The Effects of Prosthesis Inversion/Eversion Stiffness on Balance-Related Variability During Level Walking: A Pilot Study

Abstract Prosthesis features that enhance balance are desirable to people with transtibial amputation. Ankle inversion/eversion compliance is intended to improve balance on uneven ground, but its effects remain unclear on level ground. We posited that increasing ankle inversion/eversion stiffness during level-ground walking would reduce balance-related effort by assisting in recovery from small disturbances in frontal-plane motions. We performed a pilot test with an ankle-foot prosthesis emulator programmed to apply inversion/eversion torques in proportion to the deviation from a nominal inversion/eversion position trajectory. We applied a range of stiffnesses to clearly understand the effect of the stiffness on balance-related effort, hypothesizing that positive stiffness would reduce effort while negative stiffness would increase effort. Nominal joint angle trajectories were calculated online as a moving average over several steps. In experiments with K3 ambulators with unilateral transtibial amputation (N = 5), stiffness affected step-width variability, average step width, margin of stability, intact-foot center of pressure variability, and user satisfaction (p ≤ 0.05, Friedman's test), but not intact-limb evertor average, intact-limb evertor variability, and metabolic rate (p ≥ 0.38, Friedman's test). Compared to zero stiffness, high positive stiffness reduced step-width variability by 13%, step width by 3%, margin of stability by 3%, and intact-foot center of pressure variability by 14%, whereas high negative stiffness had opposite effects and decreased satisfaction by 63%. The results of this pilot study suggest that positive ankle inversion stiffness can reduce active control requirements during level walking.

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Minimal shoes improve stability and mobility in persons with a history of falls

Scientific Reports ◽

10.1038/s41598-020-78862-6 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Tomasz Cudejko ◽

James Gardiner ◽

Asangaedem Akpan ◽

Kristiaan D’Août

Keyword(s):

Fall Prevention ◽

Postural Stability ◽

Center Of Pressure ◽

Stability Margin ◽

Timed Up And Go ◽

Balance Test ◽

Margin Of Stability ◽

Eyes Open ◽

History Of ◽

Falls In Older Adults

AbstractPostural and walking instabilities contribute to falls in older adults. Given that shoes affect human locomotor stability and that visual, cognitive and somatosensory systems deteriorate during aging, we aimed to: (1) compare the effects of footwear type on stability and mobility in persons with a history of falls, and (2) determine whether the effect of footwear type on stability is altered by the absence of visual input or by an additional cognitive load. Thirty participants performed standing and walking trials in three footwear conditions, i.e. conventional shoes, minimal shoes, and barefoot. The outcomes were: (1) postural stability (movement of the center of pressure during eyes open/closed), (2) walking stability (Margin of Stability during normal/dual-task walking), (3) mobility (the Timed Up and Go test and the Star Excursion Balance test), and (4) perceptions of the shoes (Monitor Orthopaedic Shoes questionnaire). Participants were more stable during standing and walking in minimal shoes than in conventional shoes, independent of visual or walking condition. Minimal shoes were more beneficial for mobility than conventional shoes and barefoot. This study supports the need for longitudinal studies investigating whether minimal footwear is more beneficial for fall prevention in older people than conventional footwear.

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Center of Pressure Trajectory and Spatiotemporal Gait Parameters When Walking with Limited Knee Flexion

Proceedings of the Human Factors and Ergonomics Society Annual Meeting ◽

10.1177/1071181321651197 ◽

2021 ◽

Vol 65 (1) ◽

pp. 1490-1493

Author(s):

Seobin Choi ◽

Jieon Lee ◽

Gwanseob Shin

Keyword(s):

Knee Flexion ◽

Stance Phase ◽

Center Of Pressure ◽

Dynamic Balance ◽

Left Knee ◽

Step Width ◽

Normal Walking ◽

Gait Stability ◽

Gait Parameters ◽

Stiff Knee

Stiff-knee, which indicates reduced range of knee flexion, may decrease gait stability. Although it is closely related to an increase in fall risk, the effect of limited knee flexion on the balance capacity during walking has not been well studied. This study aimed at examining how walking with limited knee flexion would influence the center of pressure (COP) trajectory and spatiotemporal gait parameters. Sixteen healthy young participants conducted four different walking conditions: normal walking and walking with limited knee flexion of their left knee up to 40 and 20 degrees, respectively. Results show that the participants walked significantly (p<0.05) slower with shorter stride length, wider step width, less cadence, and decreased stance phase when walking with limited knee flexion, compared to normal walking. The increase in the asymmetry and variability of the COP was also observed. It indicates that limited knee flexion during walking might affect the dynamic balance.

