Abstract available in theJournal of Strength and Conditioning Research

Inertial measurement units (IMUs) and wearable sensors have enabled athlete monitoring and research to become more ecologically valid due to their small size and low cost. IMUs and accelerometers that are placed on the body close to the point of impact and that record at sufficiently high frequencies have demonstrated the highest validity when measuring temporal gait event moments such as ground contact time (GCT) and flight time (FT) as well as peak forces (PF) during upright running. While the use of IMUs has increased in the sport performance and athlete monitoring realm, the potential of the technology’s ability to estimate running force-time curves utilizing the two-mass model (TMM) remains unexplored. The purpose of this study was two-fold. First, was to determine the validity of measuring temporal gait events and peak forces utilizing a commercially available shank-mounted inertial measurement unit. Second, was to determine the validity of force-time curves generated from the TMM utilizing data from shank-mounted inertial measurement units. Ten subjects voluntarily completed submaximal treadmill tests equipped with a force plate while wearing shank-mounted IMUs on each leg. Using the raw data from the IMUs, GCT, FT, total step time (ST), PF, and two-mass model-based force-time (F-t) curves were generated for 25 steps at 8 different speeds. Paired sample T-tests were performed on the gait events and peak force between the IMU and treadmill with both individual step comparison and averages per each speed. 95% confidence intervals were calculated for each timepoint of the force time curves. No statistically significant differences (p > 0.05) and nearly perfect relationships were observed for the step averages for each speed with FT, ST, and PF. Confidence intervals of the corrected mean difference suggest that F-t curves calculated from the TMM may not be valid when assessing the running population as a whole. When performing a sub-group analysis of skilled runners and recreational runners, F-t curves derived from shank-mounted IMUs may be more valid in skilled runners than recreational runners. In skilled runners, the 95% CI for the mean difference contained zero within the first 60% of the GCT duration, whereas the 95% CI recreational runners contained a zero-value in a smaller percentage of the GCT located only in the middle of the GCT at the curve peak height. The results of this study suggest that interchangeability between shank-mounted IMUs and force plates may be very limited when estimating temporal gait events and kinetics. While agreement was low between F-t curves after the peak in skilled runners, use of shank-mounted IMUs to estimate F-t curves may have several benefits still in skilled runners when assessing peak forces and force development from initial contact until peak force.

Introdução - A análise da força de preensão manual durante a força realizada ao longo do tempo fornece dados referentes ao funcionamento biomecânico dos grupos musculares, com destaque à influência da musculatura flexora profunda e superficial dos dedos, bem como traz informações pertinentes ao desempenho funcional para atividades cotidianas. Objetivos - Analisar as curvas força-tempo da preensão palmar sob os aspectos de seus parâmetros discretos e de sua característica temporal. Identificar a influência da musculatura flexora profunda de dedos na preensão palmar. Método - Os voluntários realizaram o teste de esforço isométrico máximo utilizando o dinamômetro Jamar® e o transdutor de força computadorizado com duas empunhaduras, uma que permitia a ação do músculo flexor superficial de dedos e outra que a bloqueava. Foram analisadas as curvas força-tempo geradas de 9 indivíduos tanto em seus parâmetros discretos como em suas características temporais. Resultados - A força máxima média obtida com o Jamar® na Posição 1, sem distinção entre os sexos, (30,76 Kgf) aproximou-se dos valores da média nacional para mulheres (30,4 Kgf). Tanto no teste com o Jamar® como com o transdutor de força, os valores discretos foram maiores na Posição 1 (Fmáx Jamar®: 30,76/25,14 kgf; Fmáx transdutor: 22,16/17,37 kgf; Tmáx: 1,41/1,54 seg; Finf: 7,06/5,80 kgf). A fase de manutenção da força, equivalente a força de resistência, teve menor decréscimo nos testes realizados na Posição 2 (-1,02/-0,61). Além disso, os valores obtidos entre os dinamômetros mostram que o Jamar® superestima os valores de força máxima. Conclusões - Os dados apontam que há diferença na capacidade de manutenção da força, para a qual a ação do músculo flexor profundo dos dedos mostrou-se mais eficaz do que quando em conjunto com o flexor superficial dos dedos, tendo assim, grande importância funcional para a execução das atividades de vida diária. Evidencia-se que a análise da força por meio de suas características temporais fornece maior elucidação do desempenho muscular durante a força de preensão do que testes dinamométricos pontuais. / Introduction - The analysis of the manual grip force along time presents the biomechanical movement of muscle groups data, with emphasis on the deep and superficial flexor musculature of the fingers, as well as provides relevant information for the functional