Pilotos agrícolas atuam em condições de trabalho que podem acometê-los de doenças e contribuir para ocorrência de acidentes de trabalho. Nesse contexto, estudos têm direcionado seus esforços para compreender os efeitos de diversos fatores no desempenho do piloto, na saúde e/ou na segurança de voo. Exemplos típicos incluem, principalmente, a exposição aos defensivos agrícolas, seguido da exposição ao ruído ambiental e condições térmicas desfavoráveis, bem como a distribuição das responsabilidades entre os profissionais envolvidos. Outros problemas relacionados ao trabalho de pilotos agrícolas, como a operação em áreas improvisadas e o efeito dessa condição de trabalho na exposição às vibrações não é explorado. Além disso, observa-se que as queixas de dores na coluna são comuns entre os profissionais e, em função das condições de trabalho, é possível que estes tenham um risco aumentado de problemas na coluna vertebral. O objetivo dessa tese é de explorar a exposição dos pilotos agrícolas à Vibração de Corpo Inteiro (VCI) e identificar os efeitos desta na saúde, principalmente, no que diz respeito aos sintomas musculoesqueléticos da coluna vertebral. A metodologia compreendeu três etapas que incluem: uma pesquisa de campo orientada ao entendimento das condições de trabalho dos pilotos agrícolas, principalmente sobre os fatores capazes de influenciar na exposição ocupacional à VCI e na ocorrência de distúrbios musculoesqueléticos; a coleta e análise de dados sobre a exposição ocupacional dos pilotos agrícolas à VCI; e, a coleta e análise de dados sobre os sintomas musculoesqueléticos da coluna vertebral. Como resultados da pesquisa de campo, são apresentados dados sobre a rugosidade da superfície das áreas de pouso, perfil de exposição à VCI e prevalência de sintomas musculoesqueléticos em pilotos agrícolas. Os fatores significativos identificados como na exposição dos pilotos agrícolas à VCI foram o modelo de aeronave usada, as condições de rugosidade superficial das áreas de pouso, bem como as etapas do voo. Com relação à saúde da coluna vertebral dos pilotos, apenas a exposição ocupacional à VCI se apresentou como significativa. Dada a complexidade das relações de trabalho no contexto da aviação agrícola, com o envolvimento de diferentes tipos de trabalhadores, são incluídos três tipos de soluções para prevenir a ocorrência de distúrbios musculoesqueléticos em pilotos agrícolas: a manutenção frequente das áreas de pouso, de responsabilidade dos produtores rurais; a gestão do tempo de exposição diário, de responsabilidade dos gestores operacionais e de segurança operacional; e, alterações no projeto de aeronaves, seja na interface com o piloto, para atenuar a transmissibilidade das vibrações oriundas da aeronave, ou, nos sistemas de amortecimento, capazes de isolar a fonte das vibrações, impedindo sua propagação. / Agricultural pilots work in conditions that can affect them and contribute to the occurrence of work-related accidents. In this context, earlier studies have focused their efforts on the understanding of the effects of many factors on pilot performance, health and/or flight safety. Typical examples include exposure to pesticides, exposure to environmental noise and unfavorable thermal conditions, as well as the distribution of responsibilities among the professionals involved with the aerial application. Other problems related to the work of agricultural pilots, such as operation on improvised runways and the effect of this working condition on exposure to vibrations is not explored. In addition, it is noted that complaints of pain in the spine are common among professionals and, depending on working conditions, they may have an increased risk of spinal problems. The objective of this thesis is to explore the exposure of agricultural pilots to Whole-Body Vibrations (WBV) and to identify the effects of this on health, especially regarding to musculoskeletal symptoms of the spine. The methodology consisted of three stages: a field research aimed at understanding the working conditions of agricultural pilots, mainly on the factors capable of influencing the occupational exposure to WBV and the occurrence of musculoskeletal disorders; The data collection and analysis about occupational exposure of agricultural pilots to WBV; and, the data collection and analysis about musculoskeletal symptoms of the spine. As results of the field research, data are presented on surface roughness of landing fields, exposure to WBV and prevalence of musculoskeletal symptoms in agricultural pilots. The significant factors identified as in the exposure of the agricultural pilots to the WBV were the aircraft model used, the surface roughness conditions of the landing areas, as well as the flight stages. Regarding the health of the spine of the pilots, only the occupational exposure to the WBV was presented as significant. Given the complexity of labor relations in the context of agricultural aviation with the involvement of different types of workers, three types of solutions are included to prevent the occurrence of musculoskeletal disorders in agricultural pilots: frequent maintenance of landing areas, farmers; The management of the daily exposure time, the responsibility of the operational managers and operational safety; And changes in aircraft design, either at the interface with the pilot, to mitigate the transmissibility of vibrations from the aircraft, or, in damping systems, capable of isolating the source from vibrations, preventing their propagation.

