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Über dieses Buch

This book presents the proceedings of the “International Conference of the Polish Society of Biomechanics – BIOMECHANICS 2018” held in Zielona Góra, Poland from September 5 to 7, 2018, and discusses recent research on innovations in biomechanics.

It includes a collection of selected papers in all key areas of biomechanics, including cellular, molecular, neuro and musculoskeletal biomechanics, as well as sport, clinical and rehabilitation biomechanics. These themes are extremely important in the development of engineering concepts and methods to provide new medical solutions, especially in the context of an ageing population.

Presenting the latest technical advances and research methods used in clinical biomechanics, this book is of interest to scientists as well as junior researchers and students of interdisciplinary fields of engineering, medical, and sports sciences.



Clinical Biomechanics


Human Red Blood Cell Properties and Sedimentation Rate: A Biomechanical Study

Human blood is widely used for clinical diagnostics due to its easy accessibility and high sensitivity for any metabolic disorders and diseases. In the paper different mechanical and electric properties of red blood cells (RBC) useful for diagnostics are discussed. The experimental data on the erythrocyte sedimentation rate (ESR) test in its standard procedure and continuous computer assisted assessment are presented. The review of mathematical approaches for reasonable ESR estimation is given. The continuous model of blood as three phase suspension is used for numerical estimation of aggregate ability of RBC. The problem on RBC aggregation and sedimentation in a thin vertical tube is considered. A numerical solution of the formulated hyperbolic problem is obtained by the method of characteristics. Numerical computations have been carried out for a wide range of RBC parameters proper to healthy state and patients with cancer, drug and food allergy. It is shown the continuous sedimentation curves give more diagnostic information than the standard ESR value. Based on the experimental and theoretical study, a biomechanical interpretation of the ESR curves is proposed.
Natalya Kizilova, Liliya Batyuk, Vitalina Baranets

Modeling of Pulse Wave Propagation and Reflection Along Human Aorta

Pulse wave propagation, reflection and transmission along human aorta is studied on the 92-tube cadaveric model from aortic root to bifurcation. The branching coefficients, optimal coefficients by Murray, wave reflection coefficients by J. Lighthill have been computed and compared to the result computed on the 19-tube model of aorta derived from the 55-tube model of hyman systemic arterial tree by Westerhof. Variations in the local wave speed along the aorta have been computed on the model and compared to the continuous measurement data. It is shown the aorta is an optimal waveguide ensuring almost zero local wave reflections at the branches except for the aortic bifurcation, subclavian, carotid and kidney arteries. It is first shown that most of the branches have a negative wave reflection, which promotes blood acceleration and reduces the post-load on the heart due to the suction effect. The calculated values of the branching coefficients and pulse wave velocities correspond to the experimental measurements. The wave reflections at the kidney arteries depend on their individual geometry. The proposed approach can be used for preliminary estimation of the hemodynamic parameters caused by the wave propagation along individual aorta using the MRI study, and prediction of the risk of development of the cardiovascular diseases provided by abnormal hemodynamic.
Natalya Kizilova, Helen Solovyova, Jeremi Mizerski

The Influence of Woman’s Mastectomy on Breathing Kinematics

The aim of this study is to objectively determine the effect of total mastectomy on the extent of breathing movements of the thoracic and abdominal wall in the women (n = 6) who underwent this operation, compared to the breath movements of healthy women. Another aim is to find out whether there has been a symmetrical disturbance of the extent of movement between the operated and unoperated side of the chest and abdomen during breathing.
The 3D optoelectronic kinematic analyzer (Qualisys) has been used to measure the range of breathing movements. The chest mobility was measured in a calm and deep breathing. Further data on the patient’s condition were obtained through a kinesiological analysis focused on the upper half of the body.
The mastectomy affects the extent of breathing movements in women who have undergone this operation, by generally reducing the range of breathing movements on the operative side of the fuselage. For this reason, the symmetry of the range of movements (ROM) between the operated and unoperated sides during breathing is also impaired. The most striking asymmetries are present approximately on the level of 5th ribs, where the postoperative scar is also the most common. These findings have been confirmed in both quiet and deep breathing, demonstrating our claim to the need for scar care.
Frantisek Lopot, David Ravnik, Klara Koudelkova, Petr Kubovy, Petr Stastny

