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.

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 Influence of prevalent occupational position during working day on occupational lower limb edema

2015 ◽  
Vol 14 (2) ◽  
pp. 153-160 ◽  
Author(s):  
Cleusa Ema Quilici Belczak ◽  
José Maria Pereira Godoy ◽  
Amélia Cristina Seidel ◽  
Rubiana Neves Ramos ◽  
Sergio Quilici Belczak ◽  
...  
Keyword(s):  
Lower Limb ◽  
Skin Color ◽  
Correlation Coefficients ◽  
Cumulative Effect ◽  
Study Groups ◽  
Lower Limbs ◽  
Volume Increase ◽  
Occupational Position ◽  
Limb Edema ◽  
Working Day

BACKGROUND: The lower limb edema observed in normal people at the end of their working days can vary in intensity and frequency depending on the predominant working positions required to perform different jobs.OBJECTIVES: To compare lower limb volumes of volunteers allocated to three study groups, depending on the predominant positions in which they work.METHODS: Volumetric assessments were conducted of both lower limbs of 51 people free from vascular disease, allocated to three groups of 17 individuals each by predominant working position: sitting, static standing or alternating between the two. Volumes were measured at the start and at the end of the working day and the differences in volumes were calculated for each group. Means and frequencies were compared using appropriate inferential statistics and correlation coefficients were calculated.RESULTS: The groups were homogenous in terms of sex distribution, age, skin color and BMI. The volumetric data from measurements taken before starting work revealed significant differences between all three groups. Volunteers who predominantly worked sitting down had largest volumes, followed by those who remained standing for long periods and then those who varied between these positions. The frequency of lower limb volume increase > 100 mL was significantly higher in the group of people who worked sitting down and maintained this position for long periods.CONCLUSIONS: Postural edema is more common among people who work sitting down for long periods, among whom it appears that there is a cumulative effect from the position, since they exhibit larger lower limb volumes at the start of the day.

The Effects of Uni- and Bilateral Fatigue on Postural and Power Tasks

2013 ◽  
Vol 29 (1) ◽  
pp. 44-48 ◽  
Author(s):  
Paulo H. Marchetti ◽  
Maria I.V. Orselli ◽  
Marcos Duarte
Keyword(s):  
Lower Limb ◽  
Healthy Subjects ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Lower Limbs ◽  
Quiet Standing ◽  
Ground Reaction Forces ◽  
Before And After ◽  
Reaction Forces ◽  
The Mean

The aim of this study was to investigate the effects of unilateral and bilateral fatigue on both postural and power bipedal tasks. Ten healthy subjects performed two tasks: bipedal quiet standing and a maximal bipedal counter-movement jumping before and after unilateral (with either the dominant or nondominant lower limb) and bilateral (with both lower limbs) fatigue. We employed two force plates (one under each lower limb) to measure the ground reaction forces and center of pressure produced by subjects during the tasks. To quantify the postural sway during quiet standing, we calculated the resultant center of pressure (COP) speed and COP area of sway, as well as the mean weight distribution between lower limbs. To quantify the performance during the countermovement jumping, we calculated the jump height and the peak force of each lower limb. We observed that both unilateral and bilateral fatigue affected the performance of maximal voluntary jumping and standing tasks and that the effects of unilateral and bilateral fatigue were stronger in the dominant limb than in the nondominant limb during bipedal tasks. We conclude that unilateral neuromuscular fatigue affects both postural and power tasks negatively.

scholarly journals Association between walking and strength of lower limbs after chronic stroke

2020 ◽  
Vol 27 (3) ◽  
pp. 131-138
Author(s):  
Brenno Belchior Cordeiro Silva ◽  
Iza de Faria-Fortini ◽  
Pollyana Helena Vieira Costa ◽  
Camila Torriani-Pasin ◽  
Janaine Cunha Polese
Keyword(s):  
Muscle Strength ◽  
Lower Limb ◽  
Walking Speed ◽  
Chronic Stroke ◽  
Community Dwelling ◽  
Lower Limbs ◽  
Average Strength ◽  
Paretic Side ◽  
The Difference ◽  
Muscle Groups

