A Computational Model of Muscle Recruitment for Wrist Movements

2002 ◽  
Vol 88 (6) ◽  
pp. 3348-3358 ◽  
Author(s):  
Andrew H. Fagg ◽  
Ashvin Shah ◽  
Andrew G. Barto
Keyword(s):  
Motor System ◽  
Muscle Activation ◽  
Movement Direction ◽  
Joint Motion ◽  
Muscle Recruitment ◽  
Task Constraints ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Recruitment Behavior ◽  
Total Effort

To execute a movement, the CNS must appropriately select and activate the set of muscles that will produce the desired movement. This problem is particularly difficult because a variety of muscle subsets can usually be used to produce the same joint motion. The motor system is therefore faced with a motor redundancy problem that must be resolved to produce the movement. In this paper, we present a model of muscle recruitment in the wrist step-tracking task. Muscle activation levels for five muscles are selected so as to satisfy task constraints (moving to the designated target) while also minimizing a measure of the total effort in producing the movement. Imposing these constraints yields muscle activation patterns qualitatively similar to those observed experimentally. In particular, the model reproduces the observed cosine-like recruitment of muscles as a function of movement direction and also appropriately predicts that certain muscles will be recruited most strongly in movement directions that differ significantly from their direction of action. These results suggest that the observed recruitment behavior may not be an explicit strategy employed by the nervous system, but instead may result from a process of movement optimization.

scholarly journals Effects of Short-Term Training With Uncoupled Cranks in Trained Cyclists

2012 ◽  
Vol 7 (2) ◽  
pp. 113-120 ◽  
Author(s):  
Jack M. Burns ◽  
Jeremiah J. Peiffer ◽  
Chris R. Abbiss ◽  
Greig Watson ◽  
Angus Burnett ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Biceps Femoris ◽  
Training Group ◽  
Recovery Phase ◽  
Muscle Recruitment ◽  
Short Term ◽  
Activation Patterns ◽  
Gross Efficiency ◽  
Muscle Activation Patterns

Purpose:Manufacturers of uncoupled cycling cranks claim that their use will increase economy of motion and gross efficiency. Purportedly, this occurs by altering the muscle-recruitment patterns contributing to the resistive forces occurring during the recovery phase of the pedal stroke. Uncoupled cranks use an independent-clutch design by which each leg cycles independently of the other (ie, the cranks are not fixed together). However, research examining the efficacy of training with uncoupled cranks is equivocal. The purpose of this study was to determine the effect of short-term training with uncoupled cranks on the performance-related variables economy of motion, gross efficiency, maximal oxygen uptake (VO2max), and muscle-activation patterns.Methods:Sixteen trained cyclists were matched-paired into either an uncoupled-crank or a normal-crank training group. Both groups performed 5 wk of training on their assigned cranks. Before and after training, participants completed a graded exercise test using normal cranks. Expired gases were collected to determine economy of motion, gross efficiency, and VO2max, while integrated electromyography (iEMG) was used to examine muscle-activation patterns of the vastus lateralis, biceps femoris, and gastrocnemius.Results:No significant changes between groups were observed for economy of motion, gross efficiency, VO2max, or iEMG in the uncoupled- or normal-crank group.Conclusions:Five weeks of training with uncoupled cycling cranks had no effect on economy of motion, gross efficiency, muscle recruitment, or VO2max compared with training on normal cranks.

scholarly journals Stability of Measurement Outcomes for Voluntary Task Performance in Participants With Chronic Ankle Instability and Healthy Participants

2011 ◽  
Vol 46 (4) ◽  
pp. 366-375 ◽  
Author(s):  
Sara Van Deun ◽  
Karel Stappaerts ◽  
Oron Levin ◽  
Luc Janssens ◽  
Filip Staes
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Intervention Program ◽  
Ankle Instability ◽  
Chronic Ankle Instability ◽  
Control Group ◽  
Muscle Recruitment ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Recruitment Order

Context: Acceptable measurement stability during data collection is critically important to research. To interpret differences in measurement outcomes among participants or changes within participants after an intervention program, we need to know whether the measurement is stable and consistent. Objective: To determine the within-session stability of muscle activation patterns for a voluntary postural-control task in a group of noninjured participants and a group of participants with chronic ankle instability (CAI). Design: Descriptive laboratory study. Setting: Musculoskeletal laboratory. Patients or Other Participants: Twenty control participants (8 men, 12 women; age = 21.8 ± 2.4 years, height = 164.3 ± 13.4 cm, mass = 68.4 ± 17.9 kg) and 20 participants with CAI (12 men, 8 women; age = 21.2 ± 2.1 years, height = 176 ± 10.2 cm, mass = 71.7 ± 11.3 kg). Intervention(s): Participants performed 4 barefoot standing trials, each of which included a 30-second double-legged stance followed by a 30-second single-legged stance in 3 conditions: with vision, without vision, and with vision on a balance pad. Main Outcome Measure(s): The activity of 7 muscles of the lower limb was measured for the stance task in the 3 different conditions for each trial. The onset of muscle activity and muscle recruitment order were determined and compared between the first and the fourth trials for both groups and for each condition. Results: We found no differences in the onset of muscle activity among trials for both groups or for each condition. The measurement error was 0.9 seconds at maximum for the control group and 0.12 seconds for the CAI group. In the control group, 70% to 80% of the participants used the same muscle recruitment order in both trials. In the CAI group, 75% to 90% used the same recruitment order. Conclusions: Within 1 session, measurement stability for this task was acceptable for use in further research. Furthermore, no differences were found in measurement stability across conditions in the control or CAI groups.

