scholarly journals Effects of Future Information and Trajectory Complexity on Kinematic Signal and Muscle Activation during Visual-Motor Tracking

Entropy ◽  
2021 ◽  
Vol 23 (1) ◽  
pp. 111
Author(s):  
Linchuan Deng ◽  
Jie Luo ◽  
Yueling Lyu ◽  
Rong Song
Keyword(s):  
Elbow Joint ◽  
Muscle Activation ◽  
Feedforward Control ◽  
Approximate Entropy ◽  
Task Demands ◽  
Tracking Performance ◽  
P Value ◽  
Visual Motor ◽  
Tracking Movement ◽  
Future Information

Visual-motor tracking movement is a common and essential behavior in daily life. However, the contribution of future information to visual-motor tracking performance is not well understood in current research. In this study, the visual-motor tracking performance with and without future-trajectories was compared. Meanwhile, three task demands were designed to investigate their impact. Eighteen healthy young participants were recruited and instructed to track a target on a screen by stretching/flexing their elbow joint. The kinematic signals (elbow joint angle) and surface electromyographic (EMG) signals of biceps and triceps were recorded. The normalized integrated jerk (NIJ) and fuzzy approximate entropy (fApEn) of the joint trajectories, as well as the multiscale fuzzy approximate entropy (MSfApEn) values of the EMG signals, were calculated. Accordingly, the NIJ values with the future-trajectory were significantly lower than those without future-trajectory (p-value < 0.01). The smoother movement with future-trajectories might be related to the increasing reliance of feedforward control. When the task demands increased, the fApEn values of joint trajectories increased significantly, as well as the MSfApEn of EMG signals (p-value < 0.05). These findings enrich our understanding about visual-motor control with future information.

scholarly journals Elbow Joint Fatigue and Bench-Press Training

2014 ◽  
Vol 49 (3) ◽  
pp. 317-321 ◽  
Author(s):  
Yen-Po Huang ◽  
You-Li Chou ◽  
Feng-Chun Chen ◽  
Rong-Tyai Wang ◽  
Ming-Jer Huang ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Upper Extremity ◽  
Athletic Training ◽  
Cycle Time ◽  
Elbow Joint ◽  
Muscle Activation ◽  
Bench Press ◽  
Lateral Force ◽  
Joint Force ◽  
Muscle Strengthening

Context: Bench-press exercises are among the most common form of training exercise for the upper extremity because they yield a notable improvement in both muscle strength and muscle endurance. The literature contains various investigations into the effects of different bench-press positions on the degree of muscle activation. However, the effects of fatigue on the muscular performance and kinetics of the elbow joint are not understood fully. Objective: To investigate the effects of fatigue on the kinetics and myodynamic performance of the elbow joint in bench-press training. Design: Controlled laboratory study. Setting: Motion research laboratory. Patients or Other Participants: A total of 18 physically healthy male students (age = 19.6 ± 0.8 years, height = 168.7 ± 5.5 cm, mass = 69.6 ± 8.6 kg) participated in the investigation. All participants were right-hand dominant, and none had a history of upper extremity injuries or disorders. Intervention(s): Participants performed bench-press training until fatigued. Main Outcome Measure(s): Maximal possible number of repetitions, cycle time, myodynamic decline rate, elbow-joint force, and elbow-joint moment. Results: We observed a difference in cycle time in the initial (2.1 ± 0.42 seconds) and fatigue (2.58 ± 0.46 seconds) stages of the bench-press exercise (P = .04). As the participants fatigued, we observed an increase in the medial-lateral force (P = .03) and internal-external moment (P ≤ .04) acting on the elbow joint. Moreover, a reduction in the elbow muscle strength was observed in the elbow extension-flexion (P ≤ .003) and forearm supination-pronation (P ≤ .001) conditions. Conclusions: The results suggest that performing bench-press exercises to the point of fatigue increases elbow-joint loading and may further increase the risk of injury. Therefore, when clinicians design bench-press exercise regimens for general athletic training, muscle strengthening, or physical rehabilitation, they should control carefully the maximal number of repetitions.