Impedimetric Method to Monitor Biological Layer Formation on Central Venous Catheters for Hemodialysis Made of Carbothane

The aim of the study was to specify by an impedimetric method the changes observed on the inner wall of central venous catheters for hemodialysis leading to the formation of a biological film. To evaluate these changes a patient-dialyzer model was built in which experimental parameters were kept closely similar to the clinical conditions of hemodialysis. The impedance spectra and SEM/EDS analysis of the biological layer deposited on the inner surface of the distal part of the catheter gave an insight into the structure of film formation and its chemical composition. Since an early detection of biofilm formation inside the distal part of the catheter is crucial for the safety of medical treatment and it usually prompts the implementation of antibiotic therapy. Developed impedimetric method can minimize the risk of infection and ensure the continuity of treatment.
Ewa Paradowska, Marta Nycz, Katarzyna Arkusz, Bartosz Kudliński, Elżbieta Krasicka-Cydzik

Towards Understanding of Mechanics of Hernia Managed by Synthetic Mesh in Laparoscopic Operation: A Single Case Study

In this paper a research towards understanding of mechanics of ventral hernia operated with the use of Physiomesh implant and SecureStrap staples is described. Experimental and numerical studies are conducted for that purpose. Experimental works cover uni-axial tension tests of the implant samples and of the implant-staples-tissue system. Also experiments on implant-staples-tissue models, representing operated hernia, subjected to impulse pressure loading are performed. Based on that, constitutive model of the mesh has been identified and failure load of the staples has been determined. In the experiments on the operated hernia systems subjected to pressure loading safe loading level has been determined and failure modes connected to higher pressure values have been observed. Finally, in the numerical simulations of the operated hernia model, built according to FEM rules, it has been proved that failures observed experimentally result from exceeding of the load bearing capacity of the staples considered in this study.
Agnieszka Tomaszewska, Izabela Lubowiecka, Czesław Szymczak

Numerical Analysis of the Blood Flow in an Artery with Stenosis

The study presents the results of a simulated blood flow in an artery affected with arteriosclerosis. Distribution of flow velocity vectors is presented along with distribution of shear strain on the walls of the artery. During the stent designing process, the knowledge about a pathophysiological role of the shear strains during the restenosis process and about the possible phlebitis is required. According to many studies, low shear strain levels are connected with the forming of the atherosclerotic plaques with an irregular structure. The study aims to present a process that will allow obtaining numerical models of the vessel and the atherosclerotic plaque from photographs of the cross sections made with medical equipment. Those models were later used to develop a domain of the blood flow inside the vessel. The analysis was conducted using the Finite Volume Method in Ansys Fluent software. This methods converts the differential equations into algebraic ones by integrating those equations at the limits of each finite volume. The constant development of the materials and manufacturing processes for the stents allows for improvement of their usability, however one factor is not still diagnosed adequately, namely the restenosis - a condition in which a vessel undergoes narrowing again after the treatment. The rapid progress of computer methods allows for simulating increasingly complex scenarios, which can help improve the medical treatment procedures.
Michał Tomaszewski, Jerzy Małachowski

Computational Imaging and Simulation Technologies in Biomechanics


Influence of Elevated Temperature During Crimping on Results of Numerical Simulation of a Bioresorbable Stent Deployment Process

Bioresorbable stents (BRSs) represent a promising technological development within the field of cardiovascular angioplasty because of their ability to avoid long-term side effects of conventional stents such as in-stent restenosis, late stent thrombosis and fatigue induced strut fracture. However polymer materials used for production of some of the BRSs pose new challenges raising from the fact, that mechanical properties of polymers are very different from the metallic materials used to make stents before BRSs era. These challenges manifests not only in clinical practice but mainly in the process of design of the new device. This especially applies to Finite Element based numerical simulations of the stent structure, as the first-choice tool to examine newly developed stent in early stage of design process. In the article authors investigating different scenarios of numerical simulation of stent deployment process. The goal of the exercise is to find a proper way to model influence of elevated temperature present during crimping on the behaviour of the stent.
Jakub Bukała, Krzysztof Damaziak, Jerzy Małachowski, Łukasz Mazurkiewicz

