INTRODUCTION: Although the effects of carrying loads on gait biomechanics have been well-documented, to date, little evidence has been provided whether such loads may impact spatial and temporal gait asymmetries under the different foot regions. Therefore, the main purpose of the study was to examine the effects of carrying a standardized police equipment on spatiotemporal gait parameters. MATERIALS AND METHODS: In this population-based study, participants were 845 first-year police recruits (age: 21.2 ± 2.3 years; height: 178.1 ± 10.2 cm; weight: 78.4 ± 11.3 kg; body mass index: 24.7 ± 3.2 kg/m2; 609 men and 236 women; 72.1% men and 27.9% women) measured in 2 conditions: (i) "no load" and (ii) "a 3.5 kg load." Spatiotemporal gait parameters were derived from the FDM Zebris pressure platform. Asymmetry was calculated as (xright-xleft)/0.5*(xright + xleft)*100%, where "x" represented a given parameter being calculated and a value closer to 0 denoted greater symmetry. RESULTS: When compared to "no load" condition, a standardized 3.5 kg/7.7 lb load significantly increased asymmetries in spatial gait parameters as follows: gait phases of stance (mean diff. = 1.05), load response (mean diff. = 0.31), single limb support (mean diff. = 0.56), pre-swing (mean diff. = 0.22), and swing (mean diff. = 0.90) phase, while no significant asymmetries in foot rotation, step, and stride length were observed. For temporal gait parameters, we observed significant asymmetries in step time (mean diff. = -0.01), while no differences in cadence and gait speed were shown. CONCLUSIONS: The findings indicate that the additional load of 3.5 kg/7.7 lb is more likely to increase asymmetries in spatial gait cycle components, opposed to temporal parameters. Thus, external police load may have hazardous effects in increasing overall body asymmetry, which may lead to a higher injury risk and a decreased performance for completing specific everyday tasks.

• MeSH
• biomechanika fyziologie   MeSH
• chůze (způsob) * fyziologie   MeSH
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• policie * statistika a číselné údaje   MeSH
• zatížení muskuloskeletálního systému * fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

The aim of the present study was to examine the effects of attentional focus instructions on acute changes in the transverse relaxation time (T2) of the femorotibial cartilage and in cartilage volume during repeated drop-jump landings. Ten healthy females (Mage = 20.4 ± 0.8 years) performed a drop landing task from a 50 cm high box over the course of 3 days (50 repetitions each day) across three attentional focus conditions: external focus (EF: focus on landing as soft as possible), internal focus (IF: focus on bending your knees when you land), and control (CON: no-focus instruction), which was counterbalanced across focus conditions. T2 mapping and the volume of femorotibial cartilage were determined from magnetic resonance imaging scans at 1.5 T for the dominant knee before and after completing the drop landings in each attentional focus condition per day. Results indicated a smaller change in cartilage T2 relaxation time and volumetry in the central load-bearing lateral cartilage under the EF, compared to IF and CON. Moreover, the change in T2 and cartilage volume was greater for lateral tibial cartilage as compared to femoral cartilage and was independent of attentional focus instructions. No significant acute quantitative changes were observed in the medial compartment. The peak vertical ground reaction force was found to be the lowest under the EF, compared to IF and CON. These findings suggest that external focus of attention may reduce cartilage load, potentially aiding in the control or management of cartilage injuries during landing in female athletes.

• Klíčová slova
• MRI, T2 relaxation time, focus of attention, knee loading, volumetry,
• MeSH
• biomechanika MeSH
• kloubní chrupavka * fyziologie   diagnostické zobrazování   MeSH
• kolenní kloub fyziologie   MeSH
• lidé MeSH
• magnetická rezonanční tomografie * MeSH
• mladý dospělý MeSH
• plyometrická cvičení MeSH
• pozornost * fyziologie   MeSH
• tibie fyziologie   diagnostické zobrazování   MeSH
• zatížení muskuloskeletálního systému * fyziologie   MeSH
• Check Tag
• lidé MeSH
• mladý dospělý MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

