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In this study, the novel mobile dynamometric platform, OREKA, was utilized to perform an extensive analysis of the centre of pressure behaviour during different tilt motion exercises. This platform is based on a parallel manipulator mechanism and can perform rotations around both horizontal axes and a vertical translation. A group of participants took part in an experimental campaign involving the completion of a set of exercises. The aim was to evaluate the platform’s potential practical application and investigate the impact of visual on-screen feedback on centre of pressure motion through multiple balance indicators. The use of the OREKA platform enables the study of the impact on a user’s balance control behaviour under different rotational perturbations, depending on the availability of real-time visual feedback on a screen. Furthermore, it presented data identifying postural control variations among clinically healthy individuals. These findings are fundamental to comprehending the dynamics of body balance. Further investigation is needed to explore these initial findings and fully unlock the potential of the OREKA platform for balance assessment methodologies.

Background: Low back pain (LBP) is associated with altered postural control, mostly observed at later stages in the LBP trajectory. It is unclear whether postural control differs in the acute phase of LBP. Research question: Is postural control different in the acute phase of LBP (<2 weeks) and do differences depend on pain intensity, psychological features and/or availability of vision to control posture? Methods: Cross-sectional study design. An unstable sitting paradigm (to reduce the contribution of the legs) assessed postural control of participants with acute LBP (n = 133) and pain-free controls (n = 74). Centre of pressure (CoP) reflected seat movements. Participants balanced with eyes closed, open, or with visual feedback of the anteroposterior CoP position. Balance performance was expressed by CoP displacement and velocity, and stabilogram diffusion analysis. Generalised estimating equations (GEEs) including body mass index, sex, and safety bar touch, tested differences between groups and between balance conditions. Separate GEEs were used to model performance measures and bar touch (yes/no) including pain intensity, disability and psychological features. Results: CoP displacement and critical point coordinates (time and distance where CoP diffusion rate or spread slows) were larger in LBP than pain-free controls independent of balance condition. Long-term diffusion rate was greater in LBP than controls with eyes closed. CoP velocity measures (RMS, short term diffusion rate) were not different between groups. Pain intensity and psychological features were not linearly related to balance performance in participants with acute LBP. Higher pain catastrophizing was associated with touching the safety bar. Significance: Postural control differs in acute LBP than pain-free controls. Findings might be explained by altered sensory processing, lesser ability to reweight proprioceptive information and/or less accurate trunk muscle control. Although not linearly re

Centre of mass (CoM) motion during human balance recovery is largely influenced by the ground reaction force (GRF) and the centre of pressure (CoP). During gait, foot placement creates a region of possible CoP locations in the following double support (DS). This study aims to increase insight into how humans modulate the CoP during DS, and which CoP modulations are theoretically possible to maintain balance in the sagittal plane. Three variables sufficient to describe the shape, length and duration of the DS CoP trajectory of the total GRF, were assessed in perturbed human walking. To counteract the forward perturbations, braking was required and all CoP variables showed modulations correlated to the observed change in CoM velocity over the DS phase. These correlations were absent after backward perturbations, when only little propulsion was needed to counteract the perturbation. Using a linearized inverted pendulum model we could explore how the observed parameter modulations are effective in controlling the CoM. The distance the CoP travels forward and the instant the leading leg was loaded largely affected the CoM velocity, while the duration mainly affected the CoM position. The simulations also showed that various combinations of CoP parameters can reach a desired CoM position and velocity at the end of DS, and that even a full recovery in the sagittal plane within DS would theoretically have been possible. However, the human subjects did not exploit the therefore required CoP modulations. Overall, modulating the CoP trajectory in DS does effectively contributes to balance recovery., Biomechatronics & Human-Machine Control

This thesis provides insights to what is peculiar about a solar sail attitude and orbit control system and provides the assessment, in the form of a feasibility study, of the effectiveness of sail tip vanes as a control hardware to escape the Earth sphere of influence. The demonstrator aims to prove the technology for the Sunshade project, a constellation of solar sails located at the Lagrangian point L1 to obscure part of the solar radiation directed towards earth. Solar sailing poses a few fundamental challenges to spaceflight and it is a yet-to-be-proven branch of space engineering. Other tentative design exist but there is no standard to follow or off-the-shelf component that can be straightforward used. Moreover the scalability to the final project has to be accounted for in every step of the project. The project is divided in a preliminary dimensioning, followed by a Simulink\textsuperscript{\tiny\textregistered} based simulation which tests preliminary decisions. The simulation, performed on an orbit on the ecliptic plane, integrates models of Earth's eclipse and environmental disturbance torques. The escape time for a \SI{100}{\metre \square} solar sail is found to be \SI{1215}{} days, with a nonlinear PD control algorithm and sail tip vanes as the only control hardware. Attention is also posed on the consequence of a simplified sail film deformation in terms of centre of pressure to centre of mass off-set., I detta examensarbete studeras vad som är speciellt med solsegels system för attityd- och bankontroll och ger en bedömning, i form av en möjlighetsstudie, av effektiviteten hos flöjlar som sätts på seglets hörn som kontrollhårdvara för att lämna jordens inflytelsesfär. Demonstratorn syftar till att bevisa tekniken för Sunshade-projektet, en konstellation av solsegel belägen vid lagrangepunkten L1 för att skugga en del av solstrålningen riktad mot jorden. Solsegling innebär några grundläggande utmaningar för rymdfärden och det är en ännu inte bevisad gren av rymdteknik. Annan preliminär design finns, men det finns ingen standard att följa eller standardkomponenter som enkelt kan användas. Dessutom måste skalbarheten till det slutliga projektet redovisas i varje steg i projektet.Projektet är uppdelat i en preliminär dimensionering, följt av en Simulink-baserad simulering som testar preliminära beslut. Simuleringen, utförd på en omloppsbana påekliptikan, integrerar modeller av jordens skugga och störningar av vridmoment från ett antal källor.Flykttiden för ett 100m solsegel blir 1215 dagar, med en icke-linjär PD kontrollalgoritm och segelhörnsflöjlar som den enda styrhårdvaran. Dessutom studeras förskjutningen av tryckcentrum i förhållande till masscentrum under en förenklad modell av segeldeformation.

This thesis provides insights to what is peculiar about a solar sail attitude and orbit control system and provides the assessment, in the form of a feasibility study, of the effectiveness of sail tip vanes as a control hardware to escape the Earth sphere of influence. The demonstrator aims to prove the technology for the Sunshade project, a constellation of solar sails located at the Lagrangian point L1 to obscure part of the solar radiation directed towards earth. Solar sailing poses a few fundamental challenges to spaceflight and it is a yet-to-be-proven branch of space engineering. Other tentative design exist but there is no standard to follow or off-the-shelf component that can be straightforward used. Moreover the scalability to the final project has to be accounted for in every step of the project. The project is divided in a preliminary dimensioning, followed by a Simulink\textsuperscript{\tiny\textregistered} based simulation which tests preliminary decisions. The simulation, performed on an orbit on the ecliptic plane, integrates models of Earth's eclipse and environmental disturbance torques. The escape time for a \SI{100}{\metre \square} solar sail is found to be \SI{1215}{} days, with a nonlinear PD control algorithm and sail tip vanes as the only control hardware. Attention is also posed on the consequence of a simplified sail film deformation in terms of centre of pressure to centre of mass off-set., I detta examensarbete studeras vad som är speciellt med solsegels system för attityd- och bankontroll och ger en bedömning, i form av en möjlighetsstudie, av effektiviteten hos flöjlar som sätts på seglets hörn som kontrollhårdvara för att lämna jordens inflytelsesfär. Demonstratorn syftar till att bevisa tekniken för Sunshade-projektet, en konstellation av solsegel belägen vid lagrangepunkten L1 för att skugga en del av solstrålningen riktad mot jorden. Solsegling innebär några grundläggande utmaningar för rymdfärden och det är en ännu inte bevisad gren av rymdteknik. Annan preliminär design finns, men det finns ingen standard att följa eller standardkomponenter som enkelt kan användas. Dessutom måste skalbarheten till det slutliga projektet redovisas i varje steg i projektet.Projektet är uppdelat i en preliminär dimensionering, följt av en Simulink-baserad simulering som testar preliminära beslut. Simuleringen, utförd på en omloppsbana påekliptikan, integrerar modeller av jordens skugga och störningar av vridmoment från ett antal källor.Flykttiden för ett 100m solsegel blir 1215 dagar, med en icke-linjär PD kontrollalgoritm och segelhörnsflöjlar som den enda styrhårdvaran. Dessutom studeras förskjutningen av tryckcentrum i förhållande till masscentrum under en förenklad modell av segeldeformation.