Comparison of Methods for Computing a Target Point for Aspirations and Biopsies

The aim of this study was to compare three methods for computing a target point for use in autonomous or semi-autonomous aspirations and biopsies. Given a 3D binary image of the object of interest, the procedures computed the target point. The following approaches were tested: the method #1 - center of mass, the method #2 - largest projection area + largest empty circle and the method #3 - largest empty circle + largest empty circle. Each procedure was tested on four cases obtained from Magnetic Resonance Imaging scans used to diagnose Baker’s cysts. The methods were analyzed and compared in terms of their safety and computation time. In terms of safety, the best results were obtained with the third procedure, which used the largest empty circle + largest empty circle combination. The second method - the largest projection area + largest empty circle - offered good compromise between safety and computation time. It can be used to estimate target points for medical tool path planning in aspiration or biopsy.
Adam Ciszkiewicz, Grzegorz Milewski

Predictive Models in Biomechanics

This paper investigates the opportunity of predictive musculoskeletal models that do not require experimental input of kinematics and ground reaction forces. First, the requirements of such models are reviewed and, subsequently, an example model of running is derived by means of principal component analysis. The generation of different running styles using the model is demonstrated, and we conclude that this type of models has the potential to predict motion behavior given shallow input describing the individual.
John Rasmussen

Automatic Processing and Analysis of the Quality Healing of Derma Injury

Automation of analyzing the biological data can increase the quality of analyses and decrease spending time. Analyze of the microscope’s bitmaps is usual task in biology. To illustrate the proposed method we used analyzing collagen in dermis snapshots. Methodic to automatic analyses of microscope snapshots is presented. Object of analysis can be determine by color vector. Then the snapshot can be binarized and meshed. For every element we can restore distribution of the mean intercept length. Orientation of the objects can be calculated using approximation of the mean intercept length. Equation to estimate the quality of collagen recovery was presented. We used the method on samples of three types: no ficin group (N), ficin group (F), immobilized ficin (Fi). We tested 10 bitmaps for every group and we got results for all bitmaps according described technique. Quality of collagen recovery values was: for N group – 48% ± 8%, for F group 78 ± 7%, for Fi group 68 ± 9%. It can be concluded that ficin positively influence on dermas recovery. Received results are consistent with published results.
Elena Semenova, Oleg Gerasimov, Elizaveta Koroleva, Nafis Ahmetov, Tatyana Baltina, Oskar Sachenkov

Application of Artificial Neural Networks in the Human Identification Based on Thermal Image of Hands

The aim of this study was to check the possibility of identifying the persons based on the properties of thermal maps and a temperature distribution of a hand, obtained from a thermal image, with use of artificial neural networks. For this purpose, a series of thermographs of the right hand of eight people was taken, with a thermal imaging camera. The photos were taken under the same thermal conditions, but with different state of warming of hands. After processing the photos (determining the edges, characteristic hand points and areas of interest), the parameters characterizing the metacarpal temperature distribution were determined. Eight parameters were chosen, which were average temperatures of the areas of interest. These parameters were input data of neural networks in the learning and identification process. As it was shown in this study, these parameters were sufficient to clearly identify the persons. Neural networks, designed as multi-layered perceptron, after proper learning showed very high values of identification parameters, including high values of sensitivity and specificity, what proves the high quality of classification. Such identification is possible with the natural thermal state of the hand and if thermal images are not strongly disturbed, the artificial neural networks are very good tool to implement in persons identification process.
Tomasz Walczak, Jakub Krzysztof Grabski, Martyna Michałowska, Dominika Szadkowska

