Respiratory muscle training (RMT) has been shown to improve exercise tolerance during a wide range of exercise modalities and durations of activity (McConnell & Romer, 2004b). However, there is a limited amount of research characterising the influence of RMT in specific athletic populations, or examining any sport-specific factors that may influence the benefits of RMT. Hence, the purpose of this dissertation was to evaluate the application of RMT in competitive rowers and to explore methods of optimising this to rowing. Results: Inspiratory muscle training (IMT) increased inspiratory muscle strength (~20-29%; p < 0.05) and attenuated inspiratory muscle fatigue (~8-28%; p < 0.05) during time trial performance in club-level and elite rowers. However, only in the club-level oarsmen was IMT associated with a measurable improvement in rowing performance (2.7% increase in mean power; p < 0.05). Expiratory muscle training (EMT) provided no ergogenic effect, and concurrent EMT and IMT did not enhance performance above that seen with IMT alone. IMT loads performed at 60-70% of maximal inspiratory mouth pressure (PImax) were equivalent to the widely used 30 repetition maximum, which is higher than reported for non-rowers (Caine & McConnell, 1998a); further, a load of 60% PImax was sufficient to activate the inspiratory muscle metaboreflex, as evidenced by a time-dependent rise in heart rate (70.1 ± 13.2 to 98.0 ± 22.8 bpm; p < 0.05) and mean arterial blood pressure (92.4 ± 8.5 to 99.7 ± 10.1 mmHg; p < 0.05). Higher and lower inspiratory loads did not activate the metaboreflex. Assessments of flow, pressure and volume in rowing relevant postures revealed no significant impairments, but optimal function occurred in the most upright postures. Conclusions: These data support the application of IMT, but not EMT, in elite and sub-elite rowers, and suggest that a load of 60-70% of PImax provides metaboreflex activation during loading. Further, the data do not support a requirement to undertake IMT in rowing relevant postures.

A qualitative analysis of a rotary traveling wave-type ultrasonic motor (USM) used to supply feedback forces in force-feel systems is carried out. Prior to simulation, the subsystems and contact mechanics needed to define the motor's equations of motion are discussed along with the pitfalls of modeling a USM. A mathematical model is assembled and simulated in MATLAB Simulink. Accompanying the dynamic model, a new reduced model is presented from which predictions of USM performance can be made without a complicated dynamic model. Outputs from the reduced model are compared with those of the dynamic model to show the differences in the transient solution, agreement in the steady state solution, and above all that it is an efficient tool for approximating a motor's steady state response as a function of varying the motor parameters. In addition, the reduced model provides the means of exploring the USMs response to additive loading, loads acting in the direction of motor motion, where only resistive loads, those opposite to the motor rotation, had been considered previously. Fundamental differences between force-feel systems comprising standard DC brushless motors as the feedback actuators and the proposed system using the USM are explained by referencing the USM contact mechanics. Outputs from USM model simulations are explored, and methods by which the motor can be implemented in the force-feel system are derived and proven through simulation. The results show that USMs, while capable of providing feedback forces in feel systems, are far from ideal for the task. The speed and position of the motor can be controlled through varying stator excitation parameters, but the transient motor output torque cannot; it is solely a function of the motor load, whether additive or resistive. / Master of Science

Introdução: Estudos têm mostrado a magnitude das cargas resistivas inspiratórias adicionadas externamente segue uma relação previsível com a percepção de dispneia, na qual a magnitude psicológica cresce conforme o aumento das cargas adicionadas. O efeito de medidas repetidas de percepção de dispneia utilizando o sistema de cargas resistivas não está claro na literatura. Objetivo: Estudar a repetibilidade da percepção da dispneia avaliada através de um sistema de carga resistiva inspiratória em indivíduos normais. Métodos: Estudo transversal, com coleta de dados prospectiva, realizado em indivíduos sadios com idade ≥ 18 anos. A percepção da dispneia foi avaliada através de um sistema de cargas