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1

Body balance a few years after total hip replacement

Wareńczak Agnieszka, Lisiński Przemysław

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 1

87--96

EN

These aim of the study was to conduct a long-term evaluation of whether total hip replacement permanently affects the dynamic body balance. Methods: Twenty-five patients after the unilateral total hip replacement (mean age: 69.9 ± 6.2) and 25 subjects without the total hip replacement (mean age: 68.4 ± 4.8) who matched the age and overall health participated in this study. The force platform and functional tests such as Timed Up and Go, 3m walk test, Functional Reach Test, 30s Chair Stand Test, Step Test and Berg Balance Scale were used to assess dynamic balance. The results obtained in individual trials were compared using the Student’s t-test for independent variables, the Welch test or the non-parametric Mann–Whitney U-test. Results: Subjects from the THR group exhibited significantly increased time and distance in the tests performed on the force platform, compared to the control group. We also observed worse balance and functional test scores in the THR group: Timed Up and Go test ( p < 0.001), 3 m walk test ( p < 0.001), Functional Reach Test ( p < 0.001), 30 s Chair Stand Test ( p = 0.001) and Step Test (operated leg: p < 0.001, non-operated leg: p < 0.001). The results obtained in the Berg Balance Scale tests were not significantly different between the groups ( p = 0.218). Conclusions: We observed significant differences in postural stability and dynamic balance between patients after THR and subjects in the same age without endoprosthesis. Our research shows that total hip replacement permanently impairs patients’ dynamic balance and their functionality in certain lower-extremity activities.

2

Effective utilization of man shift through sustainable workload testing for underground mining machine operators. An ergonomic based man-machine interface approach

Dey Netai Chandra, Dey Shibaji

New Trends in Production Engineering

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2019

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Vol. 2, Iss. 1

394--403

EN

Insight of man-machine interfaces during mining machine operations, better co-ordinance with human efficiencies and suitable workload selection in underground mining machine operation are the main viewpoints of the study. Total 12 side discharge loader (SDL) and load haul dumper (LHD) operators [N = 12] have been taken as participants of the study. The methodology is divided into two parts first part is devoted to measuring and analyzing workload response of machine operation with polar heart rate monitor. Machine operator’s heart rate ratio (HR ratio) for the whole shift is recorded and metabolic rate (MR) has been analyzed. Additionally, fatigue sustainability (FS) and degradation of muscle force (MF) are recorded for each work cycles up to exposure time period (ETP) of 360 minutes. In the second part of the methodology, based on the HR ratio recorded during the mining operation, a workload simulation study is undertaken on a treadmill at the surface following BRUCE protocol. At treadmill, based on HR ratio, workload achieved from mines along with three different workloads i.e. low, moderate and high has been tested. Differences in FS and degradation rate of MF after each workload experiment have been recorded. A result from the underground operational study shows that there is about 43.2% and 32.4% of decreasing MF for SDL and LHD operators after end of spells at mines. Additionally, a negative correlation (r = -0.99) is found between ETP and MF. The workload simulation study shows that there are significant differences between FS (p < 0.05) and MF (p < 0.05) data of mining and treadmill experiment with the same workload. In comparison to an underground operation, FS rate of low, moderate and high workload is recorded 60%, 35%, and 15% higher respectively than of mine workload. Higher FS rate may achieve due to availability of good environment. Among the tested workload only low kind of workload is found suitable for mining machinery job as degradation of MF is found significantly (p < 0.05) low and FS is found significantly (p < 0.01) high in this kind of workload. Therefore, it can be concluded that in mining machinery operation better to adopt low workload for effective utilization of man shift (EUMS) as it gives comparatively low MF degradation and better FS during continuous work.

3

Lower extremity muscle strength, postural stability and functional movement screen in female basketball players after ACL reconstruction : Preliminary report

Wrzesień Zuzanna, Truszczynska-Baszak Aleksandra, Rzepka Remigiusz

Acta of Bioengineering and Biomechanics

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2019

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Vol. 21, no. 2

71--81

EN

The anterior cruciate ligament (ACL) tear is a common injury in basketball. Its consequence is a long absence from training, resulting from surgical treatment and long physiotherapy. The aim of the study was to assess muscle strength, postural stability and functional movements in female basketball players, who returned to professional sport careers after anterior cruciate ligament reconstruction. Methods: The study population consisted of 10 female basketball players after surgical reconstruction of anterior cruciate ligament. The control group consisted of 10 players without ACL injury. We used the Biodex System 4 Pro dynamometer to assess the muscle strength of the knee. We used it to conduct the test of flexors and extensors of the knee in isokinetic conditions. We also used Keiser Power Squat A300 in the single leg squat to measure power and the Biodex Balance SD dynamographic platform to assess balance in single leg stance. Results: We found deficits in both movement patterns and in muscle strength in the study population, compared to control group. Conclusions: The basketball players after ACL reconstruction had significant differences between the operated and non-operated limb. The differences may predispose them towards repeated ACL injuries.

