The tibialis anterior (TA) muscle plays a vital role in human movement such as walking and running. Overuse of TA during these movements leads to an increased susceptibility of injuries e.g. chronic exertional compartment syndrome. TA activation has been shown to be affected by increases in exercise, age, and the external environment (i.e. incline and footwear). Because activation parameters of TA change with condition, it leads to the interpretation that force changes occur too. However,activation is only an approximate indicator of force output of a muscle. Therefore, the overall aim of this thesis was to investigate the parameters affecting accurate measure of TA force, leading to development of a subject-specific EMG-driven model, which takes into consideration specific methodological issues. The first study investigated the reasons why the tendon excursion and geometric method differ so vastly in terms of estimation of TA moment arm. Tendon length changes during the tendon excursion method, and location of the TA line of action and irregularities between talus and foot rotations during the geometric method, were found to affect the accuracy of TA moment arm measurement. A novel, more valid, method was proposed. The second study investigated the errors associated with methods used to account for plantar flexor antagonist co-contraction. A new approach was presented and shown to be, at worse, equivalent to current methods, but allows for accounting throughout the complete range of motion. The final study utilised the outputs from studies one and two to directly measure TA force in vivo. This was used to develop, and validate, an EMG-driven TA force model. Less error was found in the accuracy of estimating TA force when the contractile component length changes were modelled using the ankle, as opposed to the muscle. Overall, these findings increase our understanding of not only the mechanics associated with TA and the ankle, but also improves our ability to accurately monitor these.

Muscle strength capabilities are a determinant in the ability to successfully accomplish everyday tasks. As such, the quantification of this aspect of human performance is of interest in many settings. Currently, the validity of muscle strength test results is reliant on the notion that during testing, the participant exerted an effort that is sincere, and that consisted of maximal voluntary contractions. Therefore, the ability to differentiate between maximal and non maximal muscular exertions is of importance. The purpose of this dissertation was to develop and validate probability-based decision rules for differentiating between maximal and non-maximal voluntary exertions of the knee and shoulder joint musculature during isokinetic dynamometry-based testing. For development of the decision rules, healthy participants performed a series of maximal and non-maximal exertions at different testing velocities through a prescribed range of motion. Two different theory-based approaches were subsequently used for decision rule development: the first approach was based on expected better consistency in strength waveform shapes and relative magnitudes during performance of maximal efforts in comparison to non-maximal efforts. The second approach was based on the known force-velocity dependency in skeletal muscles. In terms of discriminatory performance, several of the decision rules pertaining to the knee joint markedly improve upon those previously reported. In addition, a separate investigation demonstrated that the decision rules offer excellent discriminatory performance when applied to test results of participants that have undergone surgical reconstruction of their anterior cruciate ligament. As such, clinicians and researchers may be able to ascertain voluntary maximal effort production during isokinetic testing of the knee joint musculature with a high degree of confidence, and thus be able to rely on such scores for decision-making purposes With regards to the shoulder musculature decision rules, several methodological issues related to test positioning and signal processing need to be addressed prior to consideration of their use in the clinical domain. / Thesis (Ph.D, Kinesiology & Health Studies) -- Queen's University, 2013-06-19 01:12:53.454

The purpose of this study was to determine if isokinetic testing could be used as an effective means of assessing a players potential to play a certain position. The subjects were twenty four male division IA college football players. The Cybex 340 isokinetic testing device, twenty and forty yard dash, and standing broad jump were used to collect data. An analysis of variance test with repeated measures was used for the statistical analysis (ANOVA). Based on the findings of this study, no significant difference was found between offensive and defensive lineman, through isokinetic testing. However, a significant difference was found between the groups in the twenty and forty yard dash, and in the standing broad jump. Significant differences in these areas may have been attributed to a significant difference in body weight between the two groups tested. / School of Physical Education