Centre of mass (CoM) motion during human balance recovery is largely influenced by the ground reaction force (GRF) and the centre of pressure (CoP). During gait, foot placement creates a region of possible CoP locations in the following double support (DS). This study aims to increase insight into how humans modulate the CoP during DS, and which CoP modulations are theoretically possible to maintain balance in the sagittal plane. Three variables sufficient to describe the shape, length and duration of the DS CoP trajectory of the total GRF, were assessed in perturbed human walking. To counteract the forward perturbations, braking was required and all CoP variables showed modulations correlated to the observed change in CoM velocity over the DS phase. These correlations were absent after backward perturbations, when only little propulsion was needed to counteract the perturbation. Using a linearized inverted pendulum model we could explore how the observed parameter modulations are effective in controlling the CoM. The distance the CoP travels forward and the instant the leading leg was loaded largely affected the CoM velocity, while the duration mainly affected the CoM position. The simulations also showed that various combinations of CoP parameters can reach a desired CoM position and velocity at the end of DS, and that even a full recovery in the sagittal plane within DS would theoretically have been possible. However, the human subjects did not exploit the therefore required CoP modulations. Overall, modulating the CoP trajectory in DS does effectively contributes to balance recovery., Biomechatronics & Human-Machine Control

Diabetes and neuropathy have been linked to postural instability. Aims: The purpose of this study is to determine how each system involved in balance is affected when challenged in a static standing posture. The goal was to identify postural instability by measuring balance through the amount of sway and weight bearing distribution in non-neuropathic controlled type II diabetics. Methods: Twelve participants (five males and seven females) with controlled type II diabetes mellitus and no history of peripheral neuropathy (Non-PN cDMII) formed the diabetic group, whereas eighteen participants (7 males and 11 females) without type II diabetes formed the control group. The exclusion criteria was applied via a series of screening tests (Berg Balance Scale, Five Times Sit To Stand Test, Functional Reach Test and Monofilament Test). Postural stability and weight distribution during quiet standing were measured using a Tekscan Matscan pressure mat, which measured the amount of sway and weight distribution. Static postural control was evaluated during eight sensory conditions that perturbed or stimulated the visual, proprioceptive, and vestibular systems. Results: Postural control was found to be significantly deficient when the vestibular system was stimulated, whereas the proprioceptive system was perturbed. After the data analysis, there was a significant difference in antero-posterior sway (P=0.05) with the following tasks: eyes open with head movements on an unstable surface, and eyes closed with head movements on a firm surface. Conclusions: The results revealed that the experimental group with type II diabetes had greater postural instability when compared to the control group during tasks with the vestibular system on an unstable surface. This demonstrates that, due to their deficits, individuals with non-PN cDMII are unable to maintain their balance when the vestibular and proprioceptive systems are challenged simultaneously.

Diabetes and neuropathy have been linked to postural instability. Aims: The purpose of this study is to determine how each system involved in balance is affected when challenged in a static standing posture. The goal was to identify postural instability by measuring balance through the amount of sway and weight bearing distribution in non-neuropathic controlled type II diabetics. Methods: Twelve participants (five males and seven females) with controlled type II diabetes mellitus and no history of peripheral neuropathy (Non-PN cDMII) formed the diabetic group, whereas eighteen participants (7 males and 11 females) without type II diabetes formed the control group. The exclusion criteria was applied via a series of screening tests (Berg Balance Scale, Five Times Sit To Stand Test, Functional Reach Test and Monofilament Test). Postural stability and weight distribution during quiet standing were measured using a Tekscan Matscan pressure mat, which measured the amount of sway and weight distribution. Static postural control was evaluated during eight sensory conditions that perturbed or stimulated the visual, proprioceptive, and vestibular systems. Results: Postural control was found to be significantly deficient when the vestibular system was stimulated, whereas the proprioceptive system was perturbed. After the data analysis, there was a significant difference in antero-posterior sway (P=0.05) with the following tasks: eyes open with head movements on an unstable surface, and eyes closed with head movements on a firm surface. Conclusions: The results revealed that the experimental group with type II diabetes had greater postural instability when compared to the control group during tasks with the vestibular system on an unstable surface. This demonstrates that, due to their deficits, individuals with non-PN cDMII are unable to maintain their balance when the vestibular and proprioceptive systems are challenged simultaneously.

The study compared the centre of pressure measurements (COP) and vertical ground reaction forces (vGRF) from a pressure insole system to that from force plates (FP) during two flywheel quadriceps resistance exercises: leg press and squat. The comparison was performed using a motion capture system and simultaneous measurements of COP and vGRF from FP and insoles. At lower insole-vGRF (<250 N/insole) COP accuracy deteriorated and those data were excluded from further analysis. The insoles systematically displaced the COP slightly posteriorly and medially compared to the FP measurements. Pearson's coefficient of correlation (r) between insole- and FP-COP showed good agreement in both the anteroposterior (squat: r = 0.96, leg press: r = 0.97) and mediolateral direction (squat: r = 0.84, leg press: r = 0.90), whereas the root-mean-square errors (RMSE) were lower in the mediolateral (squat: 3.9 mm, leg press: 4.5 mm) than the anteroposterior (squat and leg press: 11.8 mm) direction. Vertical GRF was slightly overestimated by the insoles in leg press and RMSE were greater in leg press (8% of peak force) than in squat (6%). Overall, results were within the range of previous studies performed on gait. The strong agreement between insole and FP measurements indicates that insoles may replace FPs in field applications and biomechanical computations during resistance exercise, provided that the applied force is sufficient., QC 20190625

El objetivo de este trabajo ha sido diseñar una geometría de unas aletas capaces de garantizar la estabilidad de un cohete supersónico durante todo el vuelo. Para lograr este objetivo se ha definido el tipo de flujo y se han realizado numerosos análisis aerodinámicos y estructurales. Se han utilizado varios módulos de un mismo programa, a saber: un módulo CAD para crear las geometrías que iban a ser analizadas; un módulo de CFD para obtener los resultados de la interacción del fluido con el cuerpo; y un módulo de FEM para obtener resultados relacionados con tensiones y deformaciones del cuerpo debido a las fuerzas aerodinámicas. Todos estos resultados han sido evaluados con el fin de seleccionar la mejor solución final posible., The aim of this projectis to design afingeometry able to guarantee the stability along the whole flightof a supersonic rocket and minimize the drag force. To achieve this goalthe type of flux has been defined; and aerodynamic and structural analysis have takenplace. Various modules o a program have beenused; actually, aCADmoduleto create the differentgeometries, a module of CFD to obtain results from the interaction between the fluid and the solid, plotting the data in various graphs, and a module of FEM to obtain the results related with the stresses and strain of the body due to the aerodynamic forces. All these data were evaluated in order to select the final solution., Lan honen helburu nagusia suzirisupersonikobaten hegalen geometria diseinatzea da, kontuan izanda suziria egonkor mantendu behar dela hegaldi osoan zehar. Horretarako, fluxu mota zehaztu da, zenbait azterketa aerodinamiko eta egiturazko beste azterketa batzuk egiteaz gain. Aurretik aipatutakoa burutzeko, programa bereko modulu desberdinak erabili dira; halaber: CAD-aren modulu bat, aztertuak izango diren geometriak sortzeko; CFD-aren modulu bat, jariakinaren eta gorputzaren arteko elkarrekintzaren emaitzak lortzeko; eta bukatzeko, FEM-aren modulu bat, indar aerodinamikoen eraginez gorputzak jasandako tentsioak eta bertan agertutako deformazioak lortzeko. Azkenik, aurretik aipatutako emaitza guztiak ebaluatu egin dira, horietatik egokiena aukeratu ahal izateko.

El objetivo de este trabajo ha sido diseñar una geometría de unas aletas capaces de garantizar la estabilidad de un cohete supersónico durante todo el vuelo. Para lograr este objetivo se ha definido el tipo de flujo y se han realizado numerosos análisis aerodinámicos y estructurales. Se han utilizado varios módulos de un mismo programa, a saber: un módulo CAD para crear las geometrías que iban a ser analizadas; un módulo de CFD para obtener los resultados de la interacción del fluido con el cuerpo; y un módulo de FEM para obtener resultados relacionados con tensiones y deformaciones del cuerpo debido a las fuerzas aerodinámicas. Todos estos resultados han sido evaluados con el fin de seleccionar la mejor solución final posible., The aim of this projectis to design afingeometry able to guarantee the stability along the whole flightof a supersonic rocket and minimize the drag force. To achieve this goalthe type of flux has been defined; and aerodynamic and structural analysis have takenplace. Various modules o a program have beenused; actually, aCADmoduleto create the differentgeometries, a module of CFD to obtain results from the interaction between the fluid and the solid, plotting the data in various graphs, and a module of FEM to obtain the results related with the stresses and strain of the body due to the aerodynamic forces. All these data were evaluated in order to select the final solution., Lan honen helburu nagusia suzirisupersonikobaten hegalen geometria diseinatzea da, kontuan izanda suziria egonkor mantendu behar dela hegaldi osoan zehar. Horretarako, fluxu mota zehaztu da, zenbait azterketa aerodinamiko eta egiturazko beste azterketa batzuk egiteaz gain. Aurretik aipatutakoa burutzeko, programa bereko modulu desberdinak erabili dira; halaber: CAD-aren modulu bat, aztertuak izango diren geometriak sortzeko; CFD-aren modulu bat, jariakinaren eta gorputzaren arteko elkarrekintzaren emaitzak lortzeko; eta bukatzeko, FEM-aren modulu bat, indar aerodinamikoen eraginez gorputzak jasandako tentsioak eta bertan agertutako deformazioak lortzeko. Azkenik, aurretik aipatutako emaitza guztiak ebaluatu egin dira, horietatik egokiena aukeratu ahal izateko.

