scholarly journals Lower-limb muscle function is influenced by changing mechanical demands in cycling

2020 ◽  
pp. jeb.228221
Author(s):  
Adrian K. M. Lai ◽  
Taylor J. M. Dick ◽  
Nicholas A. T. Brown ◽  
Andrew A. Biewener ◽  
James M. Wakeling
Keyword(s):  
Lower Limb ◽  
Muscle Activity ◽  
Muscle Function ◽  
Muscle Activation ◽  
Functional Index ◽  
Lower Limb Muscles ◽  
Wide Range ◽  
Musculoskeletal Simulations ◽  
Contractile Performance

Although cycling is often considered a seemingly simple, reciprocal task, muscles must adapt their function to satisfy changes in mechanical demands induced by higher crank torques and faster pedalling cadences. We examined if muscle function was sensitive to these changes in mechanical demands across a wide range of pedalling conditions. We collected experimental data of cycling where crank torque and pedalling cadence were independently varied from 13-44 Nm and 60-140 RPM. These data were used in conjunction with musculoskeletal simulations and a recently developed functional index-based approach to characterise the role of the human lower-limb muscles. We found that in muscles that generate most of the mechanical power and work during cycling, greater crank torque induced shifts towards greater muscle activation, greater positive muscle-tendon unit (MTU) work and a more motor-like function, particularly in the limb extensors. Conversely, with faster pedalling cadence, the same muscles exhibited a phase advance in muscle activity prior to crank top dead centre, which led to greater negative MTU power and work and shifted the muscles to contract with more spring-like behaviour. Our results illustrate the capacity for muscles to adapt their function to satisfy the mechanical demands of the task, even during highly constrained reciprocal tasks such as cycling. Understanding how muscles shift their contractile performance under varied mechanical and environmental demands may inform decisions on how to optimise pedalling performance and to design targeted cycling rehabilitation therapies for muscle-specific injuries or deficits.

Deficits in anticipatory inhibition of postural muscle activity associated with load release while standing in individuals with spastic diplegic cerebral palsy

2013 ◽  
Vol 109 (8) ◽  
pp. 1996-2006 ◽  
Author(s):  
Hidehito Tomita ◽  
Yoshiki Fukaya ◽  
Kenji Totsuka ◽  
Yuri Tsukahara
Keyword(s):  
Cerebral Palsy ◽  
Lower Limb ◽  
Muscle Activity ◽  
Erector Spinae ◽  
Lower Limbs ◽  
Control Group ◽  
Lower Limb Muscles ◽  
Limb Muscles ◽  
Postural Muscle ◽  
Load Release

This study aimed to determine whether individuals with spastic diplegic cerebral palsy (SDCP) have deficits in anticipatory inhibition of postural muscle activity. Nine individuals with SDCP (SDCP group, 3 female and 6 male, 13–24 yr of age) and nine age- and sex-matched individuals without disability (control group) participated in this study. Participants stood on a force platform, which was used to measure the position of the center of pressure (CoP), while holding a light or heavy load in front of their bodies. They then released the load by abducting both shoulders. Surface electromyograms were recorded from the rectus abdominis, erector spinae (ES), rectus femoris (RF), medial hamstring (MH), tibialis anterior (TA), and gastrocnemius (GcM) muscles. In the control group, anticipatory inhibition before load release and load-related modulation of the inhibition were observed in all the dorsal muscles recorded (ES, MH, and GcM). In the SDCP group, similar results were obtained in the trunk muscle (ES) but not in the lower limb muscles (MH and GcM), although individual differences were seen, especially in MH. Anticipatory activation of the ventral lower limb muscles (RF and TA) and load-related modulation of the activation were observed in both participant groups. CoP path length during load release was longer in the SDCP group than in the control group. The present findings suggest that individuals with SDCP exhibit deficits in anticipatory inhibition of postural muscles at the dorsal part of the lower limbs, which is likely to result in a larger disturbance of postural equilibrium.

