scholarly journals Walking With a Robotic Exoskeleton Does Not Mimic Natural Gait: A Within-Subjects Study (Preprint)

2018 ◽  
Author(s):  
Chad Swank ◽  
Sharon Wang-Price ◽  
Fan Gao ◽  
Sattam Almutairi
Keyword(s):  
Lower Extremity ◽  
Muscle Activity ◽  
Stance Phase ◽  
Swing Phase ◽  
Healthy Adults ◽  
Emg Activity ◽  
Robotic Exoskeleton ◽  
Gait Parameters ◽  
Muscle Groups ◽  
The Impact

BACKGROUND Robotic exoskeleton devices enable individuals with lower extremity weakness to stand up and walk over ground with full weight-bearing and reciprocal gait. Limited information is available on how a robotic exoskeleton affects gait characteristics. OBJECTIVE The purpose of this study was to examine whether wearing a robotic exoskeleton affects temporospatial parameters, kinematics, and muscle activity during gait. METHODS The study was completed by 15 healthy adults (mean age 26.2 [SD 8.3] years; 6 males, 9 females). Each participant performed walking under 2 conditions: with and without wearing a robotic exoskeleton (EKSO). A 10-camera motion analysis system synchronized with 6 force plates and a surface electromyography (EMG) system captured temporospatial and kinematic gait parameters and lower extremity muscle activity. For each condition, data for 5 walking trials were collected and included for analysis. RESULTS Differences were observed between the 2 conditions in temporospatial gait parameters of speed, stride length, and double-limb support time. When wearing EKSO, hip and ankle range of motion (ROM) were reduced and knee ROM increased during the stance phase. However, during the swing phase, knee and ankle ROM were reduced when wearing the exoskeleton bionic suit. When wearing EKSO, EMG activity decreased bilaterally in the stance phase for all muscle groups of the lower extremities and in the swing phase for the distal muscle groups (tibialis anterior and soleus) as well as the left medial hamstrings. CONCLUSIONS Wearing EKSO altered temporospatial gait parameters, lower extremity kinematics, and muscle activity during gait in healthy adults. EKSO appears to promote a type of gait that is disparate from normal gait in first-time users. More research is needed to determine the impact on gait training with EKSO in people with gait impairments.

scholarly journals Joint Torque and Mechanical Power of Lower Extremity and Its Relevance to Hamstring Strain during Sprint Running

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Yunjian Zhong ◽  
Weijie Fu ◽  
Shutao Wei ◽  
Qing Li ◽  
Yu Liu
Keyword(s):  
Lower Extremity ◽  
Stance Phase ◽  
Swing Phase ◽  
Joint Torque ◽  
Mechanical Power ◽  
Movement Direction ◽  
Joint Torques ◽  
Sprint Running ◽  
Lower Extremity Muscle ◽  
Muscle Groups

The aim of this study was to quantify the contributions of lower extremity joint torques and the mechanical power of lower extremity muscle groups to further elucidate the loadings on hamstring and the mechanics of its injury. Eight national-level male sprinters performed maximum-velocity sprint running on a synthetic track. The 3D kinematic data and ground reaction force (GRF) were collected synchronously. Intersegmental dynamics approach was used to analyze the lower extremity joint torques and power changes in the lower extremity joint muscle groups. During sprinting, the GRF during the stance phase and the motion-dependent torques (MDT) during the swing phase had a major effect on the lower extremity movements and muscle groups. Specifically, during the stance phase, torque produced and work performed by the hip and knee muscles were generally used to counteract the GRF. During the swing phase, the role of the muscle torque changed to mainly counteract the effect of MDT to control the movement direction of the lower extremity. Meanwhile, during the initial stance and late swing phases, the passive torques, namely, the ground reaction torques and MDT produced by the GRF and the inertial movement of the segments of the lower extremity, applied greater stress to the hamstring muscles.

scholarly journals Lower Extremity Muscle Activation in Alternative Footwear during Stance Phase of Slip Events

2021 ◽  
Vol 18 (4) ◽  
pp. 1533
Author(s):  
Harish Chander ◽  
John C. Garner ◽  
Chip Wade ◽  
Adam C. Knight
Keyword(s):  
Lower Extremity ◽  
Muscle Activity ◽  
Repeated Measures ◽  
Muscle Activation ◽  
Stance Phase ◽  
Voluntary Contraction ◽  
Repeated Measures Design ◽  
Lower Extremity Muscle ◽  
Repeated Measures Analysis ◽  
The Impact

