scholarly journals Versatile and non-versatile occupational back-support exoskeletons: A comparison in laboratory and field studies

2021 ◽  
Vol 2 ◽  
Author(s):  
Tommaso Poliero ◽  
Matteo Sposito ◽  
Stefano Toxiri ◽  
Christian Di Natali ◽  
Matteo Iurato ◽  
...  
Keyword(s):  
Control Strategy ◽  
Muscle Activity ◽  
Healthy Subjects ◽  
Muscle Activation ◽  
Recognition Performance ◽  
Field Testing ◽  
Field Studies ◽  
Manufacturing Plant ◽  
Task Recognition ◽  
Hip Flexion

Abstract Assistive strategies for occupational back-support exoskeletons have focused, mostly, on lifting tasks. However, in occupational scenarios, it is important to account not only for lifting but also for other activities. This can be done exploiting human activity recognition algorithms that can identify which task the user is performing and trigger the appropriate assistive strategy. We refer to this ability as exoskeleton versatility. To evaluate versatility, we propose to focus both on the ability of the device to reduce muscle activation (efficacy) and on its interaction with the user (dynamic fit). To this end, we performed an experimental study involving $ 10 $ healthy subjects replicating the working activities of a manufacturing plant. To compare versatile and non-versatile exoskeletons, our device, XoTrunk, was controlled with two different strategies. Correspondingly, we collected muscle activity, kinematic variables and users’ subjective feedbacks. Also, we evaluated the task recognition performance of the device. The results show that XoTrunk is capable of reducing muscle activation by up to $ 40\% $ in lifting and $ 30\% $ in carrying. However, the non-versatile control strategy hindered the users’ natural gait (e.g., $ -24\% $ reduction of hip flexion), which could potentially lower the exoskeleton acceptance. Detecting carrying activities and adapting the control strategy, resulted in a more natural gait (e.g., $ +9\% $ increase of hip flexion). The classifier analyzed in this work, showed promising performance (online accuracy > 91%). Finally, we conducted 9 hours of field testing, involving four users. Initial subjective feedbacks on the exoskeleton versatility, are presented at the end of this work.

scholarly journals Biomechanical analysis of an unpowered hip flexion orthosis on individuals with and without multiple sclerosis

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Ross M. Neuman ◽  
Staci M. Shearin ◽  
Karen J. McCain ◽  
Nicholas P. Fey
Keyword(s):  
Multiple Sclerosis ◽  
Muscle Activity ◽  
Healthy Subjects ◽  
Muscle Activation ◽  
Assistive Technologies ◽  
Lower Limbs ◽  
Biomechanical Analysis ◽  
Foot Drop ◽  
Plantar Flexors ◽  
Hip Flexion

Abstract Background Gait impairment is a common complication of multiple sclerosis (MS). Gait limitations such as limited hip flexion, foot drop, and knee hyperextension often require external devices like crutches, canes, and orthoses. The effects of mobility-assistive technologies (MATs) prescribed to people with MS are not well understood, and current devices do not cater to the specific needs of these individuals. To address this, a passive unilateral hip flexion-assisting orthosis (HFO) was developed that uses resistance bands spanning the hip joint to redirect energy in the gait cycle. The purpose of this study was to investigate the short-term effects of the HFO on gait mechanics and muscle activation for people with and without MS. We hypothesized that (1) hip flexion would increase in the limb wearing the device, and (2) that muscle activity would increase in hip extensors, and decrease in hip flexors and plantar flexors. Methods Five healthy subjects and five subjects with MS walked for minute-long sessions with the device using three different levels of band stiffness. We analyzed peak hip flexion and extension angles, lower limb joint work, and muscle activity in eight muscles on the lower limbs and trunk. Single-subjects analysis was used due to inter-subject variability. Results For subjects with MS, the HFO caused an increase in peak hip flexion angle and a decrease in peak hip extension angle, confirming our first hypothesis. Healthy subjects showed less pronounced kinematic changes when using the device. Power generated at the hip was increased in most subjects while using the HFO. The second hypothesis was not confirmed, as muscle activity showed inconsistent results, however several subjects demonstrated increased hip extensor and trunk muscle activity with the HFO. Conclusions This exploratory study showed that the HFO was well-tolerated by healthy subjects and subjects with MS, and that it promoted more normative kinematics at the hip for those with MS. Future studies with longer exposure to the HFO and personalized assistance parameters are needed to understand the efficacy of the HFO for mobility assistance and rehabilitation for people with MS.

