Initial balance in human standing postures: Roles of the joint mechanisms

2018 ◽  
Vol 232 (12) ◽  
pp. 1255-1260 ◽  
Author(s):  
Mohammed N Ashtiani ◽  
Mahmood-reza Azghani ◽  
Mohamad Parnianpour
Keyword(s):  
Inverse Dynamics ◽  
Muscular Activity ◽  
Biomechanical Model ◽  
Lower Limbs ◽  
Stable Set ◽  
Joint Angles ◽  
Lower Extremity Muscle ◽  
Ankle Muscles ◽  
Muscle Groups ◽  
Dynamics Method

The static initial postures of standing before applying perturbations may affect the maintenance of postural balance. The goal of this article was to find the stable set of postures and then determine the roles of joint mechanisms. The set of posture was defined in a biomechanical model based on three joint angles of the lower limbs. Optimized inverse dynamics method was used to solve for muscle forces in a precise model of the human musculoskeletal system posed in 4096 static sets of posture using AnyBody software. Results showed that the overall body muscular activity in standing is reduced by knee flexion. Moderate knee angles between 20° and 60° provided safer postures against possible perturbations because of higher collaboration levels of the joint mechanisms. About 36% of the overall postural infeasibilities were attributed to the inability of the ankle muscles to more sustain the exerted loads. Although the roles of the joint mechanisms were closely dependent on the postures, there was no direct relation between the joint kinematics and activation levels of their supporting muscles. Lower extremity muscle groups collaborate to maintain the balance in a considerable number of static postures.

scholarly journals Patterns of lower limb muscular activity and joint moments during directional efforts using a static dynamometer

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Mathieu Lalumiere ◽  
Cloé Villeneuve ◽  
Cassandra Bellavance ◽  
Michel Goyette ◽  
Daniel Bourbonnais
Keyword(s):  
Lower Limb ◽  
Healthy Subjects ◽  
Inverse Dynamics ◽  
Pearson Correlation ◽  
Activity Patterns ◽  
Correlation Coefficients ◽  
Muscular Activity ◽  
Lower Limbs ◽  
Joint Moments ◽  
Muscle Groups

Abstract Background Strength and coordination of lower muscle groups typically identified in healthy subjects are two prerequisites to performing functional activities. These physical qualities can be impaired following a neurological insult. A static dynamometer apparatus that measures lower limb joint moments during directional efforts at the foot was developed to recruit different patterns of muscular activity. The objectives of the present study were to 1) validate joint moments estimated by the apparatus, and 2) to characterize lower limb joint moments and muscular activity patterns of healthy subjects during progressive static efforts. Subjects were seated in a semi-reclined position with one foot attached to a force platform interfaced with a laboratory computer. Forces and moments exerted under the foot were computed using inverse dynamics, allowing for the estimation of lower limb joint moments. To achieve the study’s first objective, joint moments were validated by comparing moments of various magnitudes of force applied by turnbuckles on an instrumented leg equipped with strain gauges with those estimated by the apparatus. Concurrent validity and agreement were assessed using Pearson correlation coefficients and Bland and Altman analysis, respectively. For the second objective, joint moments and muscular activity were characterized for five healthy subjects while exerting progressive effort in eight sagittal directions. Lower limb joint moments were estimated during directional efforts using inverse dynamics. Muscular activity of eight muscles of the lower limb was recorded using surface electrodes and further analyzed using normalized root mean square data. Results The joint moments estimated with the instrumented leg were correlated (r > 0.999) with those measured by the dynamometer. Limits of agreement ranged between 8.5 and 19.2% of the average joint moment calculated by both devices. During progressive efforts on the apparatus, joint moments and patterns of muscular activity were specific to the direction of effort. Patterns of muscular activity in four directions were similar to activation patterns reported in the literature for specific portions of gait cycle. Conclusion This apparatus provides valid joint moments exerted at the lower limbs. It is suggested that this methodology be used to recruit muscular activity patterns impaired in neurological populations.