Muscle activity from the slipping leg have been previously used to analyze slip induced falls. However, the impact of casual alternative footwear on slipping leg muscle activity when exposed to slippery environments is still unknown. The purpose of the study was to analyze the impact of alternative footwear (crocs (CC) and flip-flops (FF)) compared to slip-resistant footwear (LT) on lower extremity muscle activity when exposed to dry gait (NG), unexpected (US), alert (AS), and expected slips (ES). Eighteen healthy males (age: 22.3 ± 2.2 years; height: 177.7 ± 6.9 cm; weight: 79.3 ± 7.6 kg) completed the study in a repeated measures design in three footwear sessions separated by 48 h. Electromyography (EMG) muscle activity from four muscles of the lead/slipping leg was measured during the stance phase of the gait-slip trials. A 3 (footwear) × 4 (gait-slip trials) repeated measures analysis of variance was used to analyze EMG dependent variables mean, peak, and percent of maximal voluntary contraction. Greater lower extremity muscle activation during the stance phase was seen in US and AS conditions compared to NG and ES. In addition, footwear differences were seen for the alternative footwear (CC and FF) during US and AS, while the low top slip resistant shoe had no differences across all gait trials, suggesting it as the most efficient footwear of choice, especially when maneuvering slippery flooring conditions, either with or without the knowledge of an impending slip.

Myoelectric Activity Differences in Three Learning Sessions

2002 ◽  
Vol 16 (2) ◽  
pp. 92-96
Author(s):  
Tiina Ritvanen ◽  
Reijo Koskelo ◽  
Osmo H„nninen
Keyword(s):  
High School Students ◽  
Muscle Activity ◽  
Muscle Tension ◽  
Emg Activity ◽  
Traditional Learning ◽  
Myoelectric Activity ◽  
School Students ◽  
Language Laboratory ◽  
Upper Trapezius ◽  
Muscle Groups

Abstract This study follows muscle activity in three different learning sessions (computer, language laboratory, and normal classroom) while students were studying foreign languages. Myoelectric activity was measured in 21 high school students (10 girls, 11 boys, age range 17-20 years) by surface electromyography (sEMG) from the upper trapezius and frontalis muscles during three 45-min sessions. Root mean square (RMS) average from both investigated muscles was calculated. The EMG activity was highest in both muscle groups in the computer-aided session and lowest in the language laboratory. The girls had higher EMG activity in both investigated muscle groups in all three learning situations. The measured blood pressure was highest at the beginning of the sessions, decreased within 10 min, but increased again toward the end of the sessions. Our results indicate that the use of a computer as a teaching-aid evokes more constant muscle activity than the traditional learning situations. Since muscle tension can have adverse health consequences, more research is needed to determine optimal classroom conditions, especially when technical aids are used in teaching.

Lower-Extremity Muscle Activity During Aquatic and Land Treadmill Running at the Same Speeds

2014 ◽  
Vol 23 (2) ◽  
pp. 107-122 ◽  
Author(s):  
W. Matthew Silvers ◽  
Eadric Bressel ◽  
D. Clark Dickin ◽  
Garry Killgore ◽  
Dennis G. Dolny
Keyword(s):  
Lower Extremity ◽  
Outcome Measures ◽  
Muscle Activity ◽  
Tibialis Anterior ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Swing Phase ◽  
Treadmill Running ◽  
Vastus Medialis ◽  
Lower Extremity Muscle