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 Activity of Surface Electromyographic Signal of Selected Muscles during Classic Rehabilitation Exercise

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Jinzhuang Xiao ◽  
Jinli Sun ◽  
Junmin Gao ◽  
Hongrui Wang ◽  
Xincai Yang
Keyword(s):  
Lower Limb ◽  
Muscle Activity ◽  
Activity Level ◽  
Core Stability ◽  
Median Frequency ◽  
Low Back ◽  
Lower Limb Muscles ◽  
Significant Difference ◽  
Limb Muscles ◽  
Rehabilitation Exercises

Objectives. Prone bridge, unilateral bridge, supine bridge, and bird-dog are classic rehabilitation exercises, which have been advocated as effective ways to improve core stability among healthy individuals and patients with low back pain. The aim of this study was to investigate the activity of seven selected muscles during rehabilitation exercises through the signal of surface electromyographic. Approaches. We measured the surface electromyographic signals of four lower limb muscles, two abdominal muscles, and one back muscle during rehabilitation exercises of 30 healthy students and then analyzed its activity level using the median frequency method. Results. Different levels of muscle activity during the four rehabilitation exercises were observed. The prone bridge and unilateral bridge caused the greatest muscle fatigue; however, the supine bridge generated the lowest muscle activity. There was no significant difference (P>0.05) between left and right body side muscles in the median frequency slope during the four rehabilitation exercises of seven muscles. Conclusions. The prone bridge can affect the low back and lower limb muscles of most people. The unilateral bridge was found to stimulate muscles much more active than the supine bridge. The bird-dog does not cause much fatigue to muscles but can make most selected muscles active.

scholarly journals Effect of Parkinson’s disease and two therapeutic interventions on muscle activity during walking: a systematic review

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Aisha Islam ◽  
Lisa Alcock ◽  
Kianoush Nazarpour ◽  
Lynn Rochester ◽  
Annette Pantall
Keyword(s):  
Parkinson’S Disease ◽  
Motor Activity ◽  
Lower Limb ◽  
Muscle Activity ◽  
Therapeutic Interventions ◽  
Gait Impairment ◽  
Dopaminergic Medication ◽  
Lower Limb Muscles ◽  
Limb Muscles ◽  
Functional Gait

Abstract Gait deficits are a common feature of Parkinson’s disease (PD) and predictors of future motor and cognitive impairment. Understanding how muscle activity contributes to gait impairment and effects of therapeutic interventions on motor behaviour is crucial for identifying potential biomarkers and developing rehabilitation strategies. This article reviews sixteen studies that investigate the electromyographic (EMG) activity of lower limb muscles in people with PD during walking and reports on their quality. The weight of evidence establishing differences in motor activity between people with PD and healthy older adults (HOAs) is considered. Additionally, the effect of dopaminergic medication and deep brain stimulation (DBS) on modifying motor activity is assessed. Results indicated greater proximal and decreased distal activity of lower limb muscles during walking in individuals with PD compared to HOA. Dopaminergic medication was associated with increased distal lower limb muscle activity whereas subthalamic nucleus DBS increased activity of both proximal and distal lower limb muscles. Tibialis anterior was impacted most by the interventions. Quality of the studies was not strong, with a median score of 61%. Most studies investigated only distal muscles, involved small sample sizes, extracted limited EMG features and lacked rigorous signal processing. Few studies related changes in motor activity with functional gait measures. Understanding mechanisms underpinning gait impairment in PD is essential for development of personalised rehabilitative interventions. Recommendations for future studies include greater participant numbers, recording more functionally diverse muscles, applying multi-muscle analyses, and relating EMG to functional gait measures.

scholarly journals Characteristics of Lower Limb Muscle Activity in Elderly Persons After Ergometric Exercise

2020 ◽  
Vol 6 ◽  
pp. 233372142097980
Author(s):  
Kenichi Kaneko ◽  
Hitoshi Makabe ◽  
Kazuyuki Mito ◽  
Kazuyoshi Sakamoto ◽  
Yoshiya Kawanori ◽  
...  
Keyword(s):  
Lower Limb ◽  
Muscle Activity ◽  
The Elderly ◽  
Elderly Subjects ◽  
Elderly Persons ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Lower Limb Muscles ◽  
The Mean ◽  
Young Subjects

