Design of an Orthosis for the Weight Balance of Human Lower Limbs

2012 ◽  
Author(s):  
Win-Bin Shieh ◽  
Dar-Zen Chen ◽  
Chia-Chun Wu
Keyword(s):  
Knee Joint ◽  
Lower Limb ◽  
First Generation ◽  
Lower Limbs ◽  
Gravity Effect ◽  
Normal Walking ◽  
Anthropometric Parameters ◽  
Large Power ◽  
Minimum Number ◽  
Exact Positions

Most existing lower limb orthosis use actuators and active controller to guide the motion of human lower limbs. Actuators with relatively large power are usually required to compensate the gravity effect of the human lower limbs, even for a normal walking. Hence, design of an orthosis for the weight balance of human lower limbs is desired. For the motion compatibility, the human hip joint is treated as a planar pair and the knee joint as a revolute pair. As a consequence, while the lower limb is in motion, the exact positions of the mass centers of the human lower limbs cannot be obtained. Hence, in this work, topological synthesis of the orthosis mechanisms, which can trace the mass centers of the human thigh and shank, respectively, is implemented. The weight balance of the human lower limbs is achieved by fitting a minimum number of zero-free-length springs. Based on the anthropometric parameters, dimensions of the lower limb orthosis is determined and the proposed design is justified by the simulation executed by the software of ProEngineer. Finally, a first generation prototype is built.

A Technique to Detect Fatigue in the Lower Limbs

2014 ◽  
Author(s):  
Abdullatif A. Alwasel ◽  
Eihab M. Abdel-Rahman ◽  
Carl T. Haas
Keyword(s):  
Phase Space ◽  
Knee Joint ◽  
Lower Limb ◽  
Time History ◽  
Warning System ◽  
Kinematic Chain ◽  
Kinematic Parameter ◽  
Lower Limbs ◽  
Body Parts ◽  
Reconstructed Phase Space

As muscles fatigue, their passive and active mechanical properties change increasing the susceptibility of the human body to damage. The state-of-the-art technique for muscle fatigue detection, EMG signals, is cumbersome. This paper presents a technique to detect fatigue by tracking a kinematic parameter of the musculoskeletal system. The method uses the time-history of a single joint angle to detect fatigue in the lower limbs. A sensor is mounted to the knee joint to measure the knee flexion angle. Time delay embedding is used to track the orbit of knee joint motions in a reconstructed phase-space. The reconstructed phase-space allows us to obtain information about other body parts and joints of the lower limb in addition to the knee joint, since they are all connected in an open kinematic chain. Long-time drift in the orbit location and shape in phase-space is quantified and used as a measure of lower limb fatigue. The proposed technique presents a mobile, wireless, and cheap method to assess fatigue that can act as an early warning system for the lower limb.

scholarly journals CONTRACTION OF THE TENSOR FASCIAE LATAE MUSCLE OF THE FASCIA OF THE BROAD THIGH AND FLEXION OF THE KNEE JOINT IN THE RUNNERS

2019 ◽  
Vol 72 (3) ◽  
pp. 318-322
Author(s):  
Rafał Słoniak ◽  
Tomasz Tittinger ◽  
Damian Szczepański ◽  
Tadeusz Szymon Gaździk ◽  
Małgorzata Kulesa-Mrowiecka ◽  
...  
Keyword(s):  
Knee Joint ◽  
Lower Limb ◽  
Mixed Type ◽  
Three Dimensional ◽  
Lower Limbs ◽  
Study Group ◽  
Hip Joints ◽  
Exclusion Criteria ◽  
Post Traumatic ◽  
Tensor Fasciae Latae

Introduction: The illustration of the ranges of bending the limb during the outflow allowed to divide the study group into two parts. In the majority of respondents, the initial flexion prevailed over the final one. The researchers focused on finding the reasons for the advantage of the final bend over the initial one in 30% of the subjects. The aim: The analysis of the dynamic stride under the control of the MVN Biomech system in the bending of the knee joint of the lateral limb, comparing the preparation to the leg (initial bending) and its ending (final) Materials and Methods: 18 right-handed 25 to 35 year old runners were selected after the following exclusion criteria were applied: polyarticular hypermobility, systemic diseases, Rheumatoid arthritis, osteoarthritis, post-traumatic instability. The MVN Biomech system assessed the three-dimensional movements of the joints of the free part of the lower limb and pelvis, and the flexibility of the muscles was subject to physiotherapeutic assessment. Results: In 55% of respondents dominated the pattern in which the initial flexion exceeded by min. 10⁰ final bend in both limbs (decreasing type). The researchers focused on finding the reasons for the smaller difference or the advantage of the final bending on both sides in 30% of respondents (mixed type). The comparison of physiotherapeutic examination results and measurements of MVN Biomech showed functional contractures of the tensor fasciae latea muscles in 5 subjects with a mixed type (83% of subjects with a mixed type). Conclusions: Contraction of the tensor fasciae latae constrained the initial flexion of the knee joint of the lateral limb, and also increased bilateral visitation of the hip joints during the dynamic mixed-type twitch. The remaining muscles of the lower limbs show no statistically significant differences in elasticity compared to the type of the leg.

