scholarly journals Identification of the Plant for Upright Stance in Humans: Multiple Movement Patterns From a Single Neural Strategy

2008 ◽  
Vol 100 (6) ◽  
pp. 3394-3406 ◽  
Author(s):  
Tim Kiemel ◽  
Alexander J. Elahi ◽  
John J. Jeka
Keyword(s):  
Muscle Activation ◽  
The Body ◽  
Visual Scene ◽  
Trunk Muscles ◽  
Emg Activity ◽  
Upright Stance ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Joint Torques ◽  
Intrinsic Stiffness

We determined properties of the plant during human upright stance using a closed-loop system identification method originally applied to human postural control by another group. To identify the plant, which was operationally defined as the mapping from muscle activation (rectified EMG signals) to body segment angles, we rotated the visual scene about the axis through the subject's ankles using a sum-of-sines stimulus signal. Because EMG signals from ankle muscles and from hip and lower trunk muscles showed similar responses to the visual perturbation across frequency, we combined EMG signals from all recorded muscles into a single plant input. Body kinematics were described by the trunk and leg angles in the sagittal plane. The phase responses of both angles to visual scene angle were similar at low frequencies and approached a difference of ∼150° at higher frequencies. Therefore we considered leg and trunk angles as separate plant outputs. We modeled the plant with a two-joint (ankle and hip) model of the body, a second-order low-pass filter from EMG activity to active joint torques, and intrinsic stiffness and damping at both joints. The results indicated that the in-phase (ankle) pattern was neurally generated, whereas the out-of-phase pattern was caused by plant dynamics. Thus a single neural strategy leads to multiple kinematic patterns. Moreover, estimated intrinsic stiffness in the model was insufficient to stabilize the plant.

scholarly journals Influence of Body Position on Shoulder and Trunk Muscle Activation During Resisted Isometric Shoulder External Rotation

2018 ◽  
Vol 10 (4) ◽  
pp. 355-360 ◽  
Author(s):  
David A. Krause ◽  
Lucas G. Dueffert ◽  
Jaclyn L. Postma ◽  
Eric T. Vogler ◽  
Amy J. Walsh ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Muscle Activation ◽  
External Rotation ◽  
Body Position ◽  
Trunk Muscle ◽  
Trunk Muscles ◽  
Emg Activity ◽  
Convenience Sample ◽  
Overhead Athletes ◽  
Significant Difference

Background: External rotation (ER) strengthening of the shoulder is an integral component of rehabilitative and preventative programs for overhead athletes. A variety of shoulder ER strengthening exercises are reported, including those intended to integrate the core musculature. The purpose of this study was to examine ER torque and electromyographic (EMG) activation of shoulder and trunk muscles while performing resisted isometric shoulder ER in 3 positions (standing, side lying, and side plank). Hypothesis: Significantly greater force and shoulder muscle activation would be generated while side lying given the inherent stability of the position, and greater trunk muscle activation would be generated in the less stable plank position. Study Design: Quasi-experimental repeated-measures study. Level of Evidence: Level 5. Methods: A convenience sample of 25 healthy overhead recreational athletes (9 men, 16 women) participated in this study. EMG electrodes were placed on the infraspinatus, posterior deltoid, middle trapezius, multifidi, internal obliques, and external obliques. EMG signals were normalized to a maximal isometric contraction. Participants performed resisted isometric ER in standing, side-lying, and side plank positions. Results were analyzed using a repeated-measures analysis of variance with post hoc Bonferroni corrections (α = 0.05). Results: There was no significant difference in ER torque between positions (α = 0.05). A significant difference in EMG activity of shoulder and trunk musculature between positions was found in 7 of the 8 muscles monitored. Significantly greater EMG activity in the infraspinatus, middle trapezius, and the nondominant external and internal obliques was found in the side plank position as compared with standing and side lying. Conclusion: While there was no difference in ER torque between the 3 exercise positions, EMG activity of the shoulder and trunk muscles was dependent on body position. Clinical Relevance: If a clinician is seeking to integrate trunk muscle activation while performing shoulder ER strengthening, the side plank position is preferred as compared with standing or side lying.

