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Hong CC, Schaarup SO, Calder J. Differential elongation of the gastrocnemius after Achilles tendon rupture: a novel technique of selective shortening to treat push-off weakness with case series and literature review. Knee Surg Sports Traumatol Arthrosc 2023; 31:6046-6051. [PMID: 37837575 DOI: 10.1007/s00167-023-07619-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 09/28/2023] [Indexed: 10/16/2023]
Abstract
PURPOSE Differential elongation of the gastrocnemius after Achilles tendon rupture (ATR) may compromise the ability of athletes to return to competition. Recognition of this differential elongation of the gastrocnemius relative to the soleus is vital to treat patients with weakness in push-off. This paper describes a novel technique performed for selective shortening of the gastrocnemius to treat push-off weakness. METHODS Three patients with differential proximal retraction of the gastrocnemius greater than 20 mm after treatment for ATR with inability to run and jump underwent surgical correction with this novel technique and were followed-up for 2 years. A novel selective shortening of the gastrocnemius with autologous hamstring graft was performed in these patients. The Achilles Tendon Total Rupture Score (ATRS) and American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score were recorded preoperatively and at the final follow-up. RESULTS All three patients were able to return to running and jumping at final follow-up. The ATRS improved significantly in the strength, fatigue, running and jumping domains but there appeared to be a less notable improvement in activities of daily living domain. The AOFAS score showed improvement with the greatest margin in the domain of activity limitation. CONCLUSION This procedure is the first described selective shortening method of the gastrocnemius tendons after differential elongation following ATR. It is a safe and reliable technique providing improved ATRS and AOFAS scores in three patients who were all able to return to running and jumping sports at 2-year follow-up. LEVEL OF EVIDENCE IV.
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Affiliation(s)
- Choon Chiet Hong
- Fortius Clinic (FIFA Medical Centre of Excellence), 17 Fitzhardinge Street, London, W1H 6EQ, UK.
- Department of Orthopaedic Surgery, National University Hospital of Singapore, 1E, Kent Ridge Road, Singapore, 119228, Singapore.
- Department of Orthopaedic Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
| | | | - James Calder
- Fortius Clinic (FIFA Medical Centre of Excellence), 17 Fitzhardinge Street, London, W1H 6EQ, UK
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, UK
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Lu Z, Sun D, Kovács B, Radák Z, Gu Y. Case study: The influence of Achilles tendon rupture on knee joint stress during counter-movement jump - Combining musculoskeletal modeling and finite element analysis. Heliyon 2023; 9:e18410. [PMID: 37560628 PMCID: PMC10407047 DOI: 10.1016/j.heliyon.2023.e18410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 07/15/2023] [Accepted: 07/17/2023] [Indexed: 08/11/2023] Open
Abstract
BACKGROUND Presently, the current research concerning Achilles tendon rupture repair (ATR) is predominantly centered on the ankle joint, with a paucity of evidence regarding its impact on the knee joint. ATR has the potential to significantly impede athletic performance and increase tibiofemoral contact forces in athletes. The purpose of this study was to prognosticate the distribution of stress within the knee joint during a countermovement jump through the use of a simulation method that amalgamated a musculoskeletal model of a patient who underwent Achilles tendon rupture repair with a finite element model of the knee joint. METHODS A male elite badminton player who had suffered an acute Achilles tendon rupture in his right leg one year prior was selected as our study subject. In order to analyze his biomechanical data, we employed both the OpenSim musculoskeletal model and finite element model to compute various parameters such as joint angles, joint moments, joint contact forces, and the distribution of knee joint stress. RESULTS During the jumping phase, a significantly lower knee extension angle (p < 0.001), ankle dorsiflexion angle (p = 0.002), peak vertical ground reaction force (p < 0.001), and peak tibiofemoral contact force (p = 0.009) were observed on the injured side than on the uninjured side. During the landing phase, the ankle range of motion (ROM) was significantly lower on the injured side than on the uninjured side (p = 0.009), and higher peak vertical ground reaction forces were observed (p = 0.012). Additionally, it is logical that an injured person will put higher load on the uninjured limb, but the finite element analysis indicated that the stresses on the injured side of medial meniscus and medial cartilage were significantly greater than the uninjured side. CONCLUSIONS An Achilles tendon rupture can limit ankle range of motion and lead to greater joint stress on the affected area during countermovement jumps, especially during the landing phase. This increased joint stress may also transfer more stress to the soft tissues of the medial knee, thereby increasing the risk of knee injury. It is worth noting that this study only involves the average knee flexion angle and load after ATR in one athlete. Caution should be exercised when applying the conclusions, and in the future, more participants should be recruited to establish personalized knee finite element models to validate the results.
