scholarly journals Visual feedback during pedaling allows individuals poststroke to alter inappropriately prolonged paretic vastus medialis activity

2018 ◽  
Vol 119 (6) ◽  
pp. 2334-2346 ◽  
Author(s):  
Christopher H. Mullens ◽  
David A. Brown
Keyword(s):  
Visual Feedback ◽  
Muscle Activity ◽  
Past Research ◽  
Vastus Medialis ◽  
Behavioral Context ◽  
Target Region ◽  
Paretic Limb ◽  
Significant Difference ◽  
Clinical Impairment ◽  
Muscle Phasing

Individuals who have experienced a stroke often demonstrate inappropriate muscle activity phasing in the paretic leg during locomotion. Past research has demonstrated that inappropriate paretic phasing varies between behavioral contexts and is reduced during unilateral pedaling with the nonparetic leg inactive. We investigated whether individuals could voluntarily alter activity in a target muscle of the paretic limb in a consistent behavioral context and whether this voluntary change differed between bilateral and unilateral pedaling. During a fixed-speed motorized pedaling task, participants were asked to use visual feedback to deactivate the vastus medialis (VM) before a 90° target region of the pedaling cycle, as measured by surface electromyography and by change in fraction of total cycle amplitude in the target region. We based the start of this target region on the earliest observed deactivation for this muscle (found in fast pedaling), which allowed us to challenge both the paretic and nonparetic VM. During visual feedback, participants significantly reduced the fraction of activity found in the target region, with no significant difference in degree of reduction between paretic and nonparetic legs or between bilateral and unilateral pedaling. Surprisingly, in bilateral pedaling, individuals with greater clinical impairment demonstrated greater paretic limb response to feedback. Our results demonstrated that during this tightly constrained task, the paretic VM showed a surprisingly similar flexibility of muscle activity to the nonparetic VM. Our findings show that participants were able to use provided visual feedback to modulate the degree of an observed poststroke muscle-phasing impairment.NEW & NOTEWORTHY This study demonstrates that by using visual feedback during a constrained task with minimized kinematic control requirements, participants with poststroke hemiplegia can voluntarily change muscle activity phase in the vastus medialis. Surprisingly, we did not observe a significant difference in ability to alter phasing between paretic and nonparetic legs or between bilateral and unilateral pedaling. In this visual feedback task, participants appear to modify muscle activity well in both the paretic and nonparetic legs.

Impaired muscle phasing systematically adapts to varied relative angular relationships during locomotion in people poststroke

2011 ◽  
Vol 105 (4) ◽  
pp. 1660-1670 ◽  
Author(s):  
Laila Alibiglou ◽  
David A. Brown
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Activity Patterns ◽  
Spatial Relationship ◽  
Rectus Femoris ◽  
Vastus Medialis ◽  
Muscle Coordination ◽  
Muscle Activation Patterns ◽  
Relative Contribution ◽  
Muscle Phasing

After stroke, hemiparesis will result in impairments to locomotor control. Specifically, muscle coordination deficits, in the form of inappropriately phased muscle-activity patterns, occur in both the paretic and nonparetic limbs. These dysfunctional paretic muscle-coordination patterns can adapt to somatosensory inputs, and also the sensorimotor state of nonparetic limb can influence paretic limb. However, the relative contribution of interlimb pathways for improving paretic muscle-activation patterns in terms of phasing remains unknown. In this study, we investigated whether the paretic muscle-activity phasing can be influenced by the relative angular-spatial relationship of the nonparetic limb by using a split-crank ergometer, where the cranks could be decoupled. Eighteen participants with chronic stroke were asked to pedal bilaterally during each task while surface electromyogram signals were recorded bilaterally from four lower extremity muscles (vastus medialis, rectus femoris, tibialis anterior, and soleus). During each experiment, the relative angular crank positions were manipulated by increasing or decreasing their difference by randomly ordered increments of 30° over the complete cycle [0° (in phase pedaling), 30°, 60°, 90°, 120°, 150°, 180° (standard pedaling), 210°, 240°, 270°, 300°, 330° (out of phase pedaling)]. We found that the paretic and nonparetic muscle phasing in the cycle systematically adapted to varied relative angular relationships, and this systematic relationship was well modeled by a sinusoidal relationship. Also, the paretic uniarticular muscle (vastus medialis) showed larger phase shifts compared with biarticular muscle (rectus femoris). More importantly, for each stroke subject, we demonstrated an exclusive crank-angular relation that resulted in the generation of more appropriately phased paretic muscle activity. These findings provide new evidence to better understand the capability of impaired nervous system to produce a more normalized muscle-phasing pattern poststroke.

