A Robotic Ankle–Foot Prosthesis With Active Alignment

2016 ◽  
Vol 10 (2) ◽  
Author(s):  
Andrew Kennedy LaPrè ◽  
Brian R. Umberger ◽  
Frank C. Sup
Keyword(s):  
Center Of Pressure ◽  
Reaction Force ◽  
Residual Limb ◽  
Moment Arm ◽  
Ankle Prosthesis ◽  
Socket Connection ◽  
The Moment ◽  
Socket Interface ◽  
Configuration Changes ◽  
Large Moment

An ankle–foot prosthesis designed to mimic the missing physiological limb generates a large sagittal moment during push off which must be transferred to the residual limb through the socket connection. The large moment is correlated with high internal socket pressures that are often a source of discomfort for the person with amputation, limiting prosthesis use. In this paper, the concept of active alignment is developed. Active alignment realigns the affected residual limb toward the center of pressure (CoP) during stance. During gait, the prosthesis configuration changes to shorten the moment arm between the ground reaction force (GRF) and the residual limb. This reduces the peak moment transferred through the socket interface during late stance. A tethered robotic ankle prosthesis has been developed, and evaluation results are presented for active alignment during normal walking in a laboratory setting. Preliminary testing was performed with a subject without amputation walking with able-bodied adapters at a constant speed. The results show a 33% reduction in the peak resultant moment transferred at the socket limb interface.

Multi-Digit Control of Contact Forces During Rotation of a Hand-Held Object

2008 ◽  
Vol 99 (4) ◽  
pp. 1846-1856 ◽  
Author(s):  
Sara A. Winges ◽  
Stephanie E. Eonta ◽  
John F. Soechting ◽  
Martha Flanders
Keyword(s):  
Time Course ◽  
Center Of Pressure ◽  
Temporal Patterns ◽  
Contact Forces ◽  
Emg Activity ◽  
Moment Arm ◽  
Force Amplitude ◽  
Hand Muscles ◽  
Contact Points ◽  
The Moment

Rotation of an object held with three fingers is produced by modulation of force amplitude and direction at one or more contact points. Changes in the moment arm through which these forces act can also contribute to the modulation of the rotational moment. Therefore force amplitude and direction as well as the center of pressure on each contact surface must be carefully coordinated to produce a rotation. Because there is not a single solution, this study sought to describe consistent strategies for simple position-to-position rotations in the pitch, roll, and yaw axes. Force amplitude and direction, and center of pressure on the contact surfaces (and thus the moment arm), were measured as human subjects rotated a 420 g force-transducer instrumented object, grasped with the thumb, index and ring fingers (average movement time: 500 ms). Electromyographic (EMG) activity was recorded from five intrinsic and three extrinsic hand muscles and two wrist muscles. Principal components analysis of force and EMG revealed just two main temporal patterns: the main one followed rotational position and the secondary one had a time course that resembled that of rotational velocity. Although the task could have been accomplished by dynamic modulation of the activity of wrist muscles alone, these two main dynamic EMG patterns were seen in intrinsic hand muscles as well. In contrast to previous reports of shifting in time of the phasic activity bursts of various muscles, in this task, all EMG records were well described by just two temporal patterns, resembling the position and velocity traces.

Initiating Rotation in Back and Reverse Armstand Triple Somersaults Tuck Dives

2001 ◽  
Vol 17 (4) ◽  
pp. 312-325 ◽  
Author(s):  
Karen Murtaugh ◽  
Doris I. Miller
Keyword(s):  
Angular Momentum ◽  
Lower Extremity ◽  
Upper Extremity ◽  
Reaction Force ◽  
Moment Arm ◽  
Angular Momenta ◽  
Force Moment ◽  
The Moment ◽  
Trunk Position

To determine strategies for initiating rotation in armstand back and reverse triple somersaults tuck dives from the 10-m platform, videotaped records of 17 elite male divers performing in competitions between 1995 and 1999 were analyzed. Linear and angular momenta at last contact were similar for both dives. Although the lower extremity actions were comparable, they occurred significantly earlier (p < .05) in reverse triple takeoffs, allowing divers to enter the tuck more quickly. As divers lean, the moment arm of the vertical platform reaction force increases with respect to the CG. The vertical platform reaction force moment promotes back and opposes reverse somersaulting angular momentum. Meanwhile, the horizontal platform reaction force moment promotes reverse and opposes back somersaulting angular momentum. Consequently, divers performing reverse triples maintained a more vertical trunk position during the early part of the takeoff, while those executing back triples leaned further before initiating lower and upper extremity actions to exert force against the platform. Since the strategy for reverse rotation may result in the head passing close to the platform and there is very little to gain in degree of difficulty, it is recommended that competitors execute back rather than reverse somersaulting armstand dives.

