Stretching is a widely prescribed technique that has been demonstrated to increase range of motion. Consequently it may enhance performance and aid in the prevention and treatment of injury. Few studies have investigated the frequency of stretching on a daily basis. The purpose of this study was to investigate the effect of stretching frequency on range of motion at the ankle joint. The detraining effect was also investigated after a period without stretching. Thirty-one female subjects participated in this study. They were randomly assigned to a control group who did not stretch a group who stretched two times per week (Stretch-2) or a group who stretched four times per week (Stretch-4). The stretching intervention was undertaken over four weeks and targeted the gastrocnemius and soleus muscles. Each stretch was held for duration of 30 seconds and repeated five times. Prior to the intervention (PRE), dorsiflexion was measured using a weights and pulley system that passively moved the ankle joint from a neutral position into dorsiflexion. After the four week stretching period (POST), dorsiflexion was measured once again to determine the change following the stretching programme. Following a further four week period where no stretching took place (FINAL), dorsiflexion was measured to determine the detraining effect. Electromyography was used to monitor the activity of the plantarflexors and dorsiflexors during the measuring procedure. The results of the study showed a significant increase in ankle joint range of motion for the Stretch-4 group (p<0.05) when comparing PRE and POST measurements. The Stretch-2 and control groups did not show significant differences (p>0.05) between PRE and POST measurements. When comparing the PRE and FINAL measurements of the Stretch-4 group, no significant differences were recorded (p>0.05). The POST and FINAL measurements were significantly different (p<0.05). After the detraining period the Stretch-4 group lost 99.8% of their range of motion gains. The present data provide some evidence that the viscoelastic properties of the muscle stretched were unchanged by the four week static stretching programme. The mechanism involved in the observed increase in range of motion for the Stretch-4 group is possibly that of enhanced stretch tolerance of the subject. Further research is required to support this conjecture.

Prevalence of osteoarthritis (OA) is less common in the ankle compared to other joints; however, deformation brought on by degeneration causes pain, loss of function, and overall decreased quality of life. Current surgical interventions for end-stage ankle OA are not as reliable as surgical treatments for other joints. Ankle arthroplasty currently has high failure rates, and there are lack of substantial data from long-term outcome studies. By understanding the morphometric changes that occur during the different stages of OA, we are able to identify early signs of the disease with the intention to apply treatment earlier in order to preclude the need for end-stage surgical intervention. The goals of this study are to assess morphometric parameters of the talus as it relates to the progression of OA and to evaluate the effect of gender and anatomical side. A retrospective study was performed where data from sixty-eight CT scans were obtained from two study groups, one with OA and one without. The subjects were segmented, standardized, and normalized in order to study several 3D parameters of the talus, including height, radius of curvature, and volume. Results showed that talar morphometry is influenced by gender and that geometric changes are a function of OA progression. The lateral radii of subjects with OA was significantly larger than those of normal ankles (p<0.0001), and there is evidence of inherent changes between KL grades (p=0.0003). Identifying morphometric changes of the talus at each stage of OA can inherently contribute to better understanding the degenerative process. Assessing specific characteristics at earlier stages of the diseases may help clinicians to diagnose more accurately and to better provide treatment.

Title: Consequences of injuries on stability in ballet Objectives: The main aim of the study was to find out if injuries in the ankle and foot have a negative impact on dancers' postural stability. If so then the secondary objective of this study was to see if the injury of one leg affects also the stability of the other in a one-leg stand. Methods: First part of this thesis is a systematic review. The other part is quantitative research in a prospective, cross-sectional design study. Stabilometric data from all 24 female subjects were analysed and injured and uninjured dancers were compared. The data were measured by a FootScan pressure plate (RSscan International, Belgium). Tested positions were bipodalic stance with eyes opened and closed, bipodalic calf raise (relevé) and monopodalic stance on both legs. Results: The aims of the thesis have been fulfilled but both the hypothesis have been rejected. The results have shown better stability in injured dancers to non-injured dancers in three parameters - Total Travel Way of the centre of pressure (COP) in monopodalic stance on the right foot, mediolateral movement of COP in bipodalic stance with eyes opened and calf rise (relevé). No significant differences have been shown between dancers with one leg previously injured and the non-injured ones in...