Context:Muscle activation during aquatic treadmill (ATM) running has not been examined, despite similar investigations for other modes of aquatic locomotion and increased interest in ATM running.Objectives:The objectives of this study were to compare normalized (percentage of maximal voluntary contraction; %MVC), absolute duration (aDUR), and total (tACT) lower-extremity muscle activity during land treadmill (TM) and ATM running at the same speeds.Design:Exploratory, quasi-experimental, crossover design.Setting:Athletic training facility.Participants:12 healthy recreational runners (age = 25.8 ± 5 y, height = 178.4 ± 8.2 cm, mass = 71.5 ± 11.5 kg, running experience = 8.2 ± 5.3 y) volunteered for participation.Intervention:All participants performed TM and ATM running at 174.4, 201.2, and 228.0 m/min while surface electromyographic data were collected from the vastus medialis, rectus femoris, gastrocnemius, tibialis anterior, and biceps femoris.Main Outcome Measures:For each muscle, a 2 × 3 repeated-measures ANOVA was used to analyze the main effects and environment–speed interaction (P ≤ .05) of each dependent variable: %MVC, aDUR, and tACT.Results:Compared with TM, ATM elicited significantly reduced %MVC (−44.0%) but increased aDUR (+213.1%) and tACT (+41.9%) in the vastus medialis, increased %MVC (+48.7%) and aDUR (+128.1%) in the rectus femoris during swing phase, reduced %MVC (−26.9%) and tACT (−40.1%) in the gastrocnemius, increased aDUR (+33.1%) and tACT (+35.7%) in the tibialis anterior, and increased aDUR (+41.3%) and tACT (+29.2%) in the biceps femoris. At faster running speeds, there were significant increases in tibialis anterior %MVC (+8.6−15.2%) and tACT (+12.7−17.0%) and rectus femoris %MVC (12.1−26.6%; swing phase).Conclusion:No significant environment–speed interaction effects suggested that observed muscle-activity differences between ATM and TM were due to environmental variation, ie, buoyancy (presumed to decrease %MVC) and drag forces (presumed to increase aDUR and tACT) in the water.

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.

scholarly journals Gait Parameters Associated With Responsiveness to Treadmill Training With Body-Weight Support After Stroke: An Exploratory Study

2010 ◽  
Vol 90 (2) ◽  
pp. 209-223 ◽  
Author(s):  
Sara J. Mulroy ◽  
Tara Klassen ◽  
JoAnne K. Gronley ◽  
Valerie J. Eberly ◽  
David A. Brown ◽  
...  
Keyword(s):  
Body Weight ◽  
Lower Extremity ◽  
Muscle Activation ◽  
Walking Speed ◽  
Treadmill Training ◽  
High Response ◽  
Emg Activity ◽  
Locomotor Training ◽  
Gait Parameters ◽  
Response Group

Background Task-specific training programs after stroke improve walking function, but it is not clear which biomechanical parameters of gait are most associated with improved walking speed. Objective The purpose of this study was to identify gait parameters associated with improved walking speed after a locomotor training program that included body-weight–supported treadmill training (BWSTT). Design A prospective, between-subjects design was used. Methods Fifteen people, ranging from approximately 9 months to 5 years after stroke, completed 1 of 3 different 6-week training regimens. These regimens consisted of 12 sessions of BWSTT alternated with 12 sessions of: lower-extremity resistive cycling; lower-extremity progressive, resistive strengthening; or a sham condition of arm ergometry. Gait analysis was conducted before and after the 6-week intervention program. Kinematics, kinetics, and electromyographic (EMG) activity were recorded from the hemiparetic lower extremity while participants walked at a self-selected pace. Changes in gait parameters were compared in participants who showed an increase in self-selected walking speed of greater than 0.08 m/s (high-response group) and in those with less improvement (low-response group). Results Compared with participants in the low-response group, those in the high-response group displayed greater increases in terminal stance hip extension angle and hip flexion power (product of net joint moment and angular velocity) after the intervention. The intensity of soleus muscle EMG activity during walking also was significantly higher in participants in the high-response group after the intervention. Limitations Only sagittal-plane parameters were assessed, and the sample size was small. Conclusions Task-specific locomotor training alternated with strength training resulted in kinematic, kinetic, and muscle activation adaptations that were strongly associated with improved walking speed. Changes in both hip and ankle biomechanics during late stance were associated with greater increases in gait speed.

scholarly journals Metabolic Costs and Muscle Activity Patterns During Robotic- and Therapist-Assisted Treadmill Walking in Individuals With Incomplete Spinal Cord Injury