performance of daily activities. Objectives - To analyze the force-time curves of the palmar grip under the aspects of its discrete parameters and its temporal characteristic. Either, to identify the the influence of the flexor muscles of fingers in the palmar grip. Method - The volunteers performed the maximum isometric effort test using the Jamar® dynamometer and the computerized force transducer with two grips, one that allowed the action of the flexor superficial finger muscle, and another that blocks it. The force-time curves generated from 9 individuals were analyzed in both their discrete parameters and their temporal characteristics. Results - The medium of maximum strength obtained with Jamar® at Position 1, without distinction between gender, (30.76 Kgf) approached the national average for women (30.4 Kgf). In both the Jamar® and the force transducer tests, the discrete values were higher in Position 1 (Fmax Jamar®: 30.76 / 25.14 kgf; Fmax transducer: 22.16 / 17.37 kgf; Tmax: 1.41 / 1.54 sec; Finf: 7.06 / 5.80 kgf). The strength maintenance phase, equivalent to the resistive force, had a smaller decrease in the tests performed in Position 2 (-1.02 / -0.61). In addition, the values obtained between the dynamometers show that the Jamar® overestimates the maximum force values. Conclusions - The data points that there is a difference between the action of the flexor profound muscle group of the fingers and the flexor superficial one in the capacity of maintaining the force, showing that the profound group is more effective than combined with the superficial flexor, thus, the first one has great functional importance for performing activities of daily life. It evidences that the analysis of force on its temporary characteristics is more elucidative of the muscular performance during the grip force than the punctual dynamometric tests.

Made available in DSpace on 2016-12-06T17:07:26Z (GMT). No. of bitstreams: 1 Anna Quialheiro.pdf: 4792596 bytes, checksum: d8f954e7807dbb62634090379eff89a7 (MD5) Previous issue date: 2010-03-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The rheumatoid arthritis (RA) is an auto-immune illness with incapacity potential mainly in the joints of the hands. The handgrip (FPM) is one of the forms of evaluation of the manual function and one of most common quantifying the manual muscular function and can be used as a general pointer of force and functionality. The objective of the study was to analyze the force of manual hold in women with RA being compared the parameters of the curve force versus time of isometric handgrip of the individuals with and without RA between dominant and not dominant hand and also to verify if isometric handgrip exists association between the parameters of the curve force versus time of handgrip and the disease activity index (DAS28) in the group with RA. In this study participated 28 women being 16 with RA (GA) and 12 without RA (GC), with age between 35 and 75 years. All the participants had told the right hand as dominant hand. They had been carried through: test of blood for calculation of the VHS, the demographic data, the vital signals and the anthropometry, these verify before the FPM. For the FPM test a system of dinamometria with load sensor was used with handle adjustable to the anthropometry of the hand of each participant. A protocol elaborated specifically for this study was followed that consisted of the accomplishment of the FPM isometric continues maximum. After the FPM, was carried through the counting of the pain joints, swollen joints and general evaluation of the health for composition of the disease activity index. In the group with RA it was verified that the pathology has statistical significant influence in the variables Fmax, TFmax, TDF and AFPM in both the hands, presenting significant difference does not enter the groups in the variable %Fmax however a trend to a decline of the Fmax biggest in the GA was verified. AIR significantly influenced four of the five parameters of the curve force versus time evaluated in this study. However, it did not have influence of the changeable dominância in the same parameters amongst the groups. In DAS28, this was correlated only with the Fmax 0 variable in the not dominant hand between the groups, however it not found correlate between DAS28 and dominance and disease variables in the others parameters. The comparative statistical tests had shown significant differences that confirm and validate the benefits of the FPM as the best form to foresee the force manual being able to produce a difference between healthful individuals and pathological individuals. / A artrite reumatóide (AR) é uma doença auto-imune com potencial incapacitante principalmente nas articulações das mãos. A força de preensão manual (FPM) é uma das formas de avaliação da função manual e uma das mais comuns para quantificar a função muscular manual e pode ser utilizada como um indicador geral de força e funcionalidade. O objetivo do estudo foi de analisar a força de preensão manual em mulheres com artrite reumatóide comparando os parâmetros da curva força versus tempo de preensão manual isométrica máxima dos indivíduos com e sem AR entre mão dominante e não dominante e também verificar se existe associação entre