scholarly journals Body Configuration in Cycling Affects Muscle Recruitment and Movement Pattern

2003 ◽  
Vol 19 (4) ◽  
pp. 310-324 ◽  
Author(s):  
Hans H.C.M. Savelberg ◽  
Ingrid G.L. Van de Port ◽  
Paul J.B. Willems
Keyword(s):  
Hip Joint ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Muscle Length ◽  
Movement Pattern ◽  
Joint Kinematics ◽  
Joint Torque ◽  
Muscle Recruitment ◽  
Activation Patterns ◽  
Muscle Activation Patterns

By manipulating trunk angle in ergometer cycling, we studied the effect of body configuration on muscle recruitment and joint kinematics. Changing trunk angle affects the length of muscles that span the hip joint. It is hypothesized that this affects the recruitment of the muscles directly involved, and as a consequence of affected joint torque distributions, also influences the recruitment of more distal muscles and the kinematics of distal joints. It was found that changing the trunk from an upright position to approximately 20 deg forward or backward affected muscle activation patterns and kinematics in the entire lower limb. The knee joint was the only joint not affected by manipulation of the lengths of hip joint muscles. Changes in trunk angle affected ankle and hip joint kinematics and the orientation of the thigh. A similar pattern has been demonstrated for muscle activity: Both the muscles that span the hip joint and those acting on the ankle joint were affected with respect to timing and amplitude of EMG. Moreover, it was found that the association between muscle activity and muscle length was adapted to manipulation of trunk angle. In all three conditions, most of the muscles that were considered displayed some eccentric activity. The ratio of eccentric to concentric activity changed with trunk angle. The present study showed that trunk angle influences muscle recruitment and (inter)muscular dynamics in the entire limb. As this will have consequences for the efficiency of cycling, body configuration should be a factor in bicycle design.

scholarly journals Is the Occurrence of the Sticking Region in Maximum Smith Machine Squats the Result of Diminishing Potentiation and Co-Contraction of the Prime Movers among Recreationally Resistance Trained Males?

2021 ◽  
Vol 18 (3) ◽  
pp. 1366
Author(s):  
Roland van den Tillaar ◽  
Eirik Lindset Kristiansen ◽  
Stian Larsen
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Gluteus Maximus ◽  
Knee Extensors ◽  
Force Output ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Prime Movers ◽  
Almost All ◽  
Height Data

This study compared the kinetics, barbell, and joint kinematics and muscle activation patterns between a one-repetition maximum (1-RM) Smith machine squat and isometric squats performed at 10 different heights from the lowest barbell height. The aim was to investigate if force output is lowest in the sticking region, indicating that this is a poor biomechanical region. Twelve resistance trained males (age: 22 ± 5 years, mass: 83.5 ± 39 kg, height: 1.81 ± 0.20 m) were tested. A repeated two-way analysis of variance showed that Force output decreased in the sticking region for the 1-RM trial, while for the isometric trials, force output was lowest between 0–15 cm from the lowest barbell height, data that support the sticking region is a poor biomechanical region. Almost all muscles showed higher activity at 1-RM compared with isometric attempts (p < 0.05). The quadriceps activity decreased, and the gluteus maximus and shank muscle activity increased with increasing height (p ≤ 0.024). Moreover, the vastus muscles decreased only for the 1-RM trial while remaining stable at the same positions in the isometric trials (p = 0.04), indicating that potentiation occurs. Our findings suggest that a co-contraction between the hip and knee extensors, together with potentiation from the vastus muscles during ascent, creates a poor biomechanical region for force output, and thereby the sticking region among recreationally resistance trained males during 1-RM Smith machine squats.

scholarly journals Electromyographic activation patterns during swallowing in older adults

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jin Young Ko ◽  
Hayoung Kim ◽  
Joonyoung Jang ◽  
Jun Chang Lee ◽  
Ju Seok Ryu
Keyword(s):  
Older Adults ◽  
Viscous Fluid ◽  
Muscle Activation ◽  
Fatty Infiltration ◽  
Liquid Volume ◽  
Type I ◽  
Type Ii ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Age Related