Prediction of the Lower Extremity Muscle Forces During Stair Ascent and Descent

2008 ◽  
Author(s):  
Ali Selk Ghafari ◽  
Ali Meghdari ◽  
Gholam Reza Vossoughi
Keyword(s):  
Lower Extremity ◽  
Inverse Dynamics ◽  
Sagittal Plane ◽  
Optimization Technique ◽  
The Elderly ◽  
Plantar Flexors ◽  
Stair Ascent ◽  
Lower Extremity Muscle ◽  
Anatomical Classification ◽  
Muscle Groups

An inverse dynamics musculoskeletal model of the lower extremity was combined with an optimization technique to estimate individual muscular forces and powers during stair ascent and descent. Eighteen Hill-type musculotendon actuators per leg were combined into the eleven functional muscle groups based on anatomical classification to drive the model in the sagittal plane. Simulation results illustrate the major functional differences in plantar flexors of the ankle and extensors of the knee and hip joints during ascent and descent. The results of this study not only could be employed to evaluate the rehabilitation results in the elderly but also could be used to design more anthropometric assistive devices with optimum power consumption.

scholarly journals Contributions of Limb Joints to Energy Absorption during Landing in Cats

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Xueqing Wu ◽  
Baoqing Pei ◽  
Yuyang Pei ◽  
Nan Wu ◽  
Kaiyuan Zhou ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Inverse Dynamics ◽  
Motor Program ◽  
Lower Limbs ◽  
Joint Angles ◽  
Limb Injuries ◽  
Significant Difference ◽  
Angular Velocities ◽  
Synergistic Mechanism ◽  
The Impact

There is a high risk of serious injury to the lower limbs in a human drop landing. However, cats are able to jump from the same heights without any sign of injury, which is attributed to the excellent performance of their limbs in attenuating the impact forces. The bionic study of the falling cat landing may therefore contribute to improve the landing-shock absorbing ability of lower limbs in humans. However, the contributions of cat limb joints to energy absorption remain unknown. Accordingly, a motion capture system and plantar pressure measurement platform were used to measure the joint angles and vertical ground reaction forces of jumping cats, respectively. Based on the inverse dynamics, the joint angular velocities, moments, powers, and work from different landing heights were calculated to expound the synergistic mechanism and the dominant muscle groups of cat limb joints. The results show that the buffering durations of the forelimbs exhibit no significant difference with increasing height while the hindlimbs play a greater role than the forelimbs in absorbing energy when jumping from a higher platform. Furthermore, the joint angles and angular velocities exhibit similar variations, indicating that a generalized motor program can be adopted to activate limb joints for different landing heights. Additionally, the elbow and hip are recognized as major contributors to energy absorption during landing. This experimental study can accordingly provide biological inspiration for new approaches to prevent human lower limb injuries.

A Biomechanical Study of Side Steps at Different Distances

2013 ◽  
Vol 29 (3) ◽  
pp. 336-345 ◽  
Author(s):  
Yuki Inaba ◽  
Shinsuke Yoshioka ◽  
Yoshiaki Iida ◽  
Dean C. Hay ◽  
Senshi Fukashiro
Keyword(s):  
Inverse Dynamics ◽  
Center Of Mass ◽  
Reaction Force ◽  
Biomechanical Study ◽  
Joint Torque ◽  
Large Power ◽  
Lower Extremity Muscle ◽  
Ankle Joints ◽  
Hip Abduction ◽  
Muscle Groups

Lateral quickness is a crucial component of many sports. However, biomechanical factors that contribute to quickness in lateral movements have not been understood well. Thus, the purpose of this study was to quantify 3-dimensional kinetics of hip, knee, and ankle joints in side steps to understand the function of lower extremity muscle groups. Side steps at nine different distances were performed by nine male subjects. Kinematic and ground reaction force data were recorded, and net joint torque and work were calculated by a standard inverse-dynamics method. Extension torques and work done at hip, knee, and ankle joints contributed substantially to the changes in side step distances. On the other hand, hip abduction work was not as sensitive to the changes in the side step distances. The main roles of hip abduction torque and work were to accelerate the center of mass laterally in the earlier phase of the movement and to keep the trunk upright, but not to generate large power for propulsion.