resistivas inspiratórias, utilizando dispositivo que compreende uma válvula unidirecional (Hans-Rudolph) e um circuito de reinalação. A sensação de dispneia foi mensurada durante ventilação com o aumento na carga resistiva inspiratória (≅0, 6,7, 15, 25, 46,7, 67, 78 e ≅0 L/s/cmH2O) para um fluxo de 300 mL/s. Após respirar em cada nível de resistência por dois minutos, o indivíduo expressava sua sensação de falta de ar (dispneia) usando a escala de Borg modificada. Os indivíduos foram submetidos a dois testes (intervalos de 3 a 7 dias). Resultados: Foram incluídos no estudo 16 indivíduos sadios, sendo 8 homens e 8 mulheres, todos da raça branca. A média de idade foi 36,3 ± 11,9 anos. A média do índice de massa corporal foi de 23,9 ± 2,8 kg/m2. As medianas dos escores da Escala de Borg no primeiro teste foram 0, 2, 3, 4, 5, 7, 7 e 1 ponto, respectivamente para os momentos de aplicação de carga resistiva de ≅ 0, 6,7,15, 25, 46,7, 67, 78 e ≅ 0 L/s/cmH2O. As medianas dos escores no segundo teste foram, respectivamente, 0, 0, 2, 2, 3, 4, 4 e 0,5 pontos. A concordância pelo coeficiente de correlação intraclasse foi, respectivamente para cada momento, 0,57, 0,80, 0,74, 0,80, 0,83, 0,86, 0,91 e 0,92. Observou-se diferença estatisticamente significativa entre momentos de cargas resistiva (p < 0,001) e entre os testes (p = 0,003), através do modelo de análise linear generalizada. Os valores dos escores de dispneia entre os diferentes momentos foram significativamente menores no segundo teste. As pressões inspiratórias resistivas (p=0,59) e as frequências respiratórias (p=0,81) não foram diferentes entre os testes. Conclusão: A concordância entre os dois testes de percepção de dispneia foi apenas moderada e os escores de dispneia foram menores no segundo teste. Estes resultados sugerem um efeito de aprendizagem. A sensação de dispneia pode ser modificada por uma experiência prévia. O indivíduo poderia controlar melhor o sentido de aferência cortical e/ou aprender a ventilar no sistema com medidas repetidas. / Introduction: Studies have shown that the magnitude of externally added inspiratory resistive loads follows a predictable relationship with dyspnea perception, in which the psychological magnitude grows as a power of the added loads. The effect of repeated measures of dyspnea perception using resistive loading system is not clear in literature. Objective: To study the repeatability of the dyspnea perception using an inspiratory resistive loading system in normal subjects. Methods: Cross sectional study conducted in healthy individuals aged ≥ 18 years, with data collected prospectively. Dyspnea perception was assessed using an inspiratory resistive load system previously described that comprises a unidirectional valve (Hans-Rudolph) and a rebreathing circuit. The sensation of dyspnea was assessed during ventilation with increasing in inspiratory resistive loads (≅ 0, 6.7, 15, 25, 46.7, 67, 78 and ≅ 0 L/s/cmH2O), for a flow 300 ml/s, returning to the resistance of 0. After breathing in each level of resistance for two minutes, the subject expressed the feeling of shortness of breath (dyspnea) using the modified Borg scale. Subjects were tested twice (intervals from 3 to 7 days). Results: The study included 16 healthy individuals, 8 men and 8 women and all were white. The mean age was 36.3 ±11.9 years. The body mass index averaged 23.9±2.8 kg/m2. The median scores dyspnea perception in the first test were 0, 2, 3, 4, 5, 7, 7 and 1 point, respectively, during ventilation with resistive loads of ≅ 0, 6.7,15, 25, 46.7, 67, 78 and ≅ 0 L/s/cmH2O. The median scores in the second test were, respectively, 0, 0, 2, 2, 3, 4, 4 and 0.5 points. The agreement assessed by intraclass correlation coefficient was, respectively, for each resistive load, 0.57, 0.80, 0.74, 0.80, 0.83, 0.86, 0.91, and 0.92. In a generalized linear model analysis, there was a statistically significant difference between the moments of resistive loads (p<0.001) and between tests (p=0.003). Dyspnea scores were significantly lower in the second test. There were no difference for inspiratory pressures (p=0.59) and respiratory frequency (p=0.81) between two tests. Conclusion: The agreement between the two tests of dyspnea perception was only moderate and dyspnea scores were lower in the second test. These findings suggested an evidence for a learning effect. Dyspnea perception may be modified by previous experience. The subject could control better the sense of cortical afference and/or learn to ventilate in the system with repeated measures.

