scholarly journals Biologically Inspired Design and Development of a Variable Stiffness Powered Ankle-Foot Prosthesis

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Alexander Agboola-Dobson ◽  
Guowu Wei ◽  
Lei Ren
Keyword(s):  
Lower Limb ◽  
Degrees Of Freedom ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Variable Stiffness ◽  
Plane Motion ◽  
Biologically Inspired ◽  
Passive Rotation ◽  
Ground Conditions ◽  
Biologically Inspired Design

Recent advancements in powered lower limb prostheses have appeased several difficulties faced by lower limb amputees by using a series-elastic actuator (SEA) to provide powered sagittal plane flexion. Unfortunately, these devices are currently unable to provide both powered sagittal plane flexion and two degrees of freedom (2-DOF) at the ankle, removing the ankle’s capacity to invert/evert, thus severely limiting terrain adaption capabilities and user comfort. The developed 2-DOF ankle system in this paper allows both powered flexion in the sagittal plane and passive rotation in the frontal plane; an SEA emulates the biomechanics of the gastrocnemius and Achilles tendon for flexion while a novel universal-joint system provides the 2-DOF. Several studies were undertaken to thoroughly characterize the capabilities of the device. Under both level- and sloped-ground conditions, ankle torque and kinematic data were obtained by using force-plates and a motion capture system. The device was found to be fully capable of providing powered sagittal plane motion and torque very close to that of a biological ankle while simultaneously being able to adapt to sloped terrain by undergoing frontal plane motion, thus providing 2-DOF at the ankle. These findings demonstrate that the device presented in this paper poses radical improvements to powered prosthetic ankle-foot device (PAFD) design.

Muscle Contributions to Balance Control During Amputee and Nonamputee Stair Ascent

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Nicole G. Harper ◽  
Jason M. Wilken ◽  
Richard R. Neptune
Keyword(s):  
Angular Momentum ◽  
Lower Limb ◽  
Sagittal Plane ◽  
Balance Control ◽  
Dynamic Balance ◽  
Frontal Plane ◽  
Rate Of Change ◽  
Prosthetic Devices ◽  
Stair Ascent

Abstract Dynamic balance is controlled by lower-limb muscles and is more difficult to maintain during stair ascent compared to level walking. As a result, individuals with lower-limb amputations often have difficulty ascending stairs and are more susceptible to falls. The purpose of this study was to identify the biomechanical mechanisms used by individuals with and without amputation to control dynamic balance during stair ascent. Three-dimensional muscle-actuated forward dynamics simulations of amputee and nonamputee stair ascent were developed and contributions of individual muscles, the passive prosthesis, and gravity to the time rate of change of angular momentum were determined. The prosthesis replicated the role of nonamputee plantarflexors in the sagittal plane by contributing to forward angular momentum. The prosthesis largely replicated the role of nonamputee plantarflexors in the transverse plane but resulted in a greater change of angular momentum. In the frontal plane, the prosthesis and nonamputee plantarflexors contributed oppositely during the first half of stance while during the second half of stance, the prosthesis contributed to a much smaller extent. This resulted in altered contributions from the intact leg plantarflexors, vastii and hamstrings, and the intact and residual leg hip abductors. Therefore, prosthetic devices with altered contributions to frontal-plane angular momentum could improve balance control during amputee stair ascent and minimize necessary muscle compensations. In addition, targeted training could improve the force production magnitude and timing of muscles that regulate angular momentum to improve balance control.

