Quantifying the Contributions of the Flexor Digitorum Brevis Muscle on Postural Stability

Motor Control ◽  
2015 ◽  
Vol 19 (3) ◽  
pp. 161-172 ◽  
Author(s):  
Liria Akie Okai ◽  
André Fabio Kohn
Keyword(s):  
Postural Control ◽  
Postural Stability ◽  
Center Of Pressure ◽  
Human Foot ◽  
Sustained Activity ◽  
Torque Generation ◽  
Flexor Digitorum Brevis ◽  
The Subject ◽  
Flexor Digitorum ◽  
Intrinsic Muscles

Surprisingly little attention has been devoted to the role played by the intrinsic muscles of the human foot. The aim of this study was to quantify the capabilities of the flexor digitorum brevis (FDB) muscle to contribute to upright postural control. The approaches consisted of analysis of the effects of FDB contraction elicited by external electrical stimulation and quantification of the magnitude of FDB torque generation. The results showed the FDB can produce significant changes in static posture by itself as shown by changes in the center of pressure. Moreover, the FDB contribution to counterbalance the gravity’s toppling force was estimated at around 14.5% of the total required active torque at the ankle to keep the subject from falling. A posteriori functional analysis during horizontal perturbations showed high and self-sustained activity of FDB. These results demonstrated that the FDB has a significant capability of contributing to postural control.

scholarly journals Postural Control and Stress Exposure in Young Men: Changes in Cortisol Awakening Response and Blood Lactate

2020 ◽  
Vol 17 (19) ◽  
pp. 7222 ◽  
Author(s):  
Marinella Coco ◽  
Andrea Buscemi ◽  
Emanuele Pennisi ◽  
Paolo Cavallari ◽  
Giacomo Papotto ◽  
...  
Keyword(s):  
Postural Control ◽  
Blood Lactate ◽  
Postural Stability ◽  
Center Of Pressure ◽  
Young Men ◽  
Posture Control ◽  
Cortisol Awakening Response ◽  
Free Cortisol ◽  
Lactate Levels ◽  
Blood Lactate Levels

Background: It has recently been noticed that the quantity of stress affects postural stability in young women. The study was conducted with the goal of investigating whether increased stress may damagingly effect posture control in 90 young men (71 right-handed and 19 left-handed) while maintaining an upright bipedal posture, while keeping their eyes open or closed. Perceived Stress Scale (PSS) was administered and changes in free cortisol levels were monitored (Cortisol Awakening Response, CAR) in order to evaluate the amount of stress present during awakening, while the Profile of Mood States (POMS) was used to estimate distress on the whole. Posture control was evaluated with the use of a force platform, which, while computing a confidence ellipse area of 95%, was engaged by the Center of Pressure through five stability stations and was sustained for a minimum of 52 s, with and without visual input. Another goal of the experiment was to find out whether or not cortisol increases in CAR were linked with rises of blood lactate levels. Results: CAR, PSS and POMS were found to be extensively related. Furthermore, it has been observed that increases in salivary cortisol in CAR are associated with small but significant increases in blood lactate levels. As expected, stress levels did affect postural stability. Conclusions: The results of the present study confirm that the level of stress can influence postural stability, and that this influence is principally obvious when visual information is not used in postural control.

scholarly journals Characteristics of Standing Postural Control in Women under Additional Load

2020 ◽  
Vol 17 (2) ◽  
pp. 490
Author(s):  
Bożena Wojciechowska-Maszkowska ◽  
Dorota Borzucka
Keyword(s):  
Postural Control ◽  
Postural Stability ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Stability Control ◽  
Standing Posture ◽  
Additional Load ◽  
Eyes Open ◽  
Heavy Loads ◽  
Load Conditions

The aim of this study was to evaluate the effect of additional load on postural-stability control in young women. To evaluate postural control in the 34 women in this study (mean age, 20.8 years), we measured postural sway (center of pressure, COP) in a neutral stance (with eyes open) in three trials of 30 s each. Three load conditions were used in the study: 0, 14, and 30 kg. In analysis, we used three COP parameters, variability (linear), mean sway velocity (linear), and entropy (nonlinear). Results suggested that a considerable load on a young woman’s body (approximately 48% of body weight) had significant influence on stability. Specifically, heavy loads triggered random movements, increased the dynamics of postural-stability control, and required more attention to control standing posture. The results of our study indicate that inferior postural control mainly results from insufficient experience in lifting such a load.