4

Do different muscle strength levels affect stability during unplanned gait termination?

Cen Xuanzhen, Jiang Xinyan, Gu Yaodong

Acta of Bioengineering and Biomechanics

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2019

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Vol. 21, no. 4

27--35

EN

Unplanned gait termination (UGT) widely occurs in various sports and daily life as a kind of stress response to unexpected stimulus. However, the body stability may be greatly affected when the body completely stops. The purpose of this study was to examine the association between muscle strength levels and body stability during UGT through comparing the plantar pressure. Methods: Twenty healthy participants (10 male and 10 female) with different lower limbs muscle strength and power were asked to perform planned gait termination (PGT) and unplanned gait termination (UGT) on an 8-m walkway. Related plantar pressure data including maximum pressure, maximum force, contact area and center of pressure were recorded with Footscan pressure platform. Results: Two types of gait termination have significant differences in the plantar pressure distribution. Maximum pressure and maximum force in the lateral metatarsal increased significantly during UGT, compared to PGT. At the same time, data from the current study suggested that there might be a correlation between the muscle strength levels of individual and the stability during the gait termination, especially between the muscle power and UGT, which means that the more excellent muscle power an individual has, the more stable the body is when UGT is performed. Conclusions: The findings suggest that different muscle strength levels could affect stability during unplanned gait termination.

5

Stabilometric indicators as an element of verifying rehabilitation of patients before and after reconstruction of anterior cruciate ligament

Ogrodzka-Ciechanowicz K., Czechowska D., Chwała W., Ślusarski J., Gądek A.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 1

101--107

EN

The aim of the study was to evaluate effectiveness of rehabilitation in patients before and after rACL, based on stabilographic indicators. Methods: The research group was comprised of 31 men aged 20–57 with anterior cruciate ligament injury, qualified for reconstruction surgery. A measurement of static stabilometric indicators and muscle strength was taken twice for each patient – before surgery and after 6 months. To assess stabilographic indicators the stabilographic platform was used and to asses muscle strength a dynamometer was used. In order to assess knee function the Lysholm scale and VAS scale were used. Results: The rehabilitation programme improved static stability of the knee in the frontal plane, which is manifested by a significant shortening of the SPML path length. Rehabilitation proceedings should focus on improving static stability of the knee joint in the sagittal plane, because the results obtained indicate only a slight shortening of the SPAP length. The results of the Lysholm and VAS scales point to a positive influence of the applied rehabilitation. Conclusion: Inclusion into rehabilitation diagnostic tools to assess stabilometric indicators enables for effective verification of rehabilitation proceedings focused on restoring body posture control before and after the rACL.

6

Force analysis of shoulder joint muscles in the early phase of brain stroke

Starosta M., Kostka J., Miller E.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 3

107--113

EN

Upper limb impairment in the early phase of brain stroke is one of the key problems in rehabilitation. An estimation of muscle force can be a helpful factor for functional improvement after a stroke. The primary goals of this study were to determine the muscles with the lowest force in the affected (A) and non-affected (non-A) upper limb. Moreover, the differences between men and women were compared and these values were correlated with age. Methods: One hundred (n = 35 female, n = 65 male) post-stroke patients met the inclusion criteria. The mean age of the study participants was 66.1 years. Muscle force for external and internal rotators of shoulder was measured with handheld dynamometer. Moreover, the correlation coefficients for differences in muscular force with the patient’s age were estimated. Results: Our study reports that the force of the (A) side in relation to the (non-A) was by 37% weaker. We observed about a 40% decrease in the force of the shoulder’s external rotation (female – 42%; male – 41%) and shoulder’s flexion (by 38% – female; 40% – male). Significant correlations between the muscle force and the age of post-stroke patients were also found. It was concluded that about 4 weeks after the first stroke in the patient’s life, the external rotators are the most affected group of shoulder muscles. Conclusions: Neither sex nor the side of the ischemic brain injury influence the muscle force, whereas age determines both muscle force and muscle force deficits. Older post-stroke patients demonstrate fewer deficits in muscle strength than younger ones.

