Center of pressure and total force analyses for amputees walking with a backpack load over four surfaces

Sinitski, Emily H.; Herbert-Copley, Andrew; Lemaire, Edward D.; Doyle, Sean S.; Besemann, Markus; Dudek, Nancy

doi:10.1016/j.apergo.2015.07.014

Cited by 10 publications

(11 citation statements)

References 37 publications

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“…The result was in consistent with the finding of Mei et al [20]. The additional directional changes in the anterior-posterior COP trajectory might indicate that individuals with high-arched feet were less stable [33]. This might be because the high-arched foot has less plantar sensory information to rely on compared to the normal-arched foot, which results in decreased stability [34].…”

Section: Discussionsupporting

confidence: 90%

The center of pressure progression characterizes the dynamic function of high-arched feet during walking

Xiang

Zhang

2020

J Leather Sci Eng

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Background: The medial longitudinal arch height has an effect on kinetic parameters during gait and might be related to the risk of injury. For the assessment of foot structures, the center of pressure (COP) trajectory is a more reliable and practical parameter than plantar pressure. This study aimed to clarify the COP trajectory and velocity characteristics in the medial-lateral and anterior-posterior direction of individuals with a high-arched foot during barefoot walking. Methods: Sixty-two healthy young adults were asked to walk over a Footscan pressure plate to record the COP parameters during the stance phase of walking. Results: Compared to normal arched feet, the COP during forefoot contact and foot flat phases of high-arched feet shifted anteriorly (19.9 mm and 15.1 mm, respectively), and the mean velocity of COP in anterior-posterior direction decreased by 0.26 m/s and increased by 0.044 m/s during these two phases respectively. Conclusions: The findings of this study suggest that the displacement and velocity of COP in anterior-posterior direction was different between high-arched and normal-arched subjects during barefoot walking, which can be used for the assessment of gait characteristics for high-arched individuals. The results of this study may provide insights into modifying clinical intervention for individuals with high-arched feet to enhance rehabilitation and prevent injuries and have implications for assessing the design of footwear and foot orthotics.

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Section: Discussionsupporting

confidence: 90%

The center of pressure progression characterizes the dynamic function of high-arched feet during walking

Xiang

Zhang

2020

J Leather Sci Eng

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“…Amputee subjects’ total double support time significantly increased with load ( no load impedance p < 0.001; load impedance p < 0.001), which is a common behavior for both people with and without amputation walking with load 20 , 24 , 30 , 31 . Our amputee subjects walked with a longer intact-limb terminal double support time (i.e.…”

Section: Resultsmentioning

confidence: 97%

Interactions Between Transfemoral Amputees and a Powered Knee Prosthesis During Load Carriage

Brandt

Wen

Liu

et al. 2017

Sci Rep

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Machines and humans become mechanically coupled when lower limb amputees walk with powered prostheses, but these two control systems differ in adaptability. We know little about how they interact when faced with real-world physical demands (e.g. carrying loads). Here, we investigated how each system (i.e. amputee and powered prosthesis) responds to changes in the prosthesis mechanics and gravitational load. Five transfemoral amputees walked with and without load (i.e. weighted backpack) and a powered knee prosthesis with two pre-programmed controller settings (i.e. for load and no load). We recorded subjects’ kinematics, kinetics, and perceived exertion. Compared to the no load setting, the load setting reduced subjects’ perceived exertion and intact-limb stance time when they carried load. When subjects did not carry load, their perceived exertion and gait performance did not significantly change with controller settings. Our results suggest transfemoral amputees could benefit from load-adaptive powered knee controllers, and controller adjustments affect amputees more when they walk with (versus without) load. Further understanding of the interaction between powered prostheses, amputee users, and various environments may allow researchers to expand the utility of prostheses beyond simple environments (e.g. firm level ground without load) that represent only a subset of real-world environments.

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“…Future studies should also consider the effect of weight distribution about the torso, walking speed, and prosthetic alignment on the dynamic characterization of prosthetic ankle-foot systems designed for high activity users. Indeed, several previous studies of weighted walking have used different weight distribution methods (e.g., backpacks) to simulate common scenarios of load carriage (e.g., [ 3 , 6 , 7 ]). While the results of these previous studies may not be entirely generalizable to the present study, the methodological decision to utilize a weighted vest in the present study was based on ecological validity, resulting in a protocol that more closely simulates the weight distribution of protective gear and weapons/ammunition carried during dismounted operations in the military.…”

Section: Discussionmentioning

confidence: 99%

“…Schnall et al [ 5 ] found that compared to able-bodied individuals, lower-limb prosthesis users exhibit greater metabolic costs while walking with added loads, both at mid-range and high-end speeds of military foot marches. Other studies have shown that during weighted walking, lower-limb prosthesis users exhibit greater (and asymmetrical) demands on the musculoskeletal system [ 6 ] and larger deflections of the prosthetic ankle-foot system compared to unweighted walking [ 7 , 8 ]. The latter, in particular, suggests additional work focused specifically on the functional implications of these load responses is warranted.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and dynamic characterization of prosthetic feet for high activity users during weighted and unweighted walking

et al. 2018

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Many Service members and Veterans with lower-limb amputations have the potential for high function and the desire to resume physically demanding occupations that require them to carry heavy loads (e.g., military service, firefighters, farmers, ranchers, construction workers). However, it is currently unclear which prosthetic feet best accommodate heavy load carriage while also providing good overall function and mobility during unweighted activities. The main objective of this study was to investigate the ability of currently available prosthetic ankle-foot systems to accommodate weighted walking by examining the mechanical characteristics (i.e., forefoot stiffness) and dynamic function (i.e., rocker radius, effective foot length ratio, and late-stance energy return) of prosthetic feet designed for high activity users. Load versus deflection curves were obtained for nine prosthetic ankle-foot systems using a servohydraulic test frame and load cell. Effective roll-over shape characteristics and late-stance energy return measures were then obtained using quantitative gait analysis for three users with unilateral, transtibial amputation. Results from mechanical and dynamic testing showed that although forefoot stiffness varied across the nine feet investigated in this study, changes measured in roll-over shape radius and effective foot length ratio were relatively small in response to weighted walking. At the same time, prosthetic feet with more compliant forefoot keel structures appeared to provide more late-stance energy return compared to feet with stiffer forefoot keel structures. These results suggest that prosthetic ankle-foot systems with compliant forefoot keel structures may better accommodate weighted walking by reducing the metabolic cost of physically demanding activities. However, to more fully understand the biomechanical and functional implications of these results, other factors, such as the residual-limb strength of the user and the overall stiffness profile of the prosthetic foot, should also be considered.

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Center of pressure and total force analyses for amputees walking with a backpack load over four surfaces

Cited by 10 publications

References 37 publications

The center of pressure progression characterizes the dynamic function of high-arched feet during walking

The center of pressure progression characterizes the dynamic function of high-arched feet during walking

Interactions Between Transfemoral Amputees and a Powered Knee Prosthesis During Load Carriage

Mechanical and dynamic characterization of prosthetic feet for high activity users during weighted and unweighted walking

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