Electromyographic Studies of the Human Foot: Experimental Approaches to Hominid Evolution

Foot & Ankle ◽  
1983 ◽  
Vol 3 (6) ◽  
pp. 391-407 ◽  
Author(s):  
Lori A. Reeser ◽  
Randall L. Susman ◽  
Jack T. Stern
Keyword(s):  
Hominid Evolution ◽  
Abductor Hallucis ◽  
Early Hominid ◽  
Human Foot ◽  
Flexor Digitorum Brevis ◽  
Experimental Approaches ◽  
Arch Support ◽  
Flexor Digitorum ◽  
Hominid Fossils ◽  
Electromyographic Investigation

Theories about the functions of the foot muscles have centered on their role in arch support. Previous anatomical and electromyographic studies (reviewed herein) have demonstrated that the arches are normally maintained by bones and ligaments. This study reports an electromyographic investigation of five foot muscles (flexor digito-rum longus, flexor digitorum brevis, flexor accessorius, abductor hallucis, and abductor digiti quinti) conducted on four humans. The three toe flexors act together to resist extension of the toes during the stance phase of locomotion. Despite the large flexor accessorius in humans, neither this muscle nor the flexor digitorum brevis are preferentially recruited over the flexor digitorum lon-gus for any normal posture or locomotion. The abductors affect the mediolateral distribution of pressure by positioning the forefoot. We suggest that the foot muscles play an important role in positioning of the forces on the foot in both posture and locomotion. Future electromyographic experiments on human and ape foot muscles in conjunction with detailed studies of early hominid fossils promise to elucidate the pathways of human locomotor evolution.

scholarly journals Center of pressure-based postural sway differences on parallel and single leg stance in Olympic deaf basketball and volleyball players

2021 ◽  
Vol 17 (6) ◽  
pp. 418-427
Author(s):  
Yücel Makaracı ◽  
Recep Soslu ◽  
Ömer Özer ◽  
Abdullah Uysal
Keyword(s):  
Postural Control ◽  
Postural Stability ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Force Plate ◽  
Basketball Players ◽  
Male Athletes ◽  
Significant Difference ◽  
Single Leg Stance ◽  
Volleyball Players

In sports such as basketball and volleyball, loss of balance due to the inability to maintain body stability and lack of postural control adversely affect athletic performance. Deaf athletes appear to struggle with balance and postural stability problems. The purpose of this study was to examine postural sway values in parallel and single leg stance of Olympic deaf basketball and volleyball players and reveal differences between the branches. Twenty-three male athletes from the Turkish national deaf basketball (n= 11) and volleyball (n= 12) teams participated in the study. After anthropometric measurements, the subjects completed postural sway (PS) tests in parallel/single leg stances with open eyes and closed eyes on a force plate. PS parameters (sway path, velocity, and area) obtained from the device software were used for the statistical analysis. The Mann-Whitney U-test was used to compare differences in PS parameters between basketball and volleyball players, and the alpha value was accepted as 0.05. Volleyball players had significantly better results in parallel stance and dominant leg PS values than basketball players (P<0.05). There was no significant difference between the groups in nondominant leg PS values (P>0.05). We think that proprioceptive and vestibular system enhancing training practices to be performed with stability exercises will be beneficial in terms of both promoting functional stability and interlimb coordination. Trainers and strength coaches should be aware of differences in the postural control mechanism of deaf athletes.

scholarly journals Virtual-Reality-Induced Visual Perturbations Impact Postural Control System Behavior

