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 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 Assessment of an Assistive Control Approach Applied in an Active Knee Orthosis Plus Walker for Post-Stroke Gait Rehabilitation

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2452
Author(s):  
Ana Cecilia Villa-Parra ◽  
Jessica Lima ◽  
Denis Delisle-Rodriguez ◽  
Laura Vargas-Valencia ◽  
Anselmo Frizera-Neto ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Muscle Activation ◽  
Inertial Sensors ◽  
Lower Limbs ◽  
Trunk Muscles ◽  
Control Group ◽  
Gait Rehabilitation ◽  
Control Approach ◽  
Post Stroke ◽  
Knee Orthosis

The goal of this study is the assessment of an assistive control approach applied to an active knee orthosis plus a walker for gait rehabilitation. The study evaluates post-stroke patients and healthy subjects (control group) in terms of kinematics, kinetics, and muscle activity. Muscle and gait information of interest were acquired from their lower limbs and trunk, and a comparison was conducted between patients and control group. Signals from plantar pressure, gait phase, and knee angle and torque were acquired during gait, which allowed us to verify that the stance control strategy proposed here was efficient at improving the patients’ gaits (comparing their results to the control group), without the necessity of imposing a fixed knee trajectory. An innovative evaluation of trunk muscles related to the maintenance of dynamic postural equilibrium during gait assisted by our active knee orthosis plus walker was also conducted through inertial sensors. An increase in gait cycle (stance phase) was also observed when comparing the results of this study to our previous work. Regarding the kinematics, the maximum knee torque was lower for patients when compared to the control group, which implies that our orthosis did not demand from the patients a knee torque greater than that for healthy subjects. Through surface electromyography (sEMG) analysis, a significant reduction in trunk muscle activation and fatigability, before and during the use of our orthosis by patients, was also observed. This suggest that our orthosis, together with the assistive control approach proposed here, is promising and could be considered to complement post-stroke patient gait rehabilitation.

Contralateral Strength Training as Preparation for Direct Strength Training in a Patient With Unilateral Foot-Drop Because of Multiple Sclerosis: A Case Report

2020 ◽  
Vol 100 (10) ◽  
pp. 1816-1824
Author(s):  
Andrea Manca ◽  
Lucia Ventura ◽  
Gianluca Martinez ◽  
Elena Aiello ◽  
Franca Deriu
Keyword(s):  
Multiple Sclerosis ◽  
Strength Training ◽  
Foot Drop ◽  
Plantar Flexors ◽  
Unaffected Side ◽  
Patient Functioning ◽  
Direct Training ◽  
Sequential Combination ◽  
The Right ◽  
Unilateral Weakness

Abstract Objective Direct strength training (DST) is effective in managing unilateral weakness in people with multiple sclerosis (MS). Its feasibility, however, is considerably reduced if one limb is too compromised to train. In this case, contralateral strength training (CST) of the unaffected side to induce a strength transfer to the untrained homologous muscles can help to establish a strength baseline in the weaker limb, eventually allowing direct training. Limited effects for CST, however, have been reported on patient functioning. We tested the effects on dynamometric, electromyographic, and functional outcomes of a sequential combination of CST and DST of the ankle dorsiflexors in a case of MS-related foot-drop. Methods A 56-year-old man diagnosed with relapsing-remitting MS exhibited severe weakness of the right dorsiflexors impairing functional dorsiflexion. The intervention consisted of a 6-week CST of the unaffected dorsiflexors followed by 2 consecutive 6-week DST cycles targeting the weaker dorsiflexors. Results At baseline, the participant could not dorsiflex his right ankle but could do so after CST. Maximal strength of the affected dorsiflexors increased by 80% following CST, by 31.1% following DST-1, and by a further 44.6% after DST-2. Neuromuscular recruitment was found progressively increased, with the largest changes occurring after DST-1. Improvements in mobility and walking speed were also detected, although plantar flexors’ spasticity on the Modified Ashworth Scale increased from 1+ to 2. Conclusion In this case, the sequential combination of CST and DST proved a feasible approach to manage severe unilateral weakness in a patient who was not able, at least initially, to dorsiflex his weaker ankle. In this perspective, CST may prime a minimum gain in strength necessary to allow subsequent direct training.

