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publications:publications_podcasts_pick_of_the_month [2020/01/06 08:41] Christian |
publications:publications_podcasts_pick_of_the_month [2020/05/08 17:05] Maziar Sharbafi |
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+ | ==== Human Lower Limb Joint Biomechanics in Daily Life Activities: A Literature Based Requirement Analysis for Anthropomorphic Robot Design | ||
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+ | Human lower limb biomechanics of daily activities were investigated in one of our latest studies by [[lab_members: | ||
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+ | **Abstract: | ||
+ | Daily human activity is characterized by a broad variety of movement tasks. This work summarizes the sagittal hip, knee, and ankle joint biomechanics for a broad range of daily movements, based on previously published literature, to identify requirements for robotic design. Maximum joint power, moment, angular velocity, and angular acceleration, | ||
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+ | For further projects and publications of [[lab_members: | ||
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+ | ==== Review of balance recovery in response to external perturbations during daily activities | ||
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+ | Balance related responses to perturbations were investigated in one of our latest studies by Dr. Dario Tokur, Dr. [[lab_members: | ||
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+ | **Abstract: | ||
+ | Balance is an essential capability to ensure upright standing and locomotion. Various external perturbations challenge our balance in daily life and increase the risk for falling and associated injury. Researchers try to identify the human mechanisms to maintain balance by intentional perturbations. The objectives of this work were to point out which areas of perturbation based research are well covered and not well covered and to extract which coping mechanisms humans use to respond to external perturbations. A literature review was performed to analyze mechanisms in response to external perturbations such as pushes to the body or ground level changes during standing, walking, running and hopping. To get a well-structured overview on the two dimensions, the perturbation type and the task, the Perturbation Matrix (PMA) was designed. We found that multiple studies exist for the tasks walking and standing, while hopping and running are covered less. However, all tasks still offer opportunities for both in-depth and fundamental research. Regarding the recovery mechanisms we found that humans can recover from various types of perturbations with versatile mechanisms using combinations of trunk, as well as upper and lower limb movements. The recovery movements will adapt depending on the perturbation intensity, direction and timing. Changes in joint kinetics, joint kinematics and muscle activity were identified on the joint level and leg stiffness and leg length on the global leg level. We believe that the insights from the extracted mechanisms may be applied to the hardware and control of robotic limbs or lower limb exoskeletons to improve the balance and robustness during standing or locomotion. | ||
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+ | For further projects and publications of [[lab_members: | ||
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+ | ==== Biomechanical effects of passive hip springs during walking | ||
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+ | The effects of passive springs at the hip were investigated in a collaboration project of Florian Haufe, Peter Wolf and Robert Riener from the [[https:// | ||
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+ | **Abstract: | ||
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+ | Passive spring-like structures can store and return energy during cyclic movements and thereby reduce the energetic cost of locomotion. That makes them important components of the human body and wearable assistive devices alike. This study investigates how springs placed anteriorly across the hip joint affect leg joint angles and powers, and leg muscle activities during level walking at 0.5 to 2.1 m/s. | ||
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+ | We hypothesized that the anterior hip springs (I) load hip extension, (II) support hip flexion and (III) affect ankle muscle activity and dynamics during walking. Effects at the ankle were expected because hip and ankle redistribute segmental power in concert to achieve forward progression. | ||
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+ | We observed that the participants’ contribution to hip power did not increase during hip extension as the spring stored energy. Simultaneously, | ||
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+ | Instead of loading hip extension, anterior hip springs seem to store and return parts of the energy normally exchanged with the Achilles tendon. Thereby, the springs support hip flexion but may reduce elastic energy storage in and hence recoil from the Achilles tendon. This interaction should be considered during the design and simulation of wearable assistive devices as it might – depending on user characteristics – enhance or diminish their overall functionality. | ||
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+ | For further projects and publications of [[lab_members: | ||
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+ | ==== Biarticular muscles are most responsive to upper-body pitch perturbations in human standing ==== | ||
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+ | Our latest publication features the results of [[http:// | ||
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+ | **Abstract: | ||
+ | Balancing the upper body is pivotal for upright and efficient gait. While models have identified potentially useful characteristics of biarticular thigh muscles for postural control of the upper body, experimental evidence for their specific role is lacking. Based on theoretical findings, we hypothesised that biarticular muscle activity would increase strongly in response to upper-body perturbations. To test this hypothesis, we used a novel Angular Momentum Perturbator (AMP) that, in contrast to existing methods, perturbs the upper-body posture with only minimal effect on Centre of Mass (CoM) excursions. The impulse-like AMP torques applied to the trunk of subjects resulted in upper-body pitch deflections of up to 17° with only small CoM excursions below 2 cm. Biarticular thigh muscles (biceps femoris long head and rectus femoris) showed the strongest increase in muscular activity (mid- and long-latency reflexes, starting 100 ms after perturbation onset) of all eight measured leg muscles which highlights the importance of biarticular muscles for restoring upper-body balance. These insights could be used for improving technological aids like rehabilitation or assistive devices, and the effectiveness of physical training for fall prevention e.g. for elderly people. \\ | ||
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