Ankle Control in Walking and Running: Speed- and Gait-Related Changes in Dynamic Mean Ankle Moment Arm

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Peter Gabriel Adamczyk
Keyword(s):  
High Speed ◽  
Center Of Pressure ◽  
Human Subjects ◽  
Reaction Force ◽  
Qualitative Change ◽  
Ground Contact ◽  
Moment Arm ◽  
Running Speed ◽  
Ankle Moment ◽  
Quantitative Evidence

Abstract The human foot–ankle complex uses heel-to-toe ground contact progression in walking, but primarily forefoot contact in high-speed running. This qualitative change in ankle control is clear to the runner, but current measures of ankle behavior cannot isolate the effect, and it is unknown how it changes across moderate speeds. We investigated this dynamic ankle control across a range of walking and running speeds using a new measure, the dynamic mean ankle moment arm (DMAMA): the ratio of sagittal ankle moment impulse to ground reaction force impulse on a single limb. We hypothesized that DMAMA would increase with speed in both walking and running, indicating more forefoot-dominated gait with ground reaction forces more anterior to the ankle. Human subjects walked (1.0–2.0 m/s) and ran (2.25–5.25 m/s) on an instrumented treadmill with motion capture and pressure insoles to estimate DMAMA. DMAMA decreased with increasing walking speed, then increased upon the transition to running, and increased further with increasing running speed. These results provide quantitative evidence that walking becomes more hindfoot-dominated as speed increases—similar to behavior during acceleration—and that running is more forefoot-dominated than walking. The instantaneous center of pressure (COP) at initial ground contact did not follow the same trends. The discrepancy highlights the value of DMAMA in summarizing ankle control across the whole stance phase. DMAMA may provide a useful outcome metric for evaluating biomimetic prostheses and for quantifying foot contact styles in running.

The Influence of Heel Lift Manipulation on Achilles Tendon Loading in Running

1998 ◽  
Vol 14 (4) ◽  
pp. 374-389 ◽  
Author(s):  
Sharon J. Dixon ◽  
David G. Kerwin
Keyword(s):  
Achilles Tendon ◽  
Ground Reaction Force ◽  
Reaction Force ◽  
Tendon Injury ◽  
Moment Arm ◽  
The Common ◽  
Tendon Force ◽  
The Moment ◽  
Joint Center ◽  
Heel Lift

In this study, a modeling method was developed to estimate Achilles tendon forces in running. Owing to the common use of heel lift devices in the treatment of Achilles tendon injury, we investigated the influence of increased heel lift on Achilles tendon loading. The hypothesis was that heel lift manipulation can influence maximum Achilles tendon force. Responses to heel lift variation were found to differ among 3 elite runners demonstrating distinct running styles. A rearfoot and a midfoot striker demonstrated significant increases in maximum Achilles tendon force with increased heel lift, whereas a forefoot striker demonstrated no changes in maximum Achilles tendon force values with heel lift manipulation (p < .05). Analysis of the factors contributing to the observed changes in maximum Achilles tendon force highlighted the influence of the moment arm of ground reaction force and the moment arm of the Achilles tendon about the ankle joint center. The finding that increased heel lift may increase maximum Achilles tendon force suggests that caution is advised in the routine use of this intervention. The different responses to heel lift increase between subjects highlight the importance of classifying subjects based on running style.

COMPARISON OF ANKLE JOINT LOAD IN DIFFERENT FOOT STRIKE STRATEGIES DURING STAIR ASCENT

2019 ◽  
Vol 19 (07) ◽  
pp. 1940043
Author(s):  
EUI BUM CHOI ◽  
HYEONG MIN JEON ◽  
JAE HOON HEO ◽  
GWANG MOON EOM
Keyword(s):  
Ankle Joint ◽  
Ground Reaction Force ◽  
Center Of Pressure ◽  
Reaction Force ◽  
Moment Arm ◽  
Joint Reaction Force ◽  
Stair Ascent ◽  
Foot Strike ◽  
Joint Load ◽  
Weight Acceptance