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Affiliation(s)
- Zhenghui Lu
- Faculty of Sports Science, Ningbo University, Ningbo, 315211, China
| | - Dong Sun
- Faculty of Sports Science, Ningbo University, Ningbo, 315211, China
| | - Bálint Kovács
- Faculty of Sports Science, Ningbo University, Ningbo, 315211, China
- Research Institute of Sport Science, Hungarian University of Sport Science, Budapest, 1123, Hungary
| | - Zsolt Radák
- Research Institute of Sport Science, Hungarian University of Sport Science, Budapest, 1123, Hungary
| | - Yaodong Gu
- Faculty of Sports Science, Ningbo University, Ningbo, 315211, China
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Vonwirth P, Berns K. Muscular Damping Distribution Strategy for Bio-Inspired, Soft Motion Control at Variable Precision. SENSORS (BASEL, SWITZERLAND) 2023; 23:2428. [PMID: 36904631 PMCID: PMC10007275 DOI: 10.3390/s23052428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/16/2023] [Accepted: 02/17/2023] [Indexed: 06/18/2023]
Abstract
Bio-inspired and compliant control approaches have been studied by roboticists for decades to achieve more natural robot motion. Independent of this, medical and biological researchers have discovered a wide variety of muscular properties and higher-level motion characteristics. Although both disciplines strive to better understand natural motion and muscle coordination, they have yet to meet. This work introduces a novel robotic control strategy that bridges the gap between these distinct areas. By applying biological characteristics to electrical series elastic actuators, we developed a simple yet efficient distributed damping control strategy. The presented control covers the entire robotic drive train, from abstract whole-body commands to the applied current. The functionality of this control is biologically motivated, theoretically discussed, and finally evaluated through experiments on the bipedal robot Carl. Together, these results demonstrate that the proposed strategy fulfills all requirements that are necessary to continue developing more complex robotic tasks based on this novel muscular control philosophy.
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Jabeen S, Baines PM, Harlaar J, Vallery H, Berry A. Reaction moments matter when designing lower-extremity robots for tripping recovery. PLoS One 2023; 18:e0280158. [PMID: 36809378 PMCID: PMC9942996 DOI: 10.1371/journal.pone.0280158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 12/21/2022] [Indexed: 02/23/2023] Open
Abstract
Balance recovery after tripping often requires an active adaptation of foot placement. Thus far, few attempts have been made to actively assist forward foot placement for balance recovery employing wearable devices. This study aims to explore the possibilities of active forward foot placement through two paradigms of actuation: assistive moments exerted with the reaction moments either internal or external to the human body, namely 'joint' moments and 'free' moments, respectively. Both paradigms can be applied to manipulate the motion of segments of the body (e.g., the shank or thigh), but joint actuators also exert opposing reaction moments on neighbouring body segments, altering posture and potentially inhibiting tripping recovery. We therefore hypothesised that a free moment paradigm is more effective in assisting balance recovery following tripping. The simulation software SCONE was used to simulate gait and tripping over various ground-fixed obstacles during the early swing phase. To aid forward foot placement, joint moments and free moments were applied either on the thigh to augment hip flexion or on the shank to augment knee extension. Two realizations of joint moments on the hip were simulated, with the reaction moment applied to either the pelvis or the contralateral thigh. The simulation results show that assisting hip flexion with either actuation paradigm on the thigh can result in full recovery of gait with a margin of stability and leg kinematics closely matching the unperturbed case. However, when assisting knee extension with moments on the shank, free moment effectively assist balance but joint moments with the reaction moment on the thigh do not. For joint moments assisting hip flexion, placement of the reaction moment on the contralateral thigh was more effective in achieving the desired limb dynamics than placing the reaction on the pelvis. Poor choice of placement of reaction moments may therefore have detrimental consequences for balance recovery, and removing them entirely (i.e., free moment) could be a more effective and reliable alternative. These results challenge conventional assumptions and may inform the design and development of a new generation of minimalistic wearable devices to promote balance during gait.
