A passive exoskeleton reduces peak and mean EMG during symmetric and asymmetric lifting

Alemi, Mohammad Mehdi; Geissinger, Jack; Simon, Athulya A.; Chang, Samantha; Asbeck, Alan T.

doi:10.1016/j.jelekin.2019.05.003

Cited by 127 publications

(102 citation statements)

References 26 publications

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“…The peak compression forces found in this study were within the range of expected values during dynamical lifting of loads of around 10-15 kg (Bazrgari et al, 2008;Kingma et al, 2016;Marras and Davis, 1998). The effect of the exoskeletons during lifting was somewhat small in comparison to other devices, that showed reductions of back muscle activity up to 30% (Abdoli et al, 2006;Abdoli and Stevenson, 2008;Alemi et al, 2019). However, it should be noted that in these studies no information on lumbar flexion and/or compression forces was available.…”

Section: Discussionsupporting

confidence: 68%

“…spinal ligaments) those of active muscles (Dolan et al, 1994). Consequently, especially if kinematics change with using an exoskeleton, a reduction in back muscle electromyography (EMG) (Alemi et al, 2019;Bosch et al, 2016;Kobayashi and Nozaki, 2008;Ulrey and Fathallah, 2013a, b) does not necessarily imply a reduction in spine loading. In addition, application of supportive extension torques with flexion-relaxation being present may be counterproductive, because, if the sum of the passive moment and the moment provided by the exoskeleton exceeds the net joint moment, the participant will need to activate abdominal muscles to maintain or reach the same posture (Koopman et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

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Effects of a passive back exoskeleton on the mechanical loading of the low-back during symmetric lifting

Koopman

Kingma

Looze

et al. 2020

Journal of Biomechanics

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Low-back pain is the number one cause of disability in the world, with mechanical loading as one of the major risk factors. Exoskeletons have been introduced in the workplace to reduce low back loading. During static forward bending, exoskeletons have been shown to reduce back muscle activity by 10% to 40%. However, effects during dynamic lifting are not well documented. Relative support of the exoskeleton might be smaller in lifting compared to static bending due to higher peak loads. In addition, exoskeletons might also result in changes in lifting behavior, which in turn could affect low back loading.The present study investigated the effect of a passive exoskeleton on peak compression forces, moments, muscle activity and kinematics during symmetric lifting. Two types (LOW and HIGH) of the device, which generate peak support moments at large and moderate flexion angles, respectively, were tested during lifts from knee and ankle height from a near and far horizontal position, with a load of 10 kg.Both types of the trunk exoskeleton tested here reduced the peak L5S1 compression force by around 5-10% for lifts from the FAR position from both KNEE and ANKLE height. Subjects did adjust their lifting style when wearing the device with a 17% reduced peak trunk angular velocity and 5 degrees increased lumbar flexion, especially during ANKLE height lifts.In conclusion, the exoskeleton had a minor and varying effect on the peak L5S1 compression force with only significant differences in the FAR lifts.3

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Section: Discussionsupporting

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Effects of a passive back exoskeleton on the mechanical loading of the low-back during symmetric lifting

Koopman

Kingma

Looze

et al. 2020

Journal of Biomechanics

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“…In a dynamic task, such as repetitive lifting, this is not the case and this explains why we did not find as high reductions in back muscle activity. Alemi et al (2019) reported a reduction of back muscle activity by 29% when using the VT-Lowe's exoskeleton during symmetric lifting. Potential causes for the greater reduction in comparison to the present study are the higher loads lifted by the participants in the study of Alemi et al (2019) and unknown difference in support provided by the respective exoskeleton.…”