Impact/Injury Biomechanics


Stability of the EMG Signal Level Within a Six-Day Measuring Cycle

This paper presents the results of research on the identification of changes in the electromyographic (EMG) signal recorded with the surface method (sEMG) over the course of six consecutive days. The signal was recorded for two people. The electrodes were fixed on the upper limb in two places of the forearm (over the brachioradialis and the bully of the superficial flexor (flexor digitorum superficialis). Muscles were activated by the hand clamp on the handle in the range of 25 \(\div \) 100 N. 21 measurement series were analysed, which consisted of 966 individual clamps. Estimates like root mean square, average value, energy and turn per second were used for the research. Due to the lack of a normal distribution of the estimators, non-parametric tests were performed in most cases. The tests carried out did not allow us to infer about the lack of changes in the signal over the period of six days under investigation. Moreover, by shortening the period of the tested series even to several successive series of measurements, it was also impossible to determine consistent conclusions for all the tested forces. Registered signals were characterized by very high variability between particular series. What’s more, the correlation studies between changes of individual forces per day also do not support the hypothesis that there is a constant, time-independent measurement of the relationship between the recorded EMG signal and the force.
Robert Barański

Prediction of the Segmental Pelvic Ring Fractures Under Impact Loadings During Car Crash

The Pelvis is the most susceptible part of the body to damage during car accidents and is characterized by the highest mortality rate, especially in the case of multiple fractures. The mechanism of these fractures remains unclear and this makes the development of effective crash protection more difficult. A geometric model of the lumbo-pelvic-hip complex (LPHC) including elements of skeletal, muscular and ligament structure stabilizing the pelvis was elaborated on the computed tomography images of a 25-year-old patient. The influence of pelvic boundary conditions on the type of injuries was subjected to analysis using the Finite Element Method (FEM). The cases of a model anchorage dependent on the position of the passenger’s body in the vehicle, where the impact of interior vehicle elements, such as seat belts or a car seat, were taken into account. A fracture threshold was established by applying lateral loads from 0 to 10 kN to a greater trochanter of the femoral bone in each of a five cases of boundary conditions reflecting the influence of different car parts on a passenger’s body. The magnitude of the contact force between the body and the vehicle parts during a side collision against the driver’s door were determined using the elaborated model. Furthermore, a pelvis lateral collision theory model was built and validated with the use of clinical data. The obtained results can provide an estimate for a threshold of the initial failure in the pelvis bone due to an impact compression transmitted through an overlying tissue. Therefore, it was assumed that the properties of the fractured structure are similar to the cancellous bone.
Tomasz Klekiel, Katarzyna Arkusz, Grzegorz Sławiński, Romuald Bȩdziński

Analysis of the Lower Limb Model Response Under Impact Load

The paper presents a problem of soldiers’ lower limbs safety in military vehicles during high impact loads derived from explosion of Improvised Explosion Devices (IED) charges. The numerical studies concerned the function of combat boots as an element of the soldier’s equipment. The model of a lower limb with cooperation with a sole was prepared as a multibody dynamic system. For this model the governing equations have been prepared and solved numerically with the Runge-Kutta method. The results were obtained for the load acting on the sole as the velocity generated proportionally in relation to the mass of an IED charge. The changes of material property for the sole were analysed to select the best parameters for protection of both a foot and a whole leg. The results show the conditions for increasing the safety of a passenger’s feet formulated as damping properties for soles and were compared with the similar data from an experimental study.
Tomasz Klekiel, Grzegorz Sławiński, Romuald Bȩdziński

Numerical Analysis of the Biomechanical Factors of a Soldier Inside a Vehicle with the Pulse Load Resulting from a Side Explosion