Osteochondral lesions of the talus (OLTs) are the third most common type of osteochondral lesion and can cause pain and instability of the ankle joint. Episurf Medical AB is a medical technology company that develops individualized implants for patients who are suffering from focal cartilage lesions. Episurf have recently started a project that aims to implement their implantation technique in the treatment of OLTs. This master thesis was a part of Episurf’s talus project and the main goal of the thesis was to find the optimal implantation angle of the Episurf implant when treating OLTs. The optimal implantation angle was defined as the angle that minimized the maximum equivalent (von Mises) strain acting on the implant shaft during the stance phase of a normal gait cycle. It is desirable to minimize the strain acting on the implant shaft, since a reduction of the strain can improve the longevity of the implant. To find the optimal implantation angle a finite element model of an ankle joint treated with the Episurf implant was developed. In the model an implant with a diameter of 12 millimeters was placed in the middle part of the medial side of the talar dome. An optimization algorithm was designed to find the implantation angle, which minimized the maximum equivalent strain acting on the implant shaft. The optimal implantation angle was found to be a sagittal angle of 12.5 degrees and a coronal angle of 0 degrees. Both the magnitude and the direction of the force applied to the ankle joint in the simulated stance phase seemed to influence the maximum equivalent strain acting on the implant shaft. A number of simplifications have been done in the simulation of this project, which might affect the accuracy of the results. Therefore it is recommended that further, more detailed, simulations based on this project are performed in order to improve the result accuracy. / Fokala broskskador på talusbenet är den tredje vanligaste typen av fokala broskskador och kan ge upphov till smärta och instabilitet av fotleden. Episurf Medical AB är ett medicintekniskt företag som utvecklar individanpassade implantat för patienter med fokala broskskador. Episurf har nyligen påbörjat ett projekt där deras teknik ska användas i behandlingen av fokala broskskador på talusbenet. Den här masteruppsatsen var en del i Episurfs talusprojekt och dess huvudmål var att finna den optimala implantationsvinkeln av Episurfs implantat i behandlingen av fokala broskskador på talusbenet. Den optimala implanteringsvinkeln definierades som den vinkel som minimerade den effektiva von Mises-töjningen som verkade på implantatskaftet under stance-fasen i en normal gångcykel. Det är eftersträvansvärt att minimera belastningen på implantatskaftet eftersom en reducering av belastningen kan förbättra implantatets livslängd. En finita element-modell av en fotled behandlad med Episurfs implantat utvecklades för att för att finna den optimala implantationsvinkeln. I modellen placerades ett implantat med en diameter på 12 millimeter på mittendelen av talus mediala sida. En optimeringsalgoritm utformades för att finna implantationsvinkeln som minimerade den effektiva von Mises-töjningen på implantatskaftet. Den funna optimala implantationsvinkeln bestod av en vinkel på 12.5 grader i sagittalplan och en vinkel på 0 grader i koronalplan. Både storleken och riktningen på kraften som applicerats på fotleden under den simulerade stance-fasen av gångcykeln verkade påverka belastningen på implantatskaftet. Ett antal förenklingar har gjorts i projektets simuleringar, vilket kan påverka noggrannheten i resultatet. Därför rekommenderas att ytterligare, mer detaljerade simuleringar baserade på det här projektet görs för att förbättra resultatets noggrannhet.

Diploma thesis title: Influence of tissue flossing therapy on the range of motion and fascial chains in the lower limbs. Objectives: The main objective is to present theoretical facts about tissue flossing therapy, to document the effect of this method on the active range of motion in the lower limbs and to investigate whether this increase in movement can be achieved by influencing fascial chains in distant parts of the musculoskeletal system. Methods: The research was completed by 30 recreational or high-level athletes aged 19 to 26 years. Initial testing and subsequent treatment of the ankle joint and surrounding fascial structures were done using the tissue flossing technique. The initial tests consisted of a weight- bearing lunge test to test the dorsal flexion of the ankle joint and a Thomayer test to test the range of motion within the fascial superficial back line. Treatment of both ankle joints and surrounding fascial structures on both lower limbs was followed by final testing. The resulting data were processed using mathematical software R. A paired t-test, a two-sample t-test for independent selections assuming different variables and a test of the agreement of the fraction with a known constant were used to calculate the p-values. Statistical significance was determined at the critical...