os parâmetros da curva força vs tempo de preensão manual isométrica máxima e o índice da atividade da doença (DAS28) no grupo com AR. Participaram deste estudo 28 mulheres sendo 16 com AR (GA) e 12 sem AR (GC), com idade entre 35 e 75 anos. Todas as participantes relataram a mão direita como mão dominante. Foram realizados: coleta de sangue para cálculo do VHS, dos dados demográficos, dos sinais vitais e da antropometria, estes mensurados antes da FPM. Para o teste de FPM foi utilizado um sistema de dinamometria com sensor de carga com empunhaduras ajustáveis à antropometria da mão de cada participante. Foi seguido um protocolo elaborado especificamente para este estudo que consistiu na realização da FPM isométrica continua máxima. Após a FPM, foi realizada a contagem das articulações doloridas, edemaciadas e avaliação geral da saúde para composição do índice da atividade da doença. No grupo com AR foi verificado que a patologia tem influência estatisticamente significativa nas variáveis Fmax, TFmax, TDF e AFPM em ambas as mãos, não apresentando diferença significativa entre os grupos na variável %Fmax porém verificou-se uma tendência a um declínio da Fmax maior no GA. A AR influenciou significativamente quatro dos cinco os parâmetros da curva força versus tempo avaliados neste estudo. Entretanto, não houve influência da variável dominância nos mesmos parâmetros dentre os grupos. Quanto ao DAS28, este correlacionou-se apenas com a variável Fmax na mão não dominante entre os grupos, porém não foi encontrado correlação do DAS28 com as variáveis dominância e grupo nos demais parâmetros. Os testes estatísticos comparativos mostraram diferenças significativas que confirmam e validam os benefícios da FPM como a melhor forma de prever a força manual podendo produzir uma diferença entre indivíduos saudáveis e indivíduos patológicos.

The purpose of this investigation was to study the effects of an 11-week training period performed by female weightlifters. Two weeks before this investigation, baseline measures for total testosterone, cortisol, and testosterone:cortisol ratio were collected. The 11-week training program consisted of the core exercises (i.e., clean, clean and jerk, and snatch) and other supplemental exercises (i.e., clean pull, snatch pull, squat, and front squat). Hormonal, isometric, and dynamic middle thigh pull force-time curve characteristics were assessed biweekly throughout the duration of the investigation, whereas volume load and training intensity were assessed weekly throughout the investigation. The testosterone:cortisol ratio of the baseline (1.19 ± 0.64) was significantly different from the ratio of weeks 1 (0.67 ± 0.36) and 9 (0.94 ± 0.66). When the week-to-week values were compared, week 1 (0.67 ± 0.36) was significantly different (P < 0.05; ηsup>2= 0.84) from week 3 (1.06 ± 0.54). A very strong correlation (r = −0.83; r 2 = 0.69) was found between the percentage change of the testosterone:cortisol ratio and volume load from weeks 1 to 11. Moderate to very strong correlations were noted between the percentage change in volume load and isometric peak force, peak force during the 30% isometric peak force trial, and peak force during the 100-kg trial during the 11 weeks of training. The primary finding of this study was that alterations in training volume load can result in concomitant changes in the anabolic-to-catabolic balance, as indicated by the testosterone:cortisol ratio, and the ability to generate maximal forces.

This dissertation aimed to explore the usefulness of using force derivatives for onset detection in the isometric mid-thigh pull test. First, we examined applications of three differential calculus principles, first and second derivative, and curvature using visual detection as a reference under different baseline conditions. Second, we compared the best derivative method to a threshold-based method using visual detection as a reference. Results of our first investigation showed trivial differences between many differential calculus methods and visual detection. However, statistical differences exceeding a trivial effect was observed when instantaneous force and rate of force develop were examined. Through the first investigation, first and second derivative emerged as possible viable methods for baseline with a countermovement and for all other baseline conditions, respectively. Results of the second investigation showed similarities to the first investigation with respect to onset time. However, examination of instantaneous force and rate of force development indicated that a threshold-based method tended to overestimate compared to visual detection and a first and second derivative combined method. In fact, the difference between visual detection and the first and second derivative combined method ranged from trivial to moderate under all baseline conditions while the threshold-based method often reached a large difference. Overestimation by the threshold-method was more pronounced for rate of force development. In conclusion, while not perfect, the first and second derivative 3 combined method appears to hold possible practical potential and may be used as an assistant method for entry-level sport scientist plus using visual detection for obvious erroneous values.