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 Poststroke Muscle Architectural Parameters of the Tibialis Anterior and the Potential Implications for Rehabilitation of Foot Drop

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
John W. Ramsay ◽  
Molly A. Wessel ◽  
Thomas S. Buchanan ◽  
Jill S. Higginson
Keyword(s):  
Tibialis Anterior ◽  
Muscle Activation ◽  
Imaging Techniques ◽  
Tibialis Anterior Muscle ◽  
Functional Mobility ◽  
Foot Drop ◽  
Neutral Position ◽  
Plantar Flexors ◽  
Fascicle Length ◽  
Bilateral Differences

Poststroke dorsiflexor weakness and paretic limb foot drop increase the risk of stumbling and falling and decrease overall functional mobility. It is of interest whether dorsiflexor muscle weakness is primarily neurological in origin or whether morphological differences also contribute to the impairment. Ten poststroke hemiparetic individuals were imaged bilaterally using noninvasive medical imaging techniques. Magnetic resonance imaging was used to identify changes in tibialis anterior muscle volume and muscle belly length. Ultrasonography was used to measure fascicle length and pennation angle in a neutral position. We found no clinically meaningful bilateral differences in any architectural parameter across all subjects, which indicates that these subjects have the muscular capacity to dorsiflex their foot. Therefore, poststroke dorsiflexor weakness is primarily neural in origin and likely due to muscle activation failure or increased spasticity of the plantar flexors. The current finding suggests that electrical stimulation methods or additional neuromuscular retraining may be more beneficial than targeting muscle strength (i.e., increasing muscle mass).

scholarly journals A Biomechanical Analysis of Wide, Medium, and Narrow Grip Width Effects on Kinematics, Horizontal Kinetics, and Muscle Activity on the Sticking Region in Recreationally Trained Males During 1-RM Bench Pressing

2021 ◽  
Vol 2 ◽  
Author(s):  
Stian Larsen ◽  
Olav Gomo ◽  
Roland van den Tillaar
Keyword(s):  
Muscle Activity ◽  
Elbow Joint ◽  
Muscle Activation ◽  
Bench Press ◽  
Biomechanical Analysis ◽  
Vertical Force ◽  
Moment Arm ◽  
Joint Moments ◽  
The One ◽  
Resultant Forces

Grip width has been found to affect lifting performance, especially around the sticking region; however, little is known about the kinetics and muscle activities that could explain these differences in performance. This study aimed to investigate the effects of grip width on the joint, barbell kinematics, and horizontal kinetics, analyzed in tandem with the effects of muscle activation around the sticking region in the one repetition maximum (1-RM) barbell bench press. Fourteen healthy bench press-trained males (body mass: 87.8 ± 18.4, age: 25 ± 5.4) performed 1-RM with a small, medium, and wide grip width. The participants bench pressed 109.8 ± 24.5 kg, 108.9 ± 26.4 kg, and 103.7 ± 24 kg with the wide, medium, and narrow grip widths. Furthermore, the wide grip width produced 13.1–15.7% lateral forces, while the medium and narrow grip widths produced 0.4–1.8 and 8.5–10.1% medially directed forces of the vertical force produced during the sticking region, respectively. Horizontal forces did not increase during the sticking region, and the resultant forces decreased during the sticking region for all grip widths. The wide and medium grip widths produced greater horizontal shoulder moments than the narrow grip width during the sticking region. Hence, the wide and medium grip widths produced similar shoulder and elbow joint moments and moment arm at the first located lowest barbell velocity. Furthermore, triceps medialis muscle activity was greater for the medium and narrow grip widths than the wide grip width. This study suggests that the sticking region for the wide and medium grip widths may be specific to the horizontal elbow and shoulder joint moments created during this region. Therefore, when the goal is to lift as much as possible during 1-RM bench press attempts among recreationally trained males, our findings suggest that bench pressing with a wide or medium grip width may be beneficial.

scholarly journals The Relationship of Trunk Muscle Activation and Core Stability: A Biomechanical Analysis of Pilates-Based Stabilization Exercise

2021 ◽  
Vol 18 (23) ◽  
pp. 12804
Author(s):  
Kyeongjin Lee
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Core Stability ◽  
Biomechanical Analysis ◽  
Kinematic Data ◽  
Stabilization Exercise ◽  
The Core ◽  
3D Motion Analysis ◽  
Significant Difference ◽  
The Relationship

Pilates is an effective exercise method for rehabilitating musculoskeletal disorders as its principles are based on the activation of local muscles. This study aimed to compare the subjects with and without Pilates experience to find out the effect of the experience on the core muscle activity and muscle co-contraction, and to examine the relationship between the core muscle activation level and the kinematic data. This study involved 32 subjects, including 16 experienced Pilates practitioners and 16 non-experienced subjects. The knee stretch on the reformer was performed in three different positions: flat back with a neutral pelvis, round back with posteriorly tilted pelvis (RPP), and extended back anteriorly tilted pelvis (EAP). The electromyography of the internal oblique (IO), rectus abdominis (RA), multifidus (MU), and iliocostalis lumborum (IL) muscles were measured, as well as kinematic data from a 3D motion analysis system. Compared to the non-experienced subjects, the experienced subjects activated the IO muscles more than the RA muscles, and the most significant difference was seen in the RPP position (p < 0.05). The experienced patients activated the MU muscles more often than the IL muscles, with the most significant difference observed in the RPP position and the least significant in the EAP position (p < 0.05). All kinematic data and muscle activity (IO, IO/RA ratio, MU/IL ratio) showed significant differences between the experienced and non-experienced subjects (p < 0.05). The subjects presented a moderate correlation between muscle activation and core stability. It was confirmed that the experienced Pilates practitioners activated the abdominal and low back core muscles effectively, and the stability of the pelvis and trunk were better than that of the non-experienced participants. In addition, the better the trunk stability was maintained, the larger and more accurate movement of the mobility segment was observed.