scholarly journals Effect of lower limb dominance on walking adaptations in young adults when stepping into a hole

2020 ◽  
Vol 13 (5) ◽  
pp. 133-143
Author(s):  
Luciana Oliveira Dos Santos ◽  
Andréia Abud da Silva Costa ◽  
Renato Moraes
Keyword(s):  
Young Adults ◽  
Lower Limb ◽  
The Other ◽  
Lower Limbs ◽  
Normal Walking ◽  
Other Hand ◽  
The Individual ◽  
Limb Dominance

Background. Depending on the dimensions of a hole, the characteristics of the walking surface, and the position of the hole relative to normal walking, individuals may need to step into the hole with the dominant or non-dominant limb. Aim. We investigated the effect of the lower limb dominance in walking adaptations in the presence of a hole on the ground. Methods: Twenty young adults walked and stepped into a hole positioned in the middle of the pathway using the dominant and non-dominant lower limbs. Results. For the trailing limb, the impulses were not affected by the lower limb dominance, but for the leading limb, the non-dominant leg increased the braking and propulsive impulses compared to the dominant leg. On the other hand, toe-off velocity increased when the non-dominant leg was used as trailing and leading limbs. Stride speed increased when the non-dominant leg was the trailing limb. Interpretation. Our results were consistent with asymmetrical behavior between dominant and non-dominant legs. Although the differences between the dominant and non-dominant legs have not affected the success in the task, they can put the individual at higher risk of stumbling and consequently a fall when stepping with the non-dominant leg into the hole.

scholarly journals Biomechanical study on the stress distribution of the knee joint after residual rotation deformity of tibial fracture

2020 ◽  
Author(s):  
Ming Li ◽  
Yanbin Zhu ◽  
Ning Wei ◽  
Wenli Chang ◽  
Zeyue Jin ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Knee Joint ◽  
Lower Limb ◽  
External Rotation ◽  
Biomechanical Study ◽  
Lower Limbs ◽  
Neutral Position ◽  
Lateral Stress ◽  
Significant Difference ◽  
The Difference

Abstract Objectives To investigate the effect of residual rotation deformity on the stress distribution of the knee joint after surgery to treat middle and upper tibial fractures. Methods Fourteen adult cadaver specimens that were preserved with formalin were included, and the tibias were randomly positioned at 0 degree, 5 degrees, 10 degrees, and 15 degrees from the line of force of the lower limb. These positions modeled deformities of 5 degrees, 10 degrees, and 15 degrees from the line of force. Low-pressure pressure-sensitive film technology measured the stress distribution of the knee joint under different degrees of rotation deformity. Results Under a vertical load of 400 N, the difference between the medial and lateral stress of the knee joint was significantly different between the different tibia deformities (P<0.05), and the medial stress of the knee joint was higher than the lateral stress. The current study showed that there were statistically significant differences in the medial stress on the knee joint at all angles (including the neutral position of 0 degrees) (F=89.753, P<0.001) . There was a statistically significant difference in the lateral stresses of the knee joint between different rotation deformities (including the neutral position of 0 degrees) (F=102.998, P<0.001). Conclusions Residual rotation deformity after fracture of middle and upper tibia can lead to poor alignment of lower limb force and change of articular contact characteristics of knee joint, especially external rotation of tibia.Therefore, orthopedic surgeons should correct the malalignment of lower limbs to the greatest extent and reduce the rotation deformity as far as possible.

scholarly journals Angle Estimation for Knee Joint Movement Based on PCA-RELM Algorithm

Symmetry ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 130 ◽  
Author(s):  
Yanxia Deng ◽  
Farong Gao ◽  
Huihui Chen
Keyword(s):  
Knee Joint ◽  
Lower Limb ◽  
Joint Angle ◽  
Pearson Correlation ◽  
Lower Limbs ◽  
Human Gait ◽  
Support Vector ◽  
Joint Movement ◽  
Knee Joint Angle ◽  
Semg Signals

