Wyniki wyszukiwania - BazTech

1

Effects of vibration and passive resting on muscle stiffness and restitution after submaximal exercise analyzed by elastography

Chwała Wiesław, Pogwizd Paweł

Acta of Bioengineering and Biomechanics

|

2021

|

Vol. 23, no. 2

3--11

EN

Purpose: The research aimed to assess the influence of vibration therapy on acceleration of muscles regeneration process after physical effort. Verification of the pace of motor capabilities recovery in fatigued muscles was performed with the use of the measurement method applying shear-wave elastography. It took into account an alteration in muscle stiffness affected by created passive stresses and accompanying deformations connected with muscles work above their resting length. Methods: The research included 42 young males aged 20–24. They all were a homogeneous group regarding body build indices (body height 175.4 ± 8.1 cm; body mass 75.5 ± 8.32 kg) and the level of physical activity. Muscles of lower limbs (hip and knee joints extensors and flexors plantaris) were subject to submaximal exercise of the auxotonic muscle work character after a 90 s warm-up. The exercise comprised 20-fold overcoming the load at the level of 75% of maximal strength abilities without rest, by alternating between extension and flexion of lower limbs joints at the leg press placed at 45° angle upward and monitoring of angle setting of lower limbs joints. The post-exercise restitution used a vibration stimulus of variable frequency ranging from 20 to 50 Hz and amplitude of 0.5 mm, and passive resting in the control group. For an objective assessment of the applied vibration effect, a 5-fold measurement of rectus femoris muscles stiffness of both limbs at the middle of venter took place after each stage of the experiment. Results: After warm-up, a considerable increase of the examined muscles stiffness, that did not vary significantly, was observed. In the DW experimental group (vibration massage), where post-exercise restitution was enhanced by vibration, significantly lower values of muscle stiffness were registered after each of the post-exercise regeneration stages in relation to the DB control group (passive rest). After the I regeneration stage, a value of the Δ σ _r1-s variable ( p < 0.05) lower by 16% was noticed in favour of the group enhanced by vibration. Whereas, values of muscles stiffness after the II stage of regeneration, Δ σ _r2-s were by 14% lower in favour of DW group ( p < 0.005). Conclusions: Enhancement of the post-exercise relaxation of muscles by vibration treatment significantly lowered the values of post-exercise muscles stiffness and turned out to be a more effective method of restitution than passive resting. Recovery of the level of muscles stiffness from before the exercise was much slower in the control group than in the one enhanced by vibration. The improved method of muscle stiffness measurement with the use of shear-wave elastography with a special head attachment turned out to be a useful tool to assess post-exercise muscles restitution.

2

Which of the five classical ballet positions is the most demanding for the dancer’s body? An electromyography-based study to determine muscular activity

Gorwa Joanna, Kabaciński Jarosław, Murawa Michał, Fryzowicz Anna

Acta of Bioengineering and Biomechanics

|

2020

|

Vol. 22, no. 4

3--14

EN

The study aimed to determine which of the five classical ballet positions is the most demanding regarding muscular activity, values of external rotation in the hip joints, angular values of foot progression as well as the inclination (tilt) of the pelvis in the sagittal plane. Methods: In this cross-sectional study, 14 female pre-professional ballet dancers (aged 11–16) participated. Participants were tasked with the sequential adoption of five classical ballet positions (CP1–CP5). The electromyographic activity of the muscles of the trunk and the lower limb was recorded with surface electrodes. Kinematic data including hip and knee external rotation, foot progression angle and pelvic tilt were collected using a motion capture system. Results: Symmetric positions CP1 and CP2 were not as demanding as asymmetric CP3–CP5. Higher values of hip and foot external rotation without greater muscular effort in CP2 than CP1 was noticed. Considering asymmetric positions, CP3 did not trigger a greater activity of hip or foot muscular groups than CP4 and CP5. CP4 was characterised by the greatest pelvic anterior tilt and the lowest activity of GM in the forward lower limb. In CP5, forward lower limb entailed a higher activity of muscles supporting the foot than in the remaining positions. Conclusion: In terms of biomechanics, the most demanding classical ballet position in pre-professional dancers is CP4, followed by CP5, CP3, CP1 and CP2. This finding can be applied in educational methodology of dancers, figure skaters, synchronized swimmers, acrobatic gymnasts, rhythmic gymnasts or cheerleaders.