scholarly journals Estimation of Human Center of Mass Position through the Inertial Sensors-Based Methods in Postural Tasks: An Accuracy Evaluation

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 601 ◽  
Author(s):  
Marco Germanotta ◽  
Ilaria Mileti ◽  
Ilaria Conforti ◽  
Zaccaria Del Prete ◽  
Irene Aprile ◽  
...  
Keyword(s):  
Inertial Sensors ◽  
Center Of Mass ◽  
Correlation Coefficients ◽  
Biomechanical Model ◽  
Lower Limbs ◽  
Accuracy Evaluation ◽  
Postural Tasks ◽  
Single Sensor ◽  
Using Data ◽  
Displacement Based

The estimation of the body’s center of mass (CoM) trajectory is typically obtained using force platforms, or optoelectronic systems (OS), bounding the assessment inside a laboratory setting. The use of magneto-inertial measurement units (MIMUs) allows for more ecological evaluations, and previous studies proposed methods based on either a single sensor or a sensors’ network. In this study, we compared the accuracy of two methods based on MIMUs. Body CoM was estimated during six postural tasks performed by 15 healthy subjects, using data collected by a single sensor on the pelvis (Strapdown Integration Method, SDI), and seven sensors on the pelvis and lower limbs (Biomechanical Model, BM). The accuracy of the two methods was compared in terms of RMSE and estimation of posturographic parameters, using an OS as reference. The RMSE of the SDI was lower in tasks with little or no oscillations, while the BM outperformed in tasks with greater CoM displacement. Moreover, higher correlation coefficients were obtained between the posturographic parameters obtained with the BM and the OS. Our findings showed that the estimation of CoM displacement based on MIMU was reasonably accurate, and the use of the inertial sensors network methods should be preferred to estimate the kinematic parameters.

scholarly journals Evaluation of Individualized Functional Electrical Stimulation-Induced Acute Changes during Walking: A Case Series in Children with Cerebral Palsy

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4452
Author(s):  
Nicole Zahradka ◽  
Ahad Behboodi ◽  
Ashwini Sansare ◽  
Samuel C. K. Lee
Keyword(s):  
Cerebral Palsy ◽  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Physical Therapists ◽  
Physical Therapist ◽  
Case Series ◽  
Phase Detection ◽  
Lower Extremity Muscle ◽  
Children With Cerebral Palsy ◽  
Muscle Groups

Functional electrical stimulation (FES) walking interventions have demonstrated improvements to gait parameters; however, studies were often confined to stimulation of one or two muscle groups. Increased options such as number of muscle groups targeted, timing of stimulation delivery, and level of stimulation are needed to address subject-specific gait deviations. We aimed to demonstrate the feasibility of using a FES system with increased stimulation options during walking in children with cerebral palsy (CP). Three physical therapists designed individualized stimulation programs for six children with CP to target participant-specific gait deviations. Stimulation settings (pulse duration and current) were tuned to each participant. Participants donned our custom FES system that utilized gait phase detection to control stimulation to lower extremity muscle groups and walked on a treadmill at a self-selected speed. Motion capture data were collected during walking with and without the individualized stimulation program. Eight gait metrics and associated timing were compared between walking conditions. The prescribed participant-specific stimulation programs induced significant change towards typical gait in at least one metric for each participant with one iteration of FES-walking. FES systems with increased stimulation options have the potential to allow the physical therapist to better target the individual’s gait deviations than a one size fits all device.

scholarly journals Two-Segment Foot Model for the Biomechanical Analysis of Squat

2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
E. Panero ◽  
L. Gastaldi ◽  
W. Rapp
Keyword(s):  
Body Weight ◽  
Inverse Dynamics ◽  
Statistical Significance ◽  
Lower Limbs ◽  
Biomechanical Analysis ◽  
Wide Range ◽  
Foot Model ◽  
Partial Body ◽  
The One ◽  
Midtarsal Joint