Orientador: Sebastião Gobbi / Banca: Paulo de Tarso Veras Farinatti / Banca: Maria Elisa Pimentel Piemonte / Resumo: O presente estudo teve como objetivo analisar o efeito do treinamento de força e potência na curva força-tempo isométrica e na ativação muscular em idosos com doença de Parkinson (DP). A amostra final foi composta por 25 participantes de ambos os gêneros (n=8 - grupo controle (GC); n=8 - grupo de força (GF); n=9 - grupo de potência (GP). Os grupos GF e GP realizaram treinamento com pesos, durante oito semanas, com especificidade para desenvolvimento de força ou potência musculares, respectivamente. O grupo controle (GC), composto por idosos com DP, realizou apenas o protocolo de avaliação pré e pós oito semanas. Os participantes realizaram consecutivamente: a) avaliação da Curva força-Tempo isométrica e da atividade eletromiográfica; b) início do protocolo de treinamento para os GF e GP; c) re-avaliação ao término do protocolo de treinamento de força e de potência. Para a análise dos dados foi utilizada estatística descritiva (média e desvio-padrão) e ANOVA two-way para medidas repetidas em todas as variáveis com nível de significância de p<0,05. Os resultados apontaram interações significativas (p<0,05) em contração voluntária máxima (CVM), taxa de desenvolvimento de força (TDF) no intervalo de tempo de 0-50ms e ativação muscular (iEMG) do músculo vasto lateral. Não foram encontradas interações significativas (p>0,05) na TDF nos intervalos de tempo 0-100; 0-150 e 0-200ms, TDFpico, impulso contrátil e ativação muscular (iEMG) dos vastos lateral e medial, nos intervalos de tempo 0-50; 0-100; 0-150 e 0-200ms, como também, na ativação do músculo vasto medial no momento da contração voluntária máxima. Portanto, conclui-se que o treinamento com pesos (força e potência) é capaz de aumentar a contração voluntária máxima, contudo o protocolo de potência parece trazer maiores benefícios; a capacidade dos idosos com DP de gerar... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The purpose of this study was to analyze the effect of strength and power training on isometric force-time curve and muscular activation in elderly individuals with Parkinson's disease (PD). The initial sample was composed by 25 participants of both gender (n=8 - control group (CG); n=8 - strength group (SG); n=9 - power group (PG). Both group, SG and PG, participated of resistance training for eight weeks with specificity for development of strength and muscular power, respectively. The CG, with Parkinson's disease, participated only of evaluation protocol, before and after eight weeks. Participants performed consecutively: a) evaluation of isometric force-time curve and muscular activation; b) start the resistance training protocol for SG and PG; c) revaluation of isometric force-time curve and muscular activation. For the data analysis it was used the descriptive statistics (mean and standard deviation) and two-way ANOVA for repeated measurements of all variables. The level of significance adopted was p<0.05. The results pointed significant interactions (p<0.05) in maximum voluntary contraction (MVC), rate of force development (RFD) in time interval of 0-50 and integrated EMG of vastus lateralis (iEMG VL). No significant interactions (p>0.05) were found in rate of force development (RFD) in time intervals of 0-100; 150; and 200 ms, peak of rate of force development (RFD peak), contractile impulse (CI) and integrated EMG of vastus lateralis and vastus medialis in time intervals of 0-50, 100, 150, and 200 ms as well in integrated EMG of vastus medialis at the same moment of MVC. In conclusion, the resistance training (strength and power) it is capable to increase the MVC, however the power training protocol seems to be more beneficial; the PD seniors' capacity to generate fast force (TDF) in the first ones 50ms increase after eight weeks of power training... (Complete abstract click electronic access below) / Mestre

Abstract available in the Journal of Strength and Conditioning Research