7

Evaluation of relationship between the results of selected tests for muscle strength assessment of the hip abductors

Szczygieł E., Kotla K., Masłoń A., Golec J., Czechowska D., Staszkiewicz R., Krzywda E., Golec E.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 2

125--131

EN

Purpose: The assessment of hip joint abductor muscle strength is most often carried out using a dynamometric test. However, both in clinical practice and literature, evaluation is performed by means of the single-leg half-squat or the amount of abduction movements performed in the hip joint. In this context, the question arises whether the results of individual tests are convergent. The aim of the study is to evaluate the relationship between strength of the hip abductor muscle measured by dynamometer, the single-leg-squat and the number of repetitions of the movements in time. Methods: A group of 35 students (20 women and 15 men) between 20 and 24 years old participated in the study. Each student was subjected to three tests assessing the condition of the hip and associated abductor muscles. Those included: assessment of hip joint abduction muscle strength in a dynamometric study, assessment of the number of abdomen movements performed lying on the side and standing, during a 30-second interval, and the single-leg-squat test. Results: Based on the tests conducted, a significant relationship was observed between the muscle strength measurement results for the left and right side in the dynamometric study and the number of hip abduction repetitions in 30 seconds and the single-leg-squat test. Conclusions: The obtained results indicate a significant relationship between the results of all the tests. In practice, this means that the tests can be used interchangeably.

8

Correlations between somatic features, anteroposterior spinal curvatures and trunk muscle strength in schoolchildren

Barczyk-Pawelec K., Dziubek W., Piechura J. R., Rożek K.

Acta of Bioengineering and Biomechanics

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2017

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Vol. 19, no. 1

133--139

EN

Background: Evaluation of body posture and strength of spinal muscles in children during their progressive ontogenesis is significant for the evaluation of their physical health condition and physical fitness. It is also a reference point in a process of control and medical care. Purpose: The aim if this study was to evaluate correlation between the selected features of somatic body structure, shape of anteroposterior spinal curves and force-velocity (FV) parameters of trunk muscles in school children. Participants and methods: The sample involved 104 children aged 10–11 years, 60 females (10.74 ± 0.7) and 44 males (10.50 ± 0.9). Body posture was assessed using the Moiré photogrammetry while trunk muscles (flexors and extensors) strength was measured isokinetically. Results: The results of the research revealed the existence of many average and strong correlations observed between the analysed somatic characteristics and forcevelocity (FV) parameters of trunk muscles. Correlation between the volume of the spinal curvatures in the sagittal plane and forcevelocity parameters of trunk extensors and flexors were average or weak for both groups of children. Conclusion: Somatic features indicated stronger correlation with trunk muscles' strength than with the size of the anteroposterior spinal curves.

9

Analysis of upper limb muscle strength in the early phase of brain stroke

Starosta M., Kostka J., Redlicka J., Miller E.

Acta of Bioengineering and Biomechanics

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2017

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Vol. 19, no. 3

85--91

EN

Purpose: The aim of this study was to determine the muscles with the lowest strength in nonaffected (non-A) and affected upper limb (A), to assess differences between men and women and to correlate these values with age in patients after stroke. Methods: Sixty hospitalized in Neurorehabilitation Ward patients (40 male, 20 female), 1-2 weeks after stroke, were enrolled to the study. Their age ranged from 50 to 80 years with a mean (sd) of 65,5 (18,7) years. Muscle force values from upper limb muscles were measured using the MicroFet 2 hand-held dynamometer. The results are displayed in newtons [N], mean values of muscular force, effect sizes and confidence intervals displayed as Cohen’s d and 95% CI were determined. Moreover, we made the coefficients correlation for differences in muscular force versus the Rivermead Motor Assessment (RMA) arm section. Results: Strength of (A) upper limb in comparison to (non-A) was 39% weaker. The severely affected muscle groups were the shoulder flexion 41% (women) versus 46% (men); elbow flexion 39% (women) versus 31% (men); wrist extension 36% (women) versus 42% (men). No significant correlations were found between muscle strength results and RMA or age. Conclusions: Muscle force of (A) upper limb after stroke demonstrates 39% decrease. Men show more significant decrease than women (40% vs 35%). Functional assessment in RMA values show the better results in women (4,9 ± 4,1) than men (3,4 ± 3,2).

10

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

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2016

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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.

11

Preventive strength training improves working ergonomics during welding

Kruger K., Petermann C., Pilat C., Schubert E., Pons-Kuhnemann J., Mooren F. C.

