Kinematics study of a 10 degrees-of-freedom lower extremity exoskeleton for crutch-less walking rehabilitation

2021 ◽  
pp. 1-9
Author(s):  
Jingshuai Liu ◽  
Yong He ◽  
Feng Li ◽  
Wujing Cao ◽  
Xinyu Wu
Keyword(s):  
Lower Extremity ◽  
Lower Limb ◽  
Degrees Of Freedom ◽  
Leg Extension ◽  
Closed Form Solutions ◽  
Kinematic Characteristics ◽  
Movement Characteristics ◽  
Movement Performance ◽  
Walking Rehabilitation ◽  
Limb Structure

BACKGROUND: Wearable lower extremity exoskeletons can provide walking assistance for the physical rehabilitation of paralyzed individuals. However, most of the existing exoskeletons require crutches to maintain balance, thus a self-balancing type is needed to improve applicability. OBJECTIVE: The purpose of this work is to study the kinematic characteristics of a novel lower extremity exoskeleton for crutch-less walking rehabilitation, and evaluate the movement performance through practical experiments. METHODS: Based on the human lower limb structure and movement characteristics, a fully actuated 10 degrees-of-freedom (DoF) lower extremity exoskeleton was proposed. The kinematic characteristics of the exoskeleton were analyzed by the D-H method and geometric method, and the model validity was verified through simulations and experiments. RESULTS: The closed-form solutions for both forward and inverse kinematics models were obtained. The consistent results of theoretical calculation and numerical simulation have shown the accuracy of the established models. The practical experiments regarding six trials have demonstrated the movement performance of the proposed exoskeleton, including sit, stance, leg extension/flexion, and left/right swing. CONCLUSIONS: The kinematic characteristics of the proposed 10-DoF lower extremity exoskeleton are similar to the human lower limb, and it could meet the motion demands of crutch-less walking rehabilitation.

Design and analysis of a lightweight lower extremity exoskeleton with novel compliant ankle joints

2021 ◽  
pp. 1-14
Author(s):  
Yong He ◽  
Jingshuai Liu ◽  
Feng Li ◽  
Wujing Cao ◽  
Xinyu Wu
Keyword(s):  
Lower Extremity ◽  
Numerical Simulations ◽  
Degrees Of Freedom ◽  
Theoretical Models ◽  
Six Degrees Of Freedom ◽  
Movement Performance ◽  
Ankle Joints ◽  
Design Values ◽  
Flexible Deformation ◽  
Limb Rehabilitation

BACKGROUND: The exoskeleton for lower limb rehabilitation is an uprising field of robot technology. However, since it is difficult to achieve all the optimal design values at the same time, each lower extremity exoskeleton has its own focus. OBJECTIVE: This study aims to develop a modular lightweight lower extremity exoskeleton (MOLLEE) with novel compliant ankle joints, and evaluate the movement performance through kinematics analysis. METHODS: The overall structure of the exoskeleton was proposed and the adjustable frames, active joint modules, and compliant ankle joints were designed. The forward and inverse kinematics models were established based on the geometric method. The theoretical models were validated by numerical simulations in ADAMS, and the kinematic performance was demonstrated through walking experiments. RESULTS: The proposed lower extremity offers six degrees of freedom (DoF). The exoskeleton frame was designed adjustable to fit wearers with a height between 1.55 m and 1.80 m, and waist width from 37 cm to 45 cm. The joint modules can provide maximum torque at 107 Nm for adequate knee and hip joint motion forces. The compliant ankle can bear large flexible deformation, and the relationship between its angular deformation and the contact force can be fitted with a quadratic polynomial function. The kinematics models were established and verified through numerical simulations, and the walking experiments in different action states have shown the expected kinematic characteristics of the designed exoskeleton. CONCLUSIONS: The proposed MOLLEE exoskeleton is adjustable, modular, and compliant. The designed adjustable frame and compliant ankle can ensure comfort and safety for different wearers. In addition, the kinematics characteristics of the exoskeleton can meet the needs of daily rehabilitation activities.