Squat exercise is acquiring interest in many fields, due to its benefits in improving health and its biomechanical similarities to a wide range of sport motions and the recruitment of many body segments in a single maneuver. Several researches had examined considerable biomechanical aspects of lower limbs during squat, but not without limitations. The main goal of this study focuses on the analysis of the foot contribution during a partial body weight squat, using a two-segment foot model that considers separately the forefoot and the hindfoot. The forefoot and hindfoot are articulated by the midtarsal joint. Five subjects performed a series of three trials, and results were averaged. Joint kinematics and dynamics were obtained using motion capture system, two force plates closed together, and inverse dynamics techniques. The midtarsal joint reached a dorsiflexion peak of 4°. Different strategies between subjects revealed 4° supination and 2.5° pronation of the forefoot. Vertical GRF showed 20% of body weight concentrated on the forefoot and 30% on the hindfoot. The percentages varied during motion, with a peak of 40% on the hindfoot and correspondently 10% on the forefoot, while the traditional model depicted the unique constant 50% value. Ankle peak of plantarflexion moment, power absorption, and power generation was consistent with values estimated by the one-segment model, without statistical significance.

Lower-Limb Rehabilitation at Home

2021 ◽  
Vol 13 (2) ◽  
pp. 12-23
Author(s):  
Seanglidet Yean ◽  
Bu-Sung Lee ◽  
Chai Kiat Yeo
Keyword(s):  
Lower Limbs ◽  
Ageing Population ◽  
Joint Angles ◽  
Functional Activities ◽  
State Identification ◽  
Motion State ◽  
Limb Rehabilitation ◽  
Lower Limb Rehabilitation ◽  
Rehabilitation Exercise ◽  
At Home

Ageing causes loss of muscle strength, especially on the lower limbs, resulting in higher risk to injuries during functional activities. The path to recovery is through physiotherapy and adopt customized rehabilitation exercise to assist the patients. Hence, lowering the risk of incorrect exercise at home involves the use of biofeedback for physical rehabilitation patients and quantitative reports for clinical physiotherapy. This research topic has garnered much attention in recent years owing to the fast ageing population and the limited number of clinical experts. In this paper, the authors survey the existing works in exercise assessment and state identification. The evaluation results in the accuracy of 95.83% average classifying exercise motion state using the proposed raw signal. It confirmed that raw signals have more impact than using sensor-fused Euler and joint angles in the state identification prediction model.

scholarly journals Muscle strength and inflammatory response to the training load in rowers

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10355
Author(s):  
Tomasz Podgórski ◽  
Alicja Nowak ◽  
Katarzyna Domaszewska ◽  
Jacek Mączyński ◽  
Magdalena Jabłońska ◽  
...  
Keyword(s):  
Muscle Metabolism ◽  
Creatine Kinase Activity ◽  
Lower Limbs ◽  
Total Testosterone ◽  
Blood Biochemical ◽  
Global Force ◽  
Significant Difference ◽  
Muscle Groups ◽  
Torque Values ◽  
The Right

Background Regular exercise leads to changes in muscle metabolism. The consequence of this is the adaptation to higher training loads.The aim of this study was to evaluate biomechanical and biochemical parameters describing the functions of skeletal muscles in periods when changes in training forms were introduced. Methods Seventeen male sweep-oar rowers, members of the Polish national rowing team, participated. The study was carried out at the beginning and at the end of the preparatory period. In the first and second examination measurements of torques of selected muscle groups and blood biochemical analysis were performed. Results There was observed a statistically significant decrease in the relative global force of the right lower limb between both terms of examination. A statistically significant increase in maximum torque was found for torso flexors. In the case of muscles responsible for torso rotation, a statistically significant decrease in the torque values of right torso rotators was observed. A significant difference was found with respect to creatine kinase activity, total testosterone concentration, total testosterone to cortisol ratio and total phenolics concentration (p < 0.05). Conclusion The study shows that the rowers’ training should be more focused on building the strength of lower limbs to prevent the overload of lumbar spine and that the amount of force developed may be significantly affected by the antioxidant potential of rowers.

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