Surface electromyogram (sEMG) signals are easy to record and offer valuable motion information, such as symmetric and periodic motion in human gait. Due to these characteristics, sEMG is widely used in human-computer interaction, clinical diagnosis and rehabilitation medicine, sports medicine and other fields. This paper aims to improve the estimation accuracy and real-time performance, in the case of the knee joint angle in the lower limb, using a sEMG signal, in a proposed estimation algorithm of the continuous motion, based on the principal component analysis (PCA) and the regularized extreme learning machine (RELM). First, the sEMG signals, collected during the lower limb motion, are preprocessed, while feature samples are extracted from the acquired and preconditioned sEMG signals. Next, the feature samples dimensions are reduced by the PCA, as well as the knee joint angle system is measured by the three-dimensional motion capture system, are followed by the normalization of the feature variable value. The normalized sEMG feature is used as the input layer, in the RELM model, while the joint angle is used as the output layer. After training, the RELM model estimates the knee joint angle of the lower limbs, while it uses the root mean square error (RMSE), Pearson correlation coefficient and model training time as key performance indicators (KPIs), to be further discussed. The RELM, the traditional BP neural network and the support vector machine (SVM) estimation results are compared. The conclusions prove that the RELM method, not only has ensured the validity of results, but also has greatly reduced the learning train time. The presented work is a valuable point of reference for further study of the motion estimation in lower limb.

scholarly journals Transfer of Muscle Strength Between Single-Joint and Multi-Joint Exercises for Lower Limbs

2020 ◽  
Vol 14 (1) ◽  
pp. 23-32
Author(s):  
Tereza Hammerová ◽  
Jan Chlápek ◽  
Tereza Králová ◽  
Tomáš Vodička ◽  
Zuzana Hlavoňová ◽  
...  
Keyword(s):  
Knee Joint ◽  
Lower Limb ◽  
Intervention Program ◽  
Training Session ◽  
Eccentric Contraction ◽  
Lower Limbs ◽  
Leg Extension ◽  
Leg Press ◽  
Concentric Contraction ◽  
The Right

Most strength and conditioning coaches deal with the question in the training plan, how to supplement specific exercises, or which non-specific exercises would be the most suitable for achieving the set purpose. This study aims to assess what strength transfer with a focus on the lower limbs is projected from the selected strength intervention program (the right leg exercises only single-joint exercises: leg extension on machine and leg curl; the left leg exercises only multi-joint exercises: deadlift and leg press) to the force of the knee joint flexors and extensors during the eccentric and the concentric contraction. In one training session, the participants repeated every exercise five times in four series. The load intensity was around 90% of 1RM and was increased by 5% after the first and the fifth week. The rest interval was always three minutes long. For the left lower limb, the highest transfer (0.20) was from the leg press to the knee joint extensor at the eccentric contraction and from the deadlift was the highest transfer (0.19) to the knee joint extensor at the eccentric contraction. For the right lower limb, the highest transfer (0.53) was from the leg extension on a machine to the knee joint flexor at the concentric contraction and from the lying leg curl was the highest transfer (0.47) to the knee joint flexor at the concentric contraction.

Design of a Human Knee Reeducation Mechanism

2019 ◽  
Vol 11 (1) ◽  
pp. 42-53
Author(s):  
Allaoua Brahmia ◽  
Ridha Kelaiaia
Keyword(s):  
Lower Limb ◽  
Mechanical Design ◽  
Kinematic Chain ◽  
Lower Limbs ◽  
Kinematic Structure ◽  
Robotic Device ◽  
Human Knee ◽  
Kinematic Study ◽  
Rehabilitation Exercise ◽  
New Machine

Abstract To establish an exercise in open muscular chain rehabilitation (OMC), it is necessary to choose the type of kinematic chain of the mechanical / biomechanical system that constitutes the lower limbs in interaction with the robotic device. Indeed, it’s accepted in biomechanics that a rehabilitation exercise in OMC of the lower limb is performed with a fixed hip and a free foot. Based on these findings, a kinematic structure of a new machine, named Reeduc-Knee, is proposed, and a mechanical design is carried out. The contribution of this work is not limited to the mechanical design of the Reeduc-Knee system. Indeed, to define the minimum parameterizing defining the configuration of the device relative to an absolute reference, a geometric and kinematic study is presented.