The purpose of this study was to find a foot strike strategy that can reduce the ankle joint load during stair ascent by comparing the ankle joint load in two strategies of initial contact during stair ascent. Twenty young subjects performed ascending stairs with two strategies, i.e., rearfoot strike (RFS) and forefoot strike (FFS). Kinematic data was measured from 12 cameras and the ground reaction force was measured by a force plate inserted in the second step of four-step stairs. Stance phase was divided into three phase, i.e., weight acceptance, pull up, and forward continuance. Four ankle related kinetic variables were derived from the measured data, i.e., joint reaction force, moment, and the magnitude and moment arm of ground reaction force. Root-mean-square (RMS) was used as the representative value of the variables during each phase was compared between strategies. In the weight acceptance phase, FFS resulted in greater values of all four kinetic variables than RFS. For the pull-up and forward continuance phases, joint reaction force and ground reaction force were not different between strategies but joint moment and moment arm was greater for FFS than RFS. In weight acceptance phase, greater ground reaction forces and longer moment arm of FFS may have resulted from faster weight transfer to the ipsilateral foot and the more anterior location of center of pressure, respectively. Both have contributed greater joint moment of FFS. In pull-up and forward continuance phases, greater ankle moment of FFS was affected mainly by longer moment arms, which may reflect the persistent farther location of center of pressure from the ankle joint. The results suggest that RFS would be more advantageous than FFS in terms of ankle joint load.

Effect of Foot Progression Angle and Lateral Wedge Insole on a Reduction in Knee Adduction Moment

2016 ◽  
Vol 32 (5) ◽  
pp. 454-461 ◽  
Author(s):  
Ken Tokunaga ◽  
Yuki Nakai ◽  
Ryo Matsumoto ◽  
Ryoji Kiyama ◽  
Masayuki Kawada ◽  
...  
Keyword(s):  
Ground Reaction Force ◽  
Reaction Force ◽  
Reduction Ratio ◽  
Knee Adduction Moment ◽  
Moment Arm ◽  
3 Dimensional ◽  
Foot Progression Angle ◽  
Close Relationship ◽  
The Moment ◽  
Joint Center

This study evaluated the effect of foot progression angle on the reduction in knee adduction moment caused by a lateral wedged insole during walking. Twenty healthy, young volunteers walked 10 m at their comfortable velocity wearing a lateral wedged insole or control flat insole in 3 foot progression angle conditions: natural, toe-out, and toe-in. A 3-dimensional rigid link model was used to calculate the external knee adduction moment, the moment arm of ground reaction force to knee joint center, and the reduction ratio of knee adduction moment and moment arm. The result indicated that the toe-out condition and lateral wedged insole decreased the knee adduction moment in the whole stance phase. The reduction ratio of the knee adduction moment and the moment arm exhibited a close relationship. Lateral wedged insoles decreased the knee adduction moment in various foot progression angle conditions due to decrease of the moment arm of the ground reaction force. Moreover, the knee adduction moment during the toe-out gait with lateral wedged insole was the smallest due to the synergistic effect of the lateral wedged insole and foot progression angle. Lateral wedged insoles may be a valid intervention for patients with knee osteoarthritis regardless of the foot progression angle.

The Effects of a Lateral Wedge Insole on Knee and Ankle Joints During Slope Walking

2015 ◽  
Vol 31 (6) ◽  
pp. 476-483 ◽  
Author(s):  
Yuki Uto ◽  
Tetsuo Maeda ◽  
Ryoji Kiyama ◽  
Masayuki Kawada ◽  
Ken Tokunaga ◽  
...  
Keyword(s):  
Ground Reaction Force ◽  
Reaction Force ◽  
Force Plate ◽  
Three Dimensional ◽  
Frontal Plane ◽  
Knee Adduction Moment ◽  
Moment Arm ◽  
Level Walking ◽  
Ankle Valgus ◽  
The Moment

The purpose of this study was to determine whether a lateral wedge insole reduces the external knee adduction moment during slope walking. Twenty young, healthy subjects participated in this study. Subjects walked up and down a slope using 2 different insoles: a control flat insole and a 7° lateral wedge insole. A three-dimensional motion analysis system and force plate were used to examine the knee adduction moment, the ankle valgus moment, and the moment arm of the ground reaction force to the knee joint center in the frontal plane. The lateral wedge insole significantly decreased the moment arm of the ground reaction force, resulting in a reduction of the knee adduction moment during slope walking, similar to level walking. The reduction ratio of knee adduction moment by the lateral wedge insole during the early stance of up-slope walking was larger than that of level walking. Conversely, the lateral wedge insole increased the ankle valgus moment during slope walking, especially during the early stance phase of up-slope walking. Clinicians should examine the utilization of a lateral wedge insole for knee osteoarthritis patients who perform inclined walking during daily activity, in consideration of the load on the ankle joint.