The aim of our study was to compare gait in terms of foot loading and temporal variables after 2 different operative approaches (the extended lateral approach [ELA] and sinus tarsi approach). Twenty-two patients who sustained an intra-articular calcaneal fracture underwent plantar pressure distribution measurements 6 months after surgery. Measurements were performed while patients walked on the pedobarography platform. The values of dynamic variables were significantly lower on the operated limb in the ELA. In the sinus tarsi approach, no differences were observed between the operated and uninjured limbs (UIN) at peak pressure and at maximal vertical force. The values of temporal variables (contact time of the foot and of the heel) between the operated and UIN differed in the ELA. The hypothesis that differences in foot load between operated and UIN will be more significant in the ELA was confirmed. Our results showed that the differences in loading and temporal variables between the operated and the UIN persisted 6 months after surgery in both methods. The operated limb was less loaded, with the tendency to shift the load toward the midfoot and forefoot. After the less invasive sinus tarsi approach, the dynamic and temporal variables on the operated limb were nearly the same as those on the healthy one. The sinus tarsi surgical approach can be recommended for treatment of displaced calcaneal fractures.

• Klíčová slova
• extended lateral approach, force, pedobarography, pressure, sinus tarsi approach, time,
• MeSH
• biomechanika MeSH
• časové faktory MeSH
• chůze (způsob) fyziologie   MeSH
• chůze fyziologie   MeSH
• dislokovaná fraktura diagnostické zobrazování   chirurgie   MeSH
• dospělí MeSH
• fraktury kostí diagnostické zobrazování   chirurgie   MeSH
• hodnocení rizik MeSH
• index tělesné hmotnosti MeSH
• intraartikulární fraktury diagnostické zobrazování   chirurgie   MeSH
• kohortové studie MeSH
• lidé středního věku MeSH
• lidé MeSH
• následné studie MeSH
• neparametrická statistika MeSH
• patní kost zranění   chirurgie   MeSH
• plantární plocha MeSH
• poranění nohy (od hlezna dolů) diagnostické zobrazování   chirurgie   MeSH
• retrospektivní studie MeSH
• senioři MeSH
• skóre závažnosti úrazu MeSH
• tlak MeSH
• vnitřní fixace fraktury metody   MeSH
• výsledek terapie MeSH
• zatížení muskuloskeletálního systému fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH

OBJECTIVE: As a part of regular revision of the List of Occupational Diseases in the Czech Republic, efforts have been made to add a new item so that lumbar spine disease caused by overload may be recognized as occupational one, with adherence to the valid national rules, that is, clinical criteria are met and objective assessment confirms working conditions under which, according to recent scientific knowledge, such an occupational disease develops. The aim is to provide information on the use of a proposed method for working condition assessment in a real setting, based on the initial experiences gained from a pilot study carried out to validate the method. METHODS: Working conditions were assessed in 55 individuals with chronic low back pain (25 males, 30 females; mean age 45.6 years; mean length of employment 15.6 years). The assessment was based on estimating compressive force on the L4/L5 intervertebral disc when performing potentially high-risk work tasks which were entered into four types of checklists throughout their work shifts. The compression values were calculated using a special module that was developed. RESULTS: In 24 cases comprehensive assessment of all tasks performed showed fulfillment of the proposed criteria of working conditions needed for recognition of occupational disease. Those included healthcare, foundry and forest workers, production operators, cabinetmakers, locksmiths, bricklayers, etc. In all the cases, lumbar spine overload was associated with work tasks requiring combinations of manual handling of objects and trunk rotation or bending. The criteria were not met in 31 subjects. The mean length of employment was 15.4 and 15.8 years in patients who met and did not meet the proposed criteria, respectively. CONCLUSION: The proposed method proved to be applicable in occupational hygiene evaluation in a real setting.

• Klíčová slova
• checklists, chronic lumbar spine diseases, lumbar spine overload, occupational hygiene criteria, occupational risk factors,
• MeSH
• bederní obratle patofyziologie   MeSH
• biomechanika fyziologie   MeSH
• chronická bolest patofyziologie   MeSH
• kontrolní seznam MeSH
• lidé středního věku MeSH
• lidé MeSH
• lumbalgie patofyziologie   MeSH
• nemoci z povolání patofyziologie   MeSH
• plnění a analýza úkolů MeSH
• zaměstnání MeSH
• zatížení muskuloskeletálního systému fyziologie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH

PURPOSE OF THE STUDY Knee joint is the most common place where osteoarthritis may occur. A specific therapy is indicated to patients depending on the degree of disability and other signs. The available methods and their clinical value are regularly assessed in systematic reviews and meta-analysis of clinical studies. The evidence of working mechanism of the specific therapeutic intervention is another important part of evaluating its therapy effect. One of the possibilities of knee osteoarthritis conservative treatment is a functional prophylactic knee brace. This type of knee brace is designed to transfer the load away from the affected part of the knee joint in every step. The main goal of this study was to determine the effect of a prophylactic knee brace on dynamic parameters of the stance phase of gait in patients with knee osteoarthritis. MATERIAL AND METHODS The research involved twelve subjects with predominantly unilateral medial knee osteoarthritis of grade 2 and 3. Six patients did not complete the study. Therefore, the data of six persons were processed (average age 68.3 ± 4.4 years, average weight 83 ± 15.9 kg, average height 170.5 ± 11.7 cm). There were two piezoelectric Kistler 9286AA force plates used to determine the reaction forces. In total, six attempts were evaluated - three attempts with the knee brace and three attempts without it. Each subject completed three measurements. The first one took place at the beginning of the research, the second one after three months of using the brace, and the last one took place three months after the brace removal. The data processing methods were accustomed. At the beginning and at the end of the study the patients completed the WOMAC questionnaire and determined the level of their pain on the visual analogue scale (VAS). RESULTS The minimum value (p = 0.020) and the second maximum value (p = 0.035) of vertical reaction force significantly increased on the unaffected limb after a short-term application of a knee brace. There were significant increases found for walking without a brace in the maximum vertical force in the braking phase on the affected limb (p = 0.006) after three months of bracing, followed by similar results in the maximum vertical force in the braking (p = 0.001) as well as the propulsion (p = 0.035) phase on the unaffected side. Furthermore, we observed a significant extension in the overall duration of the stance phase of gait (p = 0.001) on the affected limb. According to the WOMAC and VAS results, three patients experienced subjective conditional improvement, two subjective deterioration and one participant remained unchanged. DISCUSSION The individualized solutions, i.e. their "adaptation" to a particular type of knee arthrosis in each patient, is the biggest problem in the treatment of knee arthrosis using a prophylactic brace. Our results confirm the usefulness of modern knee orthosis in terms of motion biomechanics. However, it still remains to be proved that it is possible to use the brace for a long time during the active time of the day and that this use brings about a significant relief from troubles, improving the patient's quality of life. CONCLUSIONS The effect of the orthosis application was reflected in force and time parameters of the vertical and anteroposterior component of the reaction force. The use of a prophylactic knee brace can influence the dynamics of gait. The short-term effect of prophylactic brace use is reflected in an increased load on the unaffected limb. From a long-term point of view, a prolongation of the stance phase in both extremities was observed. However, the positive effect of the knee brace use tended to persist even after the brace removal. There were no significant changes in the subjective assessment of pain, stiffness and function of the knee joint. Key words: osteoarthritis, knee joint, knee brace, walking, dynamic analysis, adduction moment.

• MeSH
• artróza kolenních kloubů * patofyziologie   psychologie   MeSH
• biomechanika MeSH
• chůze (způsob) MeSH
• chůze MeSH
• kolenní kloub patofyziologie   MeSH
• konzervativní terapie * přístrojové vybavení   metody   MeSH
• kvalita života * MeSH
• lidé středního věku MeSH
• lidé MeSH
• měření bolesti metody   MeSH
• rozsah kloubních pohybů MeSH
• senioři MeSH
• výztuhy * MeSH
• zatížení muskuloskeletálního systému fyziologie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVE: The human motion system reacts to both hypo and hyperactivity loads by changes to the rheological properties of tissues. This study deals with changes to the axial system (AS) compartment. Using the appropriate methodologies and mathematical-physical methods, these changes can be identified and quantified. METHODS: This study describes the noninvasive TVS (Transfer Vibration through Spine) method, which was applied to assess the AS selected mechanical properties in various modes. A pilot study was conducted on a top-level twelve-year-old girl-gymnast. The data detection was carried out in three cycles, before and after a peak 3.5 hour training session and the next day, after resting, just before the next training. RESULTS: Specifically, the values of selected rheological parameters, the AS damping coefficient b and viscosity μ, were obtained. The dynamics of their changes, in the stated load cycles, has also been shown. The damping coefficient b fell from the value of 0.626 to 0.324 before training and increased to 0.394 after resting. The viscosity coefficient μ showed a similar trend, namely falling from the value of 9.85 [Pa.s] to 2.15 [Pa.s] and then increasing to 3.8 [Pa.s] . CONCLUSIONS: With its computational solution, the TVS method,is a diagnostic apparatus making it possible to classify AS properties, both quantitatively and qualitatively, or its chosen segments and their changes, respectively. It can be used in classifying, preventing and treating the consequences of extreme motion and relaxing modes. The TVS application also makes it possible to control AS states over therapeutic, recovery, ergonomic and other loading modes of the human locomotion system.

