Dynamic loading
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Understanding of the bone remodelling process has considerably increased during the last 20 years. Since the ability to simulate (and predict) the effects of bone remodelling offers substantial insights, several models have been proposed to describe this phenomenon. The strength of the presented model is that it includes biochemical control factors (e.g., the necessity of cell-to-cell contact, which is mediated by the RANKL-RANK-OPG chain during osteoclastogenesis) and mechanical stimulation, the governing equations are derived from interaction kinetics (e.g., mass is preserved in running reactions), and the parameters are measurable. Behaviour of the model is in accordance with experimental and clinical observations, such as the role of dynamic loading, the inhibitory effect of dynamic loading on osteoclastogenesis, the observation that polykaryon osteoclasts are activated and formed by a direct cell-to-cell contact, and the correct concentrations of osteoblasts, osteoclasts, and osteocytes. The model does not yet describe the bone remodelling process in complete detail, but the implemented simplifications describe the key features and further details of control mechanisms may be added.
- MeSH
- biologické modely MeSH
- kostní denzita fyziologie MeSH
- lidé MeSH
- ligand RANK fyziologie MeSH
- mechanický stres MeSH
- osteogeneze fyziologie MeSH
- osteoklasty fyziologie MeSH
- osteoprotegerin fyziologie MeSH
- protein RANK fyziologie MeSH
- remodelace kosti fyziologie MeSH
- signální transdukce fyziologie MeSH
- termodynamika MeSH
- zatížení muskuloskeletálního systému fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- analýza metodou konečných prvků * využití MeSH
- anatomické modely MeSH
- artroplastiky kloubů metody využití MeSH
- biomechanika MeSH
- chůze (způsob) MeSH
- elektromyografie metody využití MeSH
- klouby fyziologie MeSH
- kosterní svaly MeSH
- kosti dolní končetiny * fyziologie MeSH
- lidé MeSH
- mechanické jevy MeSH
- statistika jako téma MeSH
- teoretické modely MeSH
- zatížení muskuloskeletálního systému * fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- MeSH
- acidobazická rovnováha MeSH
- lidé MeSH
- spotřeba kyslíku MeSH
- tělesná námaha MeSH
- Check Tag
- lidé MeSH
- MeSH
- aorta MeSH
- biomechanika MeSH
- cévy fyziologie MeSH
- finanční podpora výzkumu jako téma MeSH
- lidé MeSH
- lineární modely MeSH
- nelineární dynamika MeSH
- pružnost MeSH
- viskozita MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- přehledy MeSH
- srovnávací studie MeSH
Jednostranná statická záťaž, minimálna pohybová aktivita a zvýšené psychické napätie zohrávajú významnú úlohu pri vzniku bolesti chrbta. V rámci komplexnej rehabilitácie je doporučované striedanie ergonomických sedov a relaxačných sedov. Ide však len o statické pozície s predpokladaným minimalizujúcim negatívnym vplyvom na pohybový systém. V našom príspevku prezentujeme perspektívny a účinnejší terapeuticko - preventívny prístup, ktorým je dynamizácia ergonomického sedu. Z pohľadu kinezioterapie predstavuje dynamizácia sedu koaktiváciu svalových skupín prostredníctvom pohybových synergii typu uzavretých reťazcov, facilitujúc posturálny systém. Testovali sme hypotézu, či dynamizácia ergonomického sedu môže byť parciálnou prevenciou funkčnej patológie pohybového systému u pacientov so sedavvm zamestnaním. Vyšetrili a sledovali sme 25 subjektov. Sledovanie pozostávalo z hodnotenia bolestí pomocou vizuálnej analógovej škály (VAS) a z objektívneho klinického a posturografického vyšetrenia počas sedu a stoja. Pacientov sme vyšetrili pred rehabilitáciou, po rehabilitácii a po mesiaci sedenia na vzduchom plnenom PC vankúši. Vyhodnotenie VAS poukázalo na významný ústup pocitu bolesti po rehabilitácii ako aj po mesiaci sedenia na PC vankúši. Posturografické vyšetrenie oporných síl pri sede na molitane so zatvoreným očami ukázalo významné zlepšenie stability sedu po rehabilitácii a po mesiaci sedenia na PC vankúši. Po rehabilitácii ako aj po dynamizácii sedu sme zaznamenali tendenciu k úprave postúry v stoji so zatvorenými očami a extenziou hlavy. Naše výsledky podporujú predpoklad, že dynamizácia ergonomického sedu na PC vankúši, by mohla byť dôležitou zložkou prevencie a liečby funkčnej patológie pohybového systému.