International Journal of Occupational Safety and Ergonomics

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2015

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Vol. 21, No. 2

150--157

EN

To investigate the effect of a preventive strength training program on cardiovascular, metabolic and muscular strains during welding. Welders are one of the occupation groups which typically have to work in extended forced postures which are known to be an important reason for musculoskeletal disorders. Subjects (exercise group) accomplished a 12-week strength training program, while another group served as controls (control group). Pre and post training examinations included the measurements of the one repetition maximum and an experimental welding test. Local muscle activities were analysed by surface electromyography. Furthermore, heart rate, blood pressure, lactate and rating of perceived exertion were examined. In the exercise group, strength training lead to a significant increase of one repetition maximum in all examined muscles (p<.05). During the experimental welding test muscle activities of trunk and shoulder muscles and arm muscles were significantly reduced in the exercise group after intervention (p<.05). While no changes of neither cardiovascular nor metabolic parameters were found, subjects of the exercise group rated a significantly decreased rate of perceived exertion welding (p<.05). Effects of strength training can be translated in an improved working ergonomics and tolerance against the exposure to high physical demands at work.

12

Handgrip explosive force is correlated with mobility in the elderly women

Borges L. S., Fernandes M. H., Schettino L., Coqueiro R. S. da, Pereira R.

Acta of Bioengineering and Biomechanics

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2015

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Vol. 17, no. 3

145--149

EN

The analysis of explosive force, through rate of force development (RFD) and contractile impulse (CI), from handgrip strength data seems to be useful and promising information to study the aging of musculoskeletal system and health status. We aimed to test the hypothesis that, in elderly women, the handgrip explosive force could be better associated to the functional mobility than maximum handgrip strength. Handgrip strength and the performance of Timed Up & Go Test (TUG) were measured from sixty-five community-dwelling healthy elderly women. The average slope of the moment–time curve (Δ moment/Δ time) over the time interval of 0–200 ms relative to the onset of contraction was calculated to provide the RFD and CI. The highest strength achieved during the isometric contraction was used as maximum handgrip strength. Pearson correlations were used to assess the strength of the relationship between the handgrip strength parameters (Maximum strength and explosive force from 0–200 ms) and TUG test performance from older women. The correlation analysis showed that the TUG test performance was inversely correlated to the handgrip strength parameters, with better relationship with explosive force parameters. The handgrip explosive force seems to be a promising predictor of functional mobility of elderly women, since it showed a better relationship with functional mobility than maximum handgrip strength.

13

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

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2015

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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.

14

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

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2015

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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.

15

Projektowanie koncepcyjne środków transportu na rzecz rekultywacji terenów górniczych

Derlukiewicz D., Lewandowski T.

Górnictwo Odkrywkowe

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2014

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R. 55, nr 4-5

260--264

PL

W artykule zaprezentowano proces projektowania koncepcyjnego na przykładzie projektu środka transportu wykorzystującego siłę mięśni ludzkich. Celem projektu było również zagospodarowanie terenów górniczych. W artykule pokazano źródła inspiracji projektantów oraz wyniki procesu projektowego na przykładzie interdyscyplinarnego projektu „Creative Design”.

EN

The article presents the conceptual design process on the example of the means of transport that use human muscle power. The aim of the project was also to develop the mining areas. The article shows the sources of inspiration for designers and the results of the design process on the example of an interdisciplinary project “Creative Design”.

16

Wyznaczanie sił mięśniowych i reakcji w stawach kończyny dolnej podczas naskoku i odbicia

Drapała K., Dziewiecki K., Mazur Z., Blajer W.

Modelowanie Inżynierskie

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2012

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T. 13, nr 44

49-56

PL

W artykule opisano metodę wyznaczania -poprzez rozwiązanie zadania symulacji dynamicznej odwrotnej -sił mięśniowych i reakcji w stawach kończyny dolnej podczas naskoku i odbicia z jednej nogi. Kończynę wydzielono z ciała człowieka i zamodelowano jako płaski łańcuch kinematyczny zaczepiony w stawie biodrowym, sterowany za pomocą dziewięciu sił mięśniowych. Danymi wejściowymi dla symulacji są charakterystyki kinematyczne ruchu (pomierzone metodami fotogrametrycznymi) oraz, w fazie kontaktu z podłożem, reakcje od podłoża na stopę (zmierzone na platformie dynamometrycznej). Przedstawiono zarówno najistotniejsze elementy zbudowanego modelu obliczeniowego jak i wybrane wyniki symulacji dynamicznej odwrotnej analizowanego skoku.

