scholarly journals Motor control and olfaction – Influence of pleasant and disgusting odors on the Adaptive Force

2021 ◽  
Author(s):  
Laura V Schaefer ◽  
Silas Dech ◽  
Markus Aehle ◽  
Frank N Bittmann
Keyword(s):  
Motor Control ◽  
Reaction Force ◽  
Neuromuscular Control ◽  
Tension Control ◽  
Neuromuscular System ◽  
Elbow Flexors ◽  
Handheld Device ◽  
Force Increase ◽  
External Forces ◽  
Proper Length

Abstract The Adaptive Force (AF) characterizes the capability of the neuromuscular system to adapt to external forces. The aim was to measure the effects of different olfactory inputs on the AF of the hip and elbow flexors, respectively. The AF of 10 subjects was examined manually by experienced testers while smelling at sniffing sticks with neutral, pleasant or disgusting odors. The reaction force and the position of the tested limb were recorded by a handheld device. The results show, inter alia, a significantly lower maximal isometric AF and a significantly higher AF at the onset of oscillations with disgusting odor compared to pleasant or neutral odors (p < 0.001). The AF seems to reflect the functionality of the neuromuscular control, which can be impaired by disgusting olfactory inputs. An undisturbed functioning neuromuscular system appears to be characterized by a proper length-tension control and by an earlier onset of mutual oscillations during an external force increase under isometric conditions.

scholarly journals Disgusting odours affect the characteristics of the Adaptive Force in contrast to neutral and pleasant odours

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Laura V. Schaefer ◽  
Silas Dech ◽  
Markus Aehle ◽  
Frank N. Bittmann
Keyword(s):  
Reaction Force ◽  
Neuromuscular Control ◽  
Tension Control ◽  
Neuromuscular System ◽  
Strong Connection ◽  
Handheld Device ◽  
Force Increase ◽  
Olfactory Stimuli ◽  
External Forces ◽  
Proper Length

AbstractThe olfactomotor system is especially investigated by examining the sniffing in reaction to olfactory stimuli. The motor output of respiratory-independent muscles was seldomly considered regarding possible influences of smells. The Adaptive Force (AF) characterizes the capability of the neuromuscular system to adapt to external forces in a holding manner and was suggested to be more vulnerable to possible interfering stimuli due to the underlying complex control processes. The aim of this pilot study was to measure the effects of olfactory inputs on the AF of the hip and elbow flexors, respectively. The AF of 10 subjects was examined manually by experienced testers while smelling at sniffing sticks with neutral, pleasant or disgusting odours. The reaction force and the limb position were recorded by a handheld device. The results show, inter alia, a significantly lower maximal isometric AF and a significantly higher AF at the onset of oscillations by perceiving disgusting odours compared to pleasant or neutral odours (p < 0.001). The adaptive holding capacity seems to reflect the functionality of the neuromuscular control, which can be impaired by disgusting olfactory inputs. An undisturbed functioning neuromuscular system appears to be characterized by a proper length tension control and by an earlier onset of mutual oscillations during an external force increase. This highlights the strong connection of olfaction and motor control also regarding respiratory-independent muscles.

scholarly journals Dynamic analysis of a ten-link tooth-lever differential transmission

2021 ◽  
Vol 939 (1) ◽  
pp. 012024
Author(s):  
A Abdukarimov ◽  
I Saidakulov
Keyword(s):  
High Speed ◽  
Reaction Force ◽  
Transmission Mechanism ◽  
Force Analysis ◽  
Axis Of Rotation ◽  
Processed Material ◽  
Differential Transmission ◽  
External Forces ◽  
Force Calculation ◽  
Force Characteristics

Abstract This article discusses the dynamics of a ten-link tooth-lever differential transmission mechanism. The force analysis of the transmission mechanism is given in order to find the dependence for determining the reaction in kinematic pairs and the balancing moment of the pair of forces and to show some features of the tooth-lever transmission mechanism. The force calculation was carried out taking into account the accelerated movement of links since their acceleration in modern high-speed machines is very significant. To obtain a more accurate concept of the external forces and moments loading the transmission mechanism in the accelerated movement of the links, the dynamics of the transient process of roller technological machines was considered. Cases of feeding the processed material were considered both from the side of the intermediate gears and from the side opposite to the parasitic gears. Dependencies were obtained to determine the force characteristics of this mechanism. Cases of pressure unloading and overloading on the processed material from the side of the free shaft, depending on the location of the transmission mechanism are shown. The dependence of the reaction force of intermediate gears on their own axes of rotation on the angle between the levers is shown. With an increase in the angle between the levers, the reaction of the intermediate gears on the axis of rotation increases.