Stereotype in static load, minimal motor activity and psychic tension results often in low back pain. Based on present knowledge, for complex motor rehabilitation is supposed an alternation of ergonomic sitting condition with decreased static load and also relaxed sitting position. These rehabilitation approaches are of course only static positions where minimal negative influence on motor system is predicted. In our contribution we presents the perspective approach for effective therapy and prevention - an dynamic condition in the ergonomic sitting position. From point of view of kinesiotherapy the dynamic sitting means an coactivation of muscle groups through motion synergies of type closed up chains facilitating posture system. We tested hypothesis that the increase of dynamic condition during the ergonomic sitting position could be a partial prevention of the functional pathology of locomotor system in patients whose sitting position is the most common working posture. We observed 25 patients. Our observation was based on: patientës evaluation of pain by visual analog scale, physical examination, and postural activity measurement on posturography during sitting and in the upright posture. Patient was evaluated: before rehabilitation after rehabilitation and after one-month period of dynamic sitting in ergonomic position on air pillow. Assessment of pain showed significant decrease of pain after rehabilitation and after dynamic condition of seating on air pillow. During seating on soft support with eyes closed results showed significant improvement of sitting posture after rehabilitation and after dynamic sitting. Influence of rehabilitation and dynamic condition of seating on postural stability showed a tendency of balance improvement in upright posture with eyes closed and head extension. Our results support a view that the dynamic condition of seating on air pillow might be an important part of therapy and prevention of functional pathology of locomotors system
- MeSH
- bolesti zad MeSH
- kineziologie aplikovaná metody MeSH
- lidé MeSH
- obnova funkce MeSH
- postura těla MeSH
- rehabilitace metody MeSH
- Check Tag
- lidé MeSH
- Klíčová slova
- extrémní dynamická zátěž, biomechanická analýza,
- MeSH
- biomechanika * fyziologie MeSH
- kraniocerebrální traumata * etiologie patologie MeSH
- lidé MeSH
- matematické pojmy MeSH
- mechanické jevy MeSH
- soudní lékařství metody trendy MeSH
- statistika jako téma MeSH
- svalová síla fyziologie MeSH
- teoretické modely * MeSH
- Check Tag
- lidé MeSH
This case study describes the experimental determination of displacements and stresses on a composite model of a pelvis that was modified to represent a healthy intact pelvic ring. The modified model was stressed statically up to 1750 N to simulate standing on one leg and also cyclically to model walking. For two different model settings in the loading machine the values of displacements and stresses at the pelvic ring were determined. The two different settings correspond to two different loading vectors applied on the pelvic ring, boundary conditions and degrees of freedom. The experimentally determined values of displacements in both settings are very similar and in accordance with the knowledge on the behaviour of a real human pelvis. The modified model is thus suitable for testing of newly developed implants for pelvis treatment and experimental determination of displacements and stresses in pelvic ring which are caused by application of implants.
- MeSH
- biomechanika MeSH
- lidé MeSH
- pánev * MeSH
- pánevní kosti * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The influence of morphological shape of the foot on dynamic loading forces was demonstrated in many studies (Morton 1937; Kolář 2006; Moriyasu and Nishiwaki 2009). But it has never been specifically studied during ice hockey skating. Loading forces were investigated during ice hockey skating, but not in the contend a shape of the foot, but rather in contend the techniques of skating and push off strength (Kho 1996; Pearsall, Turcotte et al. 2000). It is normally considered that the shape of foot is the basic factor determining the ground reaction forces (GRF) (Nigg, Segesser et al. 1992; Kolář 2006). The Laboratory of Extreme Loading (BEZ) has been designed and validated device for measuring GRF during skating. Using this newly established device was done a pilot study exploring the relationship between morphological shape of the foot and the loading forces. As a morphological shape of a foot was rated the length ratio between first and second finger and the length ratio of first and third finger (phalanges length and metatarsophalanges length) to dynamics of loading force component Ft, bending force components Fo and point acting of the force on the skate blade- x during forward skating. The results were determined based on the correlation variables as the basis for further experiments. In a pilot study has been demonstrated the interdependence of two foot shape characteristics with dynamic of the loading forces, both dependencies were demonstrated for the first and third metatarsophalanges ratio. Specifically, it was showed the dependency with first and third metatarsophalanges ratio to the moment of maximum loading force Ft, when the statistical significance level of p = 0.03 found concordance τr = 0.79. In metatarsophalanges ratio of first and third finger was observed on the significance level of p = 0.02 the discordance τr = - 0.79 with the average position of the point of action of the force on skate blade- x.
- Klíčová slova
- zátěžové síly, měřící brusle, dynamometrie,
- MeSH
- biomechanika MeSH
- bruslení MeSH
- financování organizované MeSH
- hokej MeSH
- lidé MeSH
- noha (od hlezna dolů) anatomie a histologie fyziologie MeSH
- pilotní projekty MeSH
- pohyb fyziologie MeSH
- statistika jako téma MeSH
- svalová síla - dynamometr využití MeSH
- tělesná hmotnost MeSH
- tlak MeSH
- Check Tag
- lidé MeSH
- MeSH
- hemodynamika MeSH
- lidé středního věku MeSH
- lidé MeSH
- pletyzmografie impedanční MeSH
- srdce MeSH
- zátěžový test MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- srovnávací studie MeSH