EN

The paper developes an effective method for the determination of muscle forces and joint reaction forces in the lower limb, developed as the inverse dynamics simulation during one-leg jump composed as a sequence of a short flight phase (hurdle from one leg to another), one-leg contact phase with the ground (landing and take-off), and another flight phase (ballistic flight after the take-off). The main steps of the developed formulation are shortly presented, and selected simulation results of the sample movement are reported.

17

Biomechaniczna ocena zdolności siłowych siatkarek

Michnik R., Jurkojć J., Czapla K.

Modelowanie Inżynierskie

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2012

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T. 13, nr 44

217-222

PL

W ramach pracy przedstawiono metodykę badań umożliwiającą wyznaczenie izokinetycznych charakterystyk zespołów mięśniowych stawu kolanowego, pozwalających na ocenę stopnia wytrenowania sportowców oraz weryfikację metod treningowych. W ramach badań dokonano pomiarów momentów sił mięśniowych w warunkach pracy izokinetycznej na stanowisku pomiarowym Biodex System Pro 4. Badania przeprowadzono na grupie zawodniczek drużyny AZS Politechnika Śląska.

EN

A research methodology enabling determination of isokinetic characteristics of knee flexors and extensors muscles is presented in the paper. The methodology can be used in estimation of volleyball players fitness and evaluation of training methods. Within the frame of conducted research measurements of muscle forces torques of knee flexors and extensors were carried out. All measurements were performed by means of the Biodex System Pro 4.The group of professional volleyball players from the AZS Silesian University of Technology team was examined.

18

Wyznaczanie sił mięśniowych podczas chodu dzieci zdrowych

Głowacka A., Świtoński E., Michnik R.

Aktualne Problemy Biomechaniki

|

2012

|

z. 6

31--36

19

Zmiany mocy i skoczności u siatkarek w okresie przygotowawczym

Lipińska M., Michalski R.

Aktualne Problemy Biomechaniki

|

2011

|

z. 5

75--80

PL

Celem pracy było określenie zmian mocy kończyn dolnych i wysokości uniesienia środka masy ciała mierzonych w wyskokach CMJ i BCMJ na platformie dynamometrycznej u siatkarek w okresie przygotowawczym. W badaniach uczestniczyło 14 siatkarek. Pomiar mocy kończyn dolnych i wysokości uniesienia środka masy ciała przeprowadzono na platformie dynamometrycznej. Moc maksymalna uległa nieistotnemu zwiększeniu o 6,3% w CMJ i zmniejszeniu o 4,1% w BCMJ podczas gdy wysokość uniesienia środka masy ciała nie uległa zmianie w CMJ i zwiększyła się istotnie o 4,7% w BCMJ.

EN

The aim of this study was to determine the changes of power of lower limbs and height of rise of the body mass center at CMJ and BCMJ jumps on the dynamometric platform of female volleyball players during preparatory period. Fourteen female volleyball players took part in this study. The measurement of lower limb power and height of rise of the body mass center was carried out on a dynamometric platform. Maximal power has nonsignificantly increased by 6.3% in CMJ, and decreased by 4.1% in BCMJ while height of rise of the body mass centre did not change in the CMJ and increased significantly by 4.7% in BCMJ.

20

Finite element modelling of the articular disc behaviour of the temporo-mandibular joint under dynamic loads

Jaisson M., Lestriez P., Taiar R., Debray K.

Acta of Bioengineering and Biomechanics

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2011

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Vol. 13, no. 4

85-91

EN

The proposed biodynamic model of the articular disc joint has the ability to affect directly the complete chewing mechanism process and its related muscles defining its kinematics. When subjected to stresses from the mastication muscles, the disc absorbs one part and redistributes the other to become completely distorted. To develop a realistic model of this intricate joint a CT scan and MRI images from a patient were obtained to create sections (layers) and MRI images to create an anatomical joint CAD model, and its corresponding mesh element using a finite element method. The boundary conditions are described by the external forces applied to the joint model through a decomposition of the maximum muscular force developed by the same individual. In this study, the maximum force was operating at frequencies close to the actual chewing frequency measured through a cyclic loading condition. The reaction force at the glenoid fossa was found to be around 1035 N and is directly related to the frequency of indentation. It is also shown that over the years the areas of maximum stresses are located at the lateral portion of the disc and on its posterior rim. These forces can reach 13.2 MPa after a period of 32 seconds (s) at a frequency of 0.5 Hz. An important part of this study is to highlight resilience and the areas where stresses are at their maximum. This study provides a novel approach to improve the understanding of this complex joint, as well as to assess the different pathologies associated with the disc disease that would be difficult to study otherwise.