Could thermal imaging supplement surface electromyography measurements for skeletal muscles?

B. Zagrodny, W. Wojnicz , M. Ludwicki, J. Awrejcewicz – IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT – 2020
Abstract—(1) Background: The aim of this study is to present the results of experiments in which surface electromyography (sEMG) and thermal imaging were used to assess muscle activation during gait and to verify the hypothesis that there is a relationship in the case of low fatigue level between sEMG measured muscle activation, assessed in the frequency domain, and thermal factors calculated as minimum, maximum, kurtosis, mean, median and mode from the area of interest. (2) Methods: Comparison of activity calculated from the recorded sEMG data for rectus femoris, biceps femoris, tibialis anterior and gastrocnemius medialis with thermal data obtained from the infrared vision. (3) Results: Data of fourteen healthy volunteers obtained during 10 minutes of treadmill gait are presented and analyzed. The analysis revealed statistically significant: linear correlations for rectus femoris (five moderate relationships) and gastrocnemius medialis (one good relationship); moderate nonlinear correlations for all examined muscles. Also, a detailed protocol for precise, repeatable thermal examination is presented. (4) Conclusions: Estimated moderate linear and non-linear correlations between thermal and electromyographic parameters are found for low level of muscle fatigue, which suggests that the presented method is useful in the analysis of muscle activation with the use of a thermal imaging as a complement to sEMG.

Perceptual and Motor Effects of Muscle Co-activation in a Force Production Tas

C. Cuadra, W. Wojnicz , M. Latash, Z. Kozinc – NEUROSCIENCE – 2020
We tested several predictions of the theory of motor control with spatial referent coordinates related to effects of muscle coactivation on force production and perception. In particular, we predicted that subjects would produce unintentional force increase by finger flexors and be unaware of this force increase. Healthy subjects performed steady force production task in isometric conditions with visual feedback on the force level. They coactivated muscles of the arm trying to keep the force constant in the absence of visual feedback. This led to a consistent force increase not perceived by the subjects as reflected by their verbal reports. In contrast, when asked to match the force with the contralateral hand, adequate force matching was observed. Using the ‘‘inverse piano” apparatus confirmed no change in the referent coordinate of the fingers and an increase in its apparent stiffness. The results confirm the earlier hypothesis on the reciprocal command being hierarchically higher than the coactivation command. The observations suggest that verbal reports and force matching use different neural mechanisms of force perception; the former are dominated by sense of effort, which reflects primarily the magnitude of the reciprocal command. There were only minor differences between the dominant and non-dominant hands, likely reflecting the faster unintentional drifts of control variables in the dominant hand.

Influence of the shoe type on the ground reaction force

M. Klepczyńska, B. Zagrodny, W. Wojnicz , M. Ludwicki, J. Awrejcewicz – 2019
The aim of this work was to estimate a relationship between the type of the footwear and ground reactions. Differences in medio-lateral, anteriorposterior and vertical reactions are compared for different shoe-types for male and female volunteers. Each of the participants gait was recorded in case of different shoes and without them, also stabilograms were analyzed. Results revealed differences in ground reaction forces for different shoetypes and its influence on static stability.

Influence of the shoe type on the ground reaction forces

M. Klepczyńska, B. Zagrodny, W. Wojnicz , M. Ludwicki, J. Awrejcewicz – 2019
The aim of this work was to estimate a relationship between the type of the footwear and ground reactions. Differences in medio-lateral, anterior-posterior and vertical reactions are compared for different shoe-types for male and female volunteers. Each of the participants gait was recorded in case of different shoes and without them, also stabilograms were analyzed. Results revealed differences in ground reaction forces for different shoe-types and its influence on static stability.

Jaw biomechanics: Estimation of activity of muscles acting at the temporomandibular joint

The aim of this study was to elaborate a method of estimation of activity of surface muscles acting at the temporomandibular joint of the healthy subjects by using a surface electromyography (EMG). The scope of this study involved testing chosen jaw motions (open, close, lateral deviation) and process of mastication occurring during eating food with different toughness (chewing gum, cereal and carrot) by using mixed sides, right side and left side of the jaw.

Multibody models for gait analysis

W. Wojnicz , B. Zagrodny, M. Ludwicki, J. Mrozowski, J. Awrejcewicz, E. Wittbrodt – 2019
The aim of this study was to create multibody biomechanical models to analyze a normal gait of the human. Proposed models can be used to identify joint moments of the lower limbs during normal gait in the single and double support phases. Applying Newton-Euler formulation, following planar models were developed: 1) a mathematical 6DOF model describing a gait in the sagittal plane of the body for single support phase and double support phase; 2) a mathematical 7DOF model describing a gait in the sagittal plane of the body for single support phase and double support phase; 3) a mathematical 7DOF model describing a gait in the frontal plane of the body for single support phase and double support phase. Proposed mathematical models can be applied to solve a forward dynamic task or inverse dynamic task. A validation of these models had been performed by comparing results measured over examination of normal human gait and results calculated by solving an inverse dynamic task.