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Abstract available in the Journal of Strength and Conditioning Research

Acute exposure to vibration has been suggested to produce transient increases in muscular strength (1,2,8), vertical jump displacement (4,8), and power output (2,6,7) recorded while performing various tasks. It has been hypothesized that the reported acute vibration induced increases in performance occur as a result of alterations in neuromuscular stimulation (1,3,4). Specifically, most studies have ascribed the observed improvements to the likeliness of Whole Body Vibration (WBV) in producing a “tonic vibration reflex” (TVR) in which the primary nerve endings of the Ia afferents of the muscle spindle are activated. This is thought to result in the excitation of the alpha-motor neurons and activation of the extrafusal fibers (4) which likely leads to a greater synchronization of motor units as a result of homonymous motor unit contraction. However, not all investigations report improvements in muscular strength (4), vertical jump (7), and power production in response to acute vibration (4). While the current body of scientific knowledge offers conflicting evidence on the effectiveness of WBV in augmenting neuromuscular performance it is possible that WBV may result in alterations to specific aspects of the force-time curve during the performance of a maximal isometric contraction. Therefore, the primary purpose of this investigation was to examine the effects of WBV performed using 30 Hz frequency and 2-4 mm amplitude on the force-time curves of an isometric mid-thigh pull.

This study quantifies whole-body vibration on a range of mine machinery typically used in a South African open cast mine. The ISO 2631-1 (1997) standard was used in the computation of weighted root mean square (WRMS) and vibration dose values (VDVs) whereas the ISO 2631-5 (2004) standard was used in the computation of daily static compressive stress (Sed) and R factor values. Two methods have been used to evaluate the whole-body vibration on a wide range of equipment used in an open cast mine. There are two main parameters for each of the standards. The ISO 2631-1 (1997) standard utilises the daily exposure A(8) and VDV, whereas the new ISO 2631-5 (2004) standard methodology uses the parameters Sed and R factor. ISO 2631-1 (1997) is poor in taking account of transient shocks. This led to the development of ISO 2631-5 (2004). Signals were therefore generated in the laboratory to further explore the parameters of the two standards. Vibration signals of more-or-less steady periodic processes can be approximated by superposition of sinusoids. To investigate the effect of shocks on the WBV response parameters used in the two standards, a series of investigations were conducted using very simplified simulations to capture the essential nature of various operational conditions, and qualitatively explain the trends in the response parameters. Pure sinusoidal data was first generated without shocks and investigated. Subsequently, sinusoidal signals with higher amplitudes were generated and investigated. Sinusoidal signals with increasing shock amplitude up to and exceeding the crest factor of 9 based on ISO 2631-1 (1997) were generated and analyzed. Finally, simulated data with different shock magnitude for five typical example cases were then generated and analyzed. The pure sinusoidal data was artificially generated using the signal generator at different amplitudes and frequencies, which are similar to field observed frequencies to enable numerical investigation of parameters to be carried out. A subset of the data was selected based on frequencies and amplitudes obtained on the field so as to have a representative data set on which investigations were carried out. The two parameters of the two standard methodologies were computed using simulated sinusoidal signal data. The trends in each of the parameters corresponding to each of the standards were monitored using various scenarios obtained by varying the signal parameters and compared against each other. There was approximate proportional correlation between the two parameters (VDV and Sed) with varying degrees of slope for each scenario. The Sed and VDV parameters are plotted on the x- and y-axes respectively. The graphs with slope greater than 1 corresponded to signals with low or no shock content; whereas the graphs with slope less than 1 corresponded to high shock content. The shock parameters (VDV