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Affiliation(s)
- Saher Jabeen
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Patricia M. Baines
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
- * E-mail:
| | - Jaap Harlaar
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
- Department of Orthopedics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Heike Vallery
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
- Department of Rehabilitation Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Andrew Berry
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
- Department of Rehabilitation Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands
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Zhou T, Zhou Z, Zhang H, Chen W. Modulating Multiarticular Energy during Human Walking and Running with an Unpowered Exoskeleton. SENSORS (BASEL, SWITZERLAND) 2022; 22:8539. [PMID: 36366237 PMCID: PMC9653640 DOI: 10.3390/s22218539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/31/2022] [Accepted: 11/04/2022] [Indexed: 06/16/2023]
Abstract
Researchers have made advances in reducing the metabolic rate of both walking and running by modulating mono-articular energy with exoskeletons. However, how to modulate multiarticular energy with exoskeletons to improve the energy economy of both walking and running is still a challenging problem, due to the lack of understanding of energy transfer among human lower-limb joints. Based on the study of the energy recycling and energy transfer function of biarticular muscles, we proposed a hip-knee unpowered exoskeleton that emulates and reinforces the function of the hamstrings and rectus femoris in different gait phases. The biarticular exo-tendon of the exoskeleton assists hamstrings to recycle the kinetic energy of the leg swing while providing hip extension torque in the swing phase. In the following stance phase, the exo-tendon releases the stored energy to assist the co-contraction of gluteus maximus and rectus femoris for both hip extension and knee extension, thus realizing the phased modulation of hip and knee joint energy. The metabolic rate of both walking (1.5 m/s) and running (2.5 m/s) can be reduced by 6.2% and 4.0% with the multiarticular energy modulation of a hip-knee unpowered exoskeleton, compared to that of walking and running without an exoskeleton. The bio-inspired design method of this study may inspire people to develop devices that assist multiple gaits in the future.
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Huang B, Chen W, Liang J, Cheng L, Xiong C. Characterization and Categorization of Various Human Lower Limb Movements Based on Kinematic Synergies. Front Bioeng Biotechnol 2022; 9:793746. [PMID: 35127668 PMCID: PMC8812690 DOI: 10.3389/fbioe.2021.793746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 12/20/2021] [Indexed: 11/23/2022] Open
Abstract
A proper movement categorization reduces the complexity of understanding or reproducing human movements in fields such as physiology, rehabilitation, and robotics, through partitioning a wide variety of human movements into representative sub-motion groups. However, how to establish a categorization (especially a quantitative categorization) for various human lower limb movements is rarely investigated in literature and remains challenging due to the diversity and complexity of the lower limb movements (diverse gait modes and interaction styles with the environment). Here we present a quantitative categorization for the various lower limb movements. To this end, a similarity measure between movements was first built based on limb kinematic synergies that provide a unified and physiologically meaningful framework for evaluating the similarities among different types of movements. Then, a categorization was established via hierarchical cluster analysis for thirty-four lower limb movements, including walking, running, hopping, sitting-down-standing-up, and turning in different environmental conditions. According to the movement similarities, the various movements could be divided into three distinct clusters (cluster 1: walking, running, and sitting-down-standing-up; cluster 2: hopping; cluster 3: turning). In each cluster, cluster-specific movement synergies were required. Besides the uniqueness of each cluster, similarities were also found among part of the synergies employed by these different clusters, perhaps related to common behavioral goals in these clusters. The mix of synergies shared across the clusters and synergies for specific clusters thus suggests the coexistence of the conservation and augmentation of the kinematic synergies underlying the construction of the diverse and complex motor behaviors. Overall, the categorization presented here yields a quantitative and hierarchical representation of the various lower limb movements, which can serve as a basis for the understanding of the formation mechanisms of human locomotion and motor function assessment and reproduction in related fields.