Background: Head movements present a minor threat to the equilibrium of human balance since the head represents only a small proportion of the total body mass. However the head also contains the delicate visual and vestibular systems and acts as a reference for motion. Variables used to determine postural changes after voluntary head movements in previous studies could only assess findings as part of an overall movement. This study intends to examine kinematic changes in posture space after voluntary head shaking, discussed with regard to the aspect of the “minimal intervention” principle in the context of the optimal feedback control theory. Methods: Kinematic data from twenty healthy participants was recorded using a marker-based motion capturing system (Vicon). The participants completed four different headshaking scenarios; in the sagittal (“yes-nodding”) or frontal (“ear-towards-shoulder”) planes with eyes-open or eyes-closed. The postural movements were decomposed by a principal component analysis (PCA) into one-dimensional movement components (PMs), the control of which were assessed through five different variables: the movement velocity, the acceleration amplitude, the mean frequency of the velocity, the Sample Entropy values of the velocity and the tightness of the neuro-muscular control (Number of Zero Crossings of the acceleration). Results: Twenty participants completed the study. Results showed an effect on postural control characteristics directly after the headshaking and that participants quickly recovered to initial postural control. The eyes-closed condition only had an effect in the anterior-posterior ankle sway, PM1. Discussion: The methods and variables used in this experiment detected small changes in quiet stance more accurately than previous methods. The effect of headshaking did appear equally in different movement components, contradicting the “minimal intervention” principle. The effect of eyes-closed only emerged in a specific, task rele, Tove Kockum, Masterarbeit Universität Innsbruck 2019

Background: Head movements present a minor threat to the equilibrium of human balance since the head represents only a small proportion of the total body mass. However the head also contains the delicate visual and vestibular systems and acts as a reference for motion. Variables used to determine postural changes after voluntary head movements in previous studies could only assess findings as part of an overall movement. This study intends to examine kinematic changes in posture space after voluntary head shaking, discussed with regard to the aspect of the “minimal intervention” principle in the context of the optimal feedback control theory. Methods: Kinematic data from twenty healthy participants was recorded using a marker-based motion capturing system (Vicon). The participants completed four different headshaking scenarios; in the sagittal (“yes-nodding”) or frontal (“ear-towards-shoulder”) planes with eyes-open or eyes-closed. The postural movements were decomposed by a principal component analysis (PCA) into one-dimensional movement components (PMs), the control of which were assessed through five different variables: the movement velocity, the acceleration amplitude, the mean frequency of the velocity, the Sample Entropy values of the velocity and the tightness of the neuro-muscular control (Number of Zero Crossings of the acceleration). Results: Twenty participants completed the study. Results showed an effect on postural control characteristics directly after the headshaking and that participants quickly recovered to initial postural control. The eyes-closed condition only had an effect in the anterior-posterior ankle sway, PM1. Discussion: The methods and variables used in this experiment detected small changes in quiet stance more accurately than previous methods. The effect of headshaking did appear equally in different movement components, contradicting the “minimal intervention” principle. The effect of eyes-closed only emerged in a specific, task rele, Tove Kockum, Masterarbeit Universität Innsbruck 2019

El objetivo de este trabajo ha sido diseñar una geometría de unas aletas capaces de garantizar la estabilidad de un cohete supersónico durante todo el vuelo. Para lograr este objetivo se ha definido el tipo de flujo y se han realizado numerosos análisis aerodinámicos y estructurales. Se han utilizado varios módulos de un mismo programa, a saber: un módulo CAD para crear las geometrías que iban a ser analizadas; un módulo de CFD para obtener los resultados de la interacción del fluido con el cuerpo; y un módulo de FEM para obtener resultados relacionados con tensiones y deformaciones del cuerpo debido a las fuerzas aerodinámicas. Todos estos resultados han sido evaluados con el fin de seleccionar la mejor solución final posible., The aim of this projectis to design afingeometry able to guarantee the stability along the whole flightof a supersonic rocket and minimize the drag force. To achieve this goalthe type of flux has been defined; and aerodynamic and structural analysis have takenplace. Various modules o a program have beenused; actually, aCADmoduleto create the differentgeometries, a module of CFD to obtain results from the interaction between the fluid and the solid, plotting the data in various graphs, and a module of FEM to obtain the results related with the stresses and strain of the body due to the aerodynamic forces. All these data were evaluated in order to select the final solution., Lan honen helburu nagusia suzirisupersonikobaten hegalen geometria diseinatzea da, kontuan izanda suziria egonkor mantendu behar dela hegaldi osoan zehar. Horretarako, fluxu mota zehaztu da, zenbait azterketa aerodinamiko eta egiturazko beste azterketa batzuk egiteaz gain. Aurretik aipatutakoa burutzeko, programa bereko modulu desberdinak erabili dira; halaber: CAD-aren modulu bat, aztertuak izango diren geometriak sortzeko; CFD-aren modulu bat, jariakinaren eta gorputzaren arteko elkarrekintzaren emaitzak lortzeko; eta bukatzeko, FEM-aren modulu bat, indar aerodinamikoen eraginez gorputzak jasandako tentsioak eta bertan agertutako deformazioak lortzeko. Azkenik, aurretik aipatutako emaitza guztiak ebaluatu egin dira, horietatik egokiena aukeratu ahal izateko.

Background Postural stability deficits have been proposed to influence the onset and progression of adolescent idiopathic scoliosis (AIS). This study aimed to systematically identify, critically evaluate and meta-analyse studies assessing postural stability during unperturbed stance with posturography in AIS compared to typically developed adolescents. Methods Studies from four electronic databases (PubMed, Scopus, CINAHL, PEDro) were searched and case-control methodological quality assessed using a risk-of-bias assessment tool and a posturography methodological quality checklist. Pooled data regarding centre of pressure (COP) parameters such as sway area, Mediolateral (ML) and Anteroposterior (AP) position and range were compared for AIS and typically developed adolescents using Cohen’s d effect size (ES) and homogeneity estimates. Results Eighteen studies for quality analysis and 9 of these for meta-analysis were identified from 971 records. Risk-of-bias assessment identified 6 high, 10 moderate and 2 low risk-of-bias studies. The posturography methodological quality checklist identified 4 low, 7 moderate and 7 high-quality studies. Meta-analysis was performed for sway area whereas ML and AP are presented in three different meta-analyses due to divergent measurement units used in the studies: ML position 1 (MLP1), ML position 2 (MLP2) and ML range (MLR); AP position 1 (APP1), AP position 2 (APP2) and AP range (APR). Cohen’s d showed a medium ES difference in sway area 0.65, 95% CI (0.49–0.63), whereas ML showed no (MLP1, MLP2) and large (MLR) ES differences; MLP1 0.15, 95% CI (0.08–0.22); MLP2 0.14, 95% CI (0.08–0.19); and MLR 0.94, 95% CI (0.83–1.04). Cohen’s d for AP showed small ES (APP1) and large ES difference (APP2 and APR); APP1 0.43, 95% CI (0.31–0.54); APP2 0.85, 95% CI (0.72–0.97); and APR 0.98, 95% CI (0.87–1.09). Cochran’s Q and Higgins I2 showed homogeneity between studies. Conclusions There is moderate quality evidence for decreased postural stabilit

Background Postural stability deficits have been proposed to influence the onset and progression of adolescent idiopathic scoliosis (AIS). This study aimed to systematically identify, critically evaluate and meta-analyse studies assessing postural stability during unperturbed stance with posturography in AIS compared to typically developed adolescents. Methods Studies from four electronic databases (PubMed, Scopus, CINAHL, PEDro) were searched and case-control methodological quality assessed using a risk-of-bias assessment tool and a posturography methodological quality checklist. Pooled data regarding centre of pressure (COP) parameters such as sway area, Mediolateral (ML) and Anteroposterior (AP) position and range were compared for AIS and typically developed adolescents using Cohen’s d effect size (ES) and homogeneity estimates. Results Eighteen studies for quality analysis and 9 of these for meta-analysis were identified from 971 records. Risk-of-bias assessment identified 6 high, 10 moderate and 2 low risk-of-bias studies. The posturography methodological quality checklist identified 4 low, 7 moderate and 7 high-quality studies. Meta-analysis was performed for sway area whereas ML and AP are presented in three different meta-analyses due to divergent measurement units used in the studies: ML position 1 (MLP1), ML position 2 (MLP2) and ML range (MLR); AP position 1 (APP1), AP position 2 (APP2) and AP range (APR). Cohen’s d showed a medium ES difference in sway area 0.65, 95% CI (0.49–0.63), whereas ML showed no (MLP1, MLP2) and large (MLR) ES differences; MLP1 0.15, 95% CI (0.08–0.22); MLP2 0.14, 95% CI (0.08–0.19); and MLR 0.94, 95% CI (0.83–1.04). Cohen’s d for AP showed small ES (APP1) and large ES difference (APP2 and APR); APP1 0.43, 95% CI (0.31–0.54); APP2 0.85, 95% CI (0.72–0.97); and APR 0.98, 95% CI (0.87–1.09). Cochran’s Q and Higgins I2 showed homogeneity between studies. Conclusions There is moderate quality evidence for decreased postural stabilit