Evaluating the Spectrum of Cognitive-Motor Relationships During Dual-Task Jump Landing

2021 ◽  
pp. 1-8
Author(s):  
Patrick D. Fischer ◽  
Keith A. Hutchison ◽  
James N. Becker ◽  
Scott M. Monfort
Keyword(s):  
Working Memory ◽  
Cognitive Function ◽  
Visual Attention ◽  
Dual Task ◽  
Cruciate Ligament ◽  
Reaction Force ◽  
Neuromuscular Control ◽  
Task Demands ◽  
Jump Landing ◽  
Peak Knee

Cognitive function plays a role in understanding noncontact anterior cruciate ligament injuries, but the research into how cognitive function influences sport-specific movements is underdeveloped. The purpose of this study was to determine how various cognitive tasks influenced dual-task jump-landing performance along with how individuals’ baseline cognitive ability mediated these relationships. Forty female recreational soccer and basketball players completed baseline cognitive function assessments and dual-task jump landings. The baseline cognitive assessments quantified individual processing speed, multitasking, attentional control, and primary memory ability. Dual-task conditions for the jump landing included unanticipated and anticipated jump performance, with and without concurrent working memory and captured visual attention tasks. Knee kinematics and kinetics were acquired through motion capture and ground reaction force data. Jumping conditions that directed visual attention away from the landing, whether anticipated or unanticipated, were associated with decreased peak knee flexion angle (P < .001). No interactions between cognitive function measures and jump-landing conditions were observed for any of the biomechanical variables, suggesting that injury-relevant cognitive-motor relationships may be specific to secondary task demands and movement requirements. This work provides insight into group- and subject-specific effects of established anticipatory and novel working memory dual-task paradigms on the neuromuscular control of a sport-specific movement.

scholarly journals The Dynamic Motor Control Index as a Marker of Age-Related Neuromuscular Impairment

2021 ◽  
Vol 13 ◽  
Author(s):  
Ashley N. Collimore ◽  
Ashlyn J. Aiello ◽  
Ryan T. Pohlig ◽  
Louis N. Awad
Keyword(s):  
Motor Control ◽  
Age Groups ◽  
Neuromuscular Control ◽  
Muscle Synergies ◽  
Age Related ◽  
Index Study ◽  
Two Measures ◽  
Study Participants ◽  
Young Old ◽  
Neuromuscular Impairment

Biomarkers that can identify age-related decline in walking function have potential to promote healthier aging by triggering timely interventions that can mitigate or reverse impairments. Recent evidence suggests that changes in neuromuscular control precede changes in walking function; however, it is unclear which measures are best suited for identifying age-related changes. In this study, non-negative matrix factorization of electromyography data collected during treadmill walking was used to calculate two measures of the complexity of muscle co-activations during walking for 36 adults: (1) the number of muscle synergies and (2) the dynamic motor control index. Study participants were grouped into young (18–35 years old), young-old (65–74 years old), and old–old (75+ years old) subsets. We found that the dynamic motor control index [χ2(2) = 9.41, p = 0.009], and not the number of muscle synergies [χ2(2) = 5.42, p = 0.067], differentiates between age groups [χ2(4) = 10.62, p = 0.031, Nagelkerke R2 = 0.297]. Moreover, an impairment threshold set at a dynamic motor control index of 90 (i.e., one standard deviation below the young adults) was able to differentiate between age groups [χ2(2) = 9.351, p = 0.009]. The dynamic motor control index identifies age-related differences in neuromuscular complexity not measured by the number of muscle synergies and may have clinical utility as a marker of neuromotor impairment.

scholarly journals Age-Related Differences in Muscle Synergy Organization during Step Ascent at Different Heights and Directions

2020 ◽  
Vol 10 (6) ◽  
pp. 1987 ◽  
Author(s):  
Remco J. Baggen ◽  
Jaap H. van Dieën ◽  
Evelien Van Roie ◽  
Sabine M. Verschueren ◽  
Georgios Giarmatzis ◽  
...  
Keyword(s):  
Motor Control ◽  
Older Women ◽  
Young Women ◽  
Age Groups ◽  
Neuromuscular Control ◽  
Significant Negative Correlation ◽  
Community Dwelling ◽  
Step Height ◽  
Muscle Synergy ◽  
Age Related