and Sed) corresponding to the ISO 2631-1 (1997)and ISO 2631-5 (2004) standard methodologies were computed from field data and compared to see if the same trend obtained from the numerically obtained sinusoidal signals could be validated. It was found that the there was a gradual band correlation with slope less than 1 between the VDV and Sed parameters corresponding to signals of high shock content thereby validating the numerical findings. Since little or no extensive epidemiological studies have been carried out on the new methodology; it is recommended that more epidemiological studies be done to determine the exposure action and exposure limit values with respect to shocks in the Sed parameter for the new ISO 2631-5 (2004) standard methodology. It is advisable that caution is taking when using the new ISO 2631-5 (2004) standard methodology in evaluating whole-body vibration measurements until the limits are properly established. It is suggested that the new standard be used along with the established ISO 2631-1 (1997) standard methodology. Copyright / Dissertation (MSc)--University of Pretoria, 2009. / Mechanical and Aeronautical Engineering / Unrestricted

Decompression sickness (DCS) is a risk associated with high-altitude aviation and diving. During these activities, decompression may lead to supersaturation of inert gas dissolved in bodily tissues and subsequently activate bubble formation in various bodily tissues, including in venous blood, known as venous gas emboli (VGE). It has been shown that the amount of VGE detected during and after decompression is linked to the risk of developing DCS. Thus, lowering the incidence of VGE would lower the risk of developing DCS. Previous studies have demonstrated that a session of whole-body vibration prior to a diving session is effective in lowering VGE formation. However, no study has investigated the effect of whole-body vibration on high-altitude-induced VGE. For the present study, 3 participants were recruited. The subjects performed on separate days (interspaced by 48 h) and in a randomised manner, three different preconditioning strategies: (A) 40-min seated rest, (B) 30-min seated rest followed by 150 knee squats performed over a 10 min period and (C) 30-min whole-body vibration (40 Hz) proceeded by a 10 min seated rest. Thereafter, subjects were exposed to an altitude of 24,000 ft continuously for 90 min, whilst laying in a supine position and breathing a normoxic gas mixture (PIO2 = 21 kPa). Heart rate (HR), cardiac output (CO) and stroke volume (SV) were monitored throughout the high-altitude exposure. Every 5 min, VGE prevalence was assessed ultrasonically and graded according to the Eftedal-Brubakk 5-point scale. In addition, every 15 min, subjects were asked to perform three fast, unloaded knee-bends while in their left-side horizontal recumbent position, with VGE prevalence being estimated both before and after the three knee-bends. The control strategy was associated with a higher VGE scores (2.7 ± 1.2) compared to vibration (1.0 ± 1.0) and squats (1.3 ± 0.6) strategies. VGE appeared earlier during the control strategy (35 ± 23 min) compared to the vibration (65 ± 31 min) and squats (50 ± 17 min) strategies. A strong negative correlation was only observed in the control strategy between VGE and CO (r = -0.63) and SV (r = -0.64). This study demonstrated that whole-body vibration is the most effective preconditioning strategy in lowering the amount of high-altitude-induced VGE compared with 40-min of seated-rest and 150 knee squats performed over a period of 10 min. / Att drabbas av dekompressionssjuka (DKS) utgör en risk vid såväl höghöjdsflygning som dykning. I samband med dessa aktiviteter, kan dekompression leda till övermättnad av inert-gas löst i kroppens vävnader, vilket i sin tur kan leda till bubbelformation i olika vävnader, inklusive i venblodet, där bubblorna benämns venösa gasembolier (VGE). Det har visats föreligga ett samband mellan mängden VGE som uppmäts under och efter dekompression och risken att utveckla DKS. Således kan det antas att en minskad incidens av VGE är förknippad med minskad risk att utveckla DKS. Tidigare undersökningar har påvisat att en period med helkroppsvibration före dykning påtagligt minskar bildningen av VGE. Hittills har man dock inte undersökt om helkroppsvibration påverkar höghöjdsinducerade VGE. I föreliggande undersökning, medverkade tre försökspersoner. De exponerades vid separata tillfällen (med 48 timmars mellanrum), och i olika