scholarly journals Activity of upper limb and trunk muscles during power walking

2015 ◽  
Vol 9 (2) ◽  
Author(s):  
Johann Peter Kuhtz-Buschbeck ◽  
Antonia Frendel
Keyword(s):  
Upper Limb ◽  
Muscle Activation ◽  
Erector Spinae ◽  
Trunk Muscles ◽  
Emg Activity ◽  
Normal Walking ◽  
Arm Swing ◽  
Temporal Muscle ◽  
Limb Muscles ◽  
Emg Patterns

<p>Background: Arm swing is deliberately emphasized during power walking, a popular aerobic fitness exercise. Electromyographic (EMG) activation curves of arm and shoulder muscles during power walking have not yet been examined. Aim: To describe the amount and pattern of EMG activity of upper limb muscles during power walking. Data are compared to normal walking and jogging. Method:  Twenty volunteers were examined on a treadmill at 6 km/h during (a) normal walking, (b) power walking, (c) jogging. EMG data were collected for the trapezius (TRAP), anterior (AD) and posterior deltoid (PD), biceps (BIC), triceps (TRI), latissimus dorsi (LD) and erector spinae (ES) muscles. Results:  Activity of four muscles (AD, BIC, PD, TRAP) was three- to fivefold stronger during power walking than normal walking. Smaller significant increases involved the TRI, LD and ES. Two muscles (AD, TRAP) were more active during power walking than running. Normal walking and power walking involved similar EMG patterns of PD, LD, ES, while EMG patterns of running and walking differed. Interpretation: Emphasizing arm swing during power walking triples the EMG activity of upper limb muscles, compared to normal walking. Similar basic temporal muscle activation patterns in both modes of walking indicate a common underlying motor program. </p>

scholarly journals Activity of upper limb and trunk muscles during power walking

2015 ◽  
Vol 9 (2) ◽  
Author(s):  
Johann Peter Kuhtz-Buschbeck ◽  
Antonia Frendel
Keyword(s):  
Upper Limb ◽  
Muscle Activation ◽  
Erector Spinae ◽  
Trunk Muscles ◽  
Emg Activity ◽  
Normal Walking ◽  
Arm Swing ◽  
Temporal Muscle ◽  
Limb Muscles ◽  
Emg Patterns

Background: Arm swing is deliberately emphasized during power walking, a popular aerobic fitness exercise. Electromyographic (EMG) activation curves of arm and shoulder muscles during power walking have not yet been examined. Aim: To describe the amount and pattern of EMG activity of upper limb muscles during power walking. Data are compared to normal walking and jogging. Method: Twenty volunteers were examined on a treadmill at 6 km/h during (a) normal walking, (b) power walking, (c) jogging. EMG data were collected for the trapezius (TRAP), anterior (AD) and posterior deltoid (PD), biceps (BIC), triceps (TRI), latissimus dorsi (LD) and erector spinae (ES) muscles. Results: Activity of four muscles (AD, BIC, PD, TRAP) was three- to fivefold stronger during power walking than normal walking. Smaller significant increases involved the TRI, LD and ES. Two muscles (AD, TRAP) were more active during power walking than running. Normal walking and power walking involved similar EMG patterns of PD, LD, ES, while EMG patterns of running and walking differed. Interpretation: Emphasizing arm swing during power walking triples the EMG activity of upper limb muscles, compared to normal walking. Similar basic temporal muscle activation patterns in both modes of walking indicate a common underlying motor program.

scholarly journals Accelerometer-Based Automated Counting of Ten Exercises without Exercise-Specific Training or Tuning

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Samuel Zelman ◽  
Michael Dow ◽  
Thasina Tabashum ◽  
Ting Xiao ◽  
Mark V. Albert
Keyword(s):  
Physical Therapy ◽  
Wearable Sensors ◽  
Training And Development ◽  
The Body ◽  
Activity Tracking ◽  
Counting System ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Threshold Crossing ◽  
Low Pass

Measuring physical activity using wearable sensors is essential for quantifying adherence to exercise regiments in clinical research and motivating individuals to continue exercising. An important aspect of wearable activity tracking is counting particular movements. One limitation of many previous models is the need to design the counting for a specific exercise. However, during physical therapy, some movements are unique to the patient and also valuable to track. To address this, we create an automatic repetition counting system that is flexible enough to measure multiple distinct and repeating movements during physical therapy without being trained on the specific motion. Accelerometers, using smartphones, were attached to the body or held by participants to track repetitive motions during different exercises. 18 participants completed a series of 10 exercises for 30 seconds, including arm circles, bicep curls, bridges, sit-ups, elbow extensions, leg lifts, lunges, push-ups, squats, and upper trunk rotations. To count the repetitions of each exercise, we apply three analysis techniques: (a) threshold crossing, (b) threshold crossing with a low-pass filter, and (c) Fourier transform. The results demonstrate that arm circles and push-ups can be tracked well, while less periodic and irregular motions such as upper trunk rotations are more difficult. Overall, threshold crossing with low-pass filtering achieves the best performance among these methods. We conclude that the proposed automatic counting system is capable of tracking exercise repetition without prior training and development for that activity.

Canal-Otolith Interactions After Off-Vertical Axis Rotations I. Spatial Reorientation of Horizontal Vestibuloocular Reflex

2000 ◽  
Vol 83 (3) ◽  
pp. 1522-1535 ◽  
Author(s):  
Karin Jaggi-Schwarz ◽  
Hubert Misslisch ◽  
Bernhard J. M. Hess
Keyword(s):  
Semicircular Canal ◽  
Three Dimensional ◽  
Head Tilt ◽  
Vertical Axis ◽  
Longitudinal Axis ◽  
The Body ◽  
Spatial Transformation ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Spatial Reorientation

We examined the three-dimensional (3-D) spatial orientation of postrotatory eye velocity after horizontal off-vertical axis rotations by varying the final body orientation with respect to gravity. Three rhesus monkeys were oriented in one of two positions before the onset of rotation: pitched 24° nose-up or 90° nose-up (supine) relative to the earth-horizontal plane and rotated at ±60°/s around the body-longitudinal axis. After 10 turns, the animals were stopped in 1 of 12 final positions separated by 30°. An empirical analysis of the postrotatory responses showed that the resultant response plane remained space-invariant, i.e., accurately represented the actual head tilt plane at rotation stop. The alignment of the response vector with the spatial vertical was less complete. A complementary analysis, based on a 3-D model that implemented the spatial transformation and dynamic interaction of otolith and lateral semicircular canal signals, confirmed the empirical description of the spatial response. In addition, it allowed an estimation of the low-pass filter time constants in central otolith and semicircular canal pathways as well as the weighting ratio between direct and inertially transformed canal signals in the output. Our results support the hypothesis that the central vestibular system represents head velocity in gravity-centered coordinates by sensory integration of otolith and semicircular canal signals.

Central programming of postural movements: adaptation to altered support-surface configurations

1986 ◽  
Vol 55 (6) ◽  
pp. 1369-1381 ◽  
Author(s):  
F. B. Horak ◽  
L. M. Nashner
Keyword(s):  
Muscle Activation ◽  
The Body ◽  
Trunk Muscles ◽  
Support Surface ◽  
Horizontal Shear ◽  
Hip Joints ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Ankle Joints ◽  
Support Surfaces

We studied the extent to which automatic postural actions in standing human subjects are organized by a limited repertoire of central motor programs. Subjects stood on support surfaces of various lengths, which forced them to adopt different postural movement strategies to compensate for the same external perturbations. We assessed whether a continuum or a limited set of muscle activation patterns was used to produce different movement patterns and the extent to which movement patterns were influenced by prior experience. Exposing subjects standing on a normal support surface to brief forward and backward horizontal surface perturbations elicited relatively stereotyped patterns of leg and trunk muscle activation with 73- to 110-ms latencies. Activity began in the ankle joint muscles and then radiated in sequence to thigh and then trunk muscles on the same dorsal or ventral aspect of the body. This activation pattern exerted compensatory torques about the ankle joints, which restored equilibrium by moving the body center of mass forward or backward. This pattern has been termed the ankle strategy because it restores equilibrium by moving the body primarily around the ankle joints. To successfully maintain balance while standing on a support surface short in relation to foot length, subjects activated leg and trunk muscles at similar latencies but organized the activity differently. The trunk and thigh muscles antagonistic to those used in the ankle strategy were activated in the opposite proximal-to-distal sequence, whereas the ankle muscles were generally unresponsive. This activation pattern produced a compensatory horizontal shear force against the support surface but little, if any, ankle torque. This pattern has been termed the hip strategy, because the resulting motion is focused primarily about the hip joints. Exposing subjects to horizontal surface perturbations while standing on support surfaces intermediate in length between the shortest and longest elicited more complex postural movements and associated muscle activation patterns that resembled ankle and hip strategies combined in different temporal relations. These complex postural movements were executed with combinations of torque and horizontal shear forces and motions of ankle and hip joints. During the first 5-20 practice trials immediately following changes from one support surface length to another, response latencies were unchanged. The activation patterns, however, were complex and resembled the patterns observed during well-practiced stance on surfaces of intermediate lengths.(ABSTRACT TRUNCATED AT 400 WORDS)

LOW-POWER, LOW-VOLTAGE, DUAL-OUTPUT, SECOND GENERATION CURRENT CONVEYOR AND ITS APPLICATION IN LOW-PASS FILTER DESIGN

2013 ◽  
Vol 22 (06) ◽  
pp. 1350044 ◽  
Author(s):  
MOHAMMAD HOSSEIN MAGHAMI ◽  
AMIR M. SODAGAR
Keyword(s):  
Second Generation ◽  
Current Conveyor ◽  
The Body ◽  
Total Power ◽  
Cmos Process ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Silicon Area ◽  
Total Power Consumption ◽  
Low Pass

A new simple dual-output second generation current conveyor (DO-CCII) circuit is proposed. Designed in a standard 0.5-μm CMOS process, the circuit operates at ±1.5 V supply voltages with a total power consumption of 106 nW. Main characteristics of the proposed DO-CCII are its simplicity, small silicon area consumption, and not suffering from the body effect of MOS transistors. The proposed circuit is employed to implement a first-order low-pass filter with upper -3 dB cut-off frequency of as low as 3.2 Hz.

scholarly journals Effects of Static, Stationary, and Traveling Trunk Exercises on Muscle Activation

2017 ◽  
Vol 5 (4) ◽  
pp. 26
Author(s):  
Darien T. Pyka ◽  
Pablo B. Costa ◽  
Jared W. Coburn ◽  
Lee E. Brown
Keyword(s):  
Muscle Activation ◽  
Rectus Femoris ◽  
Random Order ◽  
Rectus Abdominis ◽  
Erector Spinae ◽  
Trunk Muscles ◽  
Emg Activity ◽  
Strength And Conditioning ◽  
Allied Health Professionals ◽  
External Oblique

Background: A new fitness trend incorporates stability exercises that challenges trunk muscles and introduces crawling as an exercise, but has yet to be investigated for muscle activity. Purpose: To compare the effects of static (STA), stationary (STN), and traveling (TRV) trunk exercises on muscle activation of the rectus abdominis, rectus femoris, external oblique, and erector spinae using surface electromyography (EMG). Methods: Seventeen recreationally active women (mean age ± SD = 22.4 ± 2.4 years, body mass 62.9 ± 6.9 kg, height 165.1 ± 5.8 cm) and twenty-three men (23.6 ±3.9 years, 83.2 ±17.1 kg, 177.1 ± 9.1 cm) volunteered to participate in this study. Subjects performed maximal voluntary contractions for normalization of each muscle’s EMG activity. They then performed the three exercises in random order for thirty seconds each with a two-minute rest in between. Results: For the rectus abdominis, STA was significantly lower than STN (P = 0.003) and TRV (P = 0.001). For the external oblique, STA was significantly lower than STN (P = 0.001) and TRV (P = 0.001) and STN was significantly greater than TRV (P = 0.009). For the erector spinae and rectus femoris, STA was significantly lower than STN (P = 0.001) and TRV (P = 0.001) Conclusions: There was greater muscle activation in all muscles tested in the stationary and traveling exercises versus the static. Strength and conditioning coaches and allied health professionals could potentially use stationary and traveling forms of trunk stabilization exercises as a viable strategy to increase muscle activation.