Older Adults Use a Unique Strategy to Lift Inertial Loads With the Elbow Flexor Muscles

2000 ◽  
Vol 83 (4) ◽  
pp. 2030-2039 ◽  
Author(s):  
Andrew E. Graves ◽  
Kurt W. Kornatz ◽  
Roger M. Enoka
Keyword(s):  
Young Adults ◽  
Elbow Joint ◽  
Muscle Activation ◽  
Angular Displacement ◽  
Elbow Flexor ◽  
Lengthening Contractions ◽  
Old Adults ◽  
Flexor Muscles ◽  
Elbow Flexor Muscles ◽  
Target Force

The purpose of this study was to determine the effect of age on the ability to exert steady forces and to perform steady flexion movements with the muscles that cross the elbow joint. An isometric task required subjects to exert a steady force to match a target force that was displayed on a monitor. An anisometric task required subjects to raise and lower inertial loads so that the angular displacement around the elbow joint matched a template displayed on a monitor. Steadiness was measured as the coefficient of variation of force and as the normalized standard deviation of wrist acceleration. For the isometric task, steadiness as a function of target force decreased similarly for old adults and young adults. For the anisometric task, steadiness increased as a function of the inertial load and there were significant differences caused by age. Old adults were less steady than young adults during both shortening and lengthening contractions with the lightest loads. Furthermore, old adults were least steady when performing lengthening contractions. These behaviors appear to be associated with the patterns of muscle activation. These results suggest that different neural strategies are used to control isometric and anisometric contractions performed with the elbow flexor muscles and that these strategies do not change in parallel with advancing age.

scholarly journals Fatigue reduces the complexity of knee extensor torque during fatiguing sustained isometric contractions

2018 ◽  
Author(s):  
Jamie Pethick ◽  
Mark Burnley ◽  
Samantha Lee Winter
Keyword(s):  
Temporal Structure ◽  
Femoral Nerve ◽  
Knee Extensor ◽  
Approximate Entropy ◽  
Task Demands ◽  
Peripheral Fatigue ◽  
Knee Extensors ◽  
Fluctuation Analysis ◽  
Isometric Contractions ◽  
Scaling Exponent

The temporal structure, or complexity, of muscle torque output reflects the adaptability of motor control to changes in task demands. This complexity is reduced by neuromuscular fatigue during intermittent isometric contractions. We tested the hypothesis that sustained fatiguing isometric contractions would result in a similar loss of complexity. To that end, nine healthy participants performed, on separate days, sustained isometric contractions of the knee extensors at 20% MVC to task failure and at 100% MVC for 60 seconds. Torque and surface EMG signals were sampled continuously. Complexity and fractal scaling were quantified by calculating approximate entropy (ApEn) and the detrended fluctuation analysis (DFA) α scaling exponent. Global, central and peripheral fatigue were quantified using maximal voluntary contractions (MVCs) with femoral nerve stimulation. Fatigue reduced the complexity of both submaximal (ApEn from 1.02 ± 0.06 to 0.41 ± 0.04, P &lt; 0.05) and maximal contractions (ApEn from 0.34 ± 0.05 to 0.26 ± 0.04, P &lt; 0.05; DFA α from 1.41 ± 0.04 to 1.52 ± 0.03, P &lt; 0.05). The losses of complexity were accompanied by significant global, central and peripheral fatigue (all P &lt; 0.05). These results demonstrate that a fatigue-induced loss of torque complexity is evident not only during fatiguing intermittent isometric contractions, but also during sustained fatiguing contractions.

scholarly journals THE EFFECT OF CO-OP APPROACH IN IMPROVING VISUAL MOTOR INTEGRATION SKILLS IN CHILDREN WITH LEARNING DISABILITY

2021 ◽  
Vol 9 (08) ◽  
pp. 716-722
Author(s):  
Sheetal S. Gupta ◽  
◽  
Pritam V. Mehta ◽  
Keyword(s):  
Visual Perception ◽  
Learning Disability ◽  
Motor Coordination ◽  
Autism Spectrum ◽  
Global Strategy ◽  
P Value ◽  
Occupational Performance ◽  
Visual Motor Integration ◽  
Significant Difference ◽  
Visual Motor

The importance of visual perception, motor coordination and visual motor integration (VMI) skills for school achievements has been shown in various studies. Cognitive orientation to daily occupational performance or CO-OP is an evidence-based approach that has been effective in children with developmental coordination disorder and autism spectrum. The present study evaluated the effect of CO-OP approach in improving VMI skills in children with learning disability. Sample of 58 children were included in the study. National Centre for Learning Disabilities (NCLD) Checklist was used as a screen tool and pre and post intervention Beery VMI and Canadian Occupational Performance Measures (COPM) was used as outcome measures.Occupational therapy program using CO-OP approach, based on each childs individualized goals. children were thought global strategy of GO-PLAN-DO-CHECK the sessions were conducted for 12 weeks one hour a day three times a week. After 12 weeks post assessment was done using t test. There significant difference in pre and post CO-OP intervention. p-value was found to be less than 0.0001 for VMI, COPM performance and satisfaction whereas, there was significant difference in motor coordination and visual perception component of Beery VMI. The result shows that CO-OP approach is effective in improving visual motor integration skills of children with learning disability.