scholarly journals Effects of Dominant and Nondominant Limb Immobilization on Muscle Activation and Physical Demand during Ambulation with Axillary Crutches

2021 ◽  
Vol 6 (1) ◽  
pp. 16
Author(s):  
Kara B. Bellenfant ◽  
Gracie L. Robbins ◽  
Rebecca R. Rogers ◽  
Thomas J. Kopec ◽  
Christopher G. Ballmann
Keyword(s):  
Lower Limb ◽  
Muscle Activation ◽  
Weight Bearing ◽  
Lower Limbs ◽  
Medial Gastrocnemius ◽  
Bipedal Walking ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Physical Demand ◽  
Limb Dominance

The purpose of this study was to investigate the effects of how limb dominance and joint immobilization alter markers of physical demand and muscle activation during ambulation with axillary crutches. In a crossover, counterbalanced study design, physically active females completed ambulation trials with three conditions: (1) bipedal walking (BW), (2) axillary crutch ambulation with their dominant limb (DOM), and (3) axillary crutch ambulation with their nondominant limb (NDOM). During the axillary crutch ambulation conditions, the non-weight-bearing knee joint was immobilized at a 30-degree flexion angle with a postoperative knee stabilizer. For each trial/condition, participants ambulated at 0.6, 0.8, and 1.0 mph for five minutes at each speed. Heart rate (HR) and rate of perceived exertion (RPE) were monitored throughout. Surface electromyography (sEMG) was used to record muscle activation of the medial gastrocnemius (MG), soleus (SOL), and tibialis anterior (TA) unilaterally on the weight-bearing limb. Biceps brachii (BB) and triceps brachii (TB) sEMG were measured bilaterally. sEMG signals for each immobilization condition were normalized to corresponding values for BW.HR (p < 0.001) and RPE (p < 0.001) were significantly higher for both the DOM and NDOM conditions compared to BW but no differences existed between the DOM and NDOM conditions (p > 0.05). No differences in lower limb muscle activation were noted for any muscles between the DOM and NDOM conditions (p > 0.05). Regardless of condition, BB activation ipsilateral to the ambulating limb was significantly lower during 0.6 mph (p = 0.005) and 0.8 mph (p = 0.016) compared to the same speeds for BB on the contralateral side. Contralateral TB activation was significantly higher during 0.6 mph compared to 0.8 mph (p = 0.009) and 1.0 mph (p = 0.029) irrespective of condition. In conclusion, limb dominance appears to not alter lower limb muscle activation and walking intensity while using axillary crutches. However, upper limb muscle activation was asymmetrical during axillary crutch use and largely dependent on speed. These results suggest that functional asymmetry may exist in upper limbs but not lower limbs during assistive device supported ambulation.

scholarly journals Energy absorption at lower limb joints in different foot contact strategies while descending stairs

2021 ◽  
Vol 29 ◽  
pp. 433-440
Author(s):  
Hyeong-Min Jeon ◽  
Ki-Kwang Lee ◽  
Jun-Young Lee ◽  
Ju-Hwan Shin ◽  
Gwang-Moon Eom
Keyword(s):  
Knee Joint ◽  
Potential Energy ◽  
Energy Absorption ◽  
Lower Limb ◽  
Mechanical Energy ◽  
Connective Tissues ◽  
Stair Descent ◽  
Young Subjects ◽  
Power And Energy ◽  
Joint Loads

BACKGROUND: Joint loads in different walking strategies during stair descent have been investigated in terms of the joint moment in association with the risk of osteoarthritis. However, the absorption mechanisms of the potential energy loss are not known. OBJECTIVE: This study aims to compare the mechanical energy absorptions in lower limb joints in different initial foot contact strategies. METHODS: Nineteen young subjects walked down on instrumented stairs with two different strategies, i.e., forefoot and rearfoot strike. Power and energy at lower limb joints during stance phase were compared between strategies. RESULTS: Lower limb joints absorbed 73 ± 11% of the potential energy released by descending stairs and there was no difference between strategies. Rearfoot strategy absorbed less energy than forefoot strategy at the ankle joint in the 1st phase, which was compensated mainly by more energy absorption at the knee in the 2nd phase and less energy generation at the hip joints in the 3rd phase. CONCLUSION: The results suggest that a leg absorbs most of the potential energy while descending stairs irrespective of the walking strategies and that any reduction of energy absorption at one joint is compensated by other joints. Greater energy absorption at the knee joint compared to the other joints suggests high burden of knee joint muscles and connective tissues during stair-descent, which is even more significant for the rearfoot strike strategy.

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