Einleitung: Klauenerkrankungen und Lahmheiten stellen ein großes ökonomisches sowie tierschutzrelevantes Problem in der modernen Milchviehhaltung dar. Diese werden wesentlich durch die Haltung auf harten Böden wie Beton oder Gussasphalt begünstigt. Daher werden in Rinderställen vermehrt Gummi-Laufflächenbeläge eingebaut, welche die mechanischen Belastungen und somit potentielle Schädigungen der Klauen reduzieren sollen. Die Einwirkung von Kräften in Abhängigkeit unterschiedlicher Böden auf die Klauenfußungsfläche kann mittels Druckmessung untersucht werden. Um dabei den direkten kinetischen Einfluss des Bodens auf die Fußungsfläche ermitteln zu können, sind dünne Sensorfolien nötig. Ziele der Untersuchung: Ziel der Arbeit war es, zunächst ein Ex-vivo-Belastungsmodell für isolierte Rindergliedmaßen zu etablieren, um mit einem folienbasierten Druckmesssystem den direkten kinetischen Einfluss verschiedener Untergründe auf die Fußungsfläche der Klauen zu ermitteln. Anschließend sollte dieses Messsystem erstmals unter lebenden Rindern angewendet werden. Tiere, Material und Methoden: Insgesamt wurden drei Versuche durchgeführt, in denen die kinetischen Einflüsse von Betonboden sowie mindestens einem Gummiboden der Firma Gummiwerk KRAIBURG Elastik GmbH & Co. KG anhand folgender Parameter untersucht wurden: Kraftverteilung, Belastungsfläche sowie durchschnittlicher und maximaler Druck. Die Datenerfassung erfolgte mit dem Hoof™System (Tekscan®). Zunächst wurde ein Ex-vivo-Versuch mit einem speziell für diese Messung angefertigten Belastungsgerät durchgeführt. Damit wurden zwölf linke isolierte distale Hintergliedmaßen auf Betonboden sowie drei Laufgang-Gummimatten (KARERA P, KURA P und profiKURA P) belastet. Außerdem wurde in diesem Versuch neben den oben aufgeführten Parametern zusätzlich die Kraft- und Druckverteilung innerhalb definierter Bereiche unter der Klaue analysiert. Diese Versuchsanordnung wurde anschließend in einen statischen In-vivo-Versuch mit elf auf Beton und KURA P Gummiboden stehenden, adulten Milchkühen überführt. Außerdem wurden die Sensorfolien in einem zweiten In-vivo-Versuch unter den Klauen der linken Hintergliedmaße von zehn adulten Milchkühen angebracht und die kinetischen Einflüsse von Beton und KURA P Gummiboden im Stand und beim Laufen ermittelt. Die statistischen Vergleiche zwischen den Böden wurden gepaart für die Klauen bzw. Kühe sowie zwischen den Versuchen mittels Wilcoxon-Vorzeichen-Rang-Test mit anschließender Post-Hoc-Korrektur nach Bonferroni-Holm berechnet. Für alle Resultate mit einer Wahrscheinlichkeit von p < 0,05 wurde eine statistische Signifikanz angenommen. Zusätzlich wurden im Laufen die Kraft-Zeit-Kurven einzeln für die laterale und mediale Klaue aufgezeichnet. Ergebnisse: In allen Versuchen sowie auf allen untersuchten Böden lastete die Kraft signifikant mehr auf den lateralen als auf den medialen Klauen. Die belastete Fläche war auf allen Gummiböden signifikant größer als auf Betonboden. Dadurch zeigten sich auf allen Gummiböden signifikant geringere Druckbelastungen als auf Betonboden: Der durchschnittliche Druck fiel im Ex-vivo-Versuch auf allen untersuchten Gummiböden im Mittel 34 - 44 % geringer aus als auf Betonboden (44,69 ± 5,39 N/cm²), während die Durchschnittsdruckwerte in den In-vivo-Versuchen auf KURA P-Gummiboden im Mittel um 16 - 21 % geringer waren als auf Beton (statisch: 32,05 ± 4,56 N/cm² bis 35,74 ± 7,66 N/cm², dynamisch: 46,60 ± 13,94 N/cm² bis 55,60 ± 9,78 N/cm²). Der auf die Klauen wirkende Maximaldruck war im Ex-vivo-Versuch auf den getesteten Gummiböden im Mittel 33 - 45 % geringer als auf Beton (130,31 ± 23,29 N/cm²) und in den In-vivo-Versuchen auf KURA P-Gummiboden im Mittel 28 - 32 % geringer als auf dem Betonboden (statisch: 92,12 ± 8,83 N/cm² bis 104,79 ± 20,40 N/cm², dynamisch: 158,47 ± 37,66 N/cm²). Die Kraft-Zeit-Kurven des dynamischen In-vivo-Versuchs zeigten weitgehend biphasische Verläufe mit lokalen Maxima bei 29 % und 79 % der Stützphase. Es traten jedoch interindividuell sowie jeweils zwischen lateralen und medialen Klauen deutliche Unterschiede im Kurvenverlauf auf. Schlussfolgerungen: Das Hoof™System konnte erfolgreich bei Rindern eingesetzt werden. Mit dem Belastungsgerät konnten standardisierte Messwiederholungen auf verschiedenen Untergründen durchgeführt werden. Künftig können damit weitere Untergründe sowie neue Klauenpflegetechniken zunächst ex vivo evaluiert werden, bevor sie an lebenden Rindern Anwendung finden. In allen Versuchen war auf Gummiboden eine mechanische Entlastung der Klauenfußungsfläche zu verzeichnen, was die Vermutung nahelegt, dass diese Böden einen Beitrag zur nachhaltigen Verbesserung der