3

Measurement of maximal isometric torque and muscle fatigue index of the knee muscles in male athletes

Danek Janusz, Wojtasik Wojciech, Szulc Adam

Acta of Bioengineering and Biomechanics

|

2019

|

Vol. 21, no. 3

31--37

EN

The aim of the paper was to analyse variables related to the force and fatigue of knee muscles in the right and left lower limbs among 17 male athletes. Methods: For both muscle groups, maximal isometric torque (Fmax) was determined with the use of Biodex System 4 Pro and the values of muscle fatigue index (FATI1–3) were calculated. Results: A significant difference was observed between the groups of short- and long-distance runners in the values of all fatigue indices of knee joint extensor muscles in the right limb. In turn, between the groups of athletes who had trained for 2–4 years or for 4.5–7 years and the group who had trained for 7.5–13 years, significant differences were observed in the values of all fatigue indices of knee joint flexor muscles in the right limb. The group training for 3–12 hours per week and the group training for 12.5–18.0 hours per week in the sports club differed significantly in the value of the maximal isometric torque of knee joint flexor muscles in the right limb and in the values of some fatigue indices (FAT1, FAT3) for knee joint flexor muscles in the right limb. The study reported numerous positive correlations between the assumed characteristics and the investigated variables of knee joint extensor and flexor muscles in the right and left lower limbs. Conclusions: Athletes present certain changes in variable values and positive correlations between some characteristics and investigated variables of selected knee muscles.

4

A two dimensional approach for modelling of pennate muscle behaviour

Wojnicz W., Zagrodny B., Ludwicki M., Awrejcewicz J., Wittbrodt E.

Biocybernetics and Biomedical Engineering

|

2017

|

Vol. 37, no. 2

302--315

EN

The purpose of this study was to elaborate a two-dimensional approach for unipennate and bipennate striated skeletal muscle modelling. Behavior of chosen flat pennate muscle is modelled as a rheological system composed of serially linked passive and active fragments having different mechanical properties. Each fragment is composed of three elements: mass element, elastic element and viscous element. Each active fragment furthermore contains the contractile element. Proposed approach takes into consideration that muscle force depends on a planar arrangement of muscle fibers. Paper presents results of numerical simulations, conclusions deduced on the base of these results and a concept of experimental verification of proposed models.

5

Influence of modified muscle morphology and activity pattern on the results of musculoskeletal system modelling in cerebral palsy patient

Ogrodnik J., Piszczatowski Sz.

Acta of Bioengineering and Biomechanics

|

2017

|

Vol. 19, no. 3

63--75

EN

Purpose: The aim of the present study was to evaluate the influence of modified morphological parameters of the muscle model and excitation pattern on the results of musculoskeletal system numerical simulation in a cerebral palsy patient. Methods: The modelling of the musculoskeletal system was performed in the AnyBody Modelling System. The standard model (MoCap) was subjected to modifications consisting of changes in morphological parameters and excitation patterns of selected muscles. The research was conducted with the use of data of a 14-year-old cerebral palsy patient. Results: A reduction of morphological parameters (variant MI) caused a decrease in the value of active force generated by the muscle with changed geometry, and as a consequence the changes in active force generated by other muscles. A simulation of the abnormal excitation pattern (MII variant) resulted in the muscle’s additional activity during its lengthening. The simultaneous modification of the muscle morphology and excitation pattern (MIII variant) points to the interdependence of both types of muscle model changes. A significant increase in the value of the reaction force in the hip joint was observed as a consequence of modification of the hip abductor activity. Conclusions: The morphological parameters and the excitation pattern of modelled muscles have a significant influence on the results of numerical simulation of the musculoskeletal system functioning.