Soft robotic sensors (SRSs) are a class of pliable, passive sensors which vary by some electrical characteristic in response to changes in geometry. The properties of SRSs make them excellent candidates for use in wearable motion analysis technology. Wearable technology is a fast-growing industry, and the improvement of existing human motion analysis tools is needed. Prior research has proven the viability of SRSs as a tool for capturing motion of the foot-ankle complex; this work covers extensive effort to improve and ruggedize a lab tool utilizing this technology. The improved lab tool is validated against a camera-based motion capture system to show either improvement or equivalence to the previous prototype while introducing enhanced data throughput, reliability, battery life, and durability.

Title: Accident rate at floorball players with previous experience with ice hockey. Objectives: To determine whether there is an increased rate of injuries of ankle joint at floorball players with previous experience with ice hockey than at floorball players without this experience. To evaluate the impact of the operation of ice hockey, the sport with permanently fixed foot in the skate, at followed up playing of floorball at the top level. Methology: For the purposes of this thesis was compiled multiple-standard questionnaire - questionnaire form. The research sample consisted of 100 probands - the first group of 25 probands top floorball players who have played at least 5 years of ice hockey at the highest level, the second group 25 floorball extra-league players, third group of 25 professional ice hockey players. Last fourth group consisted of 25 probands athletes meeting the conditions of at least 3 times a week training and 1 championship match - non focus on ice hockey and floorball. The resulting data were first analyzed and clearly captured in tables in Microsoft Office Word 2003. Then were analyzed only data relating to the ankle joint injuries in floorball players using statistical methods to confirm the hypothesis - method of association - association coefficient, Chi-square test....

Esta dissertação parte da premissa de que o desalinhamento dos arcos plantares estão associados ao mal funcionamento do pé e a subseqüentes desequilíbrios mecânicos gerados por compensações na cadeia cinética e articulações adjacentes. A bandagem plantar é uma das técnicas comumente utilizadas no tratamento e prevenção de lesões decorrentes destes desalinhamentos; no entanto, sua eficácia no controle postural ainda é incerta. Nossas hipóteses são: (i) que sujeitos com arco rebaixado apresentariam déficits do controle postural que se acentuariam em condições de perturbação sensorial, e (ii) que a bandagem aplicada no médio-­pé para melhorar a acuidade sensorial traria benefícios para o controle postural destes sujeitos, principalmente nas condições de perturbação. Assim, apresentaremos nesta dissertação dois estudos, um para investigar as alterações no controle postural de indivíduos com rebaixamento do arco plantar (estudo 1), e outro para investigar as consequências da utilização bandagem plantar nestes indivíduos (estudo 2). Para ambos os estudos, avaliamos a velocidade média e o root mean square da trajetória do centro de pressão durante a manutenção da postura quasi-­-estática em quatro condições de perturbação sensorial: (1) plataforma fixa, olhos abertos; (2) plataforma fixa, olhos fechados; (3) plataforma móvel, olhos abertos; e (4) plataforma móvel, olhos fechados. No estudo 1, 24 mulheres com arcos normais foram comparadas a 13 mulheres com arco rebaixado. No estudo 2, a comparação foi feita entre as condições sem e com a bandagem plantar para as 13 mulheres com arco rebaixado. Os resultados indicam que mulheres com rebaixamento do arco oscilam menos e mais lentamente que mulheres com arco normal, em particular na condição de maior perturbação sensorial, o que pode representar uma resposta pior, ou mais lenta de um sistema com desequilíbrios mecânicos decorrentes de um pé pouco funcional. Já a utilização da bandagem plantar resultou em aumento da oscilação do centro de pressão para a maioria das condições de perturbação sensorial, principalmente na direção médio-­-lateral, o que pode ser explicado por uma dificuldade dos sujeitos em se ajustar a uma nova postura, ou indicar um ganho de confiança e um melhor funcionamento do pé, traduzido pelo aumento da utilização dos ajustes posturais. / This dissertation is based on the premise that misalignment of plantar arches are associated to poor foot function and to subsequent mechanical compensations in the kinetic chain and adjacent joints. Foot taping is a commonly used technique in the treatment and prevention of injuries caused by these misalignments; however, its efficacy on postural control is still uncertain. Our hypotheses are: (i) subjects with low plantar arch would present postural control deficits, detectable by center of pressure sway measurement, that would be worsened in conditions of sensory perturbation, and (ii) foot taping, applied on midfoot with the intention to improve the cutaneous sensorial acuity, would bring benefits to the postural control of these subjects, especially under conditions of sensory perturbation. Thus, two studies will be presented: the first meant to investigate postural control alterations in individuals with low plantar arch (study 1), and the second, to investigate the effects of foot taping use in these subjects (study 2). For both studies, the mean velocity and root mean square of center of pressure trajectory were assessed during the maintenance of quasi-static stance in four conditions of sensory perturbations: (1) fixed support, eyes opened; (2) fixed support, eyes closed; (3) moving support, eyes opened, and (4) moving support, eyes closed. In study 1, 24 women with normal plantar arch were compared to 13 with low plantar arch. For study 2, the same 13 low arched subjects were assessed with and without foot taping. Results indicate that women with low plantar arch have less and slower center of pressure sway, particularly in the condition of highest sensory perturbation level, which may indicate a worsened, or slower, response of a mechanically altered system. When foot taping was applied to the low arched individuals, a higher and faster center of pressure sway was observed in most of the sensory perturbation conditions, especially in the medio-lateral direction. This could be explained either by a difficulty for the subjects to adapt to a new imposed postural condition, or by a gain in confidence while using the taping, reflected by the increase in postural adjustments.