Klauengesundheit in der konventionellen Milchviehhaltung leisten können. / Introduction: Claw lesions and lameness are amongst the major problems in modern dairy husbandry. They are mainly caused by keeping the cows on hard, unyielding floors like concrete or mastic asphalt. Therefore preventively, an increasing number of farmers install rubber floorings in the walking alleys to minimize the mechanical stress to the sole and consequently reduce damage of the claws. The kinetic effect of different flooring types to the sole can be analyzed by means of pressure measurement. In order to detect the direct kinetic impact of the tested flooring, thin sensor foils capturing the interactions between claw and floor are required. Aims of the study: In the present study, an ex vivo load applicator was to be developed in order to use a foil-based pressure measurement system to determine the direct kinetic effect of different flooring types on the claws’ soles. Furthermore, this system was to be applied to live dairy cows for the first time. Materials and Methods: Three trials were conducted in which the kinetic effects of concrete and at least one rubber flooring (Gummiwerk KRAIBURG Elastik GmbH & Co. KG) were analyzed considering the following parameters: force balance, contact area, mean pressure and maximum pressure. Data acquisition was performed with the Tekscan® Hoof™System. Initially, an ex vivo trial was carried out with a purpose-built load applicator. Using this method, twelve left isolated distal hind limbs were loaded on concrete and three rubber floorings (KARERA P, KURA P and profiKURA P). Beside the parameters mentioned above, force and pressure distribution were analyzed within the separate areas of the claw’s sole. Afterwards, this test setting was transposed into a static in vivo trial with eleven adult dairy cows standing on concrete and KURA P rubber mats, respectively. Subsequently, the sensor foils were attached under the left hind limbs of ten adult dairy cows and the kinetic impacts of concrete and KURA P rubber flooring were determined during standing and walking. Statistical analysis was conducted using the Wilcoxon signed-rank test in combination with Holm-Bonferroni post hoc correction. Differences were considered to be significant at p < 0.05. In addition to the parameters mentioned above, force-time-curves of the walking cows were captured separately for the lateral and medial claw. Results: In all trials and on all tested floorings load was distributed unevenly between the claws at the expense of the lateral claw. The contact area was larger on all rubber floorings than on concrete. Therefore, the mean and maximum pressure loads were lower on all rubber floorings compared to concrete: In the ex vivo trial the mean pressure was, on average, 34 - 44 % lower on all rubber floorings than on concrete (44.69 ± 5.39 N/cm²), while in the in vivo measures the mean pressure was, on average, 16 - 21 % lower on KURA P rubber flooring compared to concrete (static: between 32.05 ± 4.56 N/cm² and 35.74 ± 7.66 N/cm², dynamic: between 46.60 ± 13.94 N/cm² and 55.60 ± 9.78 N/cm²). The maximum pressure loads in the ex vivo measures were, on average, 33 - 45 % lower on the tested rubber floorings than on concrete (130.31 ± 23.29 N/cm²) and in the in vivo trials, on average, 28 - 32 % lower on KURA P rubber flooring compared to concrete (static: between 92.12 ± 8.83 N/cm² and 104.79 ± 20.40 N/cm², dynamic: 158.47 ± 37.66 N/cm²). The force-time-curves of the dynamic in vivo study essentially showed biphasic curve progression with local peaks at 29 and 79 % of the stance phase. However, considerable differences in the curve progression between individuals as well as between the respective lateral and medial claw were found. Conclusions: The Hoof™System was applied successfully in dairy cattle claws for the first time. With the load applicator standardized repeated measurements on different floorings were conducted. In the future, more flooring systems as well as novel claw trimming methods can be evaluated using this setup before they are applied on live cattle. In all trials, a mechanical relief for the sole on the rubber floorings was determined. This leads to the conclusion that these floorings may contribute to a sustainable improvement of claw health in conventional dairy husbandry.