Introdução: Estudos têm mostrado a magnitude das cargas resistivas inspiratórias adicionadas externamente segue uma relação previsível com a percepção de dispneia, na qual a magnitude psicológica cresce conforme o aumento das cargas adicionadas. O efeito de medidas repetidas de percepção de dispneia utilizando o sistema de cargas resistivas não está claro na literatura. Objetivo: Estudar a repetibilidade da percepção da dispneia avaliada através de um sistema de carga resistiva inspiratória em indivíduos normais. Métodos: Estudo transversal, com coleta de dados prospectiva, realizado em indivíduos sadios com idade ≥ 18 anos. A percepção da dispneia foi avaliada através de um sistema de cargas resistivas inspiratórias, utilizando dispositivo que compreende uma válvula unidirecional (Hans-Rudolph) e um circuito de reinalação. A sensação de dispneia foi mensurada durante ventilação com o aumento na carga resistiva inspiratória (≅0, 6,7, 15, 25, 46,7, 67, 78 e ≅0 L/s/cmH2O) para um fluxo de 300 mL/s. Após respirar em cada nível de resistência por dois minutos, o indivíduo expressava sua sensação de falta de ar (dispneia) usando a escala de Borg modificada. Os indivíduos foram submetidos a dois testes (intervalos de 3 a 7 dias). Resultados: Foram incluídos no estudo 16 indivíduos sadios, sendo 8 homens e 8 mulheres, todos da raça branca. A média de idade foi 36,3 ± 11,9 anos. A média do índice de massa corporal foi de 23,9 ± 2,8 kg/m2. As medianas dos escores da Escala de Borg no primeiro teste foram 0, 2, 3, 4, 5, 7, 7 e 1 ponto, respectivamente para os momentos de aplicação de carga resistiva de ≅ 0, 6,7,15, 25, 46,7, 67, 78 e ≅ 0 L/s/cmH2O. As medianas dos escores no segundo teste foram, respectivamente, 0, 0, 2, 2, 3, 4, 4 e 0,5 pontos. A concordância pelo coeficiente de correlação intraclasse foi, respectivamente para cada momento, 0,57, 0,80, 0,74, 0,80, 0,83, 0,86, 0,91 e 0,92. Observou-se diferença estatisticamente significativa entre momentos de cargas resistiva (p < 0,001) e entre os testes (p = 0,003), através do modelo de análise linear generalizada. Os valores dos escores de dispneia entre os diferentes momentos foram significativamente menores no segundo teste. As pressões inspiratórias resistivas (p=0,59) e as frequências respiratórias (p=0,81) não foram diferentes entre os testes. Conclusão: A concordância entre os dois testes de percepção de dispneia foi apenas moderada e os escores de dispneia foram menores no segundo teste. Estes resultados sugerem um efeito de aprendizagem. A sensação de dispneia pode ser modificada por uma experiência prévia. O indivíduo poderia controlar melhor o sentido de aferência cortical e/ou aprender a ventilar no sistema com medidas repetidas. / Introduction: Studies have shown that the magnitude of externally added inspiratory resistive loads follows a predictable relationship with dyspnea perception, in which the psychological magnitude grows as a power of the added loads. The effect of repeated measures of dyspnea perception using resistive loading system is not clear in literature. Objective: To study the repeatability of the dyspnea perception using an inspiratory resistive loading system in normal subjects. Methods: Cross sectional study conducted in healthy individuals aged ≥ 18 years, with data collected prospectively. Dyspnea perception was assessed using an inspiratory resistive load system previously described that comprises a unidirectional valve (Hans-Rudolph) and a rebreathing circuit. The sensation of dyspnea was assessed during ventilation with increasing in inspiratory resistive loads (≅ 0, 6.7, 15, 25, 46.7, 67, 78 and ≅ 0 L/s/cmH2O), for a flow 300 ml/s, returning to the resistance of 0. After breathing in each level of resistance for two minutes, the subject expressed the feeling of shortness of breath (dyspnea) using the modified Borg scale. Subjects were tested twice (intervals from 3 to 7 days). Results: The study included 16 healthy individuals, 8 men and 8 women and all were white. The mean age was 36.3 ±11.9 years. The body mass index averaged 23.9±2.8 kg/m2. The median scores dyspnea perception in the first test were 0, 2, 3, 4, 5, 7, 7 and 1 point, respectively, during ventilation with resistive loads of ≅ 0, 6.7,15, 25, 46.7, 67, 78 and ≅ 0 L/s/cmH2O. The median scores in the second test were, respectively, 0, 0, 2, 2, 3, 4, 4 and 0.5 points. The agreement assessed by intraclass correlation coefficient was, respectively, for each resistive load, 0.57, 0.80, 0.74, 0.80, 0.83, 0.86, 0.91, and 0.92. In a generalized linear model analysis, there was a statistically significant difference between the moments of resistive loads (p<0.001) and between tests (p=0.003). Dyspnea scores were significantly lower in the second test. There were no difference for inspiratory pressures (p=0.59) and respiratory frequency (p=0.81) between two tests. Conclusion: The agreement between the two tests of dyspnea perception was only moderate and dyspnea scores were lower in the second test. These findings suggested an evidence for a learning effect. Dyspnea perception may be modified by previous experience. The subject could control better the sense of cortical afference and/or learn to ventilate in the system with repeated measures.