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Joint internal moments in subjects with unilateral transtibial amputation during walking

Journal of Orthopedics and Orthopedic Surgery ◽

10.29245/2767-5130/2021/1.1118 ◽

2021 ◽

Vol 2 (1) ◽

pp. 1-6

Author(s):

Francisco Molina-Rueda ◽

Alicia Cuesta-Gómez ◽

María Carratalá-Tejada ◽

Pilar Fernández-González ◽

Juan Carlos Miangolarra-Page ◽

...

Keyword(s):

Knee Extensor ◽

Occurrence Rate ◽

Control Group ◽

Transtibial Amputation ◽

Prosthetic Limb ◽

Motion System ◽

The People ◽

Hip Abductor ◽

Kinetic Pattern ◽

Intact Limb

Background: Subjects with a unilateral transtibial amputation (UTA) that have used prosthesis for over five years have a higher occurrence rate of osteoarthritis at the knee and hip joints of the intact limb. Objective: To research the joint internal moments of the hip, knee, and ankle in the sagittal and frontal planes during gait in persons with UTA. Methods: 25 individuals with UTA (50.26 years ± 13.76) and 25 subjects without amputation (46.71 years ± 13.76) participated in this study. Gait analysis was carried out using a Vicon® Motion System (Oxford Metrics, Oxford, UK) with eight 100 Hz cameras with infrared strobes, two 1000 Hz AMTI® force-plates. Results: People with UTA walk with a greater hip extensor moment in both intact and prosthetic limbs. The hip abductor moment was lower on the prosthetic limb compared to the intact limb and the control group. At the knee joint, the subjects with UTA walked with a reduced knee extensor and valgus moment on their prosthetic limb compared to the control group. At the ankle joint, the statistical analysis showed that the individuals with UTA walked with a reduced plantarflexor moment during the stance period on the intact limb compared to the people without amputation. Conclusions: Subjects with UTA walk with a different joint kinetic pattern in the sagittal and frontal planes compared to non-disabled individuals.

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Biomechanical Effect of 3D-Printed Foot Orthoses in Patients with Knee Osteoarthritis

10.21203/rs.3.rs-90724/v1 ◽

2020 ◽

Author(s):

Kuang-Wei Lin ◽

Li-Wei Chou ◽

Yi-Tien Su ◽

Shun-Hwa Wei ◽

Chen-Sheng Chen

Keyword(s):

Center Of Pressure ◽

Medial Knee ◽

Knee Oa ◽

Ankle Inversion ◽

Ankle Eversion ◽

Peak Knee ◽

Flexion Moment ◽

3D Printed ◽

Lateral Wedges ◽

Second Peak

Abstract Background: Lateral wedges comprise a common conservative treatment for medial knee osteoarthritis (OA). However, use of lateral wedges might increases the ankle eversion moment. To minimize the risk of ankle joint, lateral wedges with custom arch support are suggested. However, the manufacturing process of a custom foot orthosis (FO) is complicated, labor intensive, and time consuming. The technology of 3D printing is an ideal method for mass customization. Therefore. the purpose of this study was to develop custom FOs using 3D printing techniques and to evaluate the biomechanical effects of 3D-printed FOs in patients with medial knee OA.Methods: Fifteen patients with medial knee OA were enrolled into this study. Kinematic and kinetic data were collected during walking by using an optical motion capture system. A paired-sample t-test was conducted to compare biomechanical variables under two conditions: walking in standard shoes (Shoe) and walking in shoes embedded with 3D-printed FOs (Shoe + FO).Results: Under the Shoe + FO condition, the center of pressure at the peak knee adduction moment significantly shifted laterally by 2.71 mm compared with the Shoe condition. No significant difference in the peak knee flexion moment was observed between the two conditions. In addition, both the first and second peak knee adduction moments were significantly reduced by 4.08% and 9.09% under the Shoe + FO condition. The 3D-printed FOs did not affect the ankle eversion moment but caused a decrease in the peak ankle inversion moment.Conclusions: The 3D-printed FOs caused a decrease in the ankle inversion moment, the first and second peak knee adduction moments by changing the center of pressure path laterally. Although the decrease in the knee flexion moment from the use of 3D-printed FOs was nonsignificant, such FOs engender biomechanical changes and positively influence the biomechanics of patients with knee OA.