The Effect of the TayCo External Ankle Brace on Multidirectional Reach Distance, Balance, and Motion in Collegiate Athletes

2020 ◽  
Vol 25 (6) ◽  
pp. 323-327
Author(s):  
Steven J. Smith ◽  
Cameron J. Powden
Keyword(s):  
Range Of Motion ◽  
Sagittal Plane ◽  
Dynamic Balance ◽  
Plantar Flexion ◽  
Collegiate Athletes ◽  
Frontal Plane ◽  
Plane Motion ◽  
Lower Extremity Function ◽  
Physically Active ◽  
Ankle Brace

Ensuring ankle stability while allowing for functional movement is important when returning patients to physical activity and attempting to prevent injury. The purpose of this study was to examine the effectiveness of the TayCo external and a lace-up ankle brace on lower extremity function, dynamic balance, and motion in 18 physically active participants. Significantly greater range of motion was demonstrated for the TayCo brace compared with the lace-up brace for dorsiflexion and plantar flexion, as well as less range of motion for the TayCo brace compared to the lace-up brace for inversion and eversion. The TayCo brace provided restricted frontal plane motion while allowing increased sagittal plane motion without impacting performance measures.

scholarly journals Accelerometer-Based Navigation in Total Knee Arthroplasty for the Management of Extra-Articular Deformity and Retained Femoral Hardware: Analysis of Component Alignment

Joints ◽  
2019 ◽  
Vol 07 (01) ◽  
pp. 001-007 ◽  
Author(s):  
Andrea Cozzi Lepri ◽  
Matteo Innocenti ◽  
Fabrizio Matassi ◽  
Marco Villano ◽  
Roberto Civinini ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Navigation System ◽  
Lower Limb ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Control Group ◽  
Navigation Systems ◽  
Level Of Evidence ◽  
Total Knee

Abstract Purpose Recent advances in total knee arthroplasty (TKA) include an accelerometer portable system designed to improve component position and alignment. The purpose of this study is to evaluate whether accelerometer navigation system can be a valuable option in complex TKAs for extra-articular deformity of the lower limb or in case of retained femoral hardware. Methods A group of 13 patients underwent TKA with an accelerometer navigation system. Three patients had a tibial extra-articular deformity, six had a femoral extra-articular deformity, and four had an intramedullary nail in the femur. Preoperative and postoperative mechanical axes were measured from full-length lower extremity radiographs to evaluate alignment. The alignment of prosthetic components in the frontal and sagittal planes was determined by postoperative radiographs. Results At 30-days postoperative radiographic check, the hip knee ankle angle was within 2.0° (0 ± 1) of the neutral mechanical axis. The alignment of the tibial component on the frontal plane was 90.0° (range 89–91) and on the sagittal plane 5.0° (range 3–7). The alignment of the femoral component on the frontal plane was 90.0° (range 89–91) and on the sagittal plane 3.0° (range 0–5). Conclusion The alignment of the prosthetic components has been accurate and comparable to other navigation systems in literature without any increase in surgical times. The accelerometer-based navigation system is therefore a useful technique that can be used to optimize TKA alignment in patients with extra-articular deformity or with lower limb hardware, where the intramedullary guides cannot be applied. Level of Evidence This is an observational study without a control group, Level III.

Sensitivity of the Toe Height to Multijoint Angular Changes in the Lower Limbs During Unobstructed and Obstructed Gait

2020 ◽  
pp. 1-9
Author(s):  
Chuyi Cui ◽  
Brittney Muir ◽  
Shirley Rietdyk ◽  
Jeffrey Haddad ◽  
Richard van Emmerik ◽  
...  
Keyword(s):  
Young Adults ◽  
Lower Limb ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Singular Value ◽  
Lower Limbs ◽  
Joint Angles ◽  
Adult Lifespan ◽  
Main Contributor ◽  
Bilateral Lower Limb

Tripping while walking is a main contributor to falls across the adult lifespan. Trip risk is proportional to variability in toe clearance. To determine the sources of this variability, the authors computed for 10 young adults the sensitivity of toe clearance to 10 bilateral lower limb joint angles during unobstructed and obstructed walking when the lead and the trail limb crossed the obstacle. The authors computed a novel measure—singular value of the appropriate Jacobian—as the combined toe clearance sensitivity to 4 groups of angles: all sagittal and all frontal plane angles and all swing and all stance limb angles. Toe clearance was most sensitive to the stance hip ab/adduction for unobstructed gait. For obstructed gait, sensitivity to other joints increased and matched the sensitivity to stance hip ab/adduction. Combined sensitivities revealed critical information that was not evident in the sensitivities to individual angles. The combined sensitivity to stance limb angles was 84% higher than swing limb angles. The combined sensitivity to the sagittal plane angles was lower than the sensitivity to the frontal plane angles during unobstructed gait, and this relation was reversed during obstacle crossing. The results highlight the importance of the stance limb joints and indicate that frontal plane angles should not be ignored.