scholarly journals Peripheral Blood T Cell Gene Expression Responses to Exercise and HMB in Sarcopenia

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2313
Author(s):  
Suk-Ling Ma ◽  
Junyi Wu ◽  
Liuying Zhu ◽  
Ruth Chan ◽  
Amy Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cell ◽  
Lower Limb ◽  
Exercise Program ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Strength Performance ◽  
Leg Extension ◽  
Cell Gene Expression ◽  
Cell Gene

Background: Sarcopenia is a major health problem in older adults. Exercise and nutrient supplementation have been shown to be effective interventions but there are limited studies to investigate their effects on the management of sarcopenia and its possible underlying mechanisms. Here, we studied T cell gene expression responses to interventions in sarcopenia. Methods: The results of this study were part of a completed trial examining the effectiveness of a 12-week intervention with exercise and nutrition supplementation in community-dwelling Chinese older adults with sarcopenia, based on the available blood samples at baseline and 12 weeks from 46 randomized participants from three study groups, namely: exercise program alone (n = 11), combined-exercise program and nutrition supplement (n = 23), and waitlist control group (n = 12). T cell gene expression was evaluated, with emphasis on inflammation-related genes. Real-time PCR (RT-PCR) was performed on CD3 T cells in 38 selected genes. Correlation analysis was performed to relate the results of gene expression analysis with lower limb muscle strength performance, measured using leg extension tests. Results: Our results showed a significant improvement in leg extension for both the exercise program alone and the combined groups (p < 0.001). Nine genes showed significant pre- and post-difference in gene expression over 12 weeks of intervention in the combined group. Seven genes (RASGRP1, BIN1, LEF1, ANXA6, IL-7R, LRRN3, and PRKCQ) showed an interaction effect between intervention and gene expression levels on leg extension in the confirmatory analysis, with confounder variables controlled and FDR correction. Conclusions: Our findings showed that T cell-specific inflammatory gene expression was changed significantly after 12 weeks of intervention with combined exercise and HMB supplementation in sarcopenia, and that this was associated with lower limb muscle strength performance.

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.

Limitations of body mass index for counseling individuals with unilateral lower extremity amputation

2016 ◽  
Vol 41 (2) ◽  
pp. 186-193 ◽  
Author(s):  
Alexandra P Frost ◽  
Tracy Norman Giest ◽  
Allison A Ruta ◽  
Teresa K Snow ◽  
Mindy Millard-Stafford
Keyword(s):  
Body Mass Index ◽  
Lower Extremity ◽  
Health Risk ◽  
Body Mass ◽  
Body Fat ◽  
Lower Limb ◽  
Dual Energy ◽  
Limb Loss ◽  
Percent Body Fat ◽  
X Ray

Background: Body composition is important for health screening, but appropriate methods for unilateral lower extremity amputees have not been validated. Objectives: To compare body mass index adjusted using Amputee Coalition equations (body mass index–Amputee Coalition) to dual-energy X-ray absorptiometry in unilateral lower limb amputees. Study design: Cross-sectional, experimental. Methods: Thirty-eight men and women with lower limb amputations (transfemoral, transtibial, hip disarticulation, Symes) participated. Body mass index (mass/height2) was compared to body mass index corrected for limb loss (body mass index–Amputee Coalition). Accuracy of classification and extrapolation of percent body fat with body mass index was compared to dual-energy X-ray absorptiometry. Results: Body mass index–Amputee Coalition increased body mass index (by ~ 1.1 kg/m2) but underestimated and mis-classified 60% of obese and overestimated 100% of lean individuals according to dual-energy X-ray absorptiometry. Estimated mean percent body fat (95% confidence interval) from body mass index–Amputee Coalition (28.3% (24.9%, 31.7%)) was similar to dual-energy X-ray absorptiometry percent body fat (29.5% (25.2%, 33.7%)) but both were significantly higher ( p < 0.05) than percent body fat estimated from uncorrected body mass index (23.6% (20.4%, 26.8%)). However, total errors for body mass index and body mass index–Amputee Coalition converted to percent body fat were unacceptably large (standard error of the estimate = 6.8%, 6.2% body fat) and the discrepancy between both methods and dual-energy X-ray absorptiometry was inversely related ( r = −0.59 and r = −0.66, p < 0.05) to the individual’s level of body fatness. Conclusions: Body mass index (despite correction) underestimates health risk for obese patients and overestimates lean, muscular individuals with lower limb amputation. Clinical relevance Clinical recommendations for an ideal body mass based on body mass index–Amputee Coalition should not be relied upon in lower extremity amputees. This is of particular concern for obese lower extremity amputees whose health risk might be significantly underestimated based on body mass index despite a “correction” formula for limb loss.