scholarly journals ELECTROMYOGRAPHIC ACTIVITY OF VARIOUS MUSCLES DURING SIT-TO-STAND IN PATIENTS WITH STROKE: A META-ANALYSIS

2018 ◽  
Vol 4 (3) ◽  
pp. 14-20 ◽  
Author(s):  
Dimple, Antiya ◽  
Suvarna Ganvir
Keyword(s):  
Lower Extremity ◽  
Tibialis Anterior ◽  
Muscle Activation ◽  
Trunk Muscles ◽  
Emg Activity ◽  
Control Group ◽  
Electromyographic Activity ◽  
Exclusion Criteria ◽  
Sit To Stand ◽  
Depth Analysis

Aims:-To provide a comprehensive information about analysis of activation of various muscles during Sit-to-Stand in patients with stroke. To determine if there exists any common pattern of muscle activation. To give direction to future studies regarding the muscles to be investigated during Sit-to-Stand. Methods-  A  literature  search  was  performed  with  help  of  the  most commonly used database i.e. PubMed to select the studies related to electromyographic activities of various lower extremity, trunk and upper extremity muscles during Sit-to-Stand activity, published till 2016. The Inclusion criteria for the study were Prospective or retrospective cohort studies, studies that included only participants with stroke leading to hemiparesis and/or along with healthy participants as control group and studies that measured the EMG activity in either trunk muscles and/or limb muscles during sit to stand. The exclusion criteria were if their population of interest also included patients with other neurological conditions and studies in any language other than English. Two independent investigators assessed the studies based on inclusion and exclusion criteria.  Keywords used during the search were Electromyography, Stroke, Sit-to-Stand. The studies were thoroughly evaluated with respect to the Sit-to-Stand procedure and variety of muscles that were investigated through EMG analysis. Results: With the help of given keywords, abstracts/articles of 21 studies were retrieved from the database. After initial screening of the abstracts 12 studies were selected for in depth analysis. Various lower extremity muscles including Tibialis Anterior, Soleus, Quadriceps, Vastusmedialis, Gluteus Maximus were investigated in the studies. In 2 studies, Trunk muscles were investigated whereas in one study Triceps muscle activity was analyzed during Sit-to Stand activity in patients with stroke. Conclusion: From this study it can be concluded that the activity of Tibialis Anterior muscle was investigated more frequently by various researchers followed by the activity of Soleus and Quadriceps muscle.

scholarly journals Temporal Processing Across Multiple Topographic Maps in the Electrosensory System

2008 ◽  
Vol 100 (2) ◽  
pp. 852-867 ◽  
Author(s):  
Rüdiger Krahe ◽  
Joseph Bastian ◽  
Maurice J. Chacron
Keyword(s):  
Frequency Tuning ◽  
Phase Locking ◽  
The Body ◽  
The Other ◽  
Stimulus Class ◽  
Cellular Mechanisms ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Sensory Stimuli ◽  
Low Pass

Multiple topographic representations of sensory space are common in the nervous system and presumably allow organisms to separately process particular features of incoming sensory stimuli that vary widely in their attributes. We compared the response properties of sensory neurons within three maps of the body surface that are arranged strictly in parallel to two classes of stimuli that mimic prey and conspecifics, respectively. We used information-theoretic approaches and measures of phase locking to quantify neuronal responses. Our results show that frequency tuning in one of the three maps does not depend on stimulus class. This map acts as a low-pass filter under both conditions. A previously described stimulus-class-dependent switch in frequency tuning is shown to occur in the other two maps. Only a fraction of the information encoded by all neurons could be recovered through a linear decoder. Particularly striking were low-pass neurons the information of which in the high-frequency range could not be decoded linearly. We then explored whether intrinsic cellular mechanisms could partially account for the differences in frequency tuning across maps. Injection of a Ca2+ chelator had no effect in the map with low-pass characteristics. However, injection of the same Ca2+ chelator in the other two maps switched the tuning of neurons from band-pass/high-pass to low-pass. These results show that Ca2+-dependent processes play an important part in determining the functional roles of different sensory maps and thus shed light on the evolution of this important feature of the vertebrate brain.

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