Certain muscle groups strength directly influence walking speed (WS), and the lower strength of the paretic side is significantly associated with lower WS of individuals after stroke. Studies that have investigated the association between the average of lower limb strength and the WS in individuals are scarce. Therefore, it is important to determine whether the strength could explain walking performance due to some muscle weakness could be compensated by the strength of others, mainly because all muscles act in group, not isolated. Objective: To investigate the association between WS and lower limbs muscle strength, and to identify whether an individual muscle group or the average strength of lower limb would best predict WS and walking speed reserve (WSR) in individuals with stroke. Methods: Sixty-four community-dwelling individuals with chronic stroke have their maximum isometric strength (hip flexors/extensors/abductors, knee flexors/extensors, and ankle dorsiflexors/plantarflexors) and self-selected and fast WS (10m walk test) measured. WSR was considered as the difference between the fast and self-selected speed. Results: Average strength of the paretic limb accounted for 19% and 20% of the variance in self-selected and fast WS, respectively. Plantarflexor strength of the paretic, knee and hip flexors of the non-paretic side explained alone 27% of the WSR scores and plantarflexor strength of the paretic side alone explained 15%.Conclusion: Average muscle strength of the paretic side contributed to self-selected and fast WS. Plantarflexor strength of the paretic side, knee and hip flexors of the non-paretic side contributed with the WSR of chronic stroke individuals.

scholarly journals Reliability of joint position sense measured in the knee using the level function of the iPhone “Measure” application

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256561
Author(s):  
Yuki Nakashima ◽  
Daisuke Iwaki ◽  
Toshihiro Kawae ◽  
Kenichi Fudeyasu ◽  
Hiroaki Kimura
Keyword(s):  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Position Sense ◽  
Joint Position Sense ◽  
Initial Position ◽  
Lower Limbs ◽  
Joint Position ◽  
Target Angle ◽  
Level Function ◽  
The Difference

An impaired joint position sense (JPS) causes activity limitations, postural imbalance, and falls. This study compares the reliability of knee JPS measurements between the iPhone’s “Measure” application and VICON motion capture system. Eleven healthy participants were recruited for the study. To conduct the study measures, the blindfolded participant, with an iPhone fixed to the lower non-dominant leg, was seated with their lower limbs in a relaxed position. The examiner held the participant’s leg at the target angle (30°/60° from initial position) for 5 s before releasing it. The participant was then instructed to move the leg to the same target angle and hold it for 5 s (replicated angle). Absolute angular error (AAE), i.e., the difference between the target and replicated angles, was measured. Intraclass and Pearson correlation coefficients established statistically significant relationships. The study comprised 6 males and 5 females of mean age 27.6±5.6 years, mean height 1.67±0.10 m, and mean body weight 60.7±10.3 kg. Strong correlations existed between iPhone and VICON 30° (ICC = 0.969, r = 0.960, P < 0.001) and 60° AAEs (ICC 0.969, r = 0.960, P < 0.001). Bland-Altman plots showed a mean difference of 0.43° and 0.20° between the AAE measurements at 30° and 60°, respectively. The iPhone’s “Measure” application is a simple and reliable method for measuring JPS in clinical practice and sports/fitness settings.

scholarly journals Brain Activity during Lower-Limb Movement with Manual Facilitation: An fMRI Study

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Patrícia Maria Duarte de Almeida ◽  
Ana Isabel Correia Matos de Ferreira Vieira ◽  
Nádia Isabel Silva Canário ◽  
Miguel Castelo-Branco ◽  
Alexandre Lemos de Castro Caldas
Keyword(s):  
Motor Control ◽  
Lower Limb ◽  
Healthy Subjects ◽  
Brain Activity ◽  
Verbal Stimulus ◽  
Limb Movement ◽  
Lower Limbs ◽  
Normal Brain ◽  
Lower Limb Movement ◽  
The Right