<p>Bol je subjektivno, neprijatno opažanje i osećaj. Čovek često oseća bol u delu tela koji<br />je znatno udaljen od mesta nastanka bola. U istraživanju je primenjena transverzalna<br />metoda, jednokratnog merenja. Ispitivanjem je obuhvaćeno 136 ispitanika, aktivnih<br />fudbalera, starosti 18-35 (20.49&plusmn;3.73) godina. Sva merenja su vr&scaron;ena od 2006. do<br />2016.godine. Ispitanici su ispunili anketu o postojanju bola u leđima, pre samog<br />početka testiranja, gde su intenzitet bolnosti subjektivno procenili Rolandovom skalom<br />bola). Celokupan uzorak je stratifikovan proporcionalnom tehnikom u pet grupa na<br />osnovu subjektivnog osećaja bola u leđima. Multivarijantnom metodom varijanse<br />utvrđivane su razlike na generalnom sistemu uzorkovanih varijabli, prilikom čega je<br />ustanovljeno da postoji statistički značajna razlika između navedenih grupa ispitanika<br />podeljenih na osnovu subjektivnog osećaja bola u leđima u izokinetičkim varijablama<br />koje su uzete u obzir ovim istraživanjem dok su Univarijantnom analizom varijanse<br />utvrđene razlike u pojedinačnim varijablama. Iz navedenih empirijskih saznanja i<br />relevantnih podataka iz stručne literature dobija se uvid u faktore koji utiču na bolno<br />stanje određene regije, disfunkciju i slabost pojedinih mi&scaron;ićnih grupa, uticaj pojedinih<br />mi&scaron;ićnih grupa na druge, kao i poremećaj u kinetičkom lancu lokomotornog aparata<br />kod fudbalera. Samo istraživanje ukazuju na značaj i potrebu da se standardizuju<br />protokoli i konstrui&scaron;u odgovarajući algoritmi za komparativnu sistematizaciju varijabli<br />dobijenih specifičnim ispitivanjima izokinetičkom dinamometrijom kod ispitanika koji<br />se bave timskim sportom sa loptom (fudbal, kosarka, rukomet i dr). Dobijeni podaci<br />poslužiće jednim delom kao deo monitoringa sportskog treninga, kao i efekata<br />različitih trenažnih protokola na parametre mi&scaron;ićne snage kod fudbalera. Sportskomedicinski značaj na polju testiranja parametara mi&scaron;ićne snage izokinetičkom<br />dinamometrijom se ogleda u prevenciji sportskih povreda ili u brzoj i efikasnoj<br />dijagnostici i terapiji istih, &scaron;to značajno utiče na ekonomski aspekt, s obzirom da je<br />profesionalni sport postao visoko komercijalizovan.</p> / <p>Pain is a subjective, uncomfortable perception and feeling. Human often feels<br />pain in the part of the body that is significantly away from the place of origin of pain.<br />The transversal method was performed during study, with a one-time measurement.<br />The study included 136 subjects, active players, ages 18-35 (20:49 &plusmn; 3.73) years. All<br />measurements were carried out from 2006 to 2016. Before the start of the test,<br />examinee completed the survey on the existence of back pain, where the intensity of<br />the pain was subjectively assessed according to Roland pain scale. The entire sample was stratified by proportional technique into five groups, based on the subjective experience of back pain. Multivariate variance method for detection of differences in the general system of sampled variables, during which it was established that there is a statistically significant difference between the groups of examinee, who were divided on the basis of subjective experience of back pain of the isokinetic variables that are taken into account in this study while the univariate analysis of variance determined differences in the individual variables. From the empirical findings above and relevant information from technical literature, an insight was obtained into the factors that influence the painful condition of a particular region, dysfunction and weakness of certain muscle groups, the impact of certain muscle groups on others, as well as the disruption in the kinetic chain of the locomotor apparatus. The research highlights the importance of and the need to standardize protocols and construct appropriate algorithms for comparative systematization of variables obtained by isokinetic dynamometry specific trials in subjects who are engaged in team sports with a ball (football, basketball, handball, etc.). The data will serve partially as part of the monitoring of sports training, as well as the effects of various parameters of training protocols on muscle strength in football. Sports and medical significance in the field of testing parameters with isokinetic muscle strength dynamometry is reflected in the prevention of sports injuries or in the quick and efficient diagnosis and treatment of the same, which significantly affects the economic aspect, considering that professional sport has become highly commercialized.</p>

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Title: The assesment of selected strength and stability parameters of an ankle plantar and dorsal flexion in slackliners. Objectives: To assess the relation between level of stability the dorsiflexion and the plantar flexion strength in slackliners. Methods: The research sample was composed of two groups - slackliners (9 person) and balanced control group (9 person) selected from physically active population. Probands were tested on the Flamingo test on the pressure plate, the test of the dorsiflexion and plantar flexion strenght on an isokinetic dynamometer. Slackliners underwent extra range of motions elements on the slackline. The level of stability was assessed by using the centre of pressure and the physical design of individual elements on the slackline. Power was assessed by using the peak torque at 30 ř and 120 ř. Results: Slackliners achieve bigger relative strength in the plantar angular velocity of rotation of 30 ř in both limbs than the control group (left: 1.51 ± 0.31 vs. 1.20 ± 0.30 Nm.kg-1 , p <0.05 , η2 = 0.21, right: 1.55 ± 0.34 vs. 1.21 ± 0.34 Nm.kg-1 , p <0.05, η2 = 0.22). The results of other parameters (postural stability, isokinetic power at the ankle angular velocity of 120 ř.s-1 and the time course of force) between the two groups did not differ significantly. Conclusion:...

Introduction: Isokinetic testing is used in rehabilitation settings on a regular basis, yet there is a lack of consistency in rest period usage among protocols. Purpose: The purpose of this study was to establish an optimal rest period that would allow reproducibility of strength during a common isokinetic strength-test. Methods: Twentyseven healthy college-aged males underwent isokinetic strength testing to determine peak torque at 60, 180 and 300 deg/sec, respectively. Work:rest ratios of 1:3, 1:8 and 1:12 were counterbalanced between sets. A 3 X 3 repeated measures ANOVA was used to analyze the data. The p < .05 level of significance was used for all tests. Results: There was no significant difference in either knee extension or knee flexion peak torque when comparing work:rest ratios. Conclusion: These findings suggest that a 1:3 work:rest ratio is sufficient during a common isokinetic strength test.

Desde seu desenvolvimento na década de 60, a fototerapia têm sido utilizada no tratamento de diversas condições patológicas, havendo um considerável corpo de evidências acerca de sua ação regenerativa, analgésica e anti-inflamatória. Tais efeitos terapêuticos podem ser explicados pela capacidade que a energia luminosa possui de ser absorvida pelos tecidos e estimular ou inibir processos intracelulares. Estudos recentes têm apresentado resultados promissores desta terapia também sobre a redução da fadiga e do dano muscular induzido pelo exercício. A fadiga muscular é um fenômeno multifacetado caracterizado por uma progressiva redução da capacidade de produção de força do músculo. O dano muscular, causado principalmente pelas ações excêntricas do exercício, é caracterizado pela desorganização da estrutura microscópica do músculo e redução da capacidade contrátil deste tecido. Assim, o objetivo do presente trabalho foi verificar o efeito da fototerapia aplicada imediatamente antes do exercício sobre: (1) a fadiga muscular de extensores de joelho submetidos a exercício isocinético concêntrico; (2) o dano muscular de extensores de joelho submetidos a exercício isocinético excêntrico. No primeiro estudo, 17 homens saudáveis e fisicamente ativos participaram de um desenho experimental cruzado no qual foram submetidos a 30 repetições concêntricas máximas de flexo-extensão do joelho, precedidas de tratamento com fototerapia ou placebo. A fototerapia foi aplicada através de um equipamento de light emitting diodes therapy (LEDT) composto por 35 diodos infravermelhos de 850 nm e 34 diodos vermelhos de 660 nm. O tratamento foi realizado em três pontos do quadríceps com aplicação de uma dose total de 125,1 J. Mensurações da função muscular dos extensores de joelho foram realizadas antes e imediatamente após o exercício através de contrações voluntárias máximas (CVM) de extensores de joelho a 60º de flexão da articulação. Como resultado, observou-se que os voluntários apresentaram um decréscimo de torque significativamente menor quando tratados com fototerapia em comparação ao tratamento placebo. No segundo estudo, 36 homens saudáveis e fisicamente ativos foram randomizados em grupo fototerapia (n=18) e grupo placebo (n=18), e submetidos a cinco séries de 15 contrações excêntricas máximas de extensores de joelho. Avaliações de dor muscular e níveis séricos das enzimas lactato desidrogenase (LDH) e creatina kinase (CK) foram mensuradas pré-exercício, 24 e 48 horas pós-exercício. Avaliações da função muscular (CVM de extensores de joelho) foram realizadas pré-exercício, imediatamente após, 24 e 48 horas após o exercício. Um equipamento de low level laser therapy (LLLT) composto por cinco diodos infravermelhos de 810 nm foi utilizado para aplicar o tratamento em seis pontos do quadríceps e transmitir uma dose total de 180 J. Como resultado, observou-se que o grupo fototerapia apresentou: (1) menores incrementos de LDH 48 horas após o exercício; (2) menores incrementos de CK 24 e 48 horas após o exercício; e (3) menor decréscimo do torque de extensores de joelho imediatamente após, 24 e 48 horas após o exercício, em comparação ao grupo placebo. Os achados destes estudos permitem concluir que o tratamento com fototerapia foi capaz de atenuar os efeitos da fadiga e do dano muscular induzidos por exercício em dinamômetro isocinético. / Since its development in the 60’s, phototherapy has been used in the treatment of several pathological conditions, with a considerable body of evidence with respect to its regenerative, analgesic and anti-inflammatory action. These therapeutic effects may be explained by the capacity that the light energy has of being absorbed by soft tissues and stimulate or inhibit intracellular processes. Recent studies have also shown promising results regarding the reduction of muscle fatigue and exercise induced muscle damage. Muscle fatigue is a multifaceted phenomenon characterized by a progressive reduction in muscle force production capacity. Muscle damage, mainly caused by eccentric exercise, is characterized by the microscopic disorganization of muscle structure and reduction of the contractile capacity of this tissue. Thus, the purpose of this study was to verify the effect of phototherapy applied immediately before exercise on: (1) knee extensors muscle fatigue after isokinetic concentric exercise; (2) knee extensor muscle damage after isokinetic eccentric exercise. In the first study 17 healthy and physically active male subjects participated of a cross-over design trial. Subjects were subjected to 30 maximal concentric repetitions of knee flexion-extension, preceded by placebo or phototherapy treatment. Phototherapy was applied with a light emitting diodes therapy (LEDT) equipment composed by 35 infrared diodes of 850 nm wavelength and 34 red diodes of 660 nm. Treatment was applied in three different points of the quadriceps muscle with a total dose of 125.1 J. Measurements of knee extensor muscle function were obtained before and immediately after exercise by maximal voluntary contractions (MVC) at a knee angle of 60º of joint flexion. Subjects showed a significant smaller decrease in torque when treated with phototherapy compared to placebo treatment. On the second study, 36 healthy and physically active male subjects were randomized into a phototherapy (n=18) and a placebo (n=18) group, and subjected to five series of 15 maximal knee extensor eccentric contractions. Measurements of pain and serum levels of lactate dehydrogenase (LDH) and creatine kinase (CK) enzymes were obtained pre-exercise, 24 and 48 hours postexercise. Evaluations of muscle function (knee extensor MVC) were obtained preexercise, immediately after, and 24 and 48 hours after exercise. A low level laser therapy (LLLT) equipment composed by five infrared diodes of 810 nm wavelength was used to apply the treatment on six different points of the quadriceps muscle with a total dose of 180 J. The phototherapy group showed: (1) smaller increments of LDH 48 hours after exercise; (2) smaller increments of CK 24 and 48 hours after exercise; and (3) smaller decrease on knee extensor torque immediately after, 24 and 48 hours after exercise compared to the placebo group. These findings allow us to conclude that the phototherapy treatment was able to attenuate the effects of fatigue and muscle damage induced by isokinetic exercise.

Healthcare costs for treating back pain have risen to 50 billion dollars a year in the past decade. In attempt reduce the risk of back pain; ergonomists use digital human modeling to assess the risks involved in functional tasks. However, current models are limited to analyzing the strength in static position. The overall goal of this study is to provide three-dimensional strength surfaces incorporating both static and dynamic strength for digital human models. Fifteen male and twenty-one female subjects were recruited. The study required two visits, were hip strength testing was performed in one visit and trunk strength testing was performed in the other visit. Hip strength was tested by completing flexion and extension isometric tests and isokinetic tests. Trunk flexion and extension strength was also measured by isometric and isokinetic tests. Isometric and Isokinetic tests were completed for trunk left and right rotation too. The data was analyzed using custom made MATLAB (Mathworks, Inc) programs and the three-dimensional strength surfaces were generated using SigmaPlot (SYSTAT Software, INC). The maximum peak torques were as followed: Hip flexion male 183Nm(57), hip flexion female 106 Nm (38), hip extension male 181 Nm (71), hip extension female 130 Nm (52), trunk flexion male 182 Nm (40.3), trunk flexion female 111.8 Nm (32), trunk extension male 328.5 Nm (52), trunk extension female 197.5 Nm (58), trunk right rotation male 71.6 Nm (20), trunk right rotation female 43 Nm (14), trunk left rotation male 71 Nm (24), and trunk left rotation female (43 Nm (17). Correlations were found between the hip and trunk joints, and the flexion and extension motion. Implementing this data into digital human models will provide realistic static and dynamic human strength parameters. Ultimately, this will help ergonomists predict and reduce high risk back injuries.

Many devices are available on the market for the evaluation and rehabilitation of patients suffering from muscular disorders. Most of them are small, low-cost, passive devices based on the use of springs and resistive elements and exhibit very limited (or even not any) evaluation capabilities; extended muscular force evaluation is only possible on stationary, expensive, multi-purpose devices, available only in hospitals, which offer many exercise modes (e.g. isokinetic mode) that are not available on other devices. The objective of this thesis is to make the functionalities currently only implemented on bulky multi-purpose devices available at a lower cost and in a portable fashion, enabling their use by a large number of independent practitioners and patients, even at home (tele-medecine applications). In order to achieve this goal, a portable rehabilitation device, using a magneto-rheological fluid brake as actuator, has been designed. This particular technology was selected for its high level of compactness, simple mechanical design, high controllability, smooth and safe operation. The first part of this thesis is devoted to the design of MR-fluid brakes and their experimental validation. The second part is dedicated to the design of the rehabilitation device and the comparison of its performances with a commercial multi-purpose device (CYBEX).