The aim of this study was to explore the underlying age-related differences in dynamic motor control during different step ascent conditions using muscle synergy analysis. Eleven older women (67.0 y ± 2.5) and ten young women (22.5 y ± 1.6) performed stepping in forward and lateral directions at step heights of 10, 20 and 30 cm. Surface electromyography was obtained from 10 lower limb and torso muscles. Non-negative matrix factorization was used to identify sets of (n) synergies across age groups and stepping conditions. In addition, variance accounted for (VAF) by the detected number of synergies was compared to assess complexity of motor control. Finally, correlation coefficients of muscle weightings and between-subject variability of the temporal activation patterns were calculated and compared between age groups and stepping conditions. Four synergies accounted for >85% VAF across age groups and stepping conditions. Age and step height showed a significant negative correlation with VAF during forward stepping but not lateral stepping, with lower VAF indicating higher synergy complexity. Muscle weightings showed higher similarity across step heights in older compared to young women. Neuromuscular control of young and community-dwelling older women could not be differentiated based on the number of synergies extracted. Additional analyses of synergy structure and complexity revealed subtle age- and step-height-related differences, indicating that older women rely on more complex neuromuscular control strategies.

scholarly journals Visual-Motor Control of Drop Landing After Anterior Cruciate Ligament Reconstruction

2018 ◽  
Vol 53 (5) ◽  
pp. 486-496 ◽  
Author(s):  
Dustin R. Grooms ◽  
Ajit Chaudhari ◽  
Stephen J. Page ◽  
Deborah S. Nichols-Larsen ◽  
James A. Onate
Keyword(s):  
Anterior Cruciate Ligament ◽  
Motor Control ◽  
Visual Feedback ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Vertical Jump ◽  
Frontal Plane ◽  
Neuromuscular Control ◽  
Visual Motor ◽  
Anterior Cruciate

Context:  Visual feedback is crucial in the control of human movement. When vision is obstructed, alterations in landing neuromuscular control may increase movements that place individuals at risk for injury. Anterior cruciate ligament (ACL) injury may further alter the motor-control response to alterations in visual feedback. The development of stroboscopic glasses that disrupt visual feedback without fully obscuring it has enabled researchers to assess visual-motor control during movements that simulate the dynamic demands of athletic activity. Objective:  To investigate the effect of stroboscopic visual-feedback disruption (SVFD) on drop vertical-jump landing mechanics and to determine whether injury history influenced the effect. Design:  Cohort study. Setting:  Movement-analysis laboratory. Patients or Other Participants:  A total of 15 participants with ACL reconstruction (ACLR; 7 men, 8 women; age = 21.41 ± 2.60 years, height = 1.72 ± 0.09 m, mass = 69.24 ± 15.24 kg, Tegner Activity Scale score = 7.30 ± 1.30, time since surgery = 36.18 ± 26.50 months, hamstrings grafts = 13, patellar tendon grafts = 2) and 15 matched healthy control participants (7 men, 8 women; age = 23.15 ± 3.48 years, height = 1.73 ± 0.09 m, mass = 69.98 ± 14.83 kg, Tegner Activity Scale score = 6.77 ± 1.48). Intervention(s):  Drop vertical-jump landings under normal and SVFD conditions. Main Outcome Measure(s):  The SVFD effect for knee sagittal- and frontal-plane excursions, peak moments, and vertical ground reaction force were calculated during landing and compared with previously established measurement error and between groups. Results:  The SVFD altered knee sagittal-plane excursion (4.04° ± 2.20°, P = .048) and frontal-plane excursion (1.98° ± 1.53°, P = .001) during landing above within-session measurement error. Joint-moment difference scores from full vision to the SVFD condition were not greater than within-session error. We observed an effect of ACLR history only for knee flexion (ACLR group = 3.12° ± 3.76°, control group = −0.84° ± 4.45°; P = .001). We did not observe an effect of side or sex. Conclusions:  The SVFD altered sagittal- and frontal-plane landing knee kinematics but did not alter moments. Anterior cruciate ligament reconstruction may induce alterations in sagittal-plane visual-motor control of the knee. The group SVFD effect was on a level similar to that of an in-flight perturbation, motor-learning intervention, or plyometric-training program, indicating that visual-motor ability may contribute to knee neuromuscular control on a clinically important level. The individual effects of the SVFD indicated possible unique sensorimotor versus visual-motor movement strategies during landing.