2006 ◽  
Vol 86 (11) ◽  
pp. 1466-1478 ◽  
Author(s):  
Jeffrey F Israel ◽  
Donielle D Campbell ◽  
Jennifer H Kahn ◽  
T George Hornby
Keyword(s):  
Spinal Cord ◽  
Muscle Activity ◽  
Activity Patterns ◽  
Swing Phase ◽  
Emg Activity ◽  
Robotic Device ◽  
Incomplete Spinal Cord Injury ◽  
Robotic Assisted ◽  
Cord Injury ◽  
Metabolic Costs

AbstractBackground and Purpose. Robotic devices that provide passive guidance and stabilization of the legs and trunk during treadmill stepping may increase the delivery of locomotor training to subjects with neurological injury. Lower-extremity guidance also may reduce voluntary muscle activity as compared with compliant assistance provided by therapists. The purpose of this study was to investigate differences in metabolic costs and lower-limb muscle activity patterns during robotic- and therapist-assisted treadmill walking. Subjects. Twelve ambulatory subjects with motor incomplete spinal cord injury participated. Methods. In 2 separate protocols, metabolic and electromyographic (EMG) data were collected during standing and stepping on a treadmill with therapist and robotic assistance. During robotic-assisted walking, subjects were asked to match the kinematic trajectories of the device and maximize their effort. During therapist-assisted walking, subjects walked on the treadmill with manual assistance provided as necessary. Results. Metabolic costs and swing-phase hip flexor EMG activity were significantly lower when subjects were asked to match the robotic device trajectories than with therapist-assisted walking. These differences were reduced when subjects were asked to maximize their effort during robotic-assisted stepping, although swing-phase plantar-flexor EMG activity was increased. In addition, during standing prior to therapist- or robotic-assisted stepping, metabolic costs were higher without stabilization from the robotic device. Discussion and Conclusion. Differences in metabolic costs and muscle activity patterns between therapist- and robotic-assisted standing and stepping illustrate the importance of minimizing passive guidance and stabilization provided during step training protocols.

scholarly journals EFFECTS OF SPEED AND INCLINE ON LOWER EXTREMITY KINEMATICS DURING TREADMILL JOGGING IN HEALTHY SUBJECTS

2006 ◽  
Vol 18 (02) ◽  
pp. 73-79 ◽  
Author(s):  
LAN-YUEN GUO ◽  
FONG-CHIN SU ◽  
CHICH-HAUNG YANG ◽  
SHU-HUI WANG ◽  
JYH-JONG CHANG ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Motion Analysis ◽  
Repeated Measures ◽  
Stance Phase ◽  
Vision System ◽  
Movement Patterns ◽  
Swing Phase ◽  
Transverse Plane ◽  
Home Setting ◽  
Maximum Flexion

Recently, there are more people jogging with a treadmill at the gym or the home setting. The main available selected modes for treadmill jogging are speed and slope of incline. Increased speeds and incline slopes will not only increase the cardiopulmonary loading but may also alter the lower extremity (LE) movement patterns. There are few systematic investigations of the effect of the speed and incline on LE kinematics. Most studies have used 2D methods which focused on movements in sagittal plane only and this has limitations in the acquired data since lower extremity movements also include frontal and transverse planes. The current study aimed to investigate LE movement during jogging at different speeds and incline slopes using a high speed three-dimensional (3D) motion analysis system. Eighteen young healthy males were recruited. The video-based motion capture system with six CCD cameras, HIRES Expert Vision System (Motion Analysis Corporation, CA, USA), was used to collect kinematic data at a sampling frequency of 120Hz. Nineteen passive reflective markers were attached to bilateral lower extremities of the subject. The joint angle is calculated by Euler angle using the rotation sequence: 2-1-3 (y-x′-z″). Four speeds were selected: 2 m/s, 2.5 m/s, 3 m/s, 3.5 m/s with the slope at 0, and four slopes were selected: 0%, 5%,10%,15% at a speed of 3 m/s. Repeated-measures ANOVA was used to test hypotheses regarding changes in jogging condition on LE kinematic variables. The significance level was set at 0.05. As the jogging slope increased, the hip, knee and ankle demonstrated a significantly greater maximum flexion in swing phase (p<0.001), but the maximum extension angles in stance phase were relatively unchanged. Increased LE flexion during swing phase is important to ensure foot clearance with increased slope. For increased speed, the hip and ankle joints had significantly greater maximum joint extension angles during stance phase and the hip and knee joint had significantly larger maximum flexion angles in swing phase (p<0.001). Increased motion during swing phase account for a larger step length and increased motion during stance phase may facilitate the generation of power during forward propulsion as the jogging speed increased. As the slope and speed increased, LE movement patterns were changed in the transverse plane: the significantly increased (p<0.01) internal hip rotation at terminal stance, the increased toe-in of foot (p<0.001) during terminal stance phase and decreased (p<0.05) toe-out during swing phase. Increased hip motion in transverse plane could lengthen the stride distance and increase foot toe-in for providing a stable lever for push off to increase propulsion force as speed or slope is increased. By way of systematic 3D kinematic investigation of the LE in jogging, the results further elucidate the effect of changing speed and incline on LE joints movements. This information could provide guidelines for rehabilitation clinicians or coaches to select an appropriate training mode for jogging.