Brain activity knowledge of healthy subjects is an important reference in the context of motor control and reeducation. While the normal brain behavior for upper-limb motor control has been widely explored, the same is not true for lower-limb control. Also the effects that different stimuli can evoke on movement and respective brain activity are important in the context of motor potentialization and reeducation. For a better understanding of these processes, a functional magnetic resonance imaging (fMRI) was used to collect data of 10 healthy subjects performing lower-limb multijoint functional movement under three stimuli: verbal stimulus, manual facilitation, and verbal + manual facilitation. Results showed that, with verbal stimulus, both lower limbs elicit bilateral cortical brain activation; with manual facilitation, only the left lower limb (LLL) elicits bilateral activation while the right lower limb (RLL) elicits contralateral activation; verbal + manual facilitation elicits bilateral activation for the LLL and contralateral activation for the RLL. Manual facilitation also elicits subcortical activation in white matter, the thalamus, pons, and cerebellum. Deactivations were also found for lower-limb movement. Manual facilitation is stimulus capable of generating brain activity in healthy subjects. Stimuli need to be specific for bilateral activation and regarding which brain areas we aim to activate.

scholarly journals Automatic pairing of inertial sensors to lower limb segments – a plug-and-play approach

2016 ◽  
Vol 2 (1) ◽  
pp. 715-718 ◽  
Author(s):  
David Graurock ◽  
Thomas Schauer ◽  
Thomas Seel
Keyword(s):  
Sensor Networks ◽  
Lower Limb ◽  
Healthy Subjects ◽  
Inertial Sensors ◽  
Inertial Sensor ◽  
Lower Limbs ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Correct Pairing ◽  
Measurement Units

AbstractInertial sensor networks enable realtime gait analysis for a multitude of applications. The usability of inertial measurement units (IMUs), however, is limited by several restrictions, e.g. a fixed and known sensor placement. To enhance the usability of inertial sensor networks in every-day live, we propose a method that automatically determines which sensor is attached to which segment of the lower limbs. The presented method exhibits a low computational workload, and it uses only the raw IMU data of 3 s of walking. Analyzing data from over 500 trials with healthy subjects and Parkinson’s patients yields a correct-pairing success rate of 99.8% after 3 s and 100% after 5 s.

scholarly journals Does grip strength predict lower limb global strength in subjects with stroke?

2020 ◽  
Vol 33 ◽  
Author(s):  
Juliane Franco ◽  
Ludmylla Ferreira Quintino ◽  
Christina Danielli Coelho de Morais Faria
Keyword(s):  
Grip Strength ◽  
Lower Limb ◽  
Pearson Correlation ◽  
Chronic Phase ◽  
Lower Limbs ◽  
Pearson Correlation Coefficient ◽  
Subacute Phase ◽  
Different Populations ◽  
Global Strength ◽  
The Relationship

Abstract Introduction: Grip strength is an important clinical measure and has been used for several purposes in different populations, including those to predict the global strength of lower limbs (LL) and upper limbs. However, little is known about the association between grip strength and lower limb (LL) global strength in subjects with stroke. Objective: To investigate the relationship between grip strength and LL global strength in stroke with subjects at both subacute and chronic phases. Method: Measures of grip strength (handgrip dynamometer) and LL global strength (hand-held dynamometer) were obtained in 20 subjects in the subacute phase of the stroke and 18 in the chronic phase. Pearson correlation coefficient was used to investigate the correlation between grip strength and LL global strength (α = 0.05). Results: Subjects in the subacute phase showed a moderate statistically significant correlation between paretic grip strength and global strength of the non-paretic LL (r = 0.50; p < 0.05), but no correlation with the paretic LL was found (p = 0.25). The non-paretic grip strength showed no statistically significant correlation with global strength of the paretic LL (p = 0.93) and of the non-paretic LL (p = 0.64). In chronic subjects, no statistically significant correlation (0.50 ≤ p ≤ 0.97) was observed. Conclusion: Grip strength does not seem to be an adequate indicator to predict LL global strength of subjects with stroke. This conclusion is different from that obtained for other populations.