scholarly journals HEART RATE AND LOWER LIMB MUSCLE ACTIVITY ON CYCLE ERGOMETER

2020 ◽  
Vol 26 (6) ◽  
pp. 487-492
Author(s):  
Paulo Rui de Oliveira ◽  
Robson Dias Scoz ◽  
Bruno Mazziotti Oliveira Alves ◽  
Thiago Rosa de Mesquita ◽  
Rubens Alexandre da Silva Junior ◽  
...  
Keyword(s):  
Heart Rate ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Rectus Femoris ◽  
Cycle Ergometer ◽  
Lower Limbs ◽  
Vastus Medialis ◽  
Emg Signal ◽  
Significant Difference ◽  
Rate Behavior

ABSTRACT Introduction: Muscle activity in the pedal stroke movement on a cycle ergometer can be measured by surface electromyography, as an effective and improved method for studying muscle action and objectively determining the different action potentials of the muscles involved in specific movements. Heart rate behavior is an important factor during exercise with load. Objective: To identify heart rate behavior and pattern of muscle activity of the rectus femoris and vastus medialis in healthy subjects in the pedaling dynamic at different loads, submaximal test, on an instrumented cycle ergometer. Methods: 20 healthy adults were evaluated. Heart rate measurement was performed, together with electromyographic analysis, in the time domain, of the rectus femoris and vastus medialis muscles during incremental exercise of the lower limbs on the cycle ergometer. Results: Heart rate behavior presented significant difference for p≥0.05 in relation to increased loads. The EMG signal intensity from the vastus medialis muscle (normalized RMS value) in each quadrant of the pedaling cycle showed significant difference for p≥0.05 in relation to quadrants I, II and IV and significant difference for p≥0.05 in relation to quadrants III and IV. In the rectus femoris (RF) muscle, there was significant difference for p≥0.05 in relation to quadrants I, II and IV and significant difference for p≥0.05 in relation to quadrants I, II and III. Conclusion: An increase in heart rate proportional to the increase in load was observed, as well as an increase in the amplitude of the electromyographic signal proportional to the increase in load. It was possible to identify the pattern of muscle activation in the studied quadrants during pedal stroke movements, independent of load. Level of evidence III; Study of non-consecutive patients; without uniform application of the “gold” standard reference.

scholarly journals Electromyography Assessments of the Vastus Medialis Muscle during Soccer Instep Kicking between Dynamic and Static Stretching

2010 ◽  
Vol 24 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Mohammadtaghi Amiri-Khorasani ◽  
Noor Osman ◽  
Ashril Yusof
Keyword(s):  
Muscle Activity ◽  
High Speed ◽  
Soccer Players ◽  
Vastus Medialis ◽  
Static Stretching ◽  
Warm Up ◽  
Dynamic Stretching ◽  
Significant Difference ◽  
Ball Velocity ◽  
Vastus Medialis Muscle

Electromyography Assessments of the Vastus Medialis Muscle during Soccer Instep Kicking between Dynamic and Static StretchingThe purpose of this study was to examine the effects of static and dynamic stretching within a pre-exercise warm-up on vastus medialis muscle activity during instep kicking and ball velocity in soccer players. The kicking motions of dominant legs were captured from using six synchronized high-speed infra-red cameras at 200 Hz and Electromyography at 100 Hz. There was significant difference in vastus medialis activity after dynamic stretching relative to no stretching condition (0.12 ± 0.06 mV) versus static stretching relative to no stretching condition (-0.21 ± 0.10 mV) with p < 0.001). In addition, there was also a significant difference in ball velocity after dynamic stretching relative to no stretching condition (4.53 ± 2.10 m/s) versus static stretching relative to no stretching condition (-1.48 ± 2.43 m/s) with p < 0.003. We concluded that dynamic stretching during the warm-up, as compared to static stretching, is probably more effective as preparation for optimal muscle activity and finally have high ball velocity which is required in soccer.