The aim of this paper is to try to classify and assess the risk of injuries of the cervical spine during an attack on a military vehicle. In that case, the focus has been placed only on the side explosion variant, which reflects new threats observed on the basis of events from Afghanistan and not only. The risk of a threat to the life and health of the vehicle’s crew increases as result of an explosion under a military vehicle. Considering that event in terms of the safety of soldiers comes down to a complex analysis of interactions between the soldier’s body, seat and vehicle’s structural elements. The effects of the shock wave result in interactions which cause vibrations resulting from the vibrations of the construction and the acceleration of the occupant’s body.
The currently applied test conditions and criteria of the injuries of LV and LAV crew members exposed to the shock wave resulting from the explosion of the AT mine are specified in Appendix E to the NATO standard [1]. However nowadays, those requirements have been extended and included in classified documents which cannot be presented to the general public. Therefore, the assumptions resulting from the analyses of the existing cases in Afghanistan have been adopted.
This paper includes an attempt to analyse the impact of the explosion of IED on the side of a military vehicle on the risk of injuries of the cervical spine of soldiers. The analysis has been made using numerical methods in the LS-DYNA software and has been conducted considering the variable values of displacement and accelerations registered during an explosion.
Grzegorz Sławiński, Piotr Malesa, Marek Świerczewski

Soft and Hard Tissue Biomechanics


Risk Assessment Regarding the Injuries of the Lower Limbs of the Driver of a Military Vehicle in the Case of an Explosion Under the Vehicle

The protection of soldiers performing tactical operations in armoured vehicles plays an important role in combat operations. The need for such protection results from threats on battle-fields or during peace-keeping missions connected with the explosion of mines or Improvised Explosive Devices (IED). As a result of an explosion, the occupants of the vehicle are exposed to the effects of the shock wave as well as overloads caused by the movement of the vehicle. Simulation and experimental tests play a significant role in ensuring the safety of occupants exposed to the effects of loads caused by an explosion. It is possible to specify the conditions creating loads to the body, and also to determine interaction forces in the lower libs of the human body, using models which include the description of the explosive, parameters of the vehicle and the model of the human body.
The case connected with the behaviour of the vehicle’s driver during the detonation of an explosive placed centrally under the driver’s compartment has been analysed in this paper. Thanks to that, it is possible to demonstrate the influence of the seize of the explosive on the overloads of limbs. Based on the results of the calculations, it has been stated that the forces coming from the shock wave transferred to the foot of the limb are so important that they largely influence the seize of limb injuries. The reduction of the interaction force of the above-mentioned sources consists mainly in developing such a construction of the vehicle which minimises the danger of damaging the plating and renders it possible to maximally dissipate the shock wave by the vehicle’s construction.
Grzegorz Sławiński, Marek Świerczewski, Piotr Malesa

Modeling Viscoelastic Behavior of Pig’s Skin in the Respect to Its Anisotropy

The purpose of this work was to analyze the influence of different strain levels on the results of fitting the quasi-linear viscoelastic material model to the experimental curves. The stress relaxation test of pig’s skin tissue was realized. Three values of strain levels were set at 5, 10, 15%. The anisotropy of material was taken into account. Correlation coefficients of fitting were evaluated. The study confirmed both the relationship between the level of strain, orientation of specimens and the values of model parameters.
Aneta Liber-Kneć, Sylwia Łagan

FEM Analysis of Hyperelastic Behavior of Pig’s Skin with Anatomical Site Consideration

The aim of this work was to compare a hyperelastic material models (Ogden and Yeoh) implemented in ANSYS software to evaluate the experimental data obtained from uniaxial tensile test of pig’s skin taken from different location of the body (back and abdomen). The results were compared with the literature data. The effects of the simulation confirmed the possibility of using hyperelastic models to assess skin properties using FEM methods based on a static tensile test. The study reveals the need to validate results based on a wider range of data.
Sylwia Łagan, Agnieszka Chojnacka-Brożek, Aneta Liber-Kneć

Trabecular Bone Microstructural FEM Analysis for Out-Of Plane Resolution Change

The paper presents comparison of two methods of voxel defining for trabecular bone structure modelling. Regular cubic voxels were considered, the size of which changed uniformly in three mutually perpendicular directions depending on the adopted resolution. Also elongated rectangular voxels were proposed, characterized with fixed in-plane resolution and variable length along out-of plane direction. For both types of voxels a number of analyses were performed using finite element method with structures of varied BV/TV values. It was stated that voxel dimension change in out-of plane direction allows for decreasing of a number of scans required for correct reflect of the modelled structure stiffness for the needs of numerical analyses.
Artur Cichański, Krzysztof Nowicki