Approach for Determination of Functioning of Lower Limb Muscles

W. Wojnicz , B. Zagrodny, M. Ludwicki, M. Syczewska, J. Mrozowski, J. Awrejcewicz – 2018
The purpose of the study is elaboration of approach for determination of functioning of chosen muscles that are essential for gait performance (Tibialis Anterior, Rectus Femoris, Gastrocnemius Medialis, Biceps Femoris). The scope of the study involves the analysis of the symmetric planar motion performing in the sagittal plane of the body by applying planar multibody model and electromyography signals (EMG) registered over normal gait performance. The analysis is performed by applying two types of multibody model: six degree of freedom system and seven degree of freedom system. Inverse dynamics task was used to calculated joint moments influenced ankle joints, knee joints and hip joints. Applied model also described single support phase and double support phase by taking into consideration the model of interaction between the ground and the contact foot. The activity states of considered muscles are determined on the base of their average activations and sequences in time.

Biomechaniczne modele układu mięśniowo-szkieletowego człowieka

W. Wojnicz – 2018
Niniejsza monografia jest poświęcona problemom modelowania zachowania układu mięśniowo-szkieletowego człowieka. Publikacja zawiera opis badań rozwijanych w zakresie: biomechaniki mięśni, biomechaniki zespołów mięśniowych, biomechaniki układu szkieletowego, biomechaniki narządu ruchu, a także zastosowania sygnałów fizjologicznych (elektromiograficznych) oraz projektowania urządzeń do rehabilitacji na podstawie zasad sterowania ruchem w układach żywych. Modele matematyczne oraz modele obliczeniowe zostały opracowane na podstawie zasad mechaniki, układów wieloczłonowych oraz metody elementów skończonych (MES). Monografia składa się z siedmiu rozdziałów, podsumowania oraz załącznika. Pierwszy rozdział stanowi wstęp. Rozdział drugi zawiera opis modeli matematycznych stosowanych do modelowania zachowania mięśni szkieletowych poprzecznie prążkowanych o budowie wrzecionowatej i budowie pierzastej. W rozdziale trzecim przedstawiono sposób modelowania zachowania kończyn człowieka traktowanych jako układy wieloczłonowe. W rozdziale czwartym zamieszczono opis modeli obliczeniowych układu szkieletowego utworzonych za pomocą metody elementów skończonych, zaimplementowanych do oprogramowania ABAQUS. W rozdziale piątym przedstawiono autorskie podejście do modelowania zachowania ciała człowieka podczas chodu, które zostało potraktowane jako układ wieloczłonowy. Rozdział szósty zawiera opis podejść stosowanych do weryfikacji proponowanych modeli za pomocą pomiaru sygnałów elektromiograficznych. W rozdziale siódmym zamieszczono syntetyczny opis teorii sterowania ruchem, której zasady potraktowano jako podstawę do rozwinięcia autorskiej koncepcji projektowania urządzenia do rehabilitacji kończyny górnej.

Cooperation of mono- and bi-articular muscles: human lower limb

B. Zagrodny, M. Ludwicki, W. Wojnicz , J. Mrozowski, J. Awrejcewicz – JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS – 2018
Objectives: The aim of this study was to create and analyze a Pareto-optimal problem that would describe cooperation between mono- and bi-articulate lower limb muscles in sagittal plane. Methods: Equations describing the problem were derived and analyzed, additional constrains were introduced and experimental verification based on gait video analysis was performed. Results: Uncertainty of Pareto-optimal solution is shown for the muscular-skeletal system. An explanation of this situation is presented and discussed. Moreover, this theoretical observation is compared with a lack of gait reproducibility. Small but noticeable differences in gait cycles are shown and explained. Conclusions: A muscular system redundancy is shown and explained by the meaning of Pareto problem. Theoretical considerations were confirmed through a gait analysis. This leads to the conclusion, that during muscle cooperation each movement cycle can be different from the previous one, however due to physiological restrictions only a narrow equivalence class of the possible solutions exists.

FEM approach to modeling of an irregular trabecular structure

The aim of the study is elaboration of a method for creating irregular scaffolds that can be used to model the behaviour of trabecular bone placed in the proximal epiphysis of the femur. The scope of the study encompasses creating six numerical models of irregular scaffolds (two solid irregular scaffolds, two shell irregular scaffolds and two shell irregular scaffolds with fortification) and performing numerical analysis of the proposed numerical models applying a finite element method.