scholarly journals Surface electromyography comparison of the abdominal hypopressive gymnastics against the prone bridge exercise

2019 ◽  
Vol 12 (3) ◽  
pp. 243-246
Author(s):  
Gonzalo Alfonso Quiroz Sandoval ◽  
Nathalie Tabilo ◽  
Cristóbal Bahamondes ◽  
Pilar Bralic
Keyword(s):  
Abdominal Wall ◽  
Muscle Activity ◽  
Surface Electromyography ◽  
Healthy Subjects ◽  
Muscle Activation ◽  
Transversus Abdominis ◽  
Abdominal Pressure ◽  
Abdominal Muscles ◽  
External Oblique ◽  
Internal Oblique

Objectives: Abdominal hypopressive gymnastics (AHG) is a little-researched method designed to train the muscles of the abdominal wall and pelvic floor under low stress. This study’s objective is to compare levels of muscle activation in AHG against prone bridge by surface electromyography (sEMG) of the abdominal wall muscles. Methods: Twenty healthy subjects were enrolled to measure the muscle activity of the rectus abdominis (RA), transversus abdominis/internal oblique (Tra/IO), and external oblique (EO) during three exercises: prone bridge (PB), orthostatic hypopressive (OH), and hypopressive bridge (HB). Root mean square values normalized to the PB (%PB) as a baseline were used to compare the PB against OH and HB. Results: The median PB ratio (%PB) for the Tra/IO showed –10.31% and +59.7% activation during OH and the HB, respectively, whereas the RA showed –77.8% and +19.3% and the EO –39.8% and +9.8%. Significant differences were found for all muscles except the Tra/IO during the OH. Conclusion: This study’s results suggest that hypopressive exercises facilitate the activation of the Tra/IO similar to bridge exercises while simultaneously reducing RA and EO activity. This suggests that hypopressive training is a valid alternative for activating the abdominal muscles, isolating the Tra/IO at low intra-abdominal pressure.

scholarly journals A Systematic Review of EMG Applications for the Characterization of Forearm and Hand Muscle Activity during Activities of Daily Living: Results, Challenges, and Open Issues

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3035
Author(s):  
Néstor J. Jarque-Bou ◽  
Joaquín L. Sancho-Bru ◽  
Margarita Vergara
Keyword(s):  
Activities Of Daily Living ◽  
Musculoskeletal System ◽  
Muscle Activity ◽  
Daily Living ◽  
Muscle Activation ◽  
Human Hand ◽  
Hand Motion ◽  
Biomechanical Models ◽  
Rehabilitation Protocols ◽  
Open Issues

The role of the hand is crucial for the performance of activities of daily living, thereby ensuring a full and autonomous life. Its motion is controlled by a complex musculoskeletal system of approximately 38 muscles. Therefore, measuring and interpreting the muscle activation signals that drive hand motion is of great importance in many scientific domains, such as neuroscience, rehabilitation, physiotherapy, robotics, prosthetics, and biomechanics. Electromyography (EMG) can be used to carry out the neuromuscular characterization, but it is cumbersome because of the complexity of the musculoskeletal system of the forearm and hand. This paper reviews the main studies in which EMG has been applied to characterize the muscle activity of the forearm and hand during activities of daily living, with special attention to muscle synergies, which are thought to be used by the nervous system to simplify the control of the numerous muscles by actuating them in task-relevant subgroups. The state of the art of the current results are presented, which may help to guide and foster progress in many scientific domains. Furthermore, the most important challenges and open issues are identified in order to achieve a better understanding of human hand behavior, improve rehabilitation protocols, more intuitive control of prostheses, and more realistic biomechanical models.

scholarly journals Is the Occurrence of the Sticking Region in Maximum Smith Machine Squats the Result of Diminishing Potentiation and Co-Contraction of the Prime Movers among Recreationally Resistance Trained Males?