Section: Discussionmentioning

confidence: 99%

“…Exoskeletons, as a mechanical intervention, are intended to reduce the mechanical load on the back by decreasing muscular activity in the back muscles, needed to counteract external moments caused by inertial and external forces. Previous research has shown that this concept of providing an assisting external extension moment can be effective in reducing lumbar L5S1 moments, back muscle activity, and compression forces in the low back (Abdoli et al 2006;Abdoli-Eramaki and Stevenson 2008;Alemi et al 2019;Bosch et al 2016;Frost et al 2009;Graham et al 2009;Koopman et al 2019;de Looze et al 2016;Ulrey and Fathallah 2013b;Wehner et al 2009).…”

Section: Electronic Supplementary Materialsmentioning

confidence: 99%

SPEXOR passive spinal exoskeleton decreases metabolic cost during symmetric repetitive lifting

et al. 2019

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Purpose Besides mechanical loading of the back, physiological strain is an important risk factor for low-back pain. Recently a passive exoskeleton (SPEXOR) has been developed to reduce loading on the low back. We aimed to assess the effect of this device on metabolic cost of repetitive lifting. To explain potential effects, we assessed kinematics, mechanical joint work, and back muscle activity. Methods We recruited ten male employees, working in the luggage handling department of an airline company and having ample experience with lifting tasks at work. Metabolic cost, kinematics, mechanical joint work and muscle activity were measured during a 5-min repetitive lifting task. Participants had to lift and lower a box of 10 kg from ankle height with and without the exoskeleton. Results Metabolic cost was significantly reduced by 18% when wearing the exoskeleton. Kinematics did not change significantly, while muscle activity decreased by up to 16%. The exoskeleton took over 18-25% of joint work at the hip and L5S1 joints. However, due to large variation in individual responses, we did not find a significant reduction of joint work around the individual joints. Conclusion Wearing the SPEXOR exoskeleton decreased metabolic cost and might, therefore, reduce fatigue development and contribute to prevention of low-back pain during repetitive lifting tasks. Reduced metabolic cost can be explained by the exoskeleton substituting part of muscle work at the hip and L5S1 joints and consequently decreasing required back muscle activity.

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“…Other examples with the same concept are LOPES [5][6][7] or MLLRE [8]. The reader is refereed to the literature for a deep review of mobile and stationary lower limb exoskeletons [9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

ALICE: Conceptual Development of a Lower Limb Exoskeleton Robot Driven by an On-Board Musculoskeletal Simulator

Cardona

Cena

Serrano

et al. 2020

Sensors

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Objective: In this article, we present the conceptual development of a robotics platform, called ALICE (Assistive Lower Limb Controlled Exoskeleton), for kinetic and kinematic gait characterization. The ALICE platform includes a robotics wearable exoskeleton and an on-board muscle driven simulator to estimate the user’s kinetic parameters. Background: Even when the kinematics patterns of the human gait are well studied and reported in the literature, there exists a considerable intra-subject variability in the kinetics of the movements. ALICE aims to be an advanced mechanical sensor that allows us to compute real-time information of both kinetic and kinematic data, opening up a new personalized rehabilitation concept. Methodology: We developed a full muscle driven simulator in an open source environment and validated it with real gait data obtained from patients diagnosed with multiple sclerosis. After that, we designed, modeled, and controlled a 6 DoF lower limb exoskeleton with inertial measurement units and a position/velocity sensor in each actuator. Significance: This novel concept aims to become a tool for improving the diagnosis of pathological gait and to design personalized robotics rehabilitation therapies. Conclusion: ALICE is the first robotics platform automatically adapted to the kinetic and kinematic gait parameters of each patient.

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A passive exoskeleton reduces peak and mean EMG during symmetric and asymmetric lifting

Cited by 127 publications

References 26 publications

Effects of a passive back exoskeleton on the mechanical loading of the low-back during symmetric lifting

Effects of a passive back exoskeleton on the mechanical loading of the low-back during symmetric lifting

SPEXOR passive spinal exoskeleton decreases metabolic cost during symmetric repetitive lifting

ALICE: Conceptual Development of a Lower Limb Exoskeleton Robot Driven by an On-Board Musculoskeletal Simulator

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