An Examination of the Degrees of Freedom of Human Jaw Motion in Speech and Mastication

1997 ◽  
Vol 40 (6) ◽  
pp. 1341-1351 ◽  
Author(s):  
David J. Ostry ◽  
Eric Vatikiotis-Bateson ◽  
Paul L. Gribble
Keyword(s):  
Degrees Of Freedom ◽  
Sagittal Plane ◽  
Plane Motion ◽  
Motion Path ◽  
Vertical Position ◽  
Horizontal Position ◽  
Jaw Movements ◽  
Jaw Opening ◽  
Jaw Position ◽  
Independent Motion

The kinematics of human jaw movements were assessed in terms of the three orientation angles and three positions that characterize the motion of the jaw as a rigid body. The analysis focused on the identification of the jaw’s independent movement dimensions, and was based on an examination of jaw motion paths that were plotted in various combinations of linear and angular coordinate frames. Overall, both behaviors were characterized by independent motion in four degrees of freedom. In general, when jaw movements were plotted to show orientation in the sagittal plane as a function of horizontal position, relatively straight paths were observed. In speech, the slopes and intercepts of these paths varied depending on the phonetic material. The vertical position of the jaw was observed to shift up or down so as to displace the overall form of the sagittal plane motion path of the jaw. Yaw movements were small but independent of pitch, and vertical and horizontal position. In mastication, the slope and intercept of the relationship between pitch and horizontal position were affected by the type of food and its size. However, the range of variation was less than that observed in speech. When vertical jaw position was plotted as a function of horizontal position, the basic form of the path of the jaw was maintained but could be shifted vertically. In general, larger bolus diameters were associated with lower jaw positions throughout the movement. The timing of pitch and yaw motion differed. The most common pattern involved changes in pitch angle during jaw opening followed by a phase predominated by lateral motion (yaw). Thus, in both behaviors there was evidence of independent motion in pitch, yaw, horizontal position, and vertical position. This is consistent with the idea that motions in these degrees of freedom are independently controlled.

Development of a Multiple Axis Robotic Platform for Ankle Studies

2016 ◽  
Author(s):  
Varun Nalam ◽  
Hyunglae Lee
Keyword(s):  
Degrees Of Freedom ◽  
Position Control ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Mechanical Impedance ◽  
Peak Torque ◽  
Angular Speed ◽  
Design Development ◽  
Robotic Platform ◽  
Prosthetic Devices

This paper describes the design, development, modeling, and control of a robotic platform developed for the characterization of mechanical impedance and reflex responses of the ankle in 2 degrees-of-freedom (DOF): sagittal (dorsiflexion-plantarflexion) and frontal plane (inversion-eversion). The platform, controlled actively along both DOFs, is capable of producing rapid and strong perturbations up to an angular speed of 200°/s and peak torque of 400 Nm. This enables study of ankle impedance characteristics even during extreme task conditions such as running. The platform is designed to provide perturbations to the ankle up to an angle of 20° in sagittal plane and 10° in frontal plane, which is sufficient for all possible configurations of the ankle during postural balance and stance phase of walking. These characteristics of the platform make it ideal for both impedance and reflex characterization along both DOFs of the ankle. The platform’s performance of position control is validated under varying loads simulating various conditions of posture and locomotion. The platform’s orientation accuracy in both sagittal and frontal planes is established for various input signals including slow sinusoid inputs and rapid ramp perturbations. Implications for future ankle studies to estimate neuro-mechanical characteristics and applications to assistive and prosthetic devices are discussed.