Leg Dominance May Not Be a Predictor of Asymmetry in Peak Joint Moments and Ground Reaction Forces During Sit-to-Stand Movements

2014 ◽  
Vol 30 (1) ◽  
pp. 179-183 ◽  
Author(s):  
Jonathon S. Schofield ◽  
Eric Parent ◽  
Justin Lewicke ◽  
Jason P. Carey ◽  
Marwan El-Rich ◽  
...  
Keyword(s):  
Lower Limb ◽  
Inverse Dynamics ◽  
Bilateral Symmetry ◽  
Joint Moment ◽  
Ground Reaction Forces ◽  
Joint Moments ◽  
Sit To Stand ◽  
Reaction Forces ◽  
Three Body ◽  
Leg Dominance

Sit-to-stand transfer is a common prerequisite for many daily tasks. Literature often assumes symmetric behavior across the left and right side. Although this assumption of bilateral symmetry is prominent, few studies have validated this supposition. This pilot study uniquely quantifies peak joint moments and ground reaction forces (GRFs), using a Euclidian norm approach, to evaluate bilateral symmetry and its relation to lower limb motor-dominance during sit to stand in ten healthy males. Peak joint moments and GRFs were determined using a motion capture system and inverse dynamics. This analysis included joint moment contributions from all three body planes (sagittal, coronal, and axial) as well as vertical and shearing GRFs. A paired, one-tailedttest was used, suggesting asymmetrical joint moment development in all three lower extremity joints as well as GRFs (P< .05). Furthermore, using an unpaired two-tailedttest, asymmetry developed during these movements does not appear to be predictable by participants’ lower limb motor-dominance (P< .025). Consequently, when evaluating sit-to-stand it is suggested the effects of asymmetry be considered in the interpretation of data. The absence of a relationship between dominance and asymmetry prevents the suggestion that one side can be tested to infer behavior of the contralateral.

scholarly journals Effect of limb rotation on radiographic alignment measurement in mal-aligned knees

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Xiaoshu Sun ◽  
Bin Yang ◽  
Shengzhao Xiao ◽  
Yichen Yan ◽  
Zifan Liu ◽  
...  
Keyword(s):  
Lower Limb ◽  
Knee Flexion ◽  
Measurement Errors ◽  
Mechanical Axis ◽  
Weight Bearing ◽  
Correlation Coefficients ◽  
Lower Limbs ◽  
Limb Alignment ◽  
Lower Limb Alignment ◽  
Accuracy Of Measurements

Abstract Purpose Long-leg-radiography (LLR) is commonly used for the measurement of lower limb alignment. However, limb rotations during radiography may interfere with the alignment measurement. This study examines the effect of limb rotation on the accuracy of measurements based on the mechanical and anatomical axes of the femur and tibia, with variations in knee flexion and coronal deformity. Methods Forty-five lower limbs of 30 patients were scanned with CT. Virtual LLRs simulating five rotational positions (neutral, ± 10$$^{\circ }$$ ∘ , and ± 20$$^{\circ }$$ ∘ internal rotation) were generated from the CT images. Changes in the hip–knee–ankle angle (HKA) and the femorotibial angle (FTA) were measured on each image with respect to neutral values. These changes were related to knee flexion and coronal deformity under both weight- and non-weight-bearing conditions. Results The measurement errors of the HKA and FTA derived from limb rotation were up to 4.84 ± 0.66$$^{\circ }$$ ∘ and 7.35 ± 0.88$$^{\circ }$$ ∘ , respectively, and were correlated with knee flexion (p < 0.001) and severe coronal deformity (p < 0.001). Compared with the non-weight-bearing position, the coronal deformity measured in the weight-bearing condition was 2.62$$^{\circ }$$ ∘ greater, the correlation coefficients between the coronal deformity and the deviation ranges of HKA and FTA were also greater. Conclusions Flexion and severe coronal deformity have a significant influence on the measurement error of lower limb alignment. Errors can be amplified in the weight-bearing condition compared with the non-weight-bearing condition. When using HKA and FTA to represent the mechanical axis and the anatomical axis on LLR, limb rotation impacts the anatomic axis more than the mechanical axis in patients with severe deformities. Considering LLR as the gold standard image modality, attention should be paid to the measurement of knee alignment. Especially for the possible errors derived from weight-bearing long-leg radiographs of patients with severe knee deformities.

Sign in / Sign up

Export Citation Format

Share Document