Sport Biomechanics and Technology


Analysis of Skeletal Muscle System Loads for the Most Optimal Positions During Lifting in Different Load Distances

The aim of this study was to determine the effect of the distance between load and the ankle joint on musculoskeletal system loading. The Any-Body software with the verified model was used for calculations of loads of muscoskeletal system during the initial phase of lifting. A total of 3,485 static musculoskeletal models in different positions were analyzed, out of which 13 with optimal lumbar spine loads were selected. Recived data from model calculation were knee joint reactions, L5S1 intervertebral disc reactions and sum of squares of muscle forces. Results confirm that the musculoskeletal system loading increase with growth of the load distance. However, it is worth to notice that optimal models basing on reactions in lumbar spine are not optimal in terms of knee joint loads and energy expenditure. In addition, there was also no change in the reactions observed in the literature for a load distance of about 0.4 m. It indicates that this change may be the result of the habits of the subjects but not the actual increase in efficiency. These study is an introduction to a broader analysis of the presented issue.
Bieniek Andrzej, Szczygioł Anna, Michnik Robert, Chrzan Miłosz, Wodarski Piotr, Jurkojć Jacek

Strength, Flexibility and Temperature Changes During Step Aerobics Training

Purpose: The purpose of this study was the analysis of temperature changes in the muscles quadriceps and biceps femoris areas of healthy subjects over a 15-week Step Aerobics Training (SAT) program. The aim of this paper is twofold. Firstly we verify if SAT training has an impact on the temperature changes in the muscles quadriceps and biceps femoris and thermoregulation of healthy subjects. Secondly, we verify if there is relationship between the index of strength and flexibility with thermal results.
Methods: The study was conducted with 11 women subjects aged between 20- and 22-years-old. Training sessions of SAT took 15 weeks. Subjects performed two training session per week for 60 min per session. Assessments included the evaluation of body mass index, waist circumference, blood pressure, vital capacity of lungs, maximal oxygen uptake and flexibility and strength. Subjects’ fitness was evaluated by testing the following tasks: standing long jumps and toe-touch test. For thermograms acquisition a thermographic camera CEDIP Titanium 560M IR (USA) was used.
Results: After 15 weeks SAT the temperature changes were found to be larger on the front surfaces than on back surfaces of lower extremities. Positive correlation between strength and skin temperature and negative correlation between flexibility and temperature was found.
Conclusions: 15-weeks-long SAT can promote improvements in the thermoregulation of apparently healthy women. This method may be used as a tool for establishing the efficiency of SAT in the training process.
Piotr Borkowski, Jolanta Grażyna Zuzda, Robert Latosiewicz

On Different Methods for Calculating the Flight Height in the Vertical Countermovement Jump Analysis

Vertical countermovement jump is a very simple and common method for assessing the jumping ability of athletes. There are different techniques for measurements of the flight height, e.g. using motion capture systems or accelerometers. In this paper for estimating the flight height the measurements coming from the force plates are used. Furthermore different methods can be applied for calculating the flight height based on these measurements. In these paper four methods of calculating the flight height during the vertical countermovement jump based on the measurements from the force plates are compared (the flight time method, the take-off velocity method, the work-energy method and the center of jumper’s body vertical position method). In addition for two of these methods (the take-off velocity method and the center of jumper’s body vertical position method) the authors applied two different methods of numerical integration (the trapezoidal rule and based on the cubic spline interpolation).
Jakub Krzysztof Grabski, Tomasz Walczak, Martyna Michałowska, Patrycja Pastusiak, Marta Szczetyńska

High Efficient Weightlifting Barbell Tracking Algorithm Based on Diamond Search Strategy

An efficient weightlifting barbell tracking algorithm has been proposed in this paper. We aim to fast and accurately extract barbell route from weightlifting competition video sequence for training. To achieve this target, a vertical enhancement diamond search pattern is adopted to find out the most similarity areas. From the experimental result, our proposed algorithm is able to keep tracking exactness of barbell object and respond in real time. It helps athletics, coaches and biomechanics scholars to gather the weightlifting performance as rapidly as required by the user.
Ching-Ting Hsu, Wei-Hau Ho, Jen-Shi Chen

Are Leg Electromyogram Profiles Symmetrical During Full Squat?