This study examined the characteristics of lower limb muscle activity in elderly persons after ergometric pedaling exercise for 1 month. To determine the effect of the exercise, surface electromyography (SEMG) of lower limb muscles was subjected to Daubechies-4 wavelet transformation, and mean wavelet coefficients were compared with the pre-exercise coefficients and the post-exercise coefficients in each wavelet level. The characteristics of muscle activity after pedaling exercise were also compared between the elderly subjects and young subjects. For the elderly subjects, the mean wavelet coefficients were significantly decreased in the tibialis anterior and the gastrocnemius medialis at wavelet levels of 3, 4, and 5 (125–62.5, 62.5–31.25, and 31.25–15.625 Hz, respectively), by pedaling exercise. However, the mean power of wavelet levels of 2 and 3 (250–125 and 125–62.5 Hz) within the rectus femoris and the biceps femoris were significantly increased in the young subjects. The effect of pedaling exercise is different from the effects of heavy-resistance training. It was suggested that the muscle coordination, motor unit (MU) firing frequency, and firing fiber type of lower limb muscles are changed with the different characteristics between elderly and young persons by pedaling exercise for 1 month.

Individual Muscle Control Using an Exoskeleton Robot for Muscle Function Testing

2009 ◽  
Author(s):  
Jun Ueda ◽  
Moiz Hyderabadwala ◽  
Ming Ding ◽  
Tsukasa Ogasawara ◽  
Vijaya Krishnamoorthy ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Muscle Function ◽  
Muscle Activation ◽  
Muscle Control ◽  
Wearable Robot ◽  
Activity Data ◽  
Individual Muscle ◽  
Exoskeleton Robot ◽  
Function Tests ◽  
Function Testing

A functionality test at the level of individual muscles by investigating the activity of a muscle of interest on various tasks may enable muscle-level force grading. This paper proposes a new method for muscle function tests using an exoskeleton robot for obtaining a wider variety of muscle activity data than standard motor tasks, e.g., pushing a handle by his/her hand. A computational algorithm systematically computes control commands to a wearable robot with actuators (an exoskeleton robot, or a power-assisting device) so that a desired muscle activation pattern for target muscle forces is induced. This individual muscle control method enables users (e.g., therapists) to efficiently conduct neuromuscular function tests for target muscles by arbitrarily inducing muscle activation patterns. Simulation results justify the use of an exoskeleton robot for muscle function testing in terms of the variety of muscle activity data.

scholarly journals A systematic review of the effect of footwear, foot orthoses and taping on lower limb muscle activity during walking and running

2019 ◽  
Vol 43 (6) ◽  
pp. 576-596 ◽  
Author(s):  
Joanna Reeves ◽  
Richard Jones ◽  
Anmin Liu ◽  
Leah Bent ◽  
Emma Plater ◽  
...  
Keyword(s):  
Lower Limb ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Frontal Plane ◽  
Triceps Surae ◽  
Tibialis Posterior ◽  
Foot Orthoses ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Therapeutic Benefits

Background: External devices are used to manage musculoskeletal pathologies by altering loading of the foot, which could result in altered muscle activity that could have therapeutic benefits. Objectives: To establish if evidence exists that footwear, foot orthoses and taping alter lower limb muscle activity during walking and running. Study design: Systematic literature review. Methods: CINAHL, MEDLINE, ScienceDirect, SPORTDiscus and Web of Science databases were searched. Quality assessment was performed using guidelines for assessing healthcare interventions and electromyography methodology. Results: Thirty-one studies were included: 22 related to footwear, eight foot orthoses and one taping. In walking, (1) rocker footwear apparently decreases tibialis anterior activity and increases triceps surae activity, (2) orthoses could decrease activity of tibialis posterior and increase activity of peroneus longus and (3) other footwear and taping effects are unclear. Conclusion: Modifications in shoe or orthosis design in the sagittal or frontal plane can alter activation in walking of muscles acting primarily in these planes. Adequately powered research with kinematic and kinetic data is needed to explain the presence/absence of changes in muscle activation with external devices. Clinical relevance This review provides some evidence that foot orthoses can reduce tibialis posterior activity, potentially benefitting specific musculoskeletal pathologies.

Role of the coordinated activities of trunk and lower limb muscles during the landing-to-jump movement

2011 ◽  
Vol 112 (6) ◽  
pp. 2223-2232 ◽  
Author(s):  
Yoshiaki Iida ◽  
Hiroaki Kanehisa ◽  
Yuki Inaba ◽  
Kimitaka Nakazawa
Keyword(s):  
Lower Limb ◽  
Lower Limb Muscles ◽  
Limb Muscles
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