scholarly journals Lower limb intersegmental forces for below-knee amputee children during standing

1991 ◽  
Vol 15 (3) ◽  
pp. 185-191 ◽  
Author(s):  
J. R. Engsberg ◽  
K. C. Aldridge ◽  
J. A. Harder
Keyword(s):  
Spatial Data ◽  
Lower Limb ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Anatomical Structure ◽  
Static Force ◽  
Force Analysis ◽  
Knee Angle ◽  
Prosthetic Knee ◽  
Hip Forces

The purpose of this investigation was to compare intersegmental knee and hip forces for below-knee amputee (BKA) and able-bodied children during standing. Three unilateral BKA children and 10 able-bodied children (7-9 years) were tested on four separate occasions at six month intervals. Three trials of external force and spatial data during standing were collected from each subject for each session. These data were utilised to determine the intersegmental forces at the knees and hips of the children using a static force analysis. Results indicated that in some instances the intersegmental forces for the BKA children were significantly greater than those of the able-bodied children and in other instances significantly lower (p < 0.05). In all cases, however, the values were substantially less than corresponding values for walking and running. The effects of the forces upon spatial orientations indicated significant differences between the two groups of children. The frontal plane prosthetic knee angle, the sagittal plane prosthetic and non-prosthetic knee angles, and the sagittal plane trunk angle were all greater for the BKA children when compared to able-bodied children. These differences may be the result of the anatomical structure of the amputee and/or the construction of the prosthesis.

scholarly journals Reliability of 3-Dimensional Measures of Single-Leg Drop Landing Across 3 Institutions: Implications for Multicenter Research for Secondary ACL-Injury Prevention

2015 ◽  
Vol 24 (2) ◽  
pp. 198-209 ◽  
Author(s):  
Gregory D. Myer ◽  
Nathaniel A. Bates ◽  
Christopher A. DiCesare ◽  
Kim D. Barber Foss ◽  
Staci M. Thomas ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Injury Prevention ◽  
Outcome Measures ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Plane Motion ◽  
3 Dimensional ◽  
Drop Landing ◽  
Prevention Studies ◽  
Acl Injury Prevention

Context:Due to the limitations of single-center studies in achieving appropriate sampling with relatively rare disorders, multicenter collaborations have been proposed to achieve desired sampling levels. However, documented reliability of biomechanical data is necessary for multicenter injury-prevention studies and is currently unavailable.Objective:To measure the reliability of 3-dimensional (3D) biomechanical waveforms from kinetic and kinematic variables during a single-leg landing (SLL) performed at 3 separate testing facilities.Design:Multicenter reliability study.Setting:3 laboratories.Patients:25 female junior varsity and varsity high school volleyball players who visited each facility over a 1-mo period.Intervention:Subjects were instrumented with 43 reflective markers to record 3D motion as they performed SLLs. During the SLL the athlete balanced on 1 leg, dropped down off of a 31-cm-high box, and landed on the same leg. Kinematic and kinetic data from both legs were processed from 2 trials across the 3 laboratories.Main Outcome Measures:Coefficients of multiple correlations (CMC) were used to statistically compare each joint angle and moment waveform for the first 500 ms of landing.Results:Average CMC for lower-extremity sagittal-plane motion was excellent between laboratories (hip .98, knee .95, ankle .99). Average CMC for lower-extremity frontal-plane motion was also excellent between laboratories (hip .98, knee .80, ankle .93). Kinetic waveforms were repeatable in each plane of rotation (3-center mean CMC ≥.71), while knee sagittal-plane moments were the most consistent measure across sites (3-center mean CMC ≥.94).Conclusions:CMC waveform comparisons were similar relative to the joint measured to previously published reports of between-sessions reliability of sagittal- and frontal-plane biomechanics performed at a single institution. Continued research is needed to further standardize technology and methods to help ensure that highly reliable results can be achieved with multicenter biomechanical screening models.

scholarly journals Runners Adapt Different Lower-Limb Movement Patterns With Respect to Different Speeds and Downhill Slopes