In order to see how electromyogram (EMG) profiles change during the squat movement with increasing loads, we determined the degree of symmetry of selected homologous muscles. Seven healthy men (age range 20–42 years), recreationally performing strength exercises voluntarily participated in the research. The participants varied in height from 172 to 183 cm and in mass from 74 to 94 kg. The participants performed consecutive sets of a single repetition of full back squatting, each time with an increased load (70–100% 1RM). To record the parameters of participant and barbell movement, the Smart-E measuring system (six infrared cameras and a wireless module for measuring the bioelectric activity of muscles) were used. Electrical activity was recorded using surface electrodes for muscles on both sides of the body (homologous): tibialis anterior (TA), gastrocnemius medialis (Gmed), biceps femoris (BF), rectus femoris (RF), gluteus maximus (Gmax) and erector spinae (ES). The mean of averages of modules of amplitude differences (MAMAD) between individual pairs of normalized homologous muscles for squat movement was accepted as a measure of symmetry of homologous muscles. A statistically significant increase of symmetry of EMG profiles (MAMAD) with increasing loads was seen only for TA and ES muscles and only in two of the six of analyzed cases. Of particular interest was the statistically significant large MAMAD increase for BF and ES muscles and for the so called prime mover (Gmax) in the ascent phase of the squat compared to the descent phase.
Henryk Król, Krzysztof Kmiecik

Does Vibration Affect Upper Limb During Nordic Walking?

Nordic Walking has become a very popular physical activity. The technique is relatively simple and Nordic Walking poles are cheap and accessible. However, it should be noted that Nordic Walking generates additional loads for upper limb joints in the form of mechanical vibrations, which may not be without effect on exercisers’ health. The aim of this paper is to address the following questions: Does Nordic Walking cause harmful mechanical vibrations? Does the use of poles with amortization reduce the level of vibration? May the mechanical vibration during this exercise be a contraindication to practise Nordic Walking? To answer these questions, the authors used a vibration measurement device, which allowed the researchers to measure vibration according to norm EN ISO 5349 during gait with Nordic Walking poles. Data collected for different types of poles were compared to the regulation of the Polish Minister of Labour and Social Policy 2002.
Wojciech Wolański, Michał Burkacki, Sławomir Suchoń, Julia Gruszka, Marek Gzik, Krzysztof Gieremek, Joanna Gorwa

Loaded Treadmill Training Improves the Spatio-Temporal Parameters in Children with Spastic Diplegia

Background: Treadmill training is a commonly used and promising technique for improving gait function in children with spastic diplegia. However, the use of loads during treadmill gait training is limited. The purpose of the present study was to determine whether using loads with treadmill training improves the spatio-temporal parameters of gait in children with spastic diplegia more effectively than conventional exercises alone. Methods: Twenty children with spastic diplegia were randomly allocated to a control group or an experimental group. Both groups received conventional therapeutic exercises for a period of eight weeks. Moreover, the experimental group underwent loads on their ankles during treadmill gait training. Spatio-temporal parameters of children were assessed at baseline (pre-training) and at their 16th training session (post-training). Results: A two-way mixed-design ANOVA showed no significant between-group differences in demographic and the spatio-temporal parameters at baseline. Based on measurements taken at the 16th training session, the experimental group achieved significantly (p < 0.05) higher average scores than the control group with regard to step length, stride length, cadence, walking velocity, stride time, and double support time. In addition, the results revealed significant within-group differences (p < 0.05) in the step and stride lengths of both groups, whereas cadence, walking velocity, stride time, and double support time also improved in the experimental group. Conclusions: Eight weeks of loaded treadmill gait training improved the gait kinematics of children with spastic diplegia, particularly cadence, walking velocity, stride time, and double support time.
Mariam A. Ameer, Walaa S. Mohammad


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