• MeSH
• biomechanika MeSH
• dítě MeSH
• gymnastika * MeSH
• lidé MeSH
• páteř fyziologie   MeSH
• pilotní projekty MeSH
• reologie * MeSH
• vibrace * MeSH
• viskozita MeSH
• zatížení muskuloskeletálního systému fyziologie   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

UNLABELLED: The strength of both femurs was estimated in 198 post-menopausal women through subject-specific finite element models. Important random differences between contralateral femurs were found in a significant number of subjects, pointing to the usefulness of further studies to understand if strength-based classification of patients at risk of fracture can be affected by laterality issues. INTRODUCTION: Significant, although small, differences exist in mineral density and anatomy of contralateral proximal femurs. These differences, and their combined effect, may result in a side difference in femurs' strength. However, this has never been tested on a large sample of a homogenous population. METHODS: The strength of both femurs was estimated in 198 post-menopausal women through CT-derived finite element models, built using a validated procedure, in sideways fall conditions. The impact of the resulting asymmetry on the classification of subjects at risk of fracture was analysed. RESULTS: The small difference observed between sides (the right femur on average 4 % stronger than the left) was statistically significant but mechanically negligible. In contrast, higher random differences (absolute difference between sides with respect to mean value) were found: on average close to 15 % (compared to 9.2 % for areal bone mineral density (aBMD) alone), with high scatter among the subjects. When using a threshold-based classification, the right and left femurs were discordant up to over 20 % of cases (K always lower than 0.60) but the left femur was concordant (mean K = 0.84) with the minimum strength between right and left. CONCLUSION: Considering both femurs may be important when trying to classify subjects at risk of failure with strength estimates. Future studies including fracture assessment would be necessary to quantify the real impact.

• Klíčová slova
• Computed tomography, Finite element, Multicentric study, Post-menopausal women, Proximal femur’s strength, Side differences,
• MeSH
• absorpční fotometrie metody   MeSH
• analýza metodou konečných prvků MeSH
• femur anatomie a histologie   diagnostické zobrazování   fyziologie   MeSH
• kostní denzita fyziologie   MeSH
• krček femuru anatomie a histologie   fyziologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• počítačová rentgenová tomografie metody   MeSH
• postmenopauza fyziologie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• zatížení muskuloskeletálního systému fyziologie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, N.I.H., Intramural MeSH

AIM: The aim of the study was to develop a computational module for the prediction of compressive force on the L4/L5 disc suitable for use in field settings. METHOD: The value of compressive force is intended to be used as a proxy measure of the mechanical burden of low-back when performing work activities. The compressive force predicted by the module in a particular worker should be compared with the NIOSH limit value of 3,400 N for the assessment of lumbar spine load during manual lifting tasks. Exceeding the limit will be considered as the fulfilment of "hygienic criterion" that should be met to acknowledge low-back disorder as an occupational disease. To develop the computational module we used the ergonomic software TECNOMATIX Classic Jack taking into account the anthropometric parameters of a worker and ergonomic parameters of his/her work activity. RESULTS: We calculated compressive forces on the L4/L5 disc in about 1,300 simulated combinations of various factors influencing compressive force. Parameters which turned out to be crucial for the compression of L4/L5 disc were included in the computational algorithm. CONCLUSION: Our study was primarily aimed at the assessment of lumbar disorders as occupational diseases. Moreover, the study can contribute to the recommendation of preventive measures to decrease health risks in occupations associated with the overload of low-back region. The graphic maps generated by the computational module enable a fast and exact analysis of particular job.