Core Stability: Implications for Dance Injuries

2012 ◽  
Vol 27 (3) ◽  
pp. 159-164 ◽  
Author(s):  
Ashley M Rickman ◽  
Jatin P Ambegaonkar ◽  
Nelson Cortes
Keyword(s):  
Motor Control ◽  
Injury Risk ◽  
Muscle Power ◽  
Core Stability ◽  
Injury Incidence ◽  
Research Areas ◽  
Sensory Motor ◽  
Dance Injury ◽  
External Forces ◽  
The Relationship

Dancers experience a high incidence of injury due to the extreme physical demands of dancing. The majority of dance injuries are chronic in nature and occur in the lower extremities and low back. Researchers have indicated decreased core stability (CS) as a risk factor for these injuries. Although decreased CS is suggested to negatively affect lower extremity joint motion and lumbar control during activity, this relationship has not been extensively discussed in previous dance literature. Understanding the relationship between CS and injury risk is important to help reduce dance injury incidence and improve performance. The purposes of this review were to discuss 1) the core and components of CS, 2) the relationship between CS and injury, 3) CS assessment techniques, and 4) future dance CS research areas. CS is the integration of passive (non-contractile), active (contractile), and neural structures to minimize the effects of external forces and maintain stability. CS is maintained by a combination of muscle power, strength, endurance, and sensory-motor control of the lumbopelvic-hip complex. CS assessments include measuring muscle strength and power using maximal voluntary isometric and isokinetic contractions and measuring endurance using the Biering-Sorensen, plank, and lateral plank tests. Measuring sensory-motor control requires specialized equipment (e.g., balance platforms). Overall, limited research has comprehensively examined all components of CS together and their relationships to injury. Rather, previous researchers have separately examined core power, strength, endurance, or sensory-motor control. Future researchers should explore the multifactorial role of CS in reducing injury risk and enhancing performance in dancers.

scholarly journals Two Different Fatigue Protocols and Lower Extremity Motion Patterns During a Stop-Jump Task

2012 ◽  
Vol 47 (1) ◽  
pp. 32-41 ◽  
Author(s):  
David Quammen ◽  
Nelson Cortes ◽  
Bonnie L. Van Lunen ◽  
Shawn Lucci ◽  
Stacie I. Ringleb ◽  
...  
Keyword(s):  
Ground Reaction Force ◽  
Knee Flexion ◽  
Reaction Force ◽  
Neuromuscular Control ◽  
Initial Contact ◽  
Vertical Ground Reaction Force ◽  
Convenience Sample ◽  
Fatigue Protocol ◽  
Vertical Ground ◽  
Hip Flexion

Context: Altered neuromuscular control strategies during fatigue probably contribute to the increased incidence of non-contact anterior cruciate ligament injuries in female athletes. Objective: To determine biomechanical differences between 2 fatigue protocols (slow linear oxidative fatigue protocol [SLO-FP] and functional agility short-term fatigue protocol [FAST-FP]) when performing a running-stop-jump task. Design: Controlled laboratory study. Setting: Laboratory. Patients or Other Participants: A convenience sample of 15 female soccer players (age = 19.2 ±0.8 years, height = 1.67±0.05m, mass = 61.7 + 8.1 kg) without injury participated. Intervention(s): Five successful trials of a running–stop-jump task were obtained prefatigue and postfatigue during the 2 protocols. For the SLO-FP, a peak oxygen consumption (V˙o2peak) test was conducted before the fatigue protocol. Five minutes after the conclusion of the V˙o2peak test, participants started the fatigue protocol by performing a 30-minute interval run. The FAST-FP consisted of 4 sets of a functional circuit. Repeated 2 (fatigue protocol) × 2 (time) analyses of variance were conducted to assess differences between the 2 protocols and time (prefatigue, postfatigue). Main Outcome Measure(s): Kinematic and kinetic measures of the hip and knee were obtained at different times while participants performed both protocols during prefatigue and postfatigue. Results: Internal adduction moment at initial contact (IC) was greater during FAST-FP (0.064 ±0.09 Nm/kgm) than SLO-FP (0.024±0.06 Nm/kgm) (F1,14 = 5.610, P=.03). At IC, participants had less hip flexion postfatigue (44.7°±8.1°) than prefatigue (50.1°±9.5°) (F1,14 = 16.229, P=.001). At peak vertical ground reaction force, participants had less hip flexion postfatigue (44.7°±8.4°) than prefatigue (50.4°±10.3°) (F1,14 = 17.026, P=.001). At peak vertical ground reaction force, participants had less knee flexion postfatigue (−35.9°±6.5°) than prefatigue (−38.8°±5.03°) (F1,14 = 11.537, P=.001). Conclusions: Our results demonstrated a more erect landing posture due to a decrease in hip and knee flexion angles in the postfatigue condition. The changes were similar between protocols; however, the FAST-FP was a clinically applicable 5-minute protocol, whereas the SLO-FP lasted approximately 45 minutes.