2019 ◽  
Vol 9 (11) ◽  
pp. 113 ◽  
Author(s):  
Harish Chander ◽  
Sachini N. K. Kodithuwakku Arachchige ◽  
Christopher M. Hill ◽  
Alana J. Turner ◽  
Shuchisnigdha Deb ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Control System ◽  
Postural Control ◽  
Repeated Measures ◽  
Postural Stability ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Postural Control System ◽  
Postural Responses ◽  
The Impact

Background: Virtual reality (VR) is becoming a widespread tool in rehabilitation, especially for postural stability. However, the impact of using VR in a “moving wall paradigm” (visual perturbation), specifically without and with anticipation of the perturbation, is unknown. Methods: Nineteen healthy subjects performed three trials of static balance testing on a force plate under three different conditions: baseline (no perturbation), unexpected VR perturbation, and expected VR perturbation. The statistical analysis consisted of a 1 × 3 repeated-measures ANOVA to test for differences in the center of pressure (COP) displacement, 95% ellipsoid area, and COP sway velocity. Results: The expected perturbation rendered significantly lower (p < 0.05) COP displacements and 95% ellipsoid area compared to the unexpected condition. A significantly higher (p < 0.05) sway velocity was also observed in the expected condition compared to the unexpected condition. Conclusions: Postural stability was lowered during unexpected visual perturbations compared to both during baseline and during expected visual perturbations, suggesting that conflicting visual feedback induced postural instability due to compensatory postural responses. However, during expected visual perturbations, significantly lowered postural sway displacement and area were achieved by increasing the sway velocity, suggesting the occurrence of postural behavior due to anticipatory postural responses. Finally, the study also concluded that VR could be used to induce different postural responses by providing visual perturbations to the postural control system, which can subsequently be used as an effective and low-cost tool for postural stability training and rehabilitation.

The Effects of Acute and Long-Term Whole-Body Vibration Training on the Postural Control During Cognitive Task in Patients With Chronic Ankle Instability

2021 ◽  
pp. 1-8
Author(s):  
Seyed Abolfazl Tohidast ◽  
Rasool Bagheri ◽  
Ziaeddin Safavi-Farokhi ◽  
Mohammad Khaleghi Hashemian ◽  
Cyrus Taghizadeh Delkhosh
Keyword(s):  
Postural Control ◽  
Postural Stability ◽  
Center Of Pressure ◽  
Ankle Instability ◽  
Lateral Displacement ◽  
Whole Body Vibration ◽  
Chronic Ankle Instability ◽  
Whole Body ◽  
Body Vibration ◽  
The Mean

Context: Chronic ankle instability (CAI) is a common problem associated with impaired postural stability. Whole-body vibration (WBV) has been developed to improve muscle function and reportedly improves postural stability. The aim of this study was to evaluate the effect of 12 sessions of WBV on postural control during standing postural task in participants with CAI. Design: A controlled clinical trial study. Methods: Sixteen participants with CAI and 16 healthy participants aged between 20 and 40 years included in this study. They received WBV (30-Hz frequency, 3 series of four 45-s exercises with a 45-s rest) for a total of 12 sessions, 2 session per week for 6 weeks. Postural control was assessed by center of pressure (COP) parameters, including mean and SD in the anterior–posterior and medial–lateral displacement during single-leg standing. Assessments were done before and immediately after the first session and after the 12th session of WBV, with opened and closed eyes associated with easy and difficult cognitive tasks. Results: The results showed that the SD of COP displacement in the x-axis was significant in eyes opened and SD of COP displacement in the x- and y-axes were significant between groups in the eyes-opened, and eyes-closed conditions (P < .05). Analysis of variance indicated that the effect of WBV training was significant for the mean of COP displacement in the y-axis. Post hoc indicated that the effect of 12 sessions of WBV on the mean of COP displacement was significant in the CAI group (P < .05). However, the acute effect of WBV was not significant on the COP displacement in all axes (P > .05). Conclusion: Higher postural sway associated with postural cognitive interactions might be considered in the rehabilitation of CAI. Twelve sessions of WBV might induce some improvement in postural control with the method of WBV used in this study.