2021 ◽  
Vol 18 (3) ◽  
pp. 1366
Author(s):  
Roland van den Tillaar ◽  
Eirik Lindset Kristiansen ◽  
Stian Larsen
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Gluteus Maximus ◽  
Knee Extensors ◽  
Force Output ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Prime Movers ◽  
Almost All ◽  
Height Data

This study compared the kinetics, barbell, and joint kinematics and muscle activation patterns between a one-repetition maximum (1-RM) Smith machine squat and isometric squats performed at 10 different heights from the lowest barbell height. The aim was to investigate if force output is lowest in the sticking region, indicating that this is a poor biomechanical region. Twelve resistance trained males (age: 22 ± 5 years, mass: 83.5 ± 39 kg, height: 1.81 ± 0.20 m) were tested. A repeated two-way analysis of variance showed that Force output decreased in the sticking region for the 1-RM trial, while for the isometric trials, force output was lowest between 0–15 cm from the lowest barbell height, data that support the sticking region is a poor biomechanical region. Almost all muscles showed higher activity at 1-RM compared with isometric attempts (p < 0.05). The quadriceps activity decreased, and the gluteus maximus and shank muscle activity increased with increasing height (p ≤ 0.024). Moreover, the vastus muscles decreased only for the 1-RM trial while remaining stable at the same positions in the isometric trials (p = 0.04), indicating that potentiation occurs. Our findings suggest that a co-contraction between the hip and knee extensors, together with potentiation from the vastus muscles during ascent, creates a poor biomechanical region for force output, and thereby the sticking region among recreationally resistance trained males during 1-RM Smith machine squats.

scholarly journals Ankle Muscle Activations during Different Foot-Strike Patterns in Running

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3422
Author(s):  
Jian-Zhi Lin ◽  
Wen-Yu Chiu ◽  
Wei-Hsun Tai ◽  
Yu-Xiang Hong ◽  
Chung-Yu Chen
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Stance Phase ◽  
Inertial Sensors ◽  
Plantar Flexion ◽  
Intraclass Correlation ◽  
Biceps Femoris ◽  
Ankle Muscle ◽  
Foot Strike ◽  
Muscle Activations

This study analysed the landing performance and muscle activity of athletes in forefoot strike (FFS) and rearfoot strike (RFS) patterns. Ten male college participants were asked to perform two foot strikes patterns, each at a running speed of 6 km/h. Three inertial sensors and five EMG sensors as well as one 24 G accelerometer were synchronised to acquire joint kinematics parameters as well as muscle activation, respectively. In both the FFS and RFS patterns, according to the intraclass correlation coefficient, excellent reliability was found for landing performance and muscle activation. Paired t tests indicated significantly higher ankle plantar flexion in the FFS pattern. Moreover, biceps femoris (BF) and gastrocnemius medialis (GM) activation increased in the pre-stance phase of the FFS compared with that of RFS. The FFS pattern had significantly decreased tibialis anterior (TA) muscle activity compared with the RFS pattern during the pre-stance phase. The results demonstrated that the ankle strategy focused on controlling the foot strike pattern. The influence of the FFS pattern on muscle activity likely indicates that an athlete can increase both BF and GM muscles activity. Altered landing strategy in cases of FFS pattern may contribute both to the running efficiency and muscle activation of the lower extremity. Therefore, neuromuscular training and education are required to enable activation in dynamic running tasks.

scholarly journals Back-Support Exoskeleton Control Strategy for Pulling Activities: Design and Preliminary Evaluation

Designs ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 39
Author(s):  
Maria Lazzaroni ◽  
Tommaso Poliero ◽  
Matteo Sposito ◽  
Stefano Toxiri ◽  
Darwin G. Caldwell ◽  
...  
Keyword(s):  
Control Strategy ◽  
Muscle Activity ◽  
Material Handling ◽  
Ease Of Use ◽  
Biomechanical Analysis ◽  
Perceived Support ◽  
Preliminary Evaluation ◽  
Subjective Measurements ◽  
Spinal Muscles ◽  
Forearm Muscle

The execution of manual material handling activities in the workplace exposes workers to large lumbar loads that increase the risk of musculoskeletal disorders and low back pain. In particular, the redesign of the workplace is making the execution of pulling activities more common, as an alternative to lifting and carrying tasks. The biomechanical analysis of the task revealed a substantial activation of the spinal muscles. This suggests that the user may benefit from the assistance of a back-support exoskeleton that reduces the spinal muscle activity and their contribution to lumbar compression. This work addresses this challenge by exploiting the versatility of an active back-support exoskeleton. A control strategy was specifically designed for assisting pulling that modulates the assistive torques using the forearm muscle activity. These torques are expected to adapt to the user’s assistance needs and the pulled object mass, as forearm muscle activity is considered an indicator of grip strength. We devised laboratory experiments to assess the feasibility and effectiveness of the proposed strategy. We found that, for the majority of the subjects, back muscle activity reductions were associated with the exoskeleton use. Furthermore, subjective measurements reveal advantages in terms of perceived support, comfort, ease of use, and intuitiveness.