scholarly journals Active Passive Nature of Assistive Wearable Gait Augment Suit for Enhanced Mobility

2018 ◽  
Vol 30 (5) ◽  
pp. 717-728 ◽  
Author(s):  
Chetan Thakur ◽  
Kazunori Ogawa ◽  
Yuichi Kurita ◽  
◽  
◽  
...  
Keyword(s):  
Lower Limb ◽  
Muscle Activation ◽  
Feedforward Control ◽  
Surface Emg ◽  
Walking Gait ◽  
Lower Limb Muscles ◽  
Air Supply ◽  
Pilot Trials ◽  
Pneumatic Valves ◽  
Enhanced Mobility

In this paper we discuss the active and passive nature of the assistive wearable gait augment suit (AWGAS). AWGAS is a soft, wearable, lightweight, and assists walking gait by reducing muscle activation during walking. It augments walking by reducing the muscle activation of the posterior and anterior muscles of the lower limb. The suit uses pneumatic gel muscles (PGM), foot sensors for gait detection, and pneumatic valves to control the air pressure. The assistive force is provided using the motion in loop feedforward control loop using foot sensors in shoes. PGMs are actuated with the help of pneumatic valves and portable air tanks. The elastic nature of the PGM allows AWGAS to assist walking in the absence of the air supply which makes AWGAS both active and passive walking assist suit. To evaluate the active and passive nature of the AWGAS, we experimented to measure surface EMG (sEMG) of the lower limb muscles. sEMG was recorded for unassisted walking, i.e., without the suit, passive assisted walking, i.e., wearing the suit with no air supply and active assisted walking, i.e., wearing the suit with air supply set at 60 kPa. The results shows reduction in the muscle activity for both passive and active assisted walking as compared to unassisted walking. The pilot trials of the AWGAS were conducted in collaboration with local farmers in the Hiroshima prefecture in Japan where feedback received is complementing the results obtained during the experiments.

scholarly journals The Effects of Elbow Joint Angle Change on the Elbow Flexor Muscle Activation in Pulley with Weight Exercise

2013 ◽  
Vol 25 (9) ◽  
pp. 1133-1136 ◽  
Author(s):  
Taewook Kang ◽  
Youngjoon Seo ◽  
Jaehoon Park ◽  
Eunseok Dong ◽  
Byungdo Seo ◽  
...  
Keyword(s):  
Elbow Joint ◽  
Muscle Activation ◽  
Joint Angle ◽  
Elbow Flexor ◽  
Flexor Muscle ◽  
Angle Change

scholarly journals Trunk Control during Gait: Walking with Wide and Narrow Step Widths Present Distinct Challenges

2020 ◽  
Author(s):  
Hai-Jung Steffi Shih ◽  
James Gordon ◽  
Kornelia Kulig
Keyword(s):  
Muscle Activation ◽  
Center Of Mass ◽  
Frontal Plane ◽  
Feedback System ◽  
Transverse Plane ◽  
Task Demands ◽  
Step Width ◽  
Trunk Control ◽  
Vector Coding ◽  
Trunk Kinematics

AbstractThe active control of the trunk plays an important role in frontal plane gait stability. We characterized trunk control in response to different step widths using a novel feedback system and examined the different effects of wide and narrow step widths as they each present unique task demands. Twenty healthy young adults walked on a treadmill at 1.25 m/s at five prescribed step widths: 0.33, 1.67, 1, 1.33, 1.67 times preferred step width. Motion capture was used to record trunk kinematics, and surface electromyography was used to record longissimus muscle activation bilaterally. Vector coding was used to analyze coordination between pelvis and thorax segments of the trunk. Results showed that while center of mass only varied across step width in the mediolateral direction, trunk kinematics in all three planes were affected by changes in step width. Angular excursions of the trunk segments increased only with wider widths in the transverse plane. Thorax-pelvis kinematic coordination was affected more by wider widths in transverse plane and by narrower widths in the frontal plane. Peak longissimus activation and bilateral co-activation increased as step widths became narrower. As a control task, walking with varied step widths is not simply a continuum of adjustments from narrow to wide. Rather, narrowing step width and widening step width from the preferred width represent distinct control challenges that are managed in different ways. This study provides foundation for future investigations on the trunk during gait in different populations.

Sign in / Sign up

Export Citation Format

Share Document