Esta dissertação parte da premissa de que o desalinhamento dos arcos plantares estão associados ao mal funcionamento do pé e a subseqüentes desequilíbrios mecânicos gerados por compensações na cadeia cinética e articulações adjacentes. A bandagem plantar é uma das técnicas comumente utilizadas no tratamento e prevenção de lesões decorrentes destes desalinhamentos; no entanto, sua eficácia no controle postural ainda é incerta. Nossas hipóteses são: (i) que sujeitos com arco rebaixado apresentariam déficits do controle postural que se acentuariam em condições de perturbação sensorial, e (ii) que a bandagem aplicada no médio-­pé para melhorar a acuidade sensorial traria benefícios para o controle postural destes sujeitos, principalmente nas condições de perturbação. Assim, apresentaremos nesta dissertação dois estudos, um para investigar as alterações no controle postural de indivíduos com rebaixamento do arco plantar (estudo 1), e outro para investigar as consequências da utilização bandagem plantar nestes indivíduos (estudo 2). Para ambos os estudos, avaliamos a velocidade média e o root mean square da trajetória do centro de pressão durante a manutenção da postura quasi-­-estática em quatro condições de perturbação sensorial: (1) plataforma fixa, olhos abertos; (2) plataforma fixa, olhos fechados; (3) plataforma móvel, olhos abertos; e (4) plataforma móvel, olhos fechados. No estudo 1, 24 mulheres com arcos normais foram comparadas a 13 mulheres com arco rebaixado. No estudo 2, a comparação foi feita entre as condições sem e com a bandagem plantar para as 13 mulheres com arco rebaixado. Os resultados indicam que mulheres com rebaixamento do arco oscilam menos e mais lentamente que mulheres com arco normal, em particular na condição de maior perturbação sensorial, o que pode representar uma resposta pior, ou mais lenta de um sistema com desequilíbrios mecânicos decorrentes de um pé pouco funcional. Já a utilização da bandagem plantar resultou em aumento da oscilação do centro de pressão para a maioria das condições de perturbação sensorial, principalmente na direção médio-­-lateral, o que pode ser explicado por uma dificuldade dos sujeitos em se ajustar a uma nova postura, ou indicar um ganho de confiança e um melhor funcionamento do pé, traduzido pelo aumento da utilização dos ajustes posturais. / This dissertation is based on the premise that misalignment of plantar arches are associated to poor foot function and to subsequent mechanical compensations in the kinetic chain and adjacent joints. Foot taping is a commonly used technique in the treatment and prevention of injuries caused by these misalignments; however, its efficacy on postural control is still uncertain. Our hypotheses are: (i) subjects with low plantar arch would present postural control deficits, detectable by center of pressure sway measurement, that would be worsened in conditions of sensory perturbation, and (ii) foot taping, applied on midfoot with the intention to improve the cutaneous sensorial acuity, would bring benefits to the postural control of these subjects, especially under conditions of sensory perturbation. Thus, two studies will be presented: the first meant to investigate postural control alterations in individuals with low plantar arch (study 1), and the second, to investigate the effects of foot taping use in these subjects (study 2). For both studies, the mean velocity and root mean square of center of pressure trajectory were assessed during the maintenance of quasi-static stance in four conditions of sensory perturbations: (1) fixed support, eyes opened; (2) fixed support, eyes closed; (3) moving support, eyes opened, and (4) moving support, eyes closed. In study 1, 24 women with normal plantar arch were compared to 13 with low plantar arch. For study 2, the same 13 low arched subjects were assessed with and without foot taping. Results indicate that women with low plantar arch have less and slower center of pressure sway, particularly in the condition of highest sensory perturbation level, which may indicate a worsened, or slower, response of a mechanically altered system. When foot taping was applied to the low arched individuals, a higher and faster center of pressure sway was observed in most of the sensory perturbation conditions, especially in the medio-lateral direction. This could be explained either by a difficulty for the subjects to adapt to a new imposed postural condition, or by a gain in confidence while using the taping, reflected by the increase in postural adjustments.