Background Postural stability deficits have been proposed to influence the onset and progression of adolescent idiopathic scoliosis (AIS). This study aimed to systematically identify, critically evaluate and meta-analyse studies assessing postural stability during unperturbed stance with posturography in AIS compared to typically developed adolescents. Methods Studies from four electronic databases (PubMed, Scopus, CINAHL, PEDro) were searched and case-control methodological quality assessed using a risk-of-bias assessment tool and a posturography methodological quality checklist. Pooled data regarding centre of pressure (COP) parameters such as sway area, Mediolateral (ML) and Anteroposterior (AP) position and range were compared for AIS and typically developed adolescents using Cohen’s d effect size (ES) and homogeneity estimates. Results Eighteen studies for quality analysis and 9 of these for meta-analysis were identified from 971 records. Risk-of-bias assessment identified 6 high, 10 moderate and 2 low risk-of-bias studies. The posturography methodological quality checklist identified 4 low, 7 moderate and 7 high-quality studies. Meta-analysis was performed for sway area whereas ML and AP are presented in three different meta-analyses due to divergent measurement units used in the studies: ML position 1 (MLP1), ML position 2 (MLP2) and ML range (MLR); AP position 1 (APP1), AP position 2 (APP2) and AP range (APR). Cohen’s d showed a medium ES difference in sway area 0.65, 95% CI (0.49–0.63), whereas ML showed no (MLP1, MLP2) and large (MLR) ES differences; MLP1 0.15, 95% CI (0.08–0.22); MLP2 0.14, 95% CI (0.08–0.19); and MLR 0.94, 95% CI (0.83–1.04). Cohen’s d for AP showed small ES (APP1) and large ES difference (APP2 and APR); APP1 0.43, 95% CI (0.31–0.54); APP2 0.85, 95% CI (0.72–0.97); and APR 0.98, 95% CI (0.87–1.09). Cochran’s Q and Higgins I2 showed homogeneity between studies. Conclusions There is moderate quality evidence for decreased postural stabilit

Background Postural stability deficits have been proposed to influence the onset and progression of adolescent idiopathic scoliosis (AIS). This study aimed to systematically identify, critically evaluate and meta-analyse studies assessing postural stability during unperturbed stance with posturography in AIS compared to typically developed adolescents. Methods Studies from four electronic databases (PubMed, Scopus, CINAHL, PEDro) were searched and case-control methodological quality assessed using a risk-of-bias assessment tool and a posturography methodological quality checklist. Pooled data regarding centre of pressure (COP) parameters such as sway area, Mediolateral (ML) and Anteroposterior (AP) position and range were compared for AIS and typically developed adolescents using Cohen’s d effect size (ES) and homogeneity estimates. Results Eighteen studies for quality analysis and 9 of these for meta-analysis were identified from 971 records. Risk-of-bias assessment identified 6 high, 10 moderate and 2 low risk-of-bias studies. The posturography methodological quality checklist identified 4 low, 7 moderate and 7 high-quality studies. Meta-analysis was performed for sway area whereas ML and AP are presented in three different meta-analyses due to divergent measurement units used in the studies: ML position 1 (MLP1), ML position 2 (MLP2) and ML range (MLR); AP position 1 (APP1), AP position 2 (APP2) and AP range (APR). Cohen’s d showed a medium ES difference in sway area 0.65, 95% CI (0.49–0.63), whereas ML showed no (MLP1, MLP2) and large (MLR) ES differences; MLP1 0.15, 95% CI (0.08–0.22); MLP2 0.14, 95% CI (0.08–0.19); and MLR 0.94, 95% CI (0.83–1.04). Cohen’s d for AP showed small ES (APP1) and large ES difference (APP2 and APR); APP1 0.43, 95% CI (0.31–0.54); APP2 0.85, 95% CI (0.72–0.97); and APR 0.98, 95% CI (0.87–1.09). Cochran’s Q and Higgins I2 showed homogeneity between studies. Conclusions There is moderate quality evidence for decreased postural stabilit

Background Postural stability deficits have been proposed to influence the onset and progression of adolescent idiopathic scoliosis (AIS). This study aimed to systematically identify, critically evaluate and meta-analyse studies assessing postural stability during unperturbed stance with posturography in AIS compared to typically developed adolescents. Methods Studies from four electronic databases (PubMed, Scopus, CINAHL, PEDro) were searched and case-control methodological quality assessed using a risk-of-bias assessment tool and a posturography methodological quality checklist. Pooled data regarding centre of pressure (COP) parameters such as sway area, Mediolateral (ML) and Anteroposterior (AP) position and range were compared for AIS and typically developed adolescents using Cohen’s d effect size (ES) and homogeneity estimates. Results Eighteen studies for quality analysis and 9 of these for meta-analysis were identified from 971 records. Risk-of-bias assessment identified 6 high, 10 moderate and 2 low risk-of-bias studies. The posturography methodological quality checklist identified 4 low, 7 moderate and 7 high-quality studies. Meta-analysis was performed for sway area whereas ML and AP are presented in three different meta-analyses due to divergent measurement units used in the studies: ML position 1 (MLP1), ML position 2 (MLP2) and ML range (MLR); AP position 1 (APP1), AP position 2 (APP2) and AP range (APR). Cohen’s d showed a medium ES difference in sway area 0.65, 95% CI (0.49–0.63), whereas ML showed no (MLP1, MLP2) and large (MLR) ES differences; MLP1 0.15, 95% CI (0.08–0.22); MLP2 0.14, 95% CI (0.08–0.19); and MLR 0.94, 95% CI (0.83–1.04). Cohen’s d for AP showed small ES (APP1) and large ES difference (APP2 and APR); APP1 0.43, 95% CI (0.31–0.54); APP2 0.85, 95% CI (0.72–0.97); and APR 0.98, 95% CI (0.87–1.09). Cochran’s Q and Higgins I2 showed homogeneity between studies. Conclusions There is moderate quality evidence for decreased postural stabilit

SCOPUS: ar.j, info:eu-repo/semantics/published

Purpose: Physical and hormonal modifications occuring during the pregnancy, can lead to an increase in postural instability and to a higher risk of falls during gait. The first objective was to describe the center of pressure (COP) during late pregnancy at different gait velocity. Comparison of nulliparous women with postpartum women were conducted in order to investigate the effects of pregnancy. The second objective was to analyse COP variability between pregnant and non-pregnant women in order to investigate the effects of pregnancy on gait variability. Methods: Fifty-eight pregnant women in the last four months of pregnancy, nine postpartum women and twenty-three healthy non-pregnant women performed gait trials at three different speeds: preferred, slow and fast. Results: In the last four months of pregnancy gait velocity decreased. During the pregnancy, gait velocity decreased by 22%, stopover time increased by 6–12%, COP excursion XY decreased by 5% and COP velocity decreased by 16% and 20% along the anteroposterior and transverse axes, respectively. After delivery, gait velocity increased by 3% but remained a lower compared to non-pregnant women (–12%). Intra-individual variability was greater for non-pregnant than pregnant women. Conclusions: COP parameters were influenced by pregnancy. This suggests that pregnant women establish very specific and individual strategies with the aim of maintaining stability during gait., SCOPUS: ar.j, info:eu-repo/semantics/published

El equilibrio es un factor determinante en las caídas que sufren las personas mayores. Las personas mayores institucionalizadas no pueden realizar ejercicios extenuantes debido a su condición física, por lo que el entrenamiento vibratorio puede ser una alternativa al ejercicio convencional. 44 personas institucionalizadas mayores de 80 años fueron aleatoriamente distribuidas en tres grupos: grupo vibración (GV), grupo sin vibración (GsV) o grupo control (GC), con el fin de determinar si un programa de ocho semanas de entrenamiento vibratorio tiene algún efecto sobre el equilibrio estático de estas personas. El entrenamiento vibratorio tuvo una frecuencia progresiva durante las ocho semanas de 30-35 Hz. y una amplitud constante de cuatro mm. Se realizaron tres sesiones a la semana. La estabilidad postural fue medida a través de una plataforma de fuerza recogiendo los datos anteroposterior (AP) y medio-lateral (ML), incluyendo distancia recorrida, velocidad media de ambos ejes y amplitud de los ejes x e y para determinar así el centro de presiones (COP) en una posición estática. De los 44 participantes aleatorizados en alguno de los grupos de estudio, sólo 33 concluyeron todos los requisitos del mismo y por tanto fueron analizados. No se encontraron diferencias significativas en ninguna de las variables de estudio referidas a la estabilidad postural entre los grupos (p> .05). Este estudio no establece que un entrenamiento vibratorio de ocho semanas de duración pueda provocar mejoras en la postura estática en bipedestación de personas institucionalizadas mayores de 80 años., Balance is a key factor in falls suffered by older people. Institutionalized older people cannot perform strenuous exercise due to their physical condition, so vibration training can be an alternative to conventional exercise. 44 institutionalized people aged over 80 years were randomly divided into three groups: vibration group (GV), no vibration group (GsV) or control group (GC), in order to determine whether a program of eight weeks of vibration training has any effect on static equilibrium of these people. The oscillation frequency progressive training had over eight weeks of 30-35 Hz. and a constant amplitude of four mm. Postural stability was measured by a force platform collecting the anterior-posterior (AP) and medium-lateral (ML), including distance, both axes main speed and amplitude of x and y axes, to determine the centre of pressure (COP) in a static position. Of the 44 participants randomized to one of the study groups, only 33 completed all requirements thereof and therefore were analysed. No significant differences in any of the study outcomes related to postural stability between the groups were found (p> .05). This study does not prove that a vibration training of eight weeks may cause improvements in static standing posture in institutionalized people over the age of 80.

El equilibrio es un factor determinante en las caídas que sufren las personas mayores. Las personas mayores institucionalizadas no pueden realizar ejercicios extenuantes debido a su condición física, por lo que el entrenamiento vibratorio puede ser una alternativa al ejercicio convencional. 44 personas institucionalizadas mayores de 80 años fueron aleatoriamente distribuidas en tres grupos: grupo vibración (GV), grupo sin vibración (GsV) o grupo control (GC), con el fin de determinar si un programa de ocho semanas de entrenamiento vibratorio tiene algún efecto sobre el equilibrio estático de estas personas. El entrenamiento vibratorio tuvo una frecuencia progresiva durante las ocho semanas de 30-35 Hz. y una amplitud constante de cuatro mm. Se realizaron tres sesiones a la semana. La estabilidad postural fue medida a través de una plataforma de fuerza recogiendo los datos anteroposterior (AP) y medio-lateral (ML), incluyendo distancia recorrida, velocidad media de ambos ejes y amplitud de los ejes x e y para determinar así el centro de presiones (COP) en una posición estática. De los 44 participantes aleatorizados en alguno de los grupos de estudio, sólo 33 concluyeron todos los requisitos del mismo y por tanto fueron analizados. No se encontraron diferencias significativas en ninguna de las variables de estudio referidas a la estabilidad postural entre los grupos (p> .05). Este estudio no establece que un entrenamiento vibratorio de ocho semanas de duración pueda provocar mejoras en la postura estática en bipedestación de personas institucionalizadas mayores de 80 años., Balance is a key factor in falls suffered by older people. Institutionalized older people cannot perform strenuous exercise due to their physical condition, so vibration training can be an alternative to conventional exercise. 44 institutionalized people aged over 80 years were randomly divided into three groups: vibration group (GV), no vibration group (GsV) or control group (GC), in order to determine whether a program of eight weeks of vibration training has any effect on static equilibrium of these people. The oscillation frequency progressive training had over eight weeks of 30-35 Hz. and a constant amplitude of four mm. Postural stability was measured by a force platform collecting the anterior-posterior (AP) and medium-lateral (ML), including distance, both axes main speed and amplitude of x and y axes, to determine the centre of pressure (COP) in a static position. Of the 44 participants randomized to one of the study groups, only 33 completed all requirements thereof and therefore were analysed. No significant differences in any of the study outcomes related to postural stability between the groups were found (p> .05). This study does not prove that a vibration training of eight weeks may cause improvements in static standing posture in institutionalized people over the age of 80.

El equilibrio es un factor determinante en las caídas que sufren las personas mayores. Las personas mayores institucionalizadas no pueden realizar ejercicios extenuantes debido a su condición física, por lo que el entrenamiento vibratorio puede ser una alternativa al ejercicio convencional. 44 personas institucionalizadas mayores de 80 años fueron aleatoriamente distribuidas en tres grupos: grupo vibración (GV), grupo sin vibración (GsV) o grupo control (GC), con el fin de determinar si un programa de ocho semanas de entrenamiento vibratorio tiene algún efecto sobre el equilibrio estático de estas personas. El entrenamiento vibratorio tuvo una frecuencia progresiva durante las ocho semanas de 30-35 Hz. y una amplitud constante de cuatro mm. Se realizaron tres sesiones a la semana. La estabilidad postural fue medida a través de una plataforma de fuerza recogiendo los datos anteroposterior (AP) y medio-lateral (ML), incluyendo distancia recorrida, velocidad media de ambos ejes y amplitud de los ejes x e y para determinar así el centro de presiones (COP) en una posición estática. De los 44 participantes aleatorizados en alguno de los grupos de estudio, sólo 33 concluyeron todos los requisitos del mismo y por tanto fueron analizados. No se encontraron diferencias significativas en ninguna de las variables de estudio referidas a la estabilidad postural entre los grupos (p> .05). Este estudio no establece que un entrenamiento vibratorio de ocho semanas de duración pueda provocar mejoras en la postura estática en bipedestación de personas institucionalizadas mayores de 80 años., Balance is a key factor in falls suffered by older people. Institutionalized older people cannot perform strenuous exercise due to their physical condition, so vibration training can be an alternative to conventional exercise. 44 institutionalized people aged over 80 years were randomly divided into three groups: vibration group (GV), no vibration group (GsV) or control group (GC), in order to determine whether a program of eight weeks of vibration training has any effect on static equilibrium of these people. The oscillation frequency progressive training had over eight weeks of 30-35 Hz. and a constant amplitude of four mm. Postural stability was measured by a force platform collecting the anterior-posterior (AP) and medium-lateral (ML), including distance, both axes main speed and amplitude of x and y axes, to determine the centre of pressure (COP) in a static position. Of the 44 participants randomized to one of the study groups, only 33 completed all requirements thereof and therefore were analysed. No significant differences in any of the study outcomes related to postural stability between the groups were found (p> .05). This study does not prove that a vibration training of eight weeks may cause improvements in static standing posture in institutionalized people over the age of 80.

El equilibrio es un factor determinante en las caídas que sufren las personas mayores. Las personas mayores institucionalizadas no pueden realizar ejercicios extenuantes debido a su condición física, por lo que el entrenamiento vibratorio puede ser una alternativa al ejercicio convencional. 44 personas institucionalizadas mayores de 80 años fueron aleatoriamente distribuidas en tres grupos: grupo vibración (GV), grupo sin vibración (GsV) o grupo control (GC), con el fin de determinar si un programa de ocho semanas de entrenamiento vibratorio tiene algún efecto sobre el equilibrio estático de estas personas. El entrenamiento vibratorio tuvo una frecuencia progresiva durante las ocho semanas de 30-35 Hz. y una amplitud constante de cuatro mm. Se realizaron tres sesiones a la semana. La estabilidad postural fue medida a través de una plataforma de fuerza recogiendo los datos anteroposterior (AP) y medio-lateral (ML), incluyendo distancia recorrida, velocidad media de ambos ejes y amplitud de los ejes x e y para determinar así el centro de presiones (COP) en una posición estática. De los 44 participantes aleatorizados en alguno de los grupos de estudio, sólo 33 concluyeron todos los requisitos del mismo y por tanto fueron analizados. No se encontraron diferencias significativas en ninguna de las variables de estudio referidas a la estabilidad postural entre los grupos (p> .05). Este estudio no establece que un entrenamiento vibratorio de ocho semanas de duración pueda provocar mejoras en la postura estática en bipedestación de personas institucionalizadas mayores de 80 años., Balance is a key factor in falls suffered by older people. Institutionalized older people cannot perform strenuous exercise due to their physical condition, so vibration training can be an alternative to conventional exercise. 44 institutionalized people aged over 80 years were randomly divided into three groups: vibration group (GV), no vibration group (GsV) or control group (GC), in order to determine whether a program of eight weeks of vibration training has any effect on static equilibrium of these people. The oscillation frequency progressive training had over eight weeks of 30-35 Hz. and a constant amplitude of four mm. Postural stability was measured by a force platform collecting the anterior-posterior (AP) and medium-lateral (ML), including distance, both axes main speed and amplitude of x and y axes, to determine the centre of pressure (COP) in a static position. Of the 44 participants randomized to one of the study groups, only 33 completed all requirements thereof and therefore were analysed. No significant differences in any of the study outcomes related to postural stability between the groups were found (p> .05). This study does not prove that a vibration training of eight weeks may cause improvements in static standing posture in institutionalized people over the age of 80.

El equilibrio es un factor determinante en las caídas que sufren las personas mayores. Las personas mayores institucionalizadas no pueden realizar ejercicios extenuantes debido a su condición física, por lo que el entrenamiento vibratorio puede ser una alternativa al ejercicio convencional. 44 personas institucionalizadas mayores de 80 años fueron aleatoriamente distribuidas en tres grupos: grupo vibración (GV), grupo sin vibración (GsV) o grupo control (GC), con el fin de determinar si un programa de ocho semanas de entrenamiento vibratorio tiene algún efecto sobre el equilibrio estático de estas personas. El entrenamiento vibratorio tuvo una frecuencia progresiva durante las ocho semanas de 30-35 Hz. y una amplitud constante de cuatro mm. Se realizaron tres sesiones a la semana. La estabilidad postural fue medida a través de una plataforma de fuerza recogiendo los datos anteroposterior (AP) y medio-lateral (ML), incluyendo distancia recorrida, velocidad media de ambos ejes y amplitud de los ejes x e y para determinar así el centro de presiones (COP) en una posición estática. De los 44 participantes aleatorizados en alguno de los grupos de estudio, sólo 33 concluyeron todos los requisitos del mismo y por tanto fueron analizados. No se encontraron diferencias significativas en ninguna de las variables de estudio referidas a la estabilidad postural entre los grupos (p> .05). Este estudio no establece que un entrenamiento vibratorio de ocho semanas de duración pueda provocar mejoras en la postura estática en bipedestación de personas institucionalizadas mayores de 80 años., Balance is a key factor in falls suffered by older people. Institutionalized older people cannot perform strenuous exercise due to their physical condition, so vibration training can be an alternative to conventional exercise. 44 institutionalized people aged over 80 years were randomly divided into three groups: vibration group (GV), no vibration group (GsV) or control group (GC), in order to determine whether a program of eight weeks of vibration training has any effect on static equilibrium of these people. The oscillation frequency progressive training had over eight weeks of 30-35 Hz. and a constant amplitude of four mm. Postural stability was measured by a force platform collecting the anterior-posterior (AP) and medium-lateral (ML), including distance, both axes main speed and amplitude of x and y axes, to determine the centre of pressure (COP) in a static position. Of the 44 participants randomized to one of the study groups, only 33 completed all requirements thereof and therefore were analysed. No significant differences in any of the study outcomes related to postural stability between the groups were found (p> .05). This study does not prove that a vibration training of eight weeks may cause improvements in static standing posture in institutionalized people over the age of 80.

Knee function after more than 20 years post injury is rarely described and none of the few follow-up studies have evaluated functional performance tasks. This thesis investigated self-reported knee function, physical activity level, physical capacity and movement pattern in the long-term perspective (on average 23 years) in persons who had suffered a unilateral ACL injury, treated either with physiotherapy in combination with surgery (ACLR, n=33) or physiotherapy alone (ACLPT, n=37) and compared to age-and-gender matched controls (n=33). This thesis shows that regardless of treatment, there are significant negative long-term consequences on self-reported knee function and physical activity more than 20 years after injury. In comparison to the controls, the ACL-groups (ACLR and ACLPT) had lower knee function as measured by the Lysholm score and the Knee injury and Osteoarthritis Outcome Score (KOOS). The persons with an ACL injury also had a lower knee-specific physical activity level (Tegner activity scale), while no differences were seen in general physical activity level (International Physical Activity Questionnaire, IPAQ) compared to healthy controls. Regarding physical capacity, both ACL groups showed inferior jump capacity in the injured leg compared to the non-injured leg. However, compared to controls the ACL-injured had a relatively good jump performance. Knee extension peak torque, concentric and eccentric, was also lower for the injured leg compared to the non-injured leg for both ACLR and ACLPT. In addition, the ACLPT group showed reduced eccentric knee flexion torque of the injured leg. The non-injured leg, on the other hand, showed almost equal jump capacity and strength as controls. Balance in single-limb stance (30s) was inferior in persons who had an ACL injury. This was true for both the injured and non-injured leg and regardless of treatment. Movement pattern during the one-leg hop was analysed by a set of kinematic variables consisting of knee a

Knee function after more than 20 years post injury is rarely described and none of the few follow-up studies have evaluated functional performance tasks. This thesis investigated self-reported knee function, physical activity level, physical capacity and movement pattern in the long-term perspective (on average 23 years) in persons who had suffered a unilateral ACL injury, treated either with physiotherapy in combination with surgery (ACLR, n=33) or physiotherapy alone (ACLPT, n=37) and compared to age-and-gender matched controls (n=33). This thesis shows that regardless of treatment, there are significant negative long-term consequences on self-reported knee function and physical activity more than 20 years after injury. In comparison to the controls, the ACL-groups (ACLR and ACLPT) had lower knee function as measured by the Lysholm score and the Knee injury and Osteoarthritis Outcome Score (KOOS). The persons with an ACL injury also had a lower knee-specific physical activity level (Tegner activity scale), while no differences were seen in general physical activity level (International Physical Activity Questionnaire, IPAQ) compared to healthy controls. Regarding physical capacity, both ACL groups showed inferior jump capacity in the injured leg compared to the non-injured leg. However, compared to controls the ACL-injured had a relatively good jump performance. Knee extension peak torque, concentric and eccentric, was also lower for the injured leg compared to the non-injured leg for both ACLR and ACLPT. In addition, the ACLPT group showed reduced eccentric knee flexion torque of the injured leg. The non-injured leg, on the other hand, showed almost equal jump capacity and strength as controls. Balance in single-limb stance (30s) was inferior in persons who had an ACL injury. This was true for both the injured and non-injured leg and regardless of treatment. Movement pattern during the one-leg hop was analysed by a set of kinematic variables consisting of knee a

Knee function after more than 20 years post injury is rarely described and none of the few follow-up studies have evaluated functional performance tasks. This thesis investigated self-reported knee function, physical activity level, physical capacity and movement pattern in the long-term perspective (on average 23 years) in persons who had suffered a unilateral ACL injury, treated either with physiotherapy in combination with surgery (ACLR, n=33) or physiotherapy alone (ACLPT, n=37) and compared to age-and-gender matched controls (n=33). This thesis shows that regardless of treatment, there are significant negative long-term consequences on self-reported knee function and physical activity more than 20 years after injury. In comparison to the controls, the ACL-groups (ACLR and ACLPT) had lower knee function as measured by the Lysholm score and the Knee injury and Osteoarthritis Outcome Score (KOOS). The persons with an ACL injury also had a lower knee-specific physical activity level (Tegner activity scale), while no differences were seen in general physical activity level (International Physical Activity Questionnaire, IPAQ) compared to healthy controls. Regarding physical capacity, both ACL groups showed inferior jump capacity in the injured leg compared to the non-injured leg. However, compared to controls the ACL-injured had a relatively good jump performance. Knee extension peak torque, concentric and eccentric, was also lower for the injured leg compared to the non-injured leg for both ACLR and ACLPT. In addition, the ACLPT group showed reduced eccentric knee flexion torque of the injured leg. The non-injured leg, on the other hand, showed almost equal jump capacity and strength as controls. Balance in single-limb stance (30s) was inferior in persons who had an ACL injury. This was true for both the injured and non-injured leg and regardless of treatment. Movement pattern during the one-leg hop was analysed by a set of kinematic variables consisting of knee a

Knee function after more than 20 years post injury is rarely described and none of the few follow-up studies have evaluated functional performance tasks. This thesis investigated self-reported knee function, physical activity level, physical capacity and movement pattern in the long-term perspective (on average 23 years) in persons who had suffered a unilateral ACL injury, treated either with physiotherapy in combination with surgery (ACLR, n=33) or physiotherapy alone (ACLPT, n=37) and compared to age-and-gender matched controls (n=33). This thesis shows that regardless of treatment, there are significant negative long-term consequences on self-reported knee function and physical activity more than 20 years after injury. In comparison to the controls, the ACL-groups (ACLR and ACLPT) had lower knee function as measured by the Lysholm score and the Knee injury and Osteoarthritis Outcome Score (KOOS). The persons with an ACL injury also had a lower knee-specific physical activity level (Tegner activity scale), while no differences were seen in general physical activity level (International Physical Activity Questionnaire, IPAQ) compared to healthy controls. Regarding physical capacity, both ACL groups showed inferior jump capacity in the injured leg compared to the non-injured leg. However, compared to controls the ACL-injured had a relatively good jump performance. Knee extension peak torque, concentric and eccentric, was also lower for the injured leg compared to the non-injured leg for both ACLR and ACLPT. In addition, the ACLPT group showed reduced eccentric knee flexion torque of the injured leg. The non-injured leg, on the other hand, showed almost equal jump capacity and strength as controls. Balance in single-limb stance (30s) was inferior in persons who had an ACL injury. This was true for both the injured and non-injured leg and regardless of treatment. Movement pattern during the one-leg hop was analysed by a set of kinematic variables consisting of knee a