6

Muscle torque of healthy individuals and individuals with spastic hemiparesis after passive static streching

Freitas S. T. T., Abreu E. M. C., Reis M. C., Cunha B. S., Prianti T. S. M., Lima F. P., Lima M. O.

Acta of Bioengineering and Biomechanics

|

2016

|

Vol. 18, no. 1

35--39

EN

Spasticity is one of the main causes of contracture, muscle weakness and subsequent functional incapacity. The passive static stretching can be included as having the purpose of increasing musculoskeletal flexibility, however, it also can influence the muscle torque. The objective is to verify the immediate effect of passive static stretching in the muscle strength of healthy and those who present spastic hemiparesis. There were assessed 20 subjects, 10 spastic hemiparetic (EG) and 10 healthy individuals (CG), including both sexes, aged between 22 and 78 years. The torque of extensor muscles of the knee was analyzed using isokinetic dynamometer. Results have shown that EG has less muscle torque compared to CG ( p < 0.01). In addition, EG presented a decrease in significance of muscle torque after stretching ( p < 0.05), however, it has not shown significant alteration in muscle torque of CG after performing the program that was prescribed. Immediately after the passive stretch, a significant torque decrease can be seen in hypertonic muscle; it is believed that this reduction may be associated with the physiological overlap between actin and myosin filaments and so preventing the muscle to develop a maximum contraction.

7

Evaluation of reliability of perioral muscle pressure measurements using a newly developed device with a lip piece

Takahashi M., Koide K., Suzuki H., Satoh Y., Iwasaki S.-I.

Acta of Bioengineering and Biomechanics

|

2016

|

Vol. 18, no. 1

145--153

EN

Purpose: We examined the reliability of measurements using a newly developed perioral muscle pressure measuring device with a lip piece in healthy adults. Methods: Subjects were 40 healthy men (25.8 years) with normal stomatognathic function. Perioral muscle pressure measuring device with a lip piece was used to measure upper lip, lower lip and tongue pressure, and a balloon-based measurement device was used to measure tongue and cheek pressure. Each measurement was taken twice with a 1-min interval between the two measurements. We determined intra-rater reliability by using the intra-class correlation coefficient as a test of relative reliability. As a test of absolute reliability, Bland–Altman analysis was used to assess systematic bias and the 95% confidence interval of the minimal detectable change was calculated. Additionally, the coefficient of variation was calculated. The Spearman–Brown formula was calculated the number of measurements needed to achieve a confidence coefficient ≥0.9. Each set of measurements was followed by a second set that were taken 1 week later. Results: All measurements showed high values of intra-class correlation coefficient. Upper lip, tongue, and cheek pressure can be determined based on a single measurement, while lower lip pressure requires averaging twice. No systematic bias was observed. The coefficients of variation of measurements were almost the same between the two devices. Conclusion: Measurements were highly reliable regardless of the type of perioral muscles. Our findings suggest that the method described in this study is useful as a quantitative chair side method for examining perioral muscle pressure.

8

Mirakhorlo M., Azghani M. R.

Acta of Bioengineering and Biomechanics

|

2015

|

Vol. 17, no. 4

21--29

EN

Lifting is known to be a major reason for musculoskeletal injuries. In this way, lifting has a crucial effect on human musculoskeletal system and intensity of this impact depends slightly on the selection of techniques. Underlying mechanisms by which trunk muscles are executed during performing lifting are central to biomechanical study of lifting techniques. In the current study, the trunk muscular control mechanisms of lifting are investigated using the synergetic control analysis. Non-negative matrix factorization has been used to extract trunk muscles synergies from their activities – which are computed by a previously validated musculoskeletal model – during different lifting techniques aimed to investigate motor control strategies. Three lifting techniques are considered; stoop, squat and semi-squat. Three synergies account for variety among muscle activation of trunk muscles with related VAF (Variability Account For) of over 95%. Trunk muscle synergy weightings and related time-varying coefficients are calculated for each kind of lifting techniques considering three synergies. Paired correlation coefficients between muscle synergies are all greater than 0.91 (P < 0.05) suggesting that trunk muscle synergies are similar for examined techniques in spite of their kinematic diversity. This similarity can be a result of their common ultimate goal. The acquired results also elucidate the mechanisms of muscle activation patterns that can be exploited in future studies and ergonomic interventions.