Infra-popliteal deep venous thrombi and the risk of symptomatic pulmonary embolism in hospitalized patients

Vascular ◽  
2011 ◽  
Vol 19 (1) ◽  
pp. 29-33 ◽  
Author(s):  
Saadi Alhalbouni ◽  
Anil Hingorani ◽  
Alexander Shiferson ◽  
Natalie Marks ◽  
Enrico Ascher
Keyword(s):  
Pulmonary Embolism ◽  
Lower Extremity ◽  
Retrospective Review ◽  
Lower Limb ◽  
Hospitalized Patients ◽  
Symptomatic Pulmonary Embolism ◽  
Number Of Patients ◽  
Significant Difference ◽  
Hospital Patients ◽  
Made In

Infra-popliteal veins include the tibial and peroneal veins, as well as the soleal and gastrocnemial veins collectively known as the calf muscle veins (CMVs). Acute infra-popliteal deep venous thrombi (DVTs) are often considered insignificant with regard to the risk of pulmonary embolism (PE). A retrospective review of 4035 consecutive lower extremity venous duplex scans were made in 3146 hospital patients at our Intersocietal Commission for the Accreditation of Vascular Laboratories (ICAVL)-accredited vascular lab. Seven hundred sixteen (17.7%) duplex scans were positive for acute DVTs, and 112 (2.8%) were associated with PEs. The breakdown of positive duplexes for acute DVTs was as follows: 202 (28.2%) isolated femoral-popliteal DVTs with PE in 23 (11.4%), 304 (42.5%) isolated infra-popliteal DVTs with PE in 24 (7.9%) and 210 (29.3%) multilevel DVTs involving both vein segments (femoral-popliteal and infra-popliteal) with PE in 38 (18.1%). Of the 304 isolated acute infra-popliteal DVTs, 207 (68.1%) were isolated CMV DVTs with evidence of PE in 12 (5.8%). No statistically significant difference ( P = 0.27) in the risk of PE between isolated femoral-popliteal and isolated infra-popliteal DVTs was noted. A significant number of patients (5.8%) with isolated CMV DVTs developed PE. Lower limb venous scans for DVTs should evaluate the infra-popliteal veins. Hospitalized patients with infra-popliteal DVTs should receive anticoagulation.

LOWER LIMB REHABILITATION ROBOT FOR GAIT TRAINING

2014 ◽  
Vol 14 (06) ◽  
pp. 1440004 ◽  
Author(s):  
SHUAI GUO ◽  
JIANCHENG JI ◽  
GUANGWEI MA ◽  
TAO SONG ◽  
JING WANG
Keyword(s):  
Lower Limb ◽  
Degrees Of Freedom ◽  
Balance Training ◽  
Gait Training ◽  
Rehabilitation Robot ◽  
Stroke Patients ◽  
Motion Characteristics ◽  
Set Up ◽  
Limb Rehabilitation ◽  
Lower Limb Rehabilitation

After analyzing the rehabilitation needs of stroke patients and the previous studies on lower limb rehabilitation robot, our lower limb rehabilitation robot is designed for stroke patients' gait and balance training. The robot consists of the mobile chassis, the support column and the pelvis mechanism and it is described in detail. As the pelvis mechanism allows most of the patient's motion degrees of freedom (DOFs), the kinematics model of the mechanism is set up, and kinematics simulation is carried out to study the motion characteristics of the mechanism. After analyzing the calculation and simulation results, the pelvis mechanism is proven to measure up to the movement needs of the paralytic's waist and pelvis in walking rehabilitation process.