scholarly journals APPLICATION OF DOMAIN INTEGRATED DESIGN METHODOLOGY FOR BIO-INSPIRED DESIGN- A CASE STUDY OF SUTURE PIN DESIGN

2021 ◽  
Vol 1 ◽  
pp. 487-496
Author(s):  
Pavan Tejaswi Velivela ◽  
Nikita Letov ◽  
Yuan Liu ◽  
Yaoyao Fiona Zhao
Keyword(s):  
Cross Sections ◽  
Design Methodology ◽  
Reaction Force ◽  
Integrated Design ◽  
Total Deformation ◽  
Insertion Force ◽  
Force Reaction ◽  
The Moment ◽  
Work Done

AbstractThis paper investigates the design and development of bio-inspired suture pins that would reduce the insertion force and thereby reducing the pain in the patients. Inspired by kingfisher's beak and porcupine quills, the conceptual design of the suture pin is developed by using a unique ideation methodology that is proposed in this research. The methodology is named as Domain Integrated Design, which involves in classifying bio-inspired structures into various domains. There is little work done on such bio-inspired multifunctional aspect. In this research we have categorized the vast biological functionalities into domains namely, cellular structures, shapes, cross-sections, and surfaces. Multi-functional bio-inspired structures are designed by combining different domains. In this research, the hypothesis is verified by simulating the total deformation of tissue and the needle at the moment of puncture. The results show that the bio-inspired suture pin has a low deformation on the tissue at higher velocities at the puncture point and low deformation in its own structure when an axial force (reaction force) is applied to its tip. This makes the design stiff and thus require less force of insertion.

scholarly journals The Design and Simulation of a 16-Sensors Plantar Pressure Insole Layout for Different Applications: From Sports to Clinics, a Pilot Study

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1450
Author(s):  
Alfredo Ciniglio ◽  
Annamaria Guiotto ◽  
Fabiola Spolaor ◽  
Zimi Sawacha
Keyword(s):  
Pressure Distribution ◽  
Plantar Pressure ◽  
Center Of Pressure ◽  
Reaction Force ◽  
Weight Lifting ◽  
Lower Limbs ◽  
Plantar Pressure Distribution ◽  
Drop Landing ◽  
Mean Pressure ◽  
Footwear Design

The quantification of plantar pressure distribution is widely done in the diagnosis of lower limbs deformities, gait analysis, footwear design, and sport applications. To date, a number of pressure insole layouts have been proposed, with different configurations according to their applications. The goal of this study is to assess the validity of a 16-sensors (1.5 × 1.5 cm) pressure insole to detect plantar pressure distribution during different tasks in the clinic and sport domains. The data of 39 healthy adults, acquired with a Pedar-X® system (Novel GmbH, Munich, Germany) during walking, weight lifting, and drop landing, were used to simulate the insole. The sensors were distributed by considering the location of the peak pressure on all trials: 4 on the hindfoot, 3 on the midfoot, and 9 on the forefoot. The following variables were computed with both systems and compared by estimating the Root Mean Square Error (RMSE): Peak/Mean Pressure, Ground Reaction Force (GRF), Center of Pressure (COP), the distance between COP and the origin, the Contact Area. The lowest (0.61%) and highest (82.4%) RMSE values were detected during gait on the medial-lateral COP and the GRF, respectively. This approach could be used for testing different layouts on various applications prior to production.

Influence of muscle anatomical cross-sectional area on the moment arm length of the triceps brachii muscle at the elbow joint

2010 ◽  
Vol 43 (14) ◽  
pp. 2844-2847 ◽  
Author(s):  
Norihide Sugisaki ◽  
Taku Wakahara ◽  
Naokazu Miyamoto ◽  
Koichiro Murata ◽  
Hiroaki Kanehisa ◽  
...  
Keyword(s):  
Elbow Joint ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Moment Arm ◽  
Triceps Brachii ◽  
Cross Sectional ◽  
Triceps Brachii Muscle ◽  
The Moment
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