scholarly journals Vision fine-tunes preparation for landing in the cane toad, Rhinella marina

2018 ◽  
Vol 14 (9) ◽  
pp. 20180397 ◽  
Author(s):  
Laura J. Ekstrom ◽  
Chris Panzini ◽  
Gary B. Gillis
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Activity Patterns ◽  
Fine Tuning ◽  
Emg Activity ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Impact Forces ◽  
Before And After ◽  
The Impact

In toad hopping, the hindlimbs generate the propulsive force for take-off while the forelimbs resist the impact forces associated with landing. Preparing to perform a safe landing, in which impact forces are managed appropriately, likely involves the integration of multiple types of sensory feedback. In toads, vestibular and/or proprioceptive feedback is critical for coordinated landing; however, the role of vision remains unclear. To clarify this, we compare pre-landing forelimb muscle activation patterns before and after removing vision. Specifically, we recorded EMG activity from two antagonistic forelimb muscles, the anconeus and coracoradialis, which demonstrate distance-dependent onset timing and recruitment intensity, respectively. Toads were first recorded hopping normally and then again after their optic nerves were severed to remove visual feedback. When blind, toads exhibited hop kinematics and pre-landing muscle activity similar to when sighted. However, distance-dependent relationships for muscle activity patterns were more variable, if present at all. This study demonstrates that blind toads are still able to perform coordinated landings, reinforcing the importance of proprioceptive and/or vestibular feedback during hopping. But the increased variability in distance-dependent activity patterns indicates that vision is more responsible for fine-tuning the motor control strategy for landing.

Walking with and without a robotic exoskeleton in people with incomplete spinal cord injury compared to a typical gait pattern

2021 ◽  
pp. 1-12
Author(s):  
Sattam M. Almutairi ◽  
Chad Swank ◽  
Sharon S. Wang-Price ◽  
Fan Gao ◽  
Ann Medley
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Lower Extremity ◽  
Rectus Femoris ◽  
Gait Pattern ◽  
Healthy Adults ◽  
Incomplete Spinal Cord Injury ◽  
Lower Extremity Weakness ◽  
Robotic Exoskeleton ◽  
Cord Injury

BACKGROUND: Robotic exoskeleton (RE) enables individuals with lower extremity weakness or paralysis to stand and walk in a stereotypical pattern. OBJECTIVE: Examine whether people with chronic incomplete spinal cord injury (SCI) demonstrate a more typical gait pattern when walking overground in a RE than when walking without. METHODS: Motion analysis system synchronized with a surface electromyographic (EMG) was used to obtain temporospatial gait parameters, lower extremity kinematics, and muscle activity in ambulatory individuals with SCI and healthy adults. RESULTS: Temporospatial parameters and kinematics for participants with SCI (n = 12; age 41.4±12.5 years) with and without RE were significantly different than a typical gait (healthy adults: n = 15; age 26.2±8.3 years). EMG amplitudes during the stance phase of a typical gait were similar to those with SCI with and without RE, except the right rectus femoris (p = 0.005) and left gluteus medius (p = 0.014) when participants with SCI walked with RE. EMG amplitudes of participants with SCI during the swing phase were significantly greater compared to those of a typical gait, except for left medial hamstring with (p = 0.025) and without (p = 0.196) RE. CONCLUSIONS: First-time walking in a RE does not appear to produce a typical gait pattern in people with incomplete SCI.

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