scholarly journals Differences in Muscle Activation Patterns during Sit to Stand Task among Subjects with and without Intellectual Disability

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Antonio I. Cuesta-Vargas ◽  
Manuel González-Sánchez
Keyword(s):  
Intellectual Disability ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Cross Sectional Study ◽  
Lower Limbs ◽  
Cross Sectional ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Sit To Stand ◽  
Basic Features

The aim of this study is to analyse the differences in muscle activity between subjects who have intellectual disability and healthy subjects when they make the transition from sitting to standing positions. A cross-sectional study. A group of adults was divided into two subgroups: with and without intellectual disability (ID). The means of the basic features in both groups were 22.13 and 22.83 for age, 66.38 and 67.67 for weight, and 173.38 and 174.33 for height, for the ID () and without ID () groups, respectively. Each subject performed three sets of five repetitions during which, starting from sitting, they had to get up and sit on the chair. The recording of muscle activity was performed using surface electromyography taking the measures of muscle activity of different muscles of the lower limbs. The results showed differences in the pattern of muscle activity between groups during sitting to standing movement.

scholarly journals Validation of the "Six Step Spot Test" for gait among patients with multiple sclerosis in Brazil

2010 ◽  
Vol 68 (2) ◽  
pp. 198-204 ◽  
Author(s):  
Karina Pavan ◽  
Charles Peter Tilbery ◽  
Sergio Lianza ◽  
Bruna Eriko Matsuda Marangoni
Keyword(s):  
Multiple Sclerosis ◽  
Healthy Subjects ◽  
Clinical Manifestations ◽  
Spot Test ◽  
Lower Limbs ◽  
Control Group ◽  
Study Group ◽  
Course Of Disease ◽  
Time Performance ◽  
Gradual Accumulation

The clinical manifestations of multiple sclerosis (MS) are variable among patients, and the course of disease is not linear. Different symptoms are presented, with gradual accumulation of disability. These variations are difficult to quantify in clinical practice, and several studies have attempted to create instruments capable of measuring these disabilities. The Six Step Spot Test (SSST) was developed for quantitative evaluation of the lower limbs (LL) over time. Performance in this test reflects the complexity of sensory-motor function, including LL strength, spasticity, coordination and balance, going beyond vision and cognition. The aim of the present study was to validate the SSST in a population of MS patients in Brazil. This prospective study included 75 patients with MS, with EDSS 0 to 6.5 in the study group. Ninety-one healthy subjects were randomly selected for the control group. The results showed that the groups were similar, and that the SSST is a reliable and reproducible test. According to the statistical analysis on the data in this study, the SSST is a valid, reliable and reproducible tool for use in the Brazilian MS patient population.

scholarly journals Muscle Activation during Gait in Unilateral Transtibial Amputee Patients with Prosthesis: The Influence of the Insole Material Density

2021 ◽  
Vol 10 (14) ◽  
pp. 3119
Author(s):  
Nuria Sarroca ◽  
María José Luesma ◽  
José Valero ◽  
Javier Deus ◽  
Josefa Casanova ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Quadriceps Muscle ◽  
Lower Limbs ◽  
Control Group ◽  
Gait Patterns ◽  
Material Density ◽  
Transtibial Amputee ◽  
Complex Process ◽  
Muscle Groups

Background: Walking is a complex process that is highly automated and efficient. This knowledge is essential for the study of pathological gait. The amputation of lower limbs involves new biomechanical load and gait patterns, and injuries due to overload or disuse may occur. The objective of this study is to assess muscle activation as part of the gait in unilateral transtibial amputee patients with prosthesis, at different speeds and with different plantar supports. Method: Included in the sample were 25 people with amputation and 25 control participants. Muscle activation was evaluated in both groups by means of surface electromyography (EMG) under normal and altered conditions. Results: Control participants did not show statistically significant differences (p ˃ 0.05) between their muscle groups, irrespective of support and speed. However, people with amputation did show differences in muscle activity in the quadriceps, all of which occurred at the highest speeds, irrespective of support. In the analysis between groups, significant differences (p < 0.05) were obtained between the leg of the amputee patient and the leg of the control participant, all of them in the quadriceps, and at speeds 3 and 4, regardless of the insole used. Conclusions: Participants with unilateral transtibial amputation carry out more quadriceps muscle activity during gait compared to the control group.

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