scholarly journals Testing telediagnostic thyroid ultrasound in Peru: a new horizon in expanding access to imaging in rural and underserved areas

2021 ◽  
Author(s):  
T. J. Marini ◽  
S. L. Weiss ◽  
A. Gupta ◽  
Y. T. Zhao ◽  
T. M. Baran ◽  
...  
Keyword(s):  
Thyroid Nodule ◽  
Standard Of Care ◽  
The United States ◽  
Epidemiological Studies ◽  
Thyroid Ultrasound ◽  
Target Region ◽  
Experienced Radiologist ◽  
Significant Difference ◽  
Size Evaluation

Abstract Purpose Thyroid ultrasound is a key tool in the evaluation of the thyroid, but billions of people around the world lack access to ultrasound imaging. In this study, we tested an asynchronous telediagnostic ultrasound system operated by individuals without prior ultrasound training which may be used to effectively evaluate the thyroid and improve access to imaging worldwide. Methods The telediagnostic system in this study utilizes volume sweep imaging (VSI), an imaging technique in which the operator scans the target region with simple sweeps of the ultrasound probe based on external body landmarks. Sweeps are recorded and saved as video clips for later interpretation by an expert. Two operators without prior ultrasound experience underwent 8 h of training on the thyroid VSI protocol and the operation of the telemedicine platform. After training, the operators scanned patients at a health center in Lima. Telediagnostic examinations were sent to the United States for remote interpretation. Standard of care thyroid ultrasound was performed by an experienced radiologist at the time of VSI examination to serve as a reference standard. Results Novice operators scanned 121 subjects with the thyroid VSI protocol. Of these exams, 88% were rated of excellent image quality showing complete or near complete thyroid visualization. There was 98.3% agreement on thyroid nodule presence between VSI teleultrasound and standard of care ultrasound (Cohen’s kappa 0.91, P < 0.0001). VSI measured the thyroid size, on average, within 5 mm compared to standard of care. Readers of VSI were also able to effectively characterize thyroid nodules, and there was no significant difference in measurement of thyroid nodule size (P = 0.74) between VSI and standard of care. Conclusion Thyroid VSI telediagnostic ultrasound demonstrated both excellent visualization of the thyroid gland and agreement with standard of care thyroid ultrasound for nodules and thyroid size evaluation. This system could be deployed for evaluation of palpable thyroid abnormalities, nodule follow-up, and epidemiological studies to promote global health and improve the availability of diagnostic imaging in underserved communities.

Adaptors and Innovators: Selection versus Induction

1991 ◽  
Vol 68 (3_suppl) ◽  
pp. 1283-1290 ◽  
Author(s):  
P. A. Holland ◽  
I. Bowskill ◽  
A. Bailey
Keyword(s):  
Cognitive Style ◽  
Past Research ◽  
Significant Shift ◽  
Occupational Groups ◽  
Significant Difference ◽  
The Mean ◽  
New Entrants ◽  
Innovative Cognitive Style ◽  
Over Time ◽  
Established Group

The hypothesis that predictable differences would exist between the mean cognitive style of new entrants and those of the longer serving “established” employees in certain departments while not in others was tested. Data from 99 employees from four departments of a large British pharmaceuticals company who completed the Kirton Adaption-Innovation Inventory provided results broadly in line with the expectations of adaption-innovation theory and past research. The mean innovative cognitive style of new entrants to adaptive departments regressed towards the mean of the establishment and the occupational mean over time. In departments where there was no initial significant difference between the mean cognitive style of the new entrants and the established group, no significant shift was shown over time. Implications of these findings are suggested. The data also indicated norms for two occupational groups where previously they did not exist.