Knee function after more than 20 years post injury is rarely described and none of the few follow-up studies have evaluated functional performance tasks. This thesis investigated self-reported knee function, physical activity level, physical capacity and movement pattern in the long-term perspective (on average 23 years) in persons who had suffered a unilateral ACL injury, treated either with physiotherapy in combination with surgery (ACLR, n=33) or physiotherapy alone (ACLPT, n=37) and compared to age-and-gender matched controls (n=33). This thesis shows that regardless of treatment, there are significant negative long-term consequences on self-reported knee function and physical activity more than 20 years after injury. In comparison to the controls, the ACL-groups (ACLR and ACLPT) had lower knee function as measured by the Lysholm score and the Knee injury and Osteoarthritis Outcome Score (KOOS). The persons with an ACL injury also had a lower knee-specific physical activity level (Tegner activity scale), while no differences were seen in general physical activity level (International Physical Activity Questionnaire, IPAQ) compared to healthy controls. Regarding physical capacity, both ACL groups showed inferior jump capacity in the injured leg compared to the non-injured leg. However, compared to controls the ACL-injured had a relatively good jump performance. Knee extension peak torque, concentric and eccentric, was also lower for the injured leg compared to the non-injured leg for both ACLR and ACLPT. In addition, the ACLPT group showed reduced eccentric knee flexion torque of the injured leg. The non-injured leg, on the other hand, showed almost equal jump capacity and strength as controls. Balance in single-limb stance (30s) was inferior in persons who had an ACL injury. This was true for both the injured and non-injured leg and regardless of treatment. Movement pattern during the one-leg hop was analysed by a set of kinematic variables consisting of knee a

The aim of this thesis was to investigate roller ski characteristics; classical and freestyle roller skis’ rolling resistance coefficients (μR) and classical style roller skis’ static friction coefficients (μS), and to study the influence of different μR and μS on cross-country skiers’ performance and both physiological and biomechanical indices. The aim was also to study differences in skiing economy and efficiency between recreational skiers, female and male junior and senior elite cross-country skiers.The experiments showed that during a time period of 30 minutes of rolling on a treadmill (warm-up), μR decreased significantly (p<0.05) to about 60-65 % and 70-75 % of its initial value for freestyle and classical roller skis respectively. Also, there was a significant influence of normal force on μR, while different velocities and inclinations of the treadmill only resulted in small changes in μR.The study of the influence on physiological variables of a ~50 % change in μR showed that during submaximal steady rate exercise, external power, oxygen uptake, heart rate and blood lactate were significantly changed, while there were non-significant or only small changes to cycle rate, cycle length and ratings of perceived exertion. Incremental maximal tests showed that time to exhaustion was significantly changed and this occurred without a change in maximal power, maximal oxygen uptake, maximal heart rate and blood lactate, and that the influence on ratings of perceived exertion was non-significant or small.The study of classical style roller skis μS showed values that were five to eight times more than the values of μS reported from on-snow skiing with grip-waxed cross-country skis.The subsequent physiological and biomechanical experiments with different μS showed a significantly lower skiing economy (~14 % higher v̇O2), higher heart rate, lower propulsive forces coming from the legs and shorter time to exhaustion (~30 %) when using a different type of roller ski wi, Syftet med denna avhandling var att undersöka fristils- och klassiska rullskidors rullmotståndskoefficienter (μR) och klassiska rullskidors statiska friktionskoefficienter (μS) samt effekter av olika μR och μS på längdskidåkares prestation vid rullskidåkning på rullande band. Syftet var även att undersöka s.k. åkekonomi och mekanisk verkningsgrad mellan motionärer och kvinnliga och manliga junior- och seniorlängdskidåkare på elitnivå.Experimenten visade att under en period av 30 minuters kontinuerligt rullande, på rullande band, så sjönk μR signifikant (p<0.05) till 60-65 % och 70-75 % av initiala värden, för fristils- respektive klassiska rullskidor. Undersökandet av olika normalkrafter, hastigheter och lutningars påverkan på μR resulterade i en signifikant, negativ korrelation för μR som funktion av normalkraft, medan olika hastigheter och lutningar endast medförde små förändringar av μR.Studien som undersökte fysiologiska effekter av olika μR visade, vid submaximala konstanta arbetsbelastningar, att yttre effekt, syreupptagning, hjärtfrekvens och blodlaktat förändrades signifikant vid ~50 % förändring av μR. Försökspersonernas frekvens och sträcka per frekvens samt skattning av upplevd ansträngning resulterade dock i mestadels icke signifikanta eller små förändringar. Protokollen med successivt ökande arbetsbelastning (maxtest) resulterade i signifikant förändrad tid till utmattning, vid ~50 % förändring av μR. Detta inträffade utan signifikant skillnad i maximal syreupptagning, hjärtfrekvens och blodlaktat, vilket även mestadels gällde för skattning av upplevd ansträngning.Experimenten som undersökte klassiska rullskidors μS visade att dessa erhöll värden som är fem till åtta gånger högre än vad som rapporterats från studier av μS på snö med fästvallade skidor.Den efterföljande studien som undersökte fysiologiska och biomekaniska influenser av olika μS visade, vid submaximala konstanta arbetsbelastningar, att åkekonomin försämrades (~14 % högre syreförbruknin

The aim of this thesis was to investigate roller ski characteristics; classical and freestyle roller skis’ rolling resistance coefficients (μR) and classical style roller skis’ static friction coefficients (μS), and to study the influence of different μR and μS on cross-country skiers’ performance and both physiological and biomechanical indices. The aim was also to study differences in skiing economy and efficiency between recreational skiers, female and male junior and senior elite cross-country skiers.The experiments showed that during a time period of 30 minutes of rolling on a treadmill (warm-up), μR decreased significantly (p<0.05) to about 60-65 % and 70-75 % of its initial value for freestyle and classical roller skis respectively. Also, there was a significant influence of normal force on μR, while different velocities and inclinations of the treadmill only resulted in small changes in μR.The study of the influence on physiological variables of a ~50 % change in μR showed that during submaximal steady rate exercise, external power, oxygen uptake, heart rate and blood lactate were significantly changed, while there were non-significant or only small changes to cycle rate, cycle length and ratings of perceived exertion. Incremental maximal tests showed that time to exhaustion was significantly changed and this occurred without a change in maximal power, maximal oxygen uptake, maximal heart rate and blood lactate, and that the influence on ratings of perceived exertion was non-significant or small.The study of classical style roller skis μS showed values that were five to eight times more than the values of μS reported from on-snow skiing with grip-waxed cross-country skis.The subsequent physiological and biomechanical experiments with different μS showed a significantly lower skiing economy (~14 % higher v̇O2), higher heart rate, lower propulsive forces coming from the legs and shorter time to exhaustion (~30 %) when using a different type of roller ski wi, Syftet med denna avhandling var att undersöka fristils- och klassiska rullskidors rullmotståndskoefficienter (μR) och klassiska rullskidors statiska friktionskoefficienter (μS) samt effekter av olika μR och μS på längdskidåkares prestation vid rullskidåkning på rullande band. Syftet var även att undersöka s.k. åkekonomi och mekanisk verkningsgrad mellan motionärer och kvinnliga och manliga junior- och seniorlängdskidåkare på elitnivå.Experimenten visade att under en period av 30 minuters kontinuerligt rullande, på rullande band, så sjönk μR signifikant (p<0.05) till 60-65 % och 70-75 % av initiala värden, för fristils- respektive klassiska rullskidor. Undersökandet av olika normalkrafter, hastigheter och lutningars påverkan på μR resulterade i en signifikant, negativ korrelation för μR som funktion av normalkraft, medan olika hastigheter och lutningar endast medförde små förändringar av μR.Studien som undersökte fysiologiska effekter av olika μR visade, vid submaximala konstanta arbetsbelastningar, att yttre effekt, syreupptagning, hjärtfrekvens och blodlaktat förändrades signifikant vid ~50 % förändring av μR. Försökspersonernas frekvens och sträcka per frekvens samt skattning av upplevd ansträngning resulterade dock i mestadels icke signifikanta eller små förändringar. Protokollen med successivt ökande arbetsbelastning (maxtest) resulterade i signifikant förändrad tid till utmattning, vid ~50 % förändring av μR. Detta inträffade utan signifikant skillnad i maximal syreupptagning, hjärtfrekvens och blodlaktat, vilket även mestadels gällde för skattning av upplevd ansträngning.Experimenten som undersökte klassiska rullskidors μS visade att dessa erhöll värden som är fem till åtta gånger högre än vad som rapporterats från studier av μS på snö med fästvallade skidor.Den efterföljande studien som undersökte fysiologiska och biomekaniska influenser av olika μS visade, vid submaximala konstanta arbetsbelastningar, att åkekonomin försämrades (~14 % högre syreförbruknin