Introdução: Estudos têm mostrado a magnitude das cargas resistivas inspiratórias adicionadas externamente segue uma relação previsível com a percepção de dispneia, na qual a magnitude psicológica cresce conforme o aumento das cargas adicionadas. O efeito de medidas repetidas de percepção de dispneia utilizando o sistema de cargas resistivas não está claro na literatura. Objetivo: Estudar a repetibilidade da percepção da dispneia avaliada através de um sistema de carga resistiva inspiratória em indivíduos normais. Métodos: Estudo transversal, com coleta de dados prospectiva, realizado em indivíduos sadios com idade ≥ 18 anos. A percepção da dispneia foi avaliada através de um sistema de cargas resistivas inspiratórias, utilizando dispositivo que compreende uma válvula unidirecional (Hans-Rudolph) e um circuito de reinalação. A sensação de dispneia foi mensurada durante ventilação com o aumento na carga resistiva inspiratória (≅0, 6,7, 15, 25, 46,7, 67, 78 e ≅0 L/s/cmH2O) para um fluxo de 300 mL/s. Após respirar em cada nível de resistência por dois minutos, o indivíduo expressava sua sensação de falta de ar (dispneia) usando a escala de Borg modificada. Os indivíduos foram submetidos a dois testes (intervalos de 3 a 7 dias). Resultados: Foram incluídos no estudo 16 indivíduos sadios, sendo 8 homens e 8 mulheres, todos da raça branca. A média de idade foi 36,3 ± 11,9 anos. A média do índice de massa corporal foi de 23,9 ± 2,8 kg/m2. As medianas dos escores da Escala de Borg no primeiro teste foram 0, 2, 3, 4, 5, 7, 7 e 1 ponto, respectivamente para os momentos de aplicação de carga resistiva de ≅ 0, 6,7,15, 25, 46,7, 67, 78 e ≅ 0 L/s/cmH2O. As medianas dos escores no segundo teste foram, respectivamente, 0, 0, 2, 2, 3, 4, 4 e 0,5 pontos. A concordância pelo coeficiente de correlação intraclasse foi, respectivamente para cada momento, 0,57, 0,80, 0,74, 0,80, 0,83, 0,86, 0,91 e 0,92. Observou-se diferença estatisticamente significativa entre momentos de cargas resistiva (p < 0,001) e entre os testes (p = 0,003), através do modelo de análise linear generalizada. Os valores dos escores de dispneia entre os diferentes momentos foram significativamente menores no segundo teste. As pressões inspiratórias resistivas (p=0,59) e as frequências respiratórias (p=0,81) não foram diferentes entre os testes. Conclusão: A concordância entre os dois testes de percepção de dispneia foi apenas moderada e os escores de dispneia foram menores no segundo teste. Estes resultados sugerem um efeito de aprendizagem. A sensação de dispneia pode ser modificada por uma experiência prévia. O indivíduo poderia controlar melhor o sentido de aferência cortical e/ou aprender a ventilar no sistema com medidas repetidas. / Introduction: Studies have shown that the magnitude of externally added inspiratory resistive loads follows a predictable relationship with dyspnea perception, in which the psychological magnitude grows as a power of the added loads. The effect of repeated measures of dyspnea perception using resistive loading system is not clear in literature. Objective: To study the repeatability of the dyspnea perception using an inspiratory resistive loading system in normal subjects. Methods: Cross sectional study conducted in healthy individuals aged ≥ 18 years, with data collected prospectively. Dyspnea perception was assessed using an inspiratory resistive load system previously described that comprises a unidirectional valve (Hans-Rudolph) and a rebreathing circuit. The sensation of dyspnea was assessed during ventilation with increasing in inspiratory resistive loads (≅ 0, 6.7, 15, 25, 46.7, 67, 78 and ≅ 0 L/s/cmH2O), for a flow 300 ml/s, returning to the resistance of 0. After breathing in each level of resistance for two minutes, the subject expressed the feeling of shortness of breath (dyspnea) using the modified Borg scale. Subjects were tested twice (intervals from 3 to 7 days). Results: The study included 16 healthy individuals, 8 men and 8 women and all were white. The mean age was 36.3 ±11.9 