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 Electromyographic activity from human laryngeal, pharyngeal, and submental muscles during swallowing

1999 ◽  
Vol 86 (5) ◽  
pp. 1663-1669 ◽  
Author(s):  
A. L. Perlman ◽  
P. M. Palmer ◽  
T. M. McCulloch ◽  
D. J. Vandaele
Keyword(s):  
Muscle Activity ◽  
Total Duration ◽  
Normal Subjects ◽  
Electromyographic Activity ◽  
Surface Electrodes ◽  
Submental Muscles ◽  
Temporal Relationships ◽  
Dependent Change ◽  
Significant Difference ◽  
High Level

The durations and temporal relationships of electromyographic activity from the submental complex, superior pharyngeal constrictor, cricopharyngeus, thyroarytenoid, and interarytenoid muscles were examined during swallowing of saliva and of 5- and 10-ml water boluses. Bipolar, hooked-wire electrodes were inserted into all muscles except for the submental complex, which was studied with bipolar surface electrodes. Eight healthy, normal, subjects produced five swallows of each of three bolus volumes for a total of 120 swallows. The total duration of electromyographic activity during the pharyngeal stage of the swallow did not alter with bolus condition; however, specific muscles did show a volume-dependent change in electromyograph duration and time of firing. Submental muscle activity was longest for saliva swallows. The interarytenoid muscle showed a significant difference in duration between the saliva and 10-ml water bolus. Finally, the interval between the onset of laryngeal muscle activity (thyroarytenoid, interarytenoid) and of pharyngeal muscle firing patterns (superior pharyngeal constrictor onset, cricopharyngeus offset) decreased as bolus volume increased. The pattern of muscle activity associated with the swallow showed a high level of intrasubject agreement; the presence of somewhat different patterns among subjects indicated a degree of population variance.

scholarly journals Effect of Isometric Hip Abduction on Foot and Ankle Muscle Activity and Medial Longitudinal Arch During Short-Foot Exercise in Individuals With Pes Planus

2020 ◽  
pp. 1-7
Author(s):  
Jung-Hoon Choi ◽  
Heon-Seock Cynn ◽  
Chung-Hwi Yi ◽  
Tae-Lim Yoon ◽  
Seung-Min Baik
Keyword(s):  
Muscle Activity ◽  
Statistical Significance ◽  
Standing Position ◽  
Medial Longitudinal Arch ◽  
Joint Stability ◽  
Abductor Hallucis ◽  
Pes Planus ◽  
Longitudinal Arch ◽  
Significant Difference ◽  
Hip Abduction

Context: The improvement of hip joint stability can significantly impact knee and rearfoot mechanics. Individuals with pes planus have a weak abductor hallucis (AbdH), and the tibialis anterior (TA) may activate to compensate for this. As yet, no studies have applied isometric hip abduction (IHA) for hip stability during short-foot exercise (SFE). Objective: To compare the effects of IHA on the muscle activity of the AbdH, TA, peroneus longus (PL), and gluteus medius (Gmed), as well as the medial longitudinal arch (MLA) angle during sitting and standing SFE. Design: Two-way repeated analyses of variance were used to determine the statistical significance of AbdH, TA, PL, and Gmed electromyography activity, as well as the change in MLA angle. Setting: University research laboratory. Participants: Thirty-two participants with pes planus. Intervention(s): The participants performed SFE with and without isometric hip abduction in sitting and standing positions. Main Outcome Measures: Surface electromyography was used to measure the activity of the AbdH, TA, PL, and Gmed muscles, and Image J was used to measure the MLA angle. Results: Significant interactions between exercise type and position were observed in terms of the PL muscle activity and in the change in MLA angle only, while other muscles showed significant main effects. The IHA during SFE significantly increased the AbdH muscle activity, while the TA muscle activity was significantly lower. The muscle activity of Gmed and PL was significantly increased in the standing position compared with sitting, but there was no significant difference with or without IHA. The change in the MLA angle was significantly greater in SFE with IHA in a standing position than in the other SFE conditions. Conclusions: IHA may be an effective method for reducing compensatory TA activity and increasing AbdH muscle activity during SFE for individuals with pes planus.