9

Investigation of mutual aerobic and lower limb muscular activity during cycling

Griskevicius P., Daunoraviciene K., Pauk J., Troskovas V.

Acta of Bioengineering and Biomechanics

|

2015

|

Vol. 17, no. 2

109--118

EN

The evaluation of physical activity is a complex task that requires performing an analysis of muscular activity and aerobic/anaerobic threshold and it is often difficult to observe and propose a single method. The purpose of the article is to evaluate a relation between aerobic capacity and activity of lower limb muscles via changes of muscle’s EMG signal during physical, sub-maximal veloergometric loading. The activity parameters of 5 lower limb muscles such as semitendinosus, rectus femoris, biceps femoris, gastrocnemius medialis, and tibialis anterior were measured and analyzed during the veloergometric exercise tests and the heart rate and the aerobic capacity were estimated from registered data. The obtained aerobic parameters allow setting an individual and overall voluntary physical capacity. The regression oxygen function presented allows analyzing and predicting the ability of subjects to generate energy while maintaining muscle activity during the exercise. The correlation between the consumption of oxygen and constant physical loading time is determined. It was found that comparing VO2max capabilities the physical effort in the male group was 16% higher than in women. Oxygen consumption and maximum muscle effort dependency on the load time was established. It was observed that the maximal muscular effort appeared before VO2max reached maximal limit in both groups. The maximal oxygen consumption is achieved in the middle or sometimes at the beginning (depending on load) of exercise while maximal muscular effort was found in several phases of cycling: at the beginning and at the end of loading time.

10

Investigation of mutual aerobic and lower limb muscular activity during cycling

Griskevicius J., Daunoraviciene K., Pauk J., Troskovas V.

Acta of Bioengineering and Biomechanics

|

2015

|

Vol. 17, no. 3

109--118

EN

The evaluation of physical activity is a complex task that requires performing an analysis of muscular activity and aerobic/anaerobic threshold and it is often difficult to observe and propose a single method. The purpose of the article is to evaluate a relation between aerobic capacity and activity of lower limb muscles via changes of muscle’s EMG signal during physical, sub-maximal veloergometric loading. The activity parameters of 5 lower limb muscles such as semitendinosus, rectus femoris, biceps femoris, gastrocnemius medialis, and tibialis anterior were measured and analyzed during the veloergometric exercise tests and the heart rate and the aerobic capacity were estimated from registered data. The obtained aerobic parameters allow setting an individual and overall voluntary physical capacity. The regression oxygen function presented allows analyzing and predicting the ability of subjects to generate energy while maintaining muscle activity during the exercise. The correlation between the consumption of oxygen and constant physical loading time is determined. It was found that comparing VO2max capabilities the physical effort in the male group was 16% higher than in women. Oxygen consumption and maximum muscle effort dependency on the load time was established. It was observed that the maximal muscular effort appeared before VO2max reached maximal limit in both groups. The maximal oxygen consumption is achieved in the middle or sometimes at the beginning (depending on load) of exercise while maximal muscular effort was found in several phases of cycling: at the beginning and at the end of loading time.