scholarly journals The Effects of Core Stabilization Exercise with the Abdominal Drawing-in Maneuver Technique versus General Strengthening Exercise on Lumbar Segmental Motion in Patients with Clinical Lumbar Instability: A Randomized Controlled Trial with 12-Month Follow-Up

2021 ◽  
Vol 18 (15) ◽  
pp. 7811
Author(s):  
Rungthip Puntumetakul ◽  
Pongsatorn Saiklang ◽  
Weerasak Tapanya ◽  
Thiwaphon Chatprem ◽  
Jaturat Kanpittaya ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Controlled Trial ◽  
Abdominal Muscle ◽  
Segmental Motion ◽  
Lumbar Instability ◽  
Stabilization Exercise ◽  
Core Stabilization ◽  
Core Stabilization Exercise

Trunk stability exercises that focus on either deep or superficial muscles might produce different effects on lumbar segmental motion. This study compared outcomes in 34 lumbar instability patients in two exercises at 10 weeks and 12 months follow up. Participants were divided into either Core stabilization (deep) exercise, incorporating abdominal drawing-in maneuver technique (CSE with ADIM), or General strengthening (superficial) exercise (STE). Outcome measures were pain, muscle activation, and lumbar segmental motion. Participants in CSE with ADIM had significantly less pain than those in STE at 10 weeks. They showed significantly more improvement of abdominal muscle activity ratio than participants in STE at 10 weeks and 12 months follow-up. Participants in CSE with ADIM had significantly reduced sagittal translation at L4-L5 and L5-S1 compared with STE at 10 weeks. Participants in CSE with ADIM had significantly reduced sagittal translations at L4-L5 and L5-S1 compared with participants in STE at 10 weeks, whereas STE demonstrated significantly increased sagittal rotation at L4-L5. However, at 12 months follow-up, levels of lumbar sagittal translation were increased in both groups. CSE with ADIM which focuses on increasing deep trunk muscle activity can reduce lumbar segmental translation and should be recommended for lumbar instability.

scholarly journals Role of Occupational Footwear and Prolonged Walking on Lower Extremity Muscle Activation during Maximal Exertions and Postural Stability Tasks

Biomechanics ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 202-213
Author(s):  
Harish Chander ◽  
Sachini N. K. Kodithuwakku Arachchige ◽  
Alana J. Turner ◽  
Reuben F. Burch V ◽  
Adam C. Knight ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Muscle Activity ◽  
Repeated Measures ◽  
Postural Stability ◽  
Muscle Activation ◽  
Medial Gastrocnemius ◽  
Lower Extremity Muscle ◽  
Prolonged Duration ◽  
The Mean ◽  
The Impact

Background: Occupational footwear and a prolonged duration of walking have been previously reported to play a role in maintaining postural stability. The purpose of this paper was to analyze the impact of three types of occupational footwear: the steel-toed work boot (ST), the tactical work boot (TB), and the low-top work shoe (LT) on previously unreported lower extremity muscle activity during postural stability tasks. Methods: Electromyography (EMG) muscle activity was measured from four lower extremity muscles (vastus medialis (VM), medial hamstrings (MH), tibialis anterior (TA), and medial gastrocnemius (MG) during maximal voluntary isometric contractions (MVIC) and during a sensory organization test (SOT) every 30 min over a 4 h simulated workload while wearing ST, TB, and LT footwear. The mean MVIC and the mean and percentage MVIC during each SOT condition from each muscle was analyzed individually using a repeated measures ANOVA at an alpha level of 0.05. Results: Significant differences (p < 0.05) were found for maximal exertions, but this was limited to only the time main effect. No significant differences existed for EMG measures during the SOT. Conclusion: The findings suggest that occupational footwear type does not influence lower extremity muscle activity during both MVIC and SOT. Significantly lower muscle activity during maximal exertions over the course of the 4 h workload was evident, which can be attributed to localized muscular fatigue, but this was not sufficient to impact muscle activity during postural stability tasks.

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