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Affiliation(s)
| | | | | | | | - Caihua Xiong
- *Correspondence: Jiejunyi Liang, ; Caihua Xiong,
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Firouzi V, Davoodi A, Bahrami F, Sharbafi MA. From a biological template model to gait assistance with an exosuit. BIOINSPIRATION & BIOMIMETICS 2021; 16:066024. [PMID: 34624880 DOI: 10.1088/1748-3190/ac2e0d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 10/08/2021] [Indexed: 06/13/2023]
Abstract
The invention of soft wearable assistive devices, known as exosuits, introduced a new aspect in assisting unimpaired subjects. In this study, we designed and developed an exosuit with compliant biarticular thigh actuators called BATEX. Unlike the conventional method of using rigid actuators in exosuits, the BATEX is made of serial elastic actuators (SEA) resembling artificial muscles. This bioinspired design is complemented by the novel control concept of using the ground reaction force to adjust the artificial muscles' stiffness in the stance phase. By locking the motors in the swing phase, the SEAs will be simplified to passive biarticular springs, which is sufficient for leg swinging. The key concept in our design and control approach is to synthesize human locomotion to develop an assistive device instead of copying human motor control outputs. Analyzing human walking assistance using experiment-based OpenSim simulations demonstrates the advantages of the proposed design and control of BATEX, such as 9.4% reduction in metabolic cost during normal walking condition. This metabolic reduction increases to 10.4% when the subjects carry a 38 kg load. The adaptability of our proposed model-based control to such an unknown condition outperforms the assistance level of the model-free optimal controller. Moreover, increasing the assistive system's efficiency by adjusting the actuator compliance with the force feedback supports our previous findings on the LOPES II exoskeleton.
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Affiliation(s)
- Vahid Firouzi
- School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Ayoob Davoodi
- School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Fariba Bahrami
- School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Maziar A Sharbafi
- School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran
- Lauflabor Laboratory, Technische Universität Darmstadt, Darmstadt, Germany
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Cheng L, Xiong C, Chen W, Liang J, Huang B, Xu X. A portable exotendon assisting hip and knee joints reduces muscular burden during walking. ROYAL SOCIETY OPEN SCIENCE 2021; 8:211266. [PMID: 34737881 PMCID: PMC8564609 DOI: 10.1098/rsos.211266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 10/08/2021] [Indexed: 06/13/2023]
Abstract
Assistive devices are used to reduce human effort during locomotion with increasing success. More assistance strategies are worth exploring, so we aimed to design a lightweight biarticular device with well-chosen parameters to reduce muscle effort. Based on the experience of previous success, we designed an exotendon to assist in swing leg deceleration. Then we conducted experiments to test the performance of the exotendon with different spring stiffness during walking. With the assistance of the exotendon, peak activation of semitendinosus decreased, with the largest reduction of 12.3% achieved with the highest spring stiffness (p = 0.004). The peak activations of other measured muscles were not significantly different (p = 0.15-0.92). The biological hip extension and knee flexion moments likewise significantly decreased with the spring stiffness (p < 0.01). The joint angle was altered during the assisted phases with decreased hip flexion and knee extension. Meanwhile, the step frequency and the step length were also altered, while the step width remained unaffected. Gait variability changed only in the frontal plane, exhibiting lower step width variability. We conclude that passive devices assisting hip extension and knee flexion can significantly reduce the burden on the hamstring muscles, while the kinematics is easily altered.
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Affiliation(s)
- Longfei Cheng
- Institute of Rehabilitation and Medical Robotics, State Key Lab of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Caihua Xiong
- Institute of Rehabilitation and Medical Robotics, State Key Lab of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Wenbin Chen
- Institute of Rehabilitation and Medical Robotics, State Key Lab of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Jiejunyi Liang
- Institute of Rehabilitation and Medical Robotics, State Key Lab of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Bo Huang
- Institute of Rehabilitation and Medical Robotics, State Key Lab of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Xiaowei Xu
- Institute of Rehabilitation and Medical Robotics, State Key Lab of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
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Sato R, Hiasa S, Wang L, Liu H, Meng F, Huang Q, Ming A. Vertical Jumping by a Legged Robot With Upper and Lower Leg Bi-Articular Muscle–Tendon Complexes. IEEE Robot Autom Lett 2021. [DOI: 10.1109/lra.2021.3099226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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10