11

Characterization of the mechanomyographic signal of three different muscles and at different levels of isometric contractions

Jotta B., Garcia M. A. C., Pino A. V., Souza M. N. de

Acta of Bioengineering and Biomechanics

|

2015

|

Vol. 17, no. 4

73--84

EN

Purpose: Lateral (X) and longitudinal (Y) mechanical oscillations of muscle fibers that take place during muscular contraction seem to contain information additionally to the myoelectric activity, which can contribute to the interpretation of some muscle gradation force mechanisms. However, no previous study was found that had investigated the relationship between the muscle force and features associated to the mechanomyographic (MMG) signal obtained by means of a biaxial accelerometer in three different muscles. Therefore, the aim of this study was to evaluate the relationship between the force output at different load levels (20% to 100%) of the maximum voluntary isometric contraction (%MVIC) and the two signals supplied by a biaxial accelerometer and, in addition, the so-called resultant (R) acceleration signal derived from the two signals mentioned previously. Twenty seven male volunteers participated in this study. Methods: The force output related to the right biceps brachii, soleus and gastrocnemius medialis muscles was studied by means of linear regression models fit to log-transformed of the root mean square (RMS) values of the MMG signals in X, Y, and R axes versus each %MVIC. The phase angle of R acceleration (PhaseR) and anthropometric data were also considered. Results: The angular coefficient a and the antilog of y-intercept b from the log-transformed of MMG data values versus force output were able to distinguish partially motor unit strategies during isometric contractions in the three muscles studied. Conclusion: The findings suggest that biaxial accelerometer seems to be an interesting approach in the assessment of muscle contraction properties.

12

Biomechanical characteristics of the jump down of healthy subjects and patients with knee injuries

Mielińska A., Czamara A., Szuba Ł., Będziński R.

Acta of Bioengineering and Biomechanics

|

2015

|

Vol. 17, no. 2

111--120

EN

Purpose: The aim of this study is to investigate the drop jump performance of male patients who underwent ACLR and a control group using combined data acquisition system. Methods: A total of 28 male subjects aged 20 to 26 were studied: 22 did not show and were not diagnosed with any knee joint dysfunction (the control group) and six men who underwent ACLR of the left limb (group of patients). The control group was age, height and body mass matched. A data acquisition setup consisting of three independent modules including force platforms, position analysis system and electromyography was used. Subjects were jumping down from 0.1, 0.2, and 0.3 m step heights. The acquired signals were used to determine the ground reaction force, muscular activity, mass centre position, velocity and acceleration. Results: Statistically significant differences were found between the groups (t-test, p < 0.05) in the maximum vertical ground reaction force in the left limb for 0.2 and 0.3 m step heights. Differences in the muscle activity between the groups were found to be statistically significant (t-test, p < 0.05) before the jump, during the landing phase, and after the jump for selected muscle groups and step heights. Conclusion: Combing the three independent measurement systems provided new information on drop jump biomechanics. The distribution of loads in different muscles was not uniform across the groups. Patients allocated more energy to control their motion and seemed to protect their operated limb by shifting the bodyweight to the healthy limb.

13

Electromechanical delay of abdominal muscles is modified by low back pain prevention exercise

Szpala A., Rutkowska-Kucharska A., Drapala J.

Acta of Bioengineering and Biomechanics

|

2014

|

Vol. 16, no. 3

95--102

EN

The objective of the research was to assess the effect of a 4-week-long training program on selected parameters: electromechanical delay (EMD) and amplitude of electromyographic signal (EMG). Fourteen female students of the University School of Physical Education participated in the study. Torques and surface electromyography were evaluated under static conditions. Surface electrodes were glued to both sides of the rectus abdominis (RA), external oblique (EO), and erector spinae (ES) muscles. The 4-week-long program was aimed at strengthening the abdominal muscles and resulted in increased EMD during maximum torque production by flexors of the trunk, increased amplitudes of the signals of the erector spinae (p = 0.005), and increased EMG amplitude asymmetry of the lower (p = 0.013) and upper part (p = 0.006) of the rectus abdominis muscle. In a training program composed of a large number of repetitions of strength exercises, in which the training person uses their own weight as the load (like in exercises such as curl-ups), the process of recruitment of motor units is similar to that found during fatiguing exercises and plyometric training.

14

Assessment of muscle load and fatigue with the usage of frequency and time-frequency analysis of the EMG signal

Bartuzi P., Roman-Liu D.