scholarly journals Influence of virtual reality visual feedback on the illusion of movement induced by tendon vibration of wrist in healthy participants

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242416
Author(s):  
Salomé Le Franc ◽  
Mathis Fleury ◽  
Mélanie Cogne ◽  
Simon Butet ◽  
Christian Barillot ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Visual Feedback ◽  
Visual Cues ◽  
Static Condition ◽  
Likert Scale ◽  
Tendon Vibration ◽  
Virtual Hand ◽  
Significant Difference ◽  
Illusory Movement ◽  
Healthy Participants

Introduction Illusion of movement induced by tendon vibration is an effective approach for motor and sensory rehabilitation in case of neurological impairments. The aim of our study was to investigate which modality of visual feedback in Virtual Reality (VR) associated with tendon vibration of the wrist could induce the best illusion of movement. Methods We included 30 healthy participants in the experiment. Tendon vibration inducing illusion of movement (wrist extension, 100Hz) was applied on their wrist during 3 VR visual conditions (10 times each): a moving virtual hand corresponding to the movement that the participants could feel during the tendon vibration (Moving condition), a static virtual hand (Static condition), or no virtual hand at all (Hidden condition). After each trial, the participants had to quantify the intensity of the illusory movement on a Likert scale, the subjective degree of extension of their wrist and afterwards they answered a questionnaire. Results There was a significant difference between the 3 visual feedback conditions concerning the Likert scale ranking and the degree of wrist’s extension (p<0.001). The Moving condition induced a higher intensity of illusion of movement and a higher sensation of wrist’s extension than the Hidden condition (p<0.001 and p<0.001 respectively) than that of the Static condition (p<0.001 and p<0.001 respectively). The Hidden condition also induced a higher intensity of illusion of movement and a higher sensation of wrist’s extension than the Static condition (p<0.01 and p<0.01 respectively). The preferred condition to facilitate movement’s illusion was the Moving condition (63.3%). Conclusions This study demonstrated the importance of carefully selecting a visual feedback to improve the illusion of movement induced by tendon vibration, and the increase of illusion by adding VR visual cues congruent to the illusion of movement. Further work will consist in testing the same hypothesis with stroke patients.

Validation and comparison of trunk muscle activities in male participants during exercise using an innovative device and abdominal bracing maneuvers

2021 ◽  
pp. 1-8
Author(s):  
Yuki Kurokawa ◽  
Satoshi Kato ◽  
Satoru Demura ◽  
Kazuya Shinmura ◽  
Noriaki Yokogawa ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Voluntary Contraction ◽  
Trunk Muscle ◽  
Erector Spinae ◽  
Trunk Muscles ◽  
Activity Levels ◽  
Significant Difference ◽  
External Oblique ◽  
Internal Oblique

BACKGROUND: Abdominal bracing is effective in strengthening the trunk muscles; however, assessing performance can be challenging. We created a device for performing abdominal trunk muscle exercises. The effectiveness of this device has not yet been evaluated or compared OBJECTIVE: We aimed to quantify muscle activity levels during exercise using our innovative device and to compare them with muscle activation during abdominal bracing maneuvers. METHODS: This study included 10 men who performed abdominal bracing exercises and exercises using our device. We measured surface electromyogram (EMG) activities of the rectus abdominis (RA), external oblique, internal oblique (IO), and erector spinae (ES) muscles in each of the exercises. The EMG data were normalized to those recorded during maximal voluntary contraction (%EMGmax). RESULTS: During the bracing exercise, the %EMGmax of IO was significantly higher than that of RA and ES (p< 0.05), whereas during the exercises using the device, the %EMGmax of IO was significantly higher than that of ES (p< 0.05). No significant difference was observed in the %EMGmax of any muscle between bracing exercises and the exercises using the device (p= 0.13–0.95). CONCLUSIONS: The use of our innovative device results in comparable activation to that observed during abdominal bracing.

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