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Schaarup SO, Wetke E, Konradsen LAG, Calder JDF. Loss of the knee-ankle coupling and unrecognized elongation in Achilles tendon rupture: effects of differential elongation of the gastrocnemius tendon. Knee Surg Sports Traumatol Arthrosc 2021; 29:2535-2544. [PMID: 33938970 DOI: 10.1007/s00167-021-06580-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/12/2021] [Indexed: 11/24/2022]
Abstract
PURPOSE The biarticular anatomy of the gastrocnemii is an important mechanism of knee-ankle coupling and differential elongation may affect this function leading to weakness of the push-off phase during the gait. Achilles tendon ruptures may cause detachment of the gastrocnemius tendon from the soleus aponeurosis with subsequent differential elongation of the individual subtendons. This study investigated the effects of such detachment by investigating tendon fusion levels of the two muscle groups, and the effect of sequential differential elongation of the gastrocnemius on the Achilles tendon resting angle (ATRA) and to the knee-ankle coupling. METHODS Conjoined tendon length (CTL) was measured in 23 cadavers. ATRA in knee extension (ATRA 0) and 90-degree knee flexion (ATRA 90) was measured with the gastrocnemius tendons (GT) intact, transected and with the gap reduced in 5-mm increments. In 15 specimens, knee-ankle coupling was examined. RESULTS Considerable anatomical variation was present with CTL ranging from 2 to 40% of fibular length. In the intact triceps, surae ATRA 0 differed from ATRA 90 by 6 degrees (p < 0.001). Cutting the gastrocnemius caused an immediate separation of the tendon ends by 19 mm. ATRA 0 and ATRA 90 increased 8 and 4 degrees (p < 0.001), significantly larger increase for ATRA 0 (p < 0.001). Lengthening the gastrocnemius 10 mm altered the coupling point 10 degrees towards dorsiflexion. Transfixing the gastrocnemius at the level of the gap where the Achilles was sectioned, decoupled the knee-ankle coupling in all but two specimens. A moderate correlation between CTL and length of the medial gastrocnemius tendon was found. CONCLUSIONS A greater relative ATRA 0 than relative ATRA 90 indicates differential elongation of the gastrocnemius. By elongating the gastrocnemius the knee-ankle coupling point shifts dorsally, and 20 mm elongation completely decouples the knee-ankle coupling. Independent lengthening of the gastrocnemius may explain the loss of power experienced by some patients following acute Achilles tendon rupture despite what would appear to be appropriate approximation of the ruptured tendon ends. Recognizing this occurrence is crucial when treating Achilles tendon ruptures and such patients require surgical correction in order to avoid long-term weakness of push-off strength.
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Affiliation(s)
| | - Eva Wetke
- Department of Orthopaedics, Zealand University Hospital Koege, Lykkebaekvej 1, 4600, Koege, Denmark
| | - Lars Aage Glud Konradsen
- Department of Orthopaedics, IOC Centre of Bispebjerg Hospital, Bispebjerg Bakke 23, 2400, Copenhagen, NV, Denmark
| | - James David Forbes Calder
- Fortius Clinic, 17 Fitzhardinge Street, London, W1H 6EQ, UK
- Department of Bioengineering, Imperial College London, Exhibition Rd, South Kensington, London, SW7 2BU, UK
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Huang B, Xiong C, Chen W, Liang J, Sun BY, Gong X. Common kinematic synergies of various human locomotor behaviours. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210161. [PMID: 33996133 PMCID: PMC8059590 DOI: 10.1098/rsos.210161] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/23/2021] [Indexed: 06/12/2023]
Abstract
Humans show a variety of locomotor behaviours in daily living, varying in locomotor modes and interaction styles with the external environment. However, how this excellent motor ability is formed, whether there are some invariants underlying various locomotor behaviours and simplifying their generation, and what factors contribute to the invariants remain unclear. Here, we find three common kinematic synergies that form the six joint motions of one lower limb during walking, running, hopping and sitting-down-standing-up (movement variance accounted for greater than 90%), through identifying the coordination characteristics of 36 lower limb motor tasks in diverse environments. This finding supports the notion that humans simplify the generation of various motor behaviours through re-using several basic motor modules, rather than developing entirely new modules for each behaviour. Moreover, a potential link is also found between these synergies and the unique biomechanical characteristics of the human musculoskeletal system (muscular-articular connective architecture and bone shape), and the patterns of inter-joint coordination are consistent with the energy-saving mechanism in locomotion by using biarticular muscles as efficient mechanical energy transducers between joints. Altogether, our work helps understand the formation mechanisms of human locomotion from a holistic viewpoint and evokes inspirations for the development of artificial limbs imitating human motor ability.