<p>Musculoskeletal degradation and musculoskeletal injuries place a substantial burden on the healthcare system. Advancing the understanding and prevention of the injury potential associated with these injuries in various demographics as well as advancing performance optimization requires knowledge of the loading distribution among the various musculoskeletal tissues at the joints. Accurate muscle force estimates are needed for characterizing these distributions due to their influence on the loading of the system. This dissertation discusses</p> <p>the development and validation of a physiologically-driven skeletal muscle force model that is suitable for application on an individualized level. The derivation of the skeletal muscle force model began with dimensional analysis and a selection of critical parameters that define muscle force generation. One of the key parameters included was measured muscle voltage using electromyography sensors. This provided the model with the ability to be easily used</p> <p>in application-based studies. It also incorporated the muscle force-length, force-velocity, and force-frequency curves, providing an even stronger physiological basis to the model. Validation was performed by multiple studies using experimental data from subjects conducting exercises chosen to target specific muscles of interest. Data was collected from a Vicon Vero motion capture system, an instrumented Bertec treadmill, and Delsys Trigno electromyography sensors. The first study analyzed the ankle joint of seventeen subjects using the two Newton-Euler equations of rigid body motion and the skeletal muscle force model. The average percent error across all subjects was 8.2% and ranged from 4.2% to 15.5%. The second study analyzed the sensitivity of two sets of parameters within the model. The first was conducted on a set of observed and fitted constants from the dimensionless pi terms and aimed to identify which, if any, could be excluded from an optimization routine. Results indicated that only two of the nine constant parameters needed to be optimized. The second sensitivity analysis focused on the anatomical kinematic parameters in order to identify the impact that the incorporation of MRI scans for subject-specific anatomical models would have on the accuracy of the model’s output. Results demonstrated sensitivity to the muscle insertion points, suggesting that the use of MRI scans could increase the accuracy of the model. The third study was a case study focused on evaluating the assumption of a constant within the skeletal muscle force model remaining constant over time. Results indicated that the collection of maximum EMG recordings for these studies may not have been controlled to a desirable level and that the inclusion of specialized equipment for maximum EMG recordings would likely validate this assumption. The final study analyzed the</p> <p>knee joint of ten subjects in a similar fashion to that of the ankle joint. The goal was to observe the model’s performance on a more anatomically complex joint. The average percent error across all subjects was 20.6%, approximately two times higher than the ankle joint.</p> <p>However, the majority of the error associated with this study came from the deviation in calculated moments about an axis of much smaller importance and magnitude than the primary flexion/extension axis. When errors were excluded from this axis, the average percent error for all subjects was 8.8%, almost identical to that of the ankle joint application. These findings as a whole indicate that the model has predictive ability and is capable of providing reasonable estimates of both muscle forces and surrounding musculoskeletal tissue loading. Therefore, the model could be used in various biomechanical advancements and applications in injury prevention, performance optimization, tissue engineering, prosthetic design, and more.</p>