Made available in DSpace on 2014-06-11T19:22:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-08-06Bitstream added on 2014-06-13T19:49:08Z : No. of bitstreams: 1 arantes_lm_me_rcla.pdf: 491035 bytes, checksum: 9c4960c1f7c34e4bc86cddd4bb744ce3 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O presente estudo teve como objetivo analisar o efeito do treinamento de força e potência na curva força-tempo isométrica e na ativação muscular em idosos com doença de Parkinson (DP). A amostra final foi composta por 25 participantes de ambos os gêneros (n=8 – grupo controle (GC); n=8 – grupo de força (GF); n=9 – grupo de potência (GP). Os grupos GF e GP realizaram treinamento com pesos, durante oito semanas, com especificidade para desenvolvimento de força ou potência musculares, respectivamente. O grupo controle (GC), composto por idosos com DP, realizou apenas o protocolo de avaliação pré e pós oito semanas. Os participantes realizaram consecutivamente: a) avaliação da Curva força-Tempo isométrica e da atividade eletromiográfica; b) início do protocolo de treinamento para os GF e GP; c) re-avaliação ao término do protocolo de treinamento de força e de potência. Para a análise dos dados foi utilizada estatística descritiva (média e desvio-padrão) e ANOVA two-way para medidas repetidas em todas as variáveis com nível de significância de p<0,05. Os resultados apontaram interações significativas (p<0,05) em contração voluntária máxima (CVM), taxa de desenvolvimento de força (TDF) no intervalo de tempo de 0-50ms e ativação muscular (iEMG) do músculo vasto lateral. Não foram encontradas interações significativas (p>0,05) na TDF nos intervalos de tempo 0-100; 0-150 e 0-200ms, TDFpico, impulso contrátil e ativação muscular (iEMG) dos vastos lateral e medial, nos intervalos de tempo 0-50; 0-100; 0-150 e 0-200ms, como também, na ativação do músculo vasto medial no momento da contração voluntária máxima. Portanto, conclui-se que o treinamento com pesos (força e potência) é capaz de aumentar a contração voluntária máxima, contudo o protocolo de potência parece trazer maiores benefícios; a capacidade dos idosos com DP de gerar... / The purpose of this study was to analyze the effect of strength and power training on isometric force-time curve and muscular activation in elderly individuals with Parkinson’s disease (PD). The initial sample was composed by 25 participants of both gender (n=8 – control group (CG); n=8 – strength group (SG); n=9 – power group (PG). Both group, SG and PG, participated of resistance training for eight weeks with specificity for development of strength and muscular power, respectively. The CG, with Parkinson’s disease, participated only of evaluation protocol, before and after eight weeks. Participants performed consecutively: a) evaluation of isometric force-time curve and muscular activation; b) start the resistance training protocol for SG and PG; c) revaluation of isometric force-time curve and muscular activation. For the data analysis it was used the descriptive statistics (mean and standard deviation) and two-way ANOVA for repeated measurements of all variables. The level of significance adopted was p<0.05. The results pointed significant interactions (p<0.05) in maximum voluntary contraction (MVC), rate of force development (RFD) in time interval of 0–50 and integrated EMG of vastus lateralis (iEMG VL). No significant interactions (p>0.05) were found in rate of force development (RFD) in time intervals of 0–100; 150; and 200 ms, peak of rate of force development (RFD peak), contractile impulse (CI) and integrated EMG of vastus lateralis and vastus medialis in time intervals of 0–50, 100, 150, and 200 ms as well in integrated EMG of vastus medialis at the same moment of MVC. In conclusion, the resistance training (strength and power) it is capable to increase the MVC, however the power training protocol seems to be more beneficial; the PD seniors’ capacity to generate fast force (TDF) in the first ones 50ms increase after eight weeks of power training... (Complete abstract click electronic access below)