years. The body mass index averaged 23.9±2.8 kg/m2. The median scores dyspnea perception in the first test were 0, 2, 3, 4, 5, 7, 7 and 1 point, respectively, during ventilation with resistive loads of ≅ 0, 6.7,15, 25, 46.7, 67, 78 and ≅ 0 L/s/cmH2O. The median scores in the second test were, respectively, 0, 0, 2, 2, 3, 4, 4 and 0.5 points. The agreement assessed by intraclass correlation coefficient was, respectively, for each resistive load, 0.57, 0.80, 0.74, 0.80, 0.83, 0.86, 0.91, and 0.92. In a generalized linear model analysis, there was a statistically significant difference between the moments of resistive loads (p<0.001) and between tests (p=0.003). Dyspnea scores were significantly lower in the second test. There were no difference for inspiratory pressures (p=0.59) and respiratory frequency (p=0.81) between two tests. Conclusion: The agreement between the two tests of dyspnea perception was only moderate and dyspnea scores were lower in the second test. These findings suggested an evidence for a learning effect. Dyspnea perception may be modified by previous experience. The subject could control better the sense of cortical afference and/or learn to ventilate in the system with repeated measures.

Le syndrome des apnées obstructives du sommeil (SAOS) est caractérisé par des épisodes répétitifs de collapsus des voies aériennes supérieures (VAS) durant le sommeil. Au cours du SAOS les propriétés mécaniques des voies aériennes supérieures sont altérées, dans le sens d'une réduction de leur capacité à laisser passer l'air, ce qui peut être assimilé à une "charge" inspiratoire. Les apnées obstructives ne se produisent jamais à l'éveil, suggérant qu'il existe, des mécanismes protecteurs d'origine corticale, de type " compensation de charge ", liés à l'éveil. Ce travail permis de caractériser ces mécanismes chez le sujet sain et le patient SAOS. Une première étude a décrit la relation pression/débit des VAS à l'éveil afin d'approcher le phénomène de compensation de charge, avant et après un traitement modulant le contrôle neurovégétatif des VAS par la compression du ganglion ptérygopalatin. La deuxième étude a mis en évidence à l'éveil chez les patients SAOS, une activité corticale motrice liée à la respiration (présence de potentiels électroencephalographiques - PPI), dont l'origine semble liée à la dysfonction des VAS, et qui est susceptible d'expliquer l'augmentation du niveau de contrôle respiratoire central connu dans le SAOS. La troisième étude a mis en évidence un phénomène de filtrage des sensations respiratoires à l'éveil chez des patients SAOS, avec restauration des ces sensations sous orthèse d'avancée mandibulaire, permettant de relier l'amélioration des propriétés mécaniques des VAS à l'intégration centrale des sensations respiratoires. Enfin la relation pression/débit a fait l'objet de deux modélisations. / The obstructive sleep apnoea syndrome (OSAS) involves recurrent sleep-related upper airways (UA) collapse. UA mechanical properties and neural control are altered imposing a mechanical load on inspiration. UA collapse does not occur during wakefulness, hence arousal-dependent compensation. Three studies in healthy and apnoeic patients allowed characterizing it. From upper-airway pressure-flow relationships, the first study described local compensation mechanisms, before and after a neurovegetative modulation based on ptérygopalatin node compression. The second study showed a respiratory-related cortical activity that could contribute to the increased neural drive to upper airway and to inspiratory muscles that has previously been described in OSAS, and could therefore contribute to the arousal-dependent compensation of upper airway abnormalities. The third study showed a sensory gating-out process of breathing sensations in OSAS that could be reversed by mandibular advancement device, allowing linking upper-airway stability improvement to central integration of respiratory sensations. Finally, upper-airway pressure-flow relationship was approached by two models.