scholarly journals QUANTITATIVE ASSESSMENT OF DANCE THERAPY INFULENCE ON THE PARKINSON’S DISEASE PATIENTS’ LOWER LIMB BIOMECHANICS / ŠOKIŲ ĮTAKA APATINIŲ GALŪNIŲ BIOMECHANIKAI SERGANT PARKINSONO LIGA

2017 ◽  
Vol 8 (6) ◽  
pp. 583-586
Author(s):  
Donatas Lukšys ◽  
Julius Griškevičius
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Lower Extremity ◽  
Lower Limb ◽  
Dance Therapy ◽  
Inertial Sensors ◽  
Dance Music ◽  
Lindy Hop ◽  
Spatio Temporal

Parkinson’s disease – progressive neurologic disorder that damages a variety of motor function and reduces the quality of life. Patients with PD are subject to various physical therapy exercises, but recently is applied more often the dance – music therapy. This study aims assessing the therapeutic effect of the modified Lindy Hop dance therapy on lower extremity biomechanics. The experimental study was performed using inertial sensors that registered lower extremity biomechanical parameters during gait. Several spatio-temporal parameters of lower limb were calculated and were found statistically significant between groups, which allows quantifying the influence of dance therapy. Parkinsono liga (PL) – progresuojantis neurologinis sutrikimas, kuris pažeidžia įvairias motorines funkcijas ir sumažina gyvenimo kokybę. Sergant PL, taikomos įvairios fizinių pratimų terapijos, bet paskutiniu metu dažniau taikoma šokių – muzikos – terapija. Eksperimentinio tyrimo metu buvo naudojami inerciniai jutikliai, siekiant registruoti apatinių galūnių biomechaninius parametrus eisenos metu. Šio straipsnio tikslas – įvertinti modifikuotos lindihopo šokių terapijos įtaką apatinių galūnių biomechanikai. Buvo apskaičiuoti apatinių galūnių kinematiniai parametrai ir surasti statistiškai reikšmingi skirtumai tarp grupių ir grupių viduje, kurie leidžia kiekybiškai įvertinti šokių įtaką.

scholarly journals Lower Extremity Motor Impairments in Ambulatory Chronic Hemiparetic Stroke: Evidence for Lower Extremity Weakness and Abnormal Muscle and Joint Torque Coupling Patterns

2017 ◽  
Vol 31 (9) ◽  
pp. 814-826 ◽  
Author(s):  
Natalia Sánchez ◽  
Ana Maria Acosta ◽  
Roberto Lopez-Rosado ◽  
Arno H. A. Stienen ◽  
Julius P. A. Dewald
Keyword(s):  
Lower Extremity ◽  
Degrees Of Freedom ◽  
Joint Torque ◽  
Motor Impairments ◽  
Lower Extremity Weakness ◽  
Joint Torques ◽  
Hemiparetic Stroke ◽  
Chronic Hemiparetic Stroke ◽  
Hip Extension ◽  
Flexion And Extension

Although global movement abnormalities in the lower extremity poststroke have been studied, the expression of specific motor impairments such as weakness and abnormal muscle and joint torque coupling patterns have received less attention. We characterized changes in strength, muscle coactivation and associated joint torque couples in the paretic and nonparetic extremity of 15 participants with chronic poststroke hemiparesis (age 59.6 ± 15.2 years) compared with 8 age-matched controls. Participants performed isometric maximum torques in hip abduction, adduction, flexion and extension, knee flexion and extension, ankle dorsi- and plantarflexion and submaximal torques in hip extension and ankle plantarflexion. Surface electromyograms (EMGs) of 10 lower extremity muscles were measured. Relative weakness (paretic extremity compared with the nonparetic extremity) was measured in poststroke participants. Differences in EMGs and joint torques associated with maximum voluntary torques were tested using linear mixed effects models. Results indicate significant poststroke torque weakness in all degrees of freedom except hip extension and adduction, adductor coactivation during extensor tasks, in addition to synergistic muscle coactivation patterns. This was more pronounced in the paretic extremity compared with the nonparetic extremity and with controls. Results also indicated significant interjoint torque couples during maximum and submaximal hip extension in both extremities of poststroke participants and in controls only during maximal hip extension. Additionally, significant interjoint torque couples were identified only in the paretic extremity during ankle plantarflexion. A better understanding of these motor impairments is expected to lead to more effective interventions for poststroke gait and posture.