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Dynamic Balancing Responses in Unilateral Transtibial Amputees Following Outward-Directed Perturbations During Slow Treadmill Walking Differ Considerably for Amputated and Non-Amputated Side

10.21203/rs.3.rs-244733/v1 ◽

2021 ◽

Author(s):

Andrej Olenšek ◽

Matjaž Zadravec ◽

Helena Burger ◽

Zlatko Matjačić

Keyword(s):

Stance Phase ◽

Center Of Pressure ◽

Center Of Mass ◽

Reaction Force ◽

Dynamic Balancing ◽

Transtibial Amputation ◽

Control Subjects ◽

Foot Strike ◽

Transtibial Amputees ◽

Proprioceptive Function

Abstract BackgroundDue to disrupted motor and proprioceptive function lower limb amputation imposes considerable challenges associated with balance and greatly increases risk of falling in case of perturbations during walking. The aim of this study was to investigate dynamic balancing responses in unilateral transtibial amputees when they were subjected to perturbing pushes to the pelvis in outward direction at the time of foot strike on non-amputated and amputated side during slow walking.MethodsFourteen subjects with unilateral transtibial amputation and nine control subjects participated in the study. They were subjected to perturbations that were delivered to the pelvis at the time of foot strike of either the left or right leg. We recorded trajectories of center of pressure and center of mass, durations of in-stance and stepping periods as well as ground reaction forces. Statistical analysis was performed to determine significant differences in dynamic balancing responses between control subjects and subjects with amputation when subjected to outward-directed perturbation upon entering stance phases with non-amputated or amputated side.ResultsWhen outward-directed perturbations were delivered at the time of foot strike of the non-amputated leg, subjects with amputation were able to modulate center of pressure and ground reaction force similarly as control subjects which indicates application of in-stance balancing strategies. On the other hand, there was a complete lack of in-stance response when perturbations were delivered when the amputated leg entered the stance phase. Subjects with amputations instead used the stepping strategy and adjusted placement of the non-amputated leg in the ensuing stance phase to make a cross-step. Such response resulted in significantly higher displacement of center of mass. ConclusionsResults of this study suggest that due to the absence of the COP modulation mechanism, which is normally supplied by ankle motor function, people with unilateral transtibial amputation are compelled to choose the stepping strategy over in-stance strategy when they are subjected to outward-directed perturbation on the amputated side. However, the stepping response is less efficient than in-stance response. To improve their balancing responses to unexpected balance perturbation people fitted with passive transtibial prostheses should undergo perturbation-based balance training during clinical rehabilitation.

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Altering Footwear Type Influences Gait During Level Walking and Downhill Transitions

Journal of Applied Biomechanics ◽

10.1123/jab.28.5.481 ◽

2012 ◽

Vol 28 (5) ◽

pp. 481-490 ◽

Cited By ~ 4

Author(s):

Keith A. Stern ◽

Jinger S. Gottschall

Keyword(s):