Control of sway using vibrotactile feedback of body tilt in patients with moderate and severe postural control deficits

2005 ◽  
Vol 15 (5-6) ◽  
pp. 313-325
Author(s):  
C. Wall ◽  
E. Kentala
Keyword(s):  
Postural Control ◽  
Postural Stability ◽  
Body Motion ◽  
Body Tilt ◽  
Joint Movement ◽  
Foot Pressure ◽  
Eyes Closed ◽  
The Subject ◽  
Anterior Posterior ◽  
Vibrotactile Display

We evaluated the effect of the vibrotactile display of body tilt upon the postural stability of vestibulopathic subjects during standing. Two groups were studied: those with moderate and with severe deficits as defined by postural stability test scores. They were studied under conditions of distorted sensory input, and during anterior-posterior perturbations. Seventeen subjects, with uni- or bilateral vestibular deficits, as determined by electronystagmography and vertical axis rotation, were tested using Equitest® computerized dynamic posturography (CDP). Based on their performance on the CDP they were divided into two groups having either moderate (nine subjects) or severe (eight subjects) postural control deficits. Their anterior-posterior (A/P) body motion at the waist was measured with a micromechanical rate gyroscope and a linear accelerometer. The resulting tilt estimate was displayed by a vibrotactile array attached to the torso. The vibration served as a tilt feedback to the subject. The subject's performance was evaluated using the root-mean-square (RMS) of both the A/P body motion and center-of-pressure (CoP) estimates. Sensory distortions were introduced using the Equitest® Sensory Organization Tests (SOT). These tests are designed to distort A/P sensory inputs while standing. The SOT 5 distorts proprioceptive information about ankle joint movement, while the subject stands eyes-closed on a moving support platform that measures foot pressure. The SOT 6 adds distorted visual information about body movement instead of testing with eyes closed. Perturbations were introduced using the Equitest® Motor Control Tests (MCT). These move the support platform forward or backward with small, medium and large displacements in the horizontal plane while measuring subjects' foot pressure responses. We used the medium and large backward tests. Vibrotactile display of body tilt reduced the subjects' A/P sway and improved their balance. The finding was more evident for those subjects with severe deficits than those moderate ones. This trend was found for both SOT 5 and 6, as well as the medium and large MCT. Additionally, during the MCT, the peak deflection and mean recovery time also decreased significantly.

AGE-RELATED CHANGES IN POSTURAL RE-BALANCED ABILITY DURING A CONTINUOUS AND UNEXPECTED PERTURBATION INTEGRATED WITH VIRTUAL REALITY SCENES

2016 ◽  
Vol 28 (03) ◽  
pp. 1650020
Author(s):  
Chun-Ju Chang ◽  
Jen-Suh Chern ◽  
Tsui-Fen Yang ◽  
Sai-Wei Yang
Keyword(s):  
Virtual Reality ◽  
Postural Control ◽  
Postural Stability ◽  
Center Of Pressure ◽  
Random Sequence ◽  
Weight Bearing ◽  
The Body ◽  
Assessment Protocol ◽  
Healthy Elderly ◽  
Age Related

The degeneration of sensory and motor systems due to aging could affect the elderly’s posture and increase the risk of falling. The strategies applied to maintain postural stability might be different between ages, especially in the condition requiring both proprioception and vision sensorimotor coupling. This study proposed a novel sensorimotor assessment protocol to evaluate the postural control ability across the aging process, by using the computerized dynamic posturography and the virtual reality (VR) system. Ten young and 20 elderly healthy adults without fall experience were recruited, and were assessed on a continuous-perturbed platform with or without the VR-based visual interference in a random sequence. Measured variables of the center of pressure as well as the weight-bearing ratio were analyzed and compared. Results showed that the postural sway was significantly larger in all subjects under the VR condition, but the young subjects could rapidly adjust the body to regain postural stability in a rhythmic and symmetric manner; whereas, the elderly adults performed less effectively in postural response. We suggested that the application of the multiple sensation disturbances with VR could effectively evaluate the postural control ability among the healthy elderly. The proposed assessing protocol is also recommended for training the sensorimotor integration to improve the dynamic postural control ability.