The aim of this thesis was to investigate roller ski characteristics; classical and freestyle roller skis’ rolling resistance coefficients (μR) and classical style roller skis’ static friction coefficients (μS), and to study the influence of different μR and μS on cross-country skiers’ performance and both physiological and biomechanical indices. The aim was also to study differences in skiing economy and efficiency between recreational skiers, female and male junior and senior elite cross-country skiers.The experiments showed that during a time period of 30 minutes of rolling on a treadmill (warm-up), μR decreased significantly (p<0.05) to about 60-65 % and 70-75 % of its initial value for freestyle and classical roller skis respectively. Also, there was a significant influence of normal force on μR, while different velocities and inclinations of the treadmill only resulted in small changes in μR.The study of the influence on physiological variables of a ~50 % change in μR showed that during submaximal steady rate exercise, external power, oxygen uptake, heart rate and blood lactate were significantly changed, while there were non-significant or only small changes to cycle rate, cycle length and ratings of perceived exertion. Incremental maximal tests showed that time to exhaustion was significantly changed and this occurred without a change in maximal power, maximal oxygen uptake, maximal heart rate and blood lactate, and that the influence on ratings of perceived exertion was non-significant or small.The study of classical style roller skis μS showed values that were five to eight times more than the values of μS reported from on-snow skiing with grip-waxed cross-country skis.The subsequent physiological and biomechanical experiments with different μS showed a significantly lower skiing economy (~14 % higher v̇O2), higher heart rate, lower propulsive forces coming from the legs and shorter time to exhaustion (~30 %) when using a different type of roller ski wi, Syftet med denna avhandling var att undersöka fristils- och klassiska rullskidors rullmotståndskoefficienter (μR) och klassiska rullskidors statiska friktionskoefficienter (μS) samt effekter av olika μR och μS på längdskidåkares prestation vid rullskidåkning på rullande band. Syftet var även att undersöka s.k. åkekonomi och mekanisk verkningsgrad mellan motionärer och kvinnliga och manliga junior- och seniorlängdskidåkare på elitnivå.Experimenten visade att under en period av 30 minuters kontinuerligt rullande, på rullande band, så sjönk μR signifikant (p<0.05) till 60-65 % och 70-75 % av initiala värden, för fristils- respektive klassiska rullskidor. Undersökandet av olika normalkrafter, hastigheter och lutningars påverkan på μR resulterade i en signifikant, negativ korrelation för μR som funktion av normalkraft, medan olika hastigheter och lutningar endast medförde små förändringar av μR.Studien som undersökte fysiologiska effekter av olika μR visade, vid submaximala konstanta arbetsbelastningar, att yttre effekt, syreupptagning, hjärtfrekvens och blodlaktat förändrades signifikant vid ~50 % förändring av μR. Försökspersonernas frekvens och sträcka per frekvens samt skattning av upplevd ansträngning resulterade dock i mestadels icke signifikanta eller små förändringar. Protokollen med successivt ökande arbetsbelastning (maxtest) resulterade i signifikant förändrad tid till utmattning, vid ~50 % förändring av μR. Detta inträffade utan signifikant skillnad i maximal syreupptagning, hjärtfrekvens och blodlaktat, vilket även mestadels gällde för skattning av upplevd ansträngning.Experimenten som undersökte klassiska rullskidors μS visade att dessa erhöll värden som är fem till åtta gånger högre än vad som rapporterats från studier av μS på snö med fästvallade skidor.Den efterföljande studien som undersökte fysiologiska och biomekaniska influenser av olika μS visade, vid submaximala konstanta arbetsbelastningar, att åkekonomin försämrades (~14 % högre syreförbruknin

Balance training is commonly used in the rehabilitation process of ankle injuries; however, the exercise prescription guidelines for prescribing balance training are poorly understood. The aim of the present study was to determine if high or low volume balance training is more effective in improving postural sway after an 8 week balance training program utilising the same exercises. Seventeen subjects (14 male, 3 female) with a mean age of 24.06 ± 5.6 years were randomly allocated into a control group (CG), low volume training (LVT) or high volume training (HVT). All subjects had sustained at least two inversion ankle injuries within the last 18 months. Subjects completed 8 weeks of balance training of up to 30 mins duration, 3 times per week. LVT consisted of 40 repetitions for week 1, progressing to 90 repetitions by week 8. HVT consisted of 60 repetitions for week 1, progressing to 130 repetitions by week 8. The maximum centre of pressure (COP) excursion was obtained from the porce plate in the medial-lateral (ML) direction and subsequently used for pre-test and post-test analysis. After the 8 week training intervention, there was a significant (P<0.001) difference in postural sway between pre and post testing for both the LVT (pre = 88.69mm ± 25.08mm, post = 72.17mm ± 27.53mm) and HVT (pre = 77.47mm ±10.57mm, post = 58.54mm ± 7.01mm) groups. There was no significant (P>0.01) difference detected for improvements between the LVT and HVT, however reported effect sizes (ES) showed large effect size chances in the high volume training (ES = 1.7) whereas low volume training showed medium effect sizes changes (ES = 0.6). This preliminary study demonstrates the importance of training volume in the rehabilitation of ankle injuries, with the HVT being superior to LVT.

The different measures used to characterize postural sway are sensitive to variations in sampling duration, yet there remains marked variability and a lack of consistency in this temporal parameter when compared between studies. We investigated the effect of sampling duration on 22 commonly used frequency and time domain measures and stabilogram diffusion coefficients. Participants stood quietly on a forceplate during two 600 s standing trials with eyes open and eyes closed. The results clearly show that the amplitudes of the descriptive measures are sensitive to sampling duration. Only measures related to the amount of sway were sensitive for eyes open versus eyes closed conditions. In addition to sample duration, the filter settings, sampling frequency and fitting windows should be standardized since they also affect the magnitude of the descriptive measures. Without such standards, the inability to accurately compare between studies will persist., Biomechanical Engineering, Mechanical, Maritime and Materials Engineering

The different measures used to characterize postural sway are sensitive to variations in sampling duration, yet there remains marked variability and a lack of consistency in this temporal parameter when compared between studies. We investigated the effect of sampling duration on 22 commonly used frequency and time domain measures and stabilogram diffusion coefficients. Participants stood quietly on a forceplate during two 600 s standing trials with eyes open and eyes closed. The results clearly show that the amplitudes of the descriptive measures are sensitive to sampling duration. Only measures related to the amount of sway were sensitive for eyes open versus eyes closed conditions. In addition to sample duration, the filter settings, sampling frequency and fitting windows should be standardized since they also affect the magnitude of the descriptive measures. Without such standards, the inability to accurately compare between studies will persist., Biomechanical Engineering, Mechanical, Maritime and Materials Engineering

this paper presents the modeling, design and construction of a rocket amateur of low cost, using an active control system through a mobile nozzle to achieve greater stability. Here describes the methods and procedures used in the experiment, developing the analysis, simulation and implementation of a prototype control for achieve a flight path., Este artículo presenta el modelado, diseño y construcción de un cohete tipo aficionado de bajo costo, empleando un sistema de control activo por medio de una tobera móvil para lograr una mayor estabilidad. Se plantean los métodos y procedimientos utilizados en el experimento, desarrollando el análisis, simulación e implementación de un prototipo de control para lograr una trayectoria de vuelo.

this paper presents the modeling, design and construction of a rocket amateur of low cost, using an active control system through a mobile nozzle to achieve greater stability. Here describes the methods and procedures used in the experiment, developing the analysis, simulation and implementation of a prototype control for achieve a flight path., Este artículo presenta el modelado, diseño y construcción de un cohete tipo aficionado de bajo costo, empleando un sistema de control activo por medio de una tobera móvil para lograr una mayor estabilidad. Se plantean los métodos y procedimientos utilizados en el experimento, desarrollando el análisis, simulación e implementación de un prototipo de control para lograr una trayectoria de vuelo.

Fine prehension is ubiquitous in everyday skilled hand manipulations. The anticipatory nature of the control of normal grip forces exerted against tangential loads has been extensively used to provide insights into the working of neural control of movements. We designed a new versatile device to measure the three dimensional forces and torques during a broad panel of precision grip tasks. The instrument measures constraints exerted independently on two grip surfaces by the thumb and the opposing fingers. In addition, the device can be loaded to increase the weight and/or induce torques and can be easily integrated in a variety of experimental contexts. Its compactness improves its stability during movement and allows an ergonomic manipulation for impaired persons or children.

Background: Rheumatoid arthritis patients alter their gait pattern to compensate for painful foot symptoms. The centre of pressure may be a useful indicator of these altered loading patterns. Our purpose was to undertake a comparison of the regionalised duration and velocity of the centre of pressure between rheumatoid arthritis patients with foot impairments and healthy able-bodied adults. Methods: The progression of the centre of pressure through the foot, heel, midfoot, forefoot and toe regions was measured using an EMED-ST pressure platform. Patients walked at self selected cadence. Variables analysed were the average and maximum velocity and the duration of the centre of pressure (as % stance). Results: In comparison with able-bodied adults, rheumatoid arthritis patients had a statistically significant decrease in the average velocity of the centre of pressure in the total foot (P < 0.001), heel (P = 0.001) and midfoot (P < 0.001) regions. The maximum velocity of the centre of pressure was slower in rheumatoid arthritis patients in only the midfoot region (P = 0.002). During stance, the duration of the centre of pressure was longer in the midfoot (P < 0.001) and shorter in the forefoot (P = 0.001) in the rheumatoid arthritis patients. Interpretation: Alteration of the foot loading patterns in patients with rheumatoid arthritis can be characterised by changes to the centre of pressure patterns. Off-loading the painful and deformed forefoot was a characteristic feature in this patient cohort.