scholarly journals Maintaining balance against force perturbations: impaired mechanisms unresponsive to levodopa in Parkinson's disease

2016 ◽  
Vol 116 (2) ◽  
pp. 493-502 ◽  
Author(s):  
Irene Di Giulio ◽  
Rebecca J. St George ◽  
Eirini Kalliolia ◽  
Amy L. Peters ◽  
Patricia Limousin ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Force Feedback ◽  
Center Of Mass ◽  
Reaction Force ◽  
Knee Extensor ◽  
Forward Direction ◽  
Postural Instability ◽  
The Body ◽  
External Forces

There is evidence that postural instability associated with Parkinson's disease (PD) is not adequately improved by levodopa, implying involvement of nondopaminergic pathways. However, the mechanisms contributing to postural instability have yet to be fully identified and tested for their levodopa responsiveness. In this report we investigate balance processes that resist external forces to the body when standing. These include in-place responses and the transition to protective stepping. Forward and backward shoulder pulls were delivered using two force-feedback-controlled motors and were randomized for direction, magnitude, and onset. Sixteen patients with PD were tested OFF and ON levodopa, and 16 healthy controls were tested twice. Response behavior was quantified from 3-dimensional ground reaction forces and kinematic measurements of body segments and total body center-of-mass (CoM) motion. In-place responses resisting the pull were significantly smaller in PD as reflected in reduced horizontal anteroposterior ground reaction force and increased CoM displacement. Ankle, knee, and hip moments contributing to this resistance were smaller in PD, with the knee extensor moment to backward pulls being the most affected. The threshold force needed to evoke a step was also smaller for PD in the forward direction. Protective steps evoked by suprathreshold pulls showed deficits in PD in the backward direction, with steps being shorter and more steps being required to arrest the body. Levodopa administration had no significant effect on either in-place or protective stepping deficits. We conclude that processes employed to maintain balance in the face of external forces show impairment in PD consistent with disruption to nondopaminergic systems.

scholarly journals Neuromechanical force-based control of a powered prosthetic foot

2020 ◽  
Vol 1 ◽  
Author(s):  
Amirreza Naseri ◽  
Martin Grimmer ◽  
André Seyfarth ◽  
Maziar Ahmad Sharbafi
Keyword(s):  
Sensory Feedback ◽  
Reaction Force ◽  
Neuromuscular Control ◽  
Target Population ◽  
Vertical Ground Reaction Force ◽  
Control Approach ◽  
Prosthetic Foot ◽  
Ankle Torque ◽  
Study Support ◽  
Walking Speeds

Abstract This article presents a novel neuromechanical force-based control strategy called FMCA (force modulated compliant ankle), to control a powered prosthetic foot. FMCA modulates the torque, based on sensory feedback, similar to neuromuscular control approaches. Instead of using a muscle reflex-based approach, FMCA directly exploits the vertical ground reaction force as sensory feedback to modulate the ankle joint impedance. For evaluation, we first demonstrated how FMCA can predict human-like ankle torque for different walking speeds. Second, we implemented the FMCA in a neuromuscular transtibial amputee walking simulation model to validate if the approach can be used to achieve stable walking and to compare the performance to a neuromuscular reflex-based controller that is already used in a powered ankle. Compared to the neuromuscular model-based approach, the FMCA is a simple solution with a sufficient push-off that can provide stable walking. Third, to assess the ability of the FMCA to generate human-like ankle biomechanics during walking at the preferred speed, we implemented this strategy in a powered prosthetic foot and performed experiments with a non-amputee subject. The results confirm that, for this subject, FMCA can be used to mimic the non-amputee reference ankle torque and the reference ankle angle. The findings of this study support the applicability and advantages of a new bioinspired control approach for assisting amputees. Future experiments should investigate the applicability to other walking speeds and the applicability to the target population.

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