• Klíčová slova
• biomechanical analysis, compressive force, criteria, ergonomic software, evaluation, frequency, low-back disorders, low-back pain, lumbar spine load assessment, manual lifting, prediction, prevention, time, trunk posture,
• MeSH
• algoritmy MeSH
• antropometrie MeSH
• bederní obratle fyziologie   MeSH
• biomechanika MeSH
• ergonomie MeSH
• lidé MeSH
• lumbalgie epidemiologie   patofyziologie   MeSH
• národní institut pro bezpečnost a zdraví při práci (USA) MeSH
• nemoci z povolání epidemiologie   patofyziologie   MeSH
• postura těla fyziologie   MeSH
• posuzování zdravotní způsobilosti MeSH
• prediktivní hodnota testů MeSH
• software MeSH
• zatížení muskuloskeletálního systému fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH
• Spojené státy americké MeSH

BACKGROUND: Femorotibial kinematics and contact patterns vary greatly with different total knee arthroplasty (TKA) designs. Therefore, guided motion knee systems were developed to restore natural knee kinematics and make them more predictable. The medial stabilized TKA design is supposed to replicate physiological kinematics more than the posterior-stabilized TKA system. We conducted this study to compare a newly developed medial stabilized design with a conventional posterior-stabilized design in terms of femorotibial kinematics and contact patterns in vitro. METHODS: Twelve fresh-frozen knee specimens were tested in a weight-bearing knee rig after implantation of a posterior stabilized and medial-stabilized total knee arthroplasty under a loaded squat from 20° to 120° of flexion. Femorotibial joint contact pressures in the medial and lateral compartments were measured by pressure sensitive films and knee kinematics were recorded by an ultrasonic 3-dimensional motion analysis system. FINDINGS: The medial stabilized design showed a reduction of medial femorotibial translation compared to posterior-stabilized design (mean 3.5mm compared to 15.7 mm, P<0.01). In the lateral compartment, both designs showed a posterior translation of the femur with flexion, but less in the medial stabilized design (mean 14.7 mm compared to 19.0mm, P<0.01). In the medial femorotibial compartment of medial stabilized design, we observed an enlarged contact area and lower peak pressure, in contrast in the lateral compartment there was a reduced contact area and an increased peak pressure. INTERPRETATION: While posterior-stabilized design enforces a medio-lateral posterior translation, the medial stabilized arthroplasty system enables a combination of a lateral translation with a medial pivot, which restores the physiological knee kinematics better.

• Klíčová slova
• Femorotibial pressure distribution, In vitro study, Knee kinematics, Medial stabilized, Posterior stabilized, Total knee arthroplasty,
• MeSH
• biomechanika MeSH
• dospělí MeSH
• femur fyziologie   chirurgie   MeSH
• kolenní kloub fyziologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mrtvola MeSH
• protézy - design * MeSH
• protézy kolene * MeSH
• rozsah kloubních pohybů fyziologie   MeSH
• senioři MeSH
• tibie fyziologie   chirurgie   MeSH
• tlak MeSH
• totální endoprotéza kolene přístrojové vybavení   MeSH
• zatížení muskuloskeletálního systému fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVE: To investigate the effects of increasing load on changes in the muscle activity ratio and onset of vastus medialis (VM), vastus lateralis (VL) and biceps femoris (BF) during load-carrying walking. MATERIALS AND METHODS: Sixteen strength-trained men performed an isometric test for knee flexion/extension using a dynamometer followed by walking with progressively increasing loads of up to 75% of their body mass (BM). During the isometric tests and load-carrying walking, electromyography (EMG) data were collected from the VM, VL and BF in both legs together with 3D kinematics. RESULTS: Significant changes in the activity ratio were found for the VM/VL (F3,93=5.92, p=0.0001) and VL onset (F3,81=6.8, p=0.0004). Other parameters showed no significant differences. VM/VL was significantly reduced between the 50BM (mean±SD: 0.89±0.4) and the 75BM condition (0.81±0.3). VL onset was significantly accelerated between the BM (26.11±8) compare and the 25% BM (19.47±9), 50% BM (21.21±10) and 75% BM (15.45±6) conditions. CONCLUSION: Load-carrying walking is an exercise and movement activity that increases the activity of VL more than the activity of VM and accelerates the VL action together with the increased load, which can negatively influence knee stability. The VM/VL ratio and onset is equal when walking under weight-bearing conditions. The inter-muscular coordination is changed due to the increased load in complex movements even in individuals with high level of neuromuscular adaptation.

• MeSH
• biomechanika MeSH
• chůze fyziologie   MeSH
• čtyřhlavý sval stehenní inervace   fyziologie   MeSH
• dospělí MeSH
• elektromyografie MeSH
• koleno inervace   fyziologie   MeSH
• lidé MeSH
• odporový trénink MeSH
• svalová síla fyziologie   MeSH
• zatížení muskuloskeletálního systému fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH