kuo et al, 2005;Soo and Donelan, 2012). When the COM power generated by the individual trailing limbs is asymmetric, metabolic power requirements have been shown to increase in both healthy (Ellis et al, 2013;Soo and Donelan, 2012) and neurologically impaired populations (Bonnet et al, 2014;Doets et al, 2009;Farris et al, 2015;Feng et al, 2014;Houdijk et al, 2009). Individuals with post-stroke hemiparesis generate less COM power from the paretic trailing limb during the step-to-step transition than healthy individuals and compensate for this by generating more COM power from the non-paretic trailing limb (Lamontagne et al, 2007;Peterson et al, 2010;Turns et al, 2007) during the subsequent step-to-step transition.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke

Bae

Awad

Long

et al. 2018

Journal of Experimental Biology

View full text Add to dashboard Cite

Stroke-induced hemiparetic gait is characteristically asymmetric and metabolically expensive. Weakness and impaired control of the paretic ankle contribute to reduced forward propulsion and ground clearance - walking subtasks critical for safe and efficient locomotion. Targeted gait interventions that improve paretic ankle function after stroke are therefore warranted. We have developed textile-based, soft wearable robots that transmit mechanical power generated by off-board or body-worn actuators to the paretic ankle using Bowden cables (soft exosuits) and have demonstrated the exosuits can overcome deficits in paretic limb forward propulsion and ground clearance, ultimately reducing the metabolic cost of hemiparetic walking. This study elucidates the biomechanical mechanisms underlying exosuit-induced reductions in metabolic power. We evaluated the relationships between exosuit-induced changes in the body center of mass (COM) power generated by each limb, individual joint power and metabolic power. Compared with walking with an exosuit unpowered, exosuit assistance produced more symmetrical COM power generation during the critical period of the step-to-step transition (22.4±6.4% more symmetric). Changes in individual limb COM power were related to changes in paretic (=0.83, 0.004) and non-paretic (0.73, 0.014) ankle power. Interestingly, despite the exosuit providing direct assistance to only the paretic limb, changes in metabolic power were related to changes in non-paretic limb COM power (=0.80, 0.007), not paretic limb COM power (0.05). These findings contribute to a fundamental understanding of how individuals post-stroke interact with an exosuit to reduce the metabolic cost of hemiparetic walking.

show abstract

Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke

Bae

Awad

Long

et al. 2018

Journal of Experimental Biology

View full text Add to dashboard Cite

show abstract

“…Connecting the geometry and stiffness of the keel to the anticipated kinematics and kinetics of the user is critical for designing a prosthetic foot with a desired biomechanical performance. Numerous studies have shown that the mechanical design of a passive prosthetic foot affects the users' gait [2][3][4][5][6][7][8][9]. However, there is no consensus on exactly how the mechanical properties of a foot relate to its biomechanical performance [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Passive Prosthetic Foot Shape and Size Optimization Using Lower Leg Trajectory Error

Olesnavage

Winter

2018

Journal of Mechanical Design

View full text Add to dashboard Cite

A method is presented to optimize the shape and size of a passive, energy-storing prosthetic foot using the lower leg trajectory error (LLTE) as the design objective. The LLTE is defined as the root-mean-square error between the lower leg trajectory calculated for a given prosthetic foot's deformed shape under typical ground reaction forces (GRFs), and a target physiological lower leg trajectory obtained from published gait data for able-bodied walking. Using the LLTE as a design objective creates a quantitative connection between the mechanical design of a prosthetic foot (stiffness and geometry) and its anticipated biomechanical performance. The authors' prior work has shown that feet with optimized, low LLTE values can accurately replicate physiological kinematics and kinetics. The size and shape of a single-part compliant prosthetic foot made out of nylon 6/6 were optimized for minimum LLTE using a wide Bezier curve to describe its geometry, with constraints to produce only shapes that could fit within a physiological foot's geometric envelope. Given its single part architecture, the foot could be cost effectively manufactured with injection molding, extrusion, or three-dimensional printing. Load testing of the foot showed that its maximum deflection was within 0.3 cm (9%) of finite element analysis (FEA) predictions, ensuring the constitutive behavior was accurately characterized. Prototypes were tested on six below-knee amputees in India—the target users for this technology—to obtain qualitative feedback, which was overall positive and confirmed the foot is ready for extended field trials.

show abstract

“…Numerous studies have shown that the mechanical design of a passive prosthetic foot affects the users' gait [1][2][3][4][5][6][7][8]. However, there is no consensus on exactly how the mechanical properties of a foot relate to the biomechanical performance of the foot [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Passive Prosthetic Foot Shape and Size Optimization Using Lower Leg Trajectory Error

Olesnavage

Winter

2017

Volume 5A: 41st Mechanisms and Robotics Conference

View full text Add to dashboard Cite

A method is presented to optimize the shape and size of a passive prosthetic foot using the Lower Leg Trajectory Error (LLTE) as the design objective. The LLTE is defined as the root-mean-square error between the lower leg trajectory calculated for a given prosthetic foot by finding the deformed shape of the foot under typical ground reaction forces and a target physiological lower leg trajectory obtained from published gait data for able-bodied walking. In previous work, the design of simple two degree-of-freedom analytical models consisting of rigid structures, rotational joints with constant stiffness, and uniform cantilevered beams, have been optimized for LLTE. However, prototypes built to replicate these simple models were large, heavy, and overly complex. In this work, the size and shape of a single-part compliant prosthetic foot keel made out of nylon 6/6 was optimized for LLTE to produce a light weight, low cost, and easily manufacturable prosthetic foot design. The shape of the keel was parameterized as a wide Bézier curve, with constraints ensuring that only physically meaningful shapes were considered. The LLTE value for each design was evaluated using a custom MATLAB script, which ran ADINA finite element analysis software to find the deformed shape of the prosthetic keel under multiple loading scenarios. The optimization was performed by MATLAB’s built-in genetic algorithm. After the optimal design for the keel was found, a heel was added to structure, sized such that when the user’s full weight acted on the heel, the structure had a factor of safety of two. The resulting optimal design has a lower LLTE value than the two degree-of-freedom analytical models, at 0.154 compared to 0.172, 0.187, and 0.269 for the two degree-of-freedom models. At 412 g, the optimal wide curve foot is nearly half the mass of the lightest prototype built from the previous models, which was 980 g. The design found through this compliant mechanism optimization method is thus far superior to the two degree-of-freedom models previously considered.

show abstract

Mechanical work performed by individual limbs of transfemoral amputees during step-to-step transitions: Effect of walking velocity

Cited by 24 publications

References 23 publications

Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke

Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke

Passive Prosthetic Foot Shape and Size Optimization Using Lower Leg Trajectory Error

Passive Prosthetic Foot Shape and Size Optimization Using Lower Leg Trajectory Error

Contact Info

Product

Resources

About