Acta of Bioengineering and Biomechanics

|

2014

|

Vol. 16, no. 2

31--39

EN

The aim of the study was to determine the effect of the muscle load and fatigue on the values of the parameters calculated on the basis of the time, frequency (Fourier transform) and time-frequency (wavelet transform) analysis of the EMG signal, for low levels of load. Fifteen young men took part in the study. The EMG signal was registered from right side biceps brachii (BB) and trapezius (TR) muscles in static conditions, at load 10%, 20% and 30% MVC (maximal voluntary contraction). On the basis of the analysis there were selected parameters sensitive to force (RMS) and parameters sensitive to fatigue but simultaneously insensitive to force (MPF – mean power frequency determined on the basis of Fourier transform, CMPFdb5 – mean power frequency determined on the basis of the wavelet transform). The results indicate that CMPFdb5 can show similar (muscle BB) or greater (muscle TR) sensitivity to fatigue than MPF. It can suggest that, for low levels of load, the wavelet transform parameters can be more effective in assessing muscle fatigue than the parameters based on the Fourier transform. The obtained results can allow for a more precise analysis of muscle fatigue at low levels of load. Further analysis for a greater number of muscles activated at low levels of load, with the usage of the parameters tested is desirable.

15

An artificial neural network approach and sensitivity analysis in predicting skeletal muscle forces

Vilimek M.

Acta of Bioengineering and Biomechanics

|

2014

|

Vol. 16, no. 3

119--127

EN

This paper presents the use of an artificial neural network (NN) approach for predicting the muscle forces around the elbow joint. The main goal was to create an artificial NN which could predict the musculotendon forces for any general muscle without significant errors. The input parameters for the network were morphological and anatomical musculotendon parameters, plus an activation level experimentally measured during a flexion/extension movement in the elbow. The muscle forces calculated by the ‘Virtual Muscle System’ provide the output. The cross-correlation coefficient expressing the ability of an artificial NN to predict the “true” force was in the range 0.97 - 0.98. A sensitivity analysis was used to eliminate the less sensitive inputs, and the final number of inputs for a sufficient prediction was nine. A variant of an artificial NN for a single specific muscle was also studied. The artificial NN for one specific muscle gives better results than a network for general muscles. This method is a good alternative to other approaches to calculating of muscle force.

16

Muscle force distribution during forward and backward locomotion

Błażkiewicz M.

Acta of Bioengineering and Biomechanics

|

2013

|

Vol. 15, no. 3

3--9

EN

Backward walking (BW) is a common technique employed in the treatment of a variety of orthopedic and neurological diseases. BW training may offer some benefits especially in balance and motor control ability beyond those experienced through forward walking (FW). The purpose of this study was to determine whether BW represented a simple reversal of FW and, hence muscle force distribution is the same. The study involved one male healthy student of physical education (22 years, h = 185 cm, m = 80 kg). Measurements of spatial-temporal gait parameters were conducted using eight Vicon system cameras, and Kistler plates. Noraxon EMG was used to obtain muscles activity. OpenSim software was used to compute muscle force distribution during both types of gait. During FW and BW there is small difference for force curves produced by m. gluteus maximus (RMS = 0.04), m. biceps femoris short head (RMS = 0.19) and m. tibialis anterior (RMS = 0.16). Good validation by EMG signal was obtained for m. rectus femoris, m. biceps femoris short head, m. tibialis posterior during FW and BW. For m. iliacus, only during BW good validation was achived.

17

Evaluation of the effectiveness of training on a machine with a variable-cam

Urbanik C., Staniszewski M., Mastalerz A., Karczewska M., Lutosławska G., Iwańska D., Madej A., Ostrowska E., Gwarek L., Tkaczyk J.