scholarly journals Regulation of dynamic postural control to attend manual steadiness constraints

2018 ◽  
Vol 120 (2) ◽  
pp. 693-702 ◽  
Author(s):  
Luis Augusto Teixeira ◽  
Joane de Figueiredo Serpa Coutinho ◽  
Daniel Boari Coelho
Keyword(s):  
Postural Control ◽  
Oscillation Frequency ◽  
Postural Stability ◽  
Center Of Pressure ◽  
Center Of Mass ◽  
Pressure Oscillation ◽  
Task Constraint ◽  
Task Constraints ◽  
Manual Task ◽  
High Oscillation Frequency

In daily living activities, performance of spatially accurate manual movements in upright stance depends on postural stability. In the present investigation, we aimed to evaluate the effect of the required manual steadiness (task constraint) on the regulation of dynamic postural control. A single group of young participants ( n = 20) were evaluated in the performance of a dual posturo-manual task of balancing on a platform oscillating in sinusoidal translations at 0.4-Hz (low) or 1-Hz (high) frequencies while stabilizing a cylinder on a handheld tray. Manual task constraint was manipulated by comparing the conditions of keeping the cylinder stationary on its flat or round side, corresponding to low and high manual task constraints, respectively. Results showed that in the low oscillation frequency the high manual task constraint led to lower oscillation amplitudes of the head, center of mass, and tray, in addition to higher relative phase values between ankle/hip-shoulder oscillatory rotations and between center of mass/center of pressure-feet oscillations as compared with values observed in the low manual task constraint. Further analyses showed that the high manual task constraint also affected variables related to both postural (increased amplitudes of center of pressure oscillation) and manual (increased amplitude of shoulder rotations) task components in the high oscillation frequency. These results suggest that control of a dynamic posturo-manual task is modulated in distinct parameters to attend the required manual steadiness in a complex and flexible way. NEW & NOTEWORTHY We evaluated dynamic postural control on a platform oscillating in sinusoidal translations at different frequencies while performing a manual task with low or high steadiness constraints. Results showed that high manual task constraint led to modulation of metric and coordination variables associated with greater postural stability. Our findings suggest that motor control is regulated in an integrative mode at the posturo-manual task level, with reciprocal interplay between the postural and manual components.

Intrinsic Foot Muscle Morphology in Active Runners With and Without a History of Exercise-Related Lower Leg Pain

2020 ◽  
Vol 25 (2) ◽  
pp. 62-67
Author(s):  
Aliza K. Nedimyer ◽  
Brian G. Pietrosimone ◽  
Brittney A. Luc-Harkey ◽  
Erik A. Wikstrom
Keyword(s):  
Visual Information ◽  
Morphological Characteristics ◽  
Lower Leg ◽  
Leg Pain ◽  
Abductor Hallucis ◽  
Flexor Digitorum Brevis ◽  
History Of ◽  
Lower Leg Pain ◽  
Flexor Digitorum ◽  
Intrinsic Muscles

Our objective was to quantify the functional and morphological characteristics of the plantar intrinsic muscles in those with and without a history of exercise-related lower leg pain (ERLLP). Thirty-two active runners—24 with a history of ERLLP—volunteered. Strength of the flexor hallucis brevis and flexor digitorum brevis, postural control, and navicular drop were recorded. Morphology of the abductor hallucis, flexor digitorum brevis, and flexor hallucis brevis muscles were captured using ultrasonography. Those with ERLLP had smaller flexor hallucis brevis morphology measures (p ≤ .015) and a greater reliance on visual information while balancing (p = .05). ERLLP appears to alter intrinsic muscle function and morphology.

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