2021 ◽  
Vol 3 ◽  
Author(s):  
David Sundström ◽  
Markus Kurz ◽  
Glenn Björklund
Keyword(s):  
Lower Limb ◽  
Energy Cost ◽  
Degrees Of Freedom ◽  
Stance Phase ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Movement Pattern ◽  
Knee Extension ◽  
Generic Model ◽  
Energy Cost Of Running

The aim of this study was to investigate the influence of slope and speed on lower-limb kinematics and energy cost of running. Six well-trained runners (VO2max 72 ± 6 mL·kg−1·min−1) were recruited for the study and performed (1) VO2max and energy cost tests and (2) an experimental running protocol at two speeds, 12 km·h−1 and a speed corresponding to 80% of VO2max (V80, 15.8 ± 1.3 km·h−1) on three different slopes (0°, −5°, and −10°), totaling six 5-min workload conditions. The workload conditions were randomly ordered and performed continuously. The tests lasted 30 min in total. All testing was performed on a large treadmill (3 × 5 m) that offered control over both speed and slope. Three-dimensional kinematic data of the right lower limb were captured during the experimental running protocol using eight infrared cameras with a sampling frequency of 150 Hz. Running kinematics were calculated using a lower body model and inverse kinematics approach. The generic model contained three, one, and two degrees of freedom at the hip, knee, and ankle joints, respectively. Oxygen uptake was measured throughout the experimental protocol. Maximum hip extension and flexion during the stance phase increased due to higher speed (p &lt; 0.01 and p &lt; 0.01, respectively). Knee extension at the touchdown and maximal knee flexion in the stance phase both increased on steeper downhill slopes (both p &lt; 0.05). Ground contact time (GCT) decreased as the speed increased (p &lt; 0.01) but was unaffected by slope (p = 0.73). Runners modified their hip movement pattern in the sagittal plane in response to changes in speed, whereas they altered their knee movement pattern during the touchdown and stance phases in response to changes in slope. While energy cost of running was unaffected by speed alone (p = 0.379), a shift in energy cost was observed for different speeds as the downhill gradient increased (p &lt; 0.001). Energy cost was lower at V80 than 12 km·h−1 on a −5° slope but worse on a −10° slope. This indicates that higher speeds are more efficient on moderate downhill slopes (−5°), while lower speeds are more efficient on steeper downhill slopes (−10°).

scholarly journals The shape of disposable diaper affects spontaneous movements of lower limbs in young infants

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hirotaka Gima ◽  
Midori Teshima ◽  
Etsuko Tagami ◽  
Toshihiro Sato ◽  
Hidenobu Ohta
Keyword(s):  
Lower Limb ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Type A ◽  
Lower Limbs ◽  
Type B ◽  
Limb Movements ◽  
Young Infants ◽  
Knee Movement ◽  
Spontaneous Movements

Abstract This study examined the characteristics of young infants’ lower limb spontaneous movements based on differences in shape of diapers. Twenty-seven healthy infants (103 ± 16.3 days old) were enrolled in this study. We measured the spontaneous movements of their lower limbs in four conditions (Naked, wearing Normal type diapers, wearing Type A diapers, and wearing Type B diapers). The Normal diaper has a wider waist belt than the Type A diaper, and the Type B diaper has a narrower crotch area than the Type A diaper. We observed them in seven indices (the velocity of lower limb movements, the trajectory area of knee movement in the sagittal plane and the frontal plane, the distance between both knees and between side of abdomen and knee, and correlation of velocities between side of abdomen and knee and between left and right ankles). The results showed that the velocity of the lower limb movements in the Naked condition was higher than when wearing Normal diapers. The value for the trajectory area of knee movement in sagittal plane, which reflects the range of lower leg lifting movements and closeness of such movements to the trunk, for the Type B diaper condition was higher than that for the Normal diaper condition. This result indicates that the shape of the diaper affects the spontaneous movements of the lower limbs of young infants.

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