Gait Cycle ◽

Dynamic Balance ◽

Step Length ◽

Lower Leg ◽

Step Width ◽

Lateral Gastrocnemius ◽

Gait Patterns ◽

Level Walking ◽

Stance Time ◽

Stable Gait

The purpose of our study was to determine if altering the insoles within footwear or walking barefoot, as an attempt to increase or decrease cutaneous stimuli, would improve dynamic balance during a hill-walking task. We hypothesize that compared with foam insoles or iced bare feet, textured insoles or bare feet will result in greater speeds, longer step lengths, narrower step width, shorter stance time, and less tibialis anterior (TA), soleus (SOL), and lateral gastrocnemius (LG) activity during key gait cycle phases. Ten, healthy college students, 5 men and 5 women, completed the protocol that consisted of level walking and downhill transition walking in five different footwear insole or barefoot conditions. During level walking, conditions with the hypothesized greater cutaneous stimuli resulted in greater step length, which relates to a more stable gait. In detail, the texture insole condition average step length was 3% longer than the regular insole condition, which was 5% longer than the ice condition (p < .01). The same signals of increased stability were evident during the more challenging downhill transition stride. Step length during the barefoot condition was 8% longer than the ice condition (p < .05) and step width during the regular footwear condition was 5% narrower than the foam condition (p = .05). To add, during the preswing phase of level walking, TA activity of the textured insole condition was 30% less than the foam insole. Although our data show that footwear conditions alter gait patterns and lower leg muscle activity during walking, there is not enough evidence to support the hypothesis that textured insoles will improve dynamic balance as compared with other footwear types.

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Severity of spine malalignment on center of pressure progression during level walking in subjects with adolescent idiopathic scoliosis

2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society ◽

10.1109/embc.2014.6944968 ◽

2014 ◽

Cited By ~ 1

Author(s):

Jen-Suh Chern ◽

Chia-Chi Kao ◽

Po-Lian Lai ◽

Chi-Wen Lung ◽

Wen-Jer Chen

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Center Of Pressure ◽

Level Walking

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Alterations in Gait Initiation Are Present in Those With Posttraumatic Ankle Osteoarthritis: A Pilot Study

Journal of Applied Biomechanics ◽

10.1123/jab.29.3.245 ◽

2013 ◽

Vol 29 (3) ◽

pp. 245-252 ◽

Cited By ~ 8

Author(s):

Erik A. Wikstrom ◽

Robert B. Anderson

Keyword(s):

Motor Control ◽

Pilot Study ◽

Postural Control ◽

Center Of Pressure ◽

Gait Initiation ◽

Static Balance ◽

Control Mechanisms ◽

Ankle Osteoarthritis ◽

Sf 36 ◽

Balance Trials

The purpose of this investigation was to determine if stereotypical patterns of gait initiation are altered in those with posttraumatic ankle osteoarthritis. Ten subjects, five with unilateral ankle osteoarthritis and five uninjured controls, participated. Subjects completed the SF-36 and Ankle Osteoarthritis Scale to quantify self-reported disability as well as 10 dual-limb static stance trials and 10 gait initiation trials with each leg. Center of pressure outcomes were calculated for static balance trials while the peak center of pressure excursions were calculated for each phase of gait initiation. The results indicate greater self-reported disability (P< .05) and worse static postural control (P< .05) in the ankle osteoarthritis group. Nonstereotypical patterns were also observed during the first and third phases of gait initiation in those with ankle osteoarthritis. The results of this pilot study suggest that supraspinal motor control mechanisms may have changed in those with posttraumatic ankle osteoarthritis.

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Use of Stabilometric Platform and Evaluation of Methods for Further Measurments – A Pilot Study

Acta Medica (Hradec Kralove Czech Republic) ◽

10.14712/18059694.2017.71 ◽

2007 ◽

Vol 50 (2) ◽

pp. 139-143 ◽

Cited By ~ 3

Author(s):

Jitka Jančová ◽

Vlasta Tošnerová

Keyword(s):

Pilot Study ◽

Center Of Pressure ◽

Quiet Standing ◽

Parallel Testing ◽

Eyes Closed ◽

Eyes Open ◽

Single Force ◽

Test Retest Reliability ◽

Evaluation Of Methods ◽

Anterior Posterior

Posture in a still stance has been quantified by changes in the center of pressure (COP), in both anterior-posterior (A/P) and medial-lateral (M/L) directions and measured on a single force platform (Bertec PRO VEC 5.0). The purpose of this study was to estimate the variance in error and the intrasession test-retest reliability, and to determine which measures shall be taken for further measurements, especially with adults age 65 and older. We used two types of approximation for the reliability coefficient. Firstly, we used the equation according to Blahuš (2) and secondly we used the Pearson’s correlation coefficient for test-retest measurements. The findings allow us to say, among other things, that the tests of quiet standing Double Narrow Stance Eyes Open (DNSEO) and Double Narrow Stance Eyes Closed (DNSEC) are parallel, in the sense of parallel testing.

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