Acta of Bioengineering and Biomechanics

|

2013

|

Vol. 15, no. 4

93--102

EN

The aim of the study was to assess the effectiveness of the training of elbow flexors through the use of 2 machines, one of which was equipped with a disc plate of constant radius, the other one with a variable-cam having a radius adjustable to muscle strength. The experiment included 45 men divided into 3 equal groups: training group A (variable-cam), training group B (circle), and control group C. The training lasted for 8 weeks, 3 times a week. In order to control the effects, the values of peak torque and power of the flexor muscles of the elbow were isokinetically measured for the angular velocities of 30°/s and 60°/s. Also taken were anthropometric measurements of the arm and the creatine kinase (CK) activity in the blood plasma. As a result of the training, significant increases of biomechanical values were noted only in group A: power increased over 20%, the peak torque over 14%. After the training, significant increases of arm circumference in the relaxed position were noted in group A (17 mm), as well as in group B (11 mm). Also, some changes in CK activity were observed between Monday and Friday in a training week. On the basis of the experimental measurements, it may be ascertained that training elbow flexor muscles on a machine with a variable-cam is more efficient for increases in strength and power, as well as for some anthropometric parameters, than training on a machine with a disc plate.

18

Biomechanics assessment of long term consequences of talocrural joint sprain in conservatively treated males

Czamara A., Emilianowicz M., Markowska I., Truszczyńska A., Trzaska T., Lewandowski J., Barinow-Wojewódzki A., Maciąg-Tymecka I.

Acta of Bioengineering and Biomechanics

|

2013

|

Vol. 15, no. 4

73--81

EN

The aim of the study was an assessment of isometric torque (IT) values under static conditions and relative torque (RT) for the plantar flexion muscles (PFM) and dorsal flexion muscles (DFM) and their mutual relations in males 5 years after talocrural joint sprain. IT measurements in PFM and DFM were performed using Biodex System 3. Group I consisted of 20 males on average 5 years after the sprain of the talocrural joint. Group II comprised 23 males with no history of talocrural joint injuries. The angles of measurement were: –15° of dorsiflexion (DF) and 0°, 15°, 30° and 45° for plantar flexion (PF) of the foot. In group I, the IT and RT obtained from PFM of involved leg were statistically significantly lower for most of the measured values of foot angle as compared to the contralateral joint and the results of the control group. The increase in the PF angle resulted in the decrease in IT values obtained from PFM, in favour of DFM. The IT values for PFM and DFM depend on the angle of foot and are represented by two different curves.

19

Application of muscle model to the musculoskeletal modeling

Wojnicz W., Wittbrodt E.

Acta of Bioengineering and Biomechanics

|

2012

|

Vol. 14, no. 3

29-39

EN

The purpose of this paper is to investigate new fusiform muscle models. Each of these models treats a muscle as a system composed of parts characterized by different mechanical properties. These models explain the influence of differences in the stiffness of lateral parts and the degree of muscle model discretization. Each muscle model is described by a system of differential equations and a single integro-differential equation. Responses of fifty-four muscle model forms are examined using a complex exertion composed of three types: eccentric-concentric exertion, isokinetic-isometric exertion and step exertion.

20

Wpływ symetrii ćwiczeń na rozkład temperatury górnej części ciała

Awrejcewicz J., Zagrodny B.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

|

2011

|

Vol. 17, nr 3

189-190

PL

W artykule zaprezentowano wyniki oceny termowizyjnej symetrii ćwiczeń fizycznych. Celem badań była analiza wpływu asymetrii pracy mięśni na rozkład temperatury ciała i porównanie ich z ćwiczeniami wykonywanymi symetrycznie. Analizowano wpływ ćwiczeń na mięśnie obręczy barkowej, przede wszystkim na zginacze, prostowniki, przywodziciele i odwodziciele ramion oraz przedramion. Wykazano, że za pomocą termowizji można wykryć asymetrię wykonywanych ćwiczeń fizycznych.

EN

The thermal imaging camera was used to examine the physical exercises symmetry. The influence of muscle work asymmetry on the body temperature distribution, was studied. The results were compared with the effects of symmetrically performed exercises. The study was focused on the girdle muscles, in particular on arm and forearm flexors and extensors, abductors and adductors. It was demonstrated that the asymmetry of physical exercises may be stated by thermovison.