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Affiliation(s)
- Bo Huang
- Institute of Robotics Research (IR2), State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China
| | - Caihua Xiong
- Institute of Robotics Research (IR2), State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China
| | - Wenbin Chen
- Institute of Robotics Research (IR2), State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China
| | - Jiejunyi Liang
- Institute of Robotics Research (IR2), State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China
| | - Bai-Yang Sun
- Institute of Robotics Research (IR2), State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China
| | - Xuan Gong
- Institute of Robotics Research (IR2), State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China
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12
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Mohammadi Nejad Rashty A, Grimmer M, Seyfarth A. Hopping frequency influences elastic energy reuse with joint series elastic actuators. J Biomech 2021; 119:110319. [PMID: 33636462 DOI: 10.1016/j.jbiomech.2021.110319] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 01/25/2021] [Accepted: 02/03/2021] [Indexed: 10/22/2022]
Abstract
Robotic limb design struggles to combine energy efficiency with human-like levels of movement versatility. High efficiency and a range of angles and torques are characteristics of human hopping at different frequencies. Humans use muscles in combination with tendons to achieve the required joint actuation. Therefore, we consider whether appropriately tuned series elastic actuators (SEAs) placed at the leg joints can be used to reduce the functional gap between robots and humans. Human hip, knee, and ankle biomechanics were recorded over a range of hopping frequencies to extract joint angles and torques, which were used as an input to a mechanical simulation SEA model. This model was used to optimize the SEA stiffness of each joint to either minimize peak power or energy requirements. This work investigated the relationship between hopping frequency and SEA stiffness, the utility of using SEAs at each joint, and the reasons behind humans' preferred hopping frequency. Although the constant stiffness values across different hopping frequencies are suitable for the knee and the ankle, a variable serial elastic actuator stiffness could still further reduce energy requirements. Optimal SEA stiffness was found to reduce peak power requirements by up to 73% at the ankle and up to 66% at the knee, with greatest benefits found around the preferred frequency. However, no SEA benefits were found for the hip and above the preferred hopping frequency for the knee. These insights could be used to aid in the design of robotic and assistive devices to achieve versatile and energy efficient human-like movements.
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Affiliation(s)
| | - M Grimmer
- Technical University of Darmstadt, Darmstadt, Germany
| | - A Seyfarth
- Technical University of Darmstadt, Darmstadt, Germany
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Grimmer M, Zeiss J, Weigand F, Zhao G, Lamm S, Steil M, Heller A. Lower limb joint biomechanics-based identification of gait transitions in between level walking and stair ambulation. PLoS One 2020; 15:e0239148. [PMID: 32936793 PMCID: PMC7494088 DOI: 10.1371/journal.pone.0239148] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/31/2020] [Indexed: 11/19/2022] Open
Abstract
Lower limb exoskeletons and lower limb prostheses have the potential to reduce gait limitations during stair ambulation. To develop robotic assistance devices, the biomechanics of stair ambulation and the required transitions to level walking have to be understood. This study aimed to identify the timing of these transitions, to determine if transition phases exist and how long they last, and to investigate if there exists a joint-related order and timing for the start and end of the transitions. Therefore, this study analyzed the kinematics and kinetics of both transitions between level walking and stair ascent, and between level walking and stair descent (12 subjects, 25.4 yrs, 74.6 kg). We found that transitions primarily start within the stance phase and end within the swing phase. Transition phases exist for each limb, all joints (hip, knee, ankle), and types of transitions. They have a mean duration of half of one stride and they do not last longer than one stride. The duration of the transition phase for all joints of a single limb in aggregate is less than 35% of one stride in all but one case. The distal joints initialize stair ascent, while the proximal joints primarily initialize the stair descent transitions. In general, the distal joints complete the transitions first. We believe that energy- and balance-related processes are responsible for the joint-specific transition timing. Regarding the existence of a transition phase for all joints and transitions, we believe that lower limb exoskeleton or prosthetic control concepts should account for these transitions in order to improve the smoothness of the transition and to thus increase the user comfort, safety, and user experience. Our gait data and the identified transition timings can provide a reference for the design and the performance of stair ambulation- related control concepts.
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Affiliation(s)
- Martin Grimmer
- Institute for Sports Science, Technical University of Darmstadt, Darmstadt, Hesse, Germany
| | - Julian Zeiss
- Institute of Automatic Control and Mechatronics, Technical University of Darmstadt, Darmstadt, Hesse, Germany
| | - Florian Weigand
- Institute of Automatic Control and Mechatronics, Technical University of Darmstadt, Darmstadt, Hesse, Germany
| | - Guoping Zhao
- Institute for Sports Science, Technical University of Darmstadt, Darmstadt, Hesse, Germany
| | - Sascha Lamm
- Technical University of Darmstadt, Darmstadt, Hesse, Germany
| | - Martin Steil
- Technical University of Darmstadt, Darmstadt, Hesse, Germany
| | - Adrian Heller
- Technical University of Darmstadt, Darmstadt, Hesse, Germany
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