ordningsföljd, för tre prekonditioneringsstrategier: (A) 40 min sittande vila, (B) 30 min sittande vila följt av 150 djupa knäböjningar som genomfördes under en 10-minutersperiod och (C) 10 min sittande vila följt av 30 min helkroppsvibration (40 Hz). Därefter exponerades försökspersonerna för en simulerad höjd motsvarande 24,000 fot ö.h. kontinuerligt under 90 min, under det att de i liggande ryggläge andades en normoxisk gasblandning (inspiratoriskt syrepartialtryck = 21 kPa). Hjärtfrekvens (HF), hjärtminutvolym (HMV) och hjärtats slagvolym (SV) mättes kontinuerligt under höghöjdsexponeringen. Var femte min bedömdes prevalensen av VGE med hjälp av ultraljudsteknik och en 5-gradig skattningsskala. Var femtonde min genomförde försökspersonerna 3 obelastade knäböjningar, liggande i vänster sidoläge, varvid VGE-prevalensen bedömdes såväl före som efter knäböjningarna. Kontrollbetingelsen (A) framkallade högre VGE-nivå (2,7 ± 1,2) än vibrationsbetingelsen (B; 1 ± 1) och knäböjbetingelsen (C; 1,3 ± 0,6). VGE uppträdde tidigare under kontrollbetingelsen (35 ± 23 min) än i vibrations- (65 ± 31 min) och knäböj-betingelserna (50 ± 17 min). Starka negativa samband påvisades mellan VGE och CO (r = -0,63) respektive SV (r = -0,64). Således visade föreliggande undersökning att helkroppsvibration.

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Orientador: Luis Carlos Paschoarelli / Resumo: Dos dispositivos de auxílio à mobilidade, a cadeira de rodas é o mais utilizado, proporcionando ao usuário, além do deslocamento, melhora na qualidade de vida, na saúde, no bem-estar social e econômico. É um equipamento comumente utilizado por tempo prolongado, estando sujeito à ocorrência de vibração e consequente transmissão da Vibração de Corpo Inteiro (VCI) ao usuário por meio das superfícies de contato, como os apoios para braços, pés, cabeça, encosto e assento. A VCI pode causar danos à saúde do usuário de cadeira de rodas se os seus níveis ultrapassarem os limites seguros. Desta forma, o objetivo principal deste trabalho foi verificar a influência das almofadas nos níveis de vibração transmitidos aos usuários de cadeira de rodas, tendo como principal foco de estudo a análise de diferentes tipos de almofadas e a vibração transmitida ao longo do eixo z, o mais afetado em posições sentadas. Também foram avaliadas as almofadas implementadas com uma superfície plana de madeira compensada. Trata-se de uma pesquisa quantitativa, aplicada, exploratória, experimental e transversal realizada com vinte e sete voluntários do gênero masculino, não usuários de cadeira de rodas. Os resultados mostram que a cadeira de rodas sem almofada transmite o menor nível de vibração [WAz=0,39m/s2]. As almofadas comerciais obtiveram valores de VCI entre WAz=0,45m/s2 e WAz=0,52m/s2. Os assentos implementados com uma superfície de madeira compensada apresentaram níveis de VCI de WAz=0,41m/s2 a WAz=... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Of the wheelchair mobility aids is the most used, providing the user, beides the displacement, improvement in the quaçity of life, health, social and economic well-being. It is a commonly used equipment for a long time, being subject to the occurrence of vibration and consequent transmission of Whole Body Vibration (WBV) to the user through contact surfaces, such as armrests, feet, headrest, backrest and seat. WBV can cause damage to the health of a wheelchair user if their levels exceed safe limits. In this way, the main objective of this work was to verify the influence of the cushions on the vibration levels transmitted to the wheelchair users, having as main focus the analysis of different types of cushions and the vibration transmitted along the z axis, the most affected in segred positions. Also evaluated were the pillows implemented with a flat plywood surface. It is a quantitative, applied, exploratory, experimental and cross-sectional study carried out with twenty-seve male volunteers, not wheelchair users. The results show that the wheelchair without cushion transmits the lowest level of vibration {WAz=0.39m/s2]. The commercial cushions obtained WBV values between WAz=0.45m/22 and WAz=0.52m/s2. The seats implemented with a plywood surface showed WBV levels of WAz=0.41m/s2 at WAz=0.44m/s2. It was concluded that the commercial cushions amplify the vibration when compared to the wheelchair without cushions, and the WBV levels measured in the research are relevant, ofte... (Complete abstract click electronic access below) / Doutor