AB1284-HPR RELIABILITY OF STEP TEST IN SUBJECTS WITH TOTAL KNEE ARTHROPLASTY

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1932.1-1933
Author(s):  
M. Eymir ◽  
E. Yuksel ◽  
B. Unver ◽  
K. Sevik ◽  
V. Karatosun
Keyword(s):  
Total Knee Arthroplasty ◽  
Motor Control ◽  
Lower Extremity ◽  
Knee Arthroplasty ◽  
Lower Limb ◽  
Standing Balance ◽  
Step Test ◽  
Retest Reliability ◽  
Total Knee ◽  
Test Retest Reliability

Background:Patients with TKA show impairments in standing balance up to 1 year after surgery. The impaired standing balance in TKA patients was found to be associated with falls risk and decreased functional level. Assessing of standing balance with objective and reliable assessments tools would therefore be extremely useful for determining accurate exercise program, and risks of falling, especially during the rehabilitative period when ambulation is at its most unsteady (1, 2). The stepping maneuver requires adequate strength and motor control to stabilize the body over the stance limb while the other leg is stepping, therefore the Step Test (ST) provides significant information for dynamic standing balance and lower limb motor control (3). The reliability of ST is reported in patient groups such as stroke, however, there is not any study that investigates the reliability of ST in patients with TKA in the current literature.Objectives:The purposes of this study were to determine the test-retest reliability and the minimal detectable change (MDC) of the ST in patients with TKA.Methods:40 patients with TKA due to knee osteoarthritis, operated by the same surgeon, were included in this study. Patients performed trials for ST twice on the same day. Between the first and second trials, patients waited for an hour on sitting position to prevent fatigue. The ST assesses an individual’s ability to place one foot onto a 7.5-cm-high step and then back down to the floor repeatedly as fast as possible for 15 seconds. The score is the number of steps completed in the 15-second period for each lower extremity. Scores for each lower extremity were recorded separately. Prior to the testing, the ST was demonstrated by the tester and all participants were allowed to a practice trial.Results:The ST showed an excellent test-retest reliability (ICC2,1=0.95) in this study. Standard error of measurement (SEM) and MDC95for ST were 0.37 and 1.02, respectively.Conclusion:This study found that the ST has an excellent test–retest reliability in patients with TKA. It is an effective and reliable tool for measuring dynamic standing balance and participant falls. As a performance-based clinical test, the ST is easy to score, can be applied in a short time as part of the routine medical examination. Therefore, inclusion of ST into a more comprehensive battery of performance-based measures of standing balance and lower limb motor control function in subjects with TKA should be considered.References:[1]Si, H. B., Zeng, Y., Zhong, J., et al. (2017). The effect of primary total knee arthroplasty on the incidence of falls and balance-related functions in patients with osteoarthritis. Scientific reports, 7(1), 1-9.[2]Moutzouri, M., Gleeson, N., Billis, E., et al. (2017). The effect of total knee arthroplasty on patients’ balance and incidence of falls: a systematic review. Knee Surgery, Sports Traumatology, Arthroscopy, 25(11), 3439-3451.[3]Hill, K. D., Bernhardt, J., McGann, A. M., et al. (1996). A new test of dynamic standing balance for stroke patients: reliability, validity and comparison with healthy elderly. Physiotherapy Canada, 48(4), 257-262.Disclosure of Interests:None declared

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