AbstractAge-related weakness due to atrophy and fatty infiltration in oropharyngeal muscles may be related to dysphagia in older adults. However, little is known about changes in the oropharyngeal muscle activation pattern in older adults. This was a prospective and experimental study. Forty healthy participants (20 older [> 60 years] and 20 young [< 60 years] adults) were enrolled. Six channel surface electrodes were placed over the bilateral suprahyoid (SH), bilateral retrohyoid (RH), thyrohyoid (TH), and sternothyroid (StH) muscles. Electromyography signals were then recorded twice for each patient during swallowing of 2 cc of water, 5 cc of water, and 5 cc of a highly viscous fluid. Latency, duration, and peak amplitude were measured. The activation patterns were the same, in the order of SH, TH, and StH, in both groups. The muscle activation patterns were classified as type I and II; the type I pattern was characterized by a monophasic shape, and the type II comprised a pre-reflex phase and a main phase. The oropharyngeal muscles and SH muscles were found to develop a pre-reflex phase specifically with increasing volume and viscosity of the swallowed fluid. Type I showed a different response to the highly viscous fluid in the older group compared to that in the younger group. However, type II showed concordant changes in the groups. Therefore, healthy older people were found to compensate for swallowing with a pre-reflex phase of muscle activation in response to increased liquid volume and viscosity, to adjust for age-related muscle weakness.

scholarly journals Inter-laboratory comparison of knee biomechanics and muscle activation patterns during gait in patients with knee osteoarthritis

The Knee ◽  
2021 ◽  
Vol 29 ◽  
pp. 500-509
Author(s):  
J.C. Schrijvers ◽  
D. Rutherford ◽  
R. Richards ◽  
J.C. van den Noort ◽  
M. van der Esch ◽  
...  
Keyword(s):  
Knee Osteoarthritis ◽  
Muscle Activation ◽  
Knee Biomechanics ◽  
Activation Patterns ◽  
Muscle Activation Patterns

scholarly journals Functional Gait Recovery after a Combination of Conventional Therapy and Overground Robot-Assisted Gait Training Is Not Associated with Significant Changes in Muscle Activation Pattern: An EMG Preliminary Study on Subjects Subacute Post Stroke

2021 ◽  
Vol 11 (4) ◽  
pp. 448
Author(s):  
Francesco Infarinato ◽  
Paola Romano ◽  
Michela Goffredo ◽  
Marco Ottaviani ◽  
Daniele Galafate ◽  
...  
Keyword(s):  
Conventional Therapy ◽  
Muscle Activation ◽  
Bilateral Symmetry ◽  
Gait Training ◽  
Robot Assisted ◽  
Activation Patterns ◽  
Post Stroke ◽  
Muscle Activation Patterns ◽  
Preliminary Study ◽  
Functional Gait

Background: Overground Robot-Assisted Gait Training (o-RAGT) appears to be a promising stroke rehabilitation in terms of clinical outcomes. The literature on surface ElectroMyoGraphy (sEMG) assessment in o-RAGT is limited. This paper aimed to assess muscle activation patterns with sEMG in subjects subacute post stroke after training with o-RAGT and conventional therapy. Methods: An observational preliminary study was carried out with subjects subacute post stroke who received 15 sessions of o-RAGT (5 sessions/week; 60 min) in combination with conventional therapy. The subjects were assessed with both clinical and instrumental evaluations. Gait kinematics and sEMG data were acquired before (T1) and after (T2) the period of treatment (during ecological gait), and during the first session of o-RAGT (o-RAGT1). An eight-channel wireless sEMG device acquired in sEMG signals. Significant differences in sEMG outcomes were found in the BS of TA between T1 and T2. There were no other significant correlations between the sEMG outcomes and the clinical results between T1 and T2. Conclusions: There were significant functional gains in gait after complex intensive clinical rehabilitation with o-RAGT and conventional therapy. In addition, there was a significant increase in bilateral symmetry of the Tibialis Anterior muscles. At this stage of the signals from the tibialis anterior (TA), gastrocnemius medialis (GM), rectus femoris (RF), and biceps femoris caput longus (BF) muscles of each lower extremity. sEMG data processing extracted the Bilateral Symmetry (BS), the Co-Contraction (CC), and the Root Mean Square (RMS) coefficients. Results: Eight of 22 subjects in the subacute stage post stroke agreed to participate in this sEMG study. This subsample demonstrated a significant improvement in the motricity index of the affected lower limb and functional ambulation. The heterogeneity of the subjects’ characteristics and the small number of subjects was associated with high variability research, functional gait recovery was associated with minimal change in muscle activation patterns.

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