DYNAMIC MEASUREMENT OF FORCE WITHIN THE SHOE DURING CONDITIONS OF PERCEIVED EXERTION

INTRODUCTION Athletics and recreation are becoming a very large component of modem day society. Now, more than ever, more people are becoming very active and involved in recreational pursuits that include aerobics and running/jogging. The resultant increase in activity has lead to a noted increase in injuries (Nigg, 1985; Mckenzie et al., 1985). James et al (cited in Cavanagh, 1990), in a study of 180 injured runners identified three categories of running injury problem areas. These areas being: a) training errors; b)anatomic factors (biomechanics); and c) shoes and surfaces. Two thirds of these injuries were accounted for by training errors (increased mileage or increased intensity). Training errors concerning sudden increases in mileage or intensity tend to subject the body to new or greater than expected physiological stressors. Voloshin and Wosk (1981), have investigated the relationship between heel strike shock wave transmission and joint degeneration in walking subjects. Taken one step further, the implications of damage to the muscle-skeletal system by running is noted by Cavanagh (1990). This combined with the Nigg et al. (1983) data that suggests a relationship between the hardness of the athletic (running) surface and the incidence of injury has serious implications for the recreational runner/athlete. Clarke et al. (1985) have highlighted the possible injurious force involved in tibial accelerations that are the result of the runner taking longer strides. Since most people retain a constant stride frequency, as velocity increases, the athlete tends to increase their stride length. The resultant increase in stride length increases impact forces at the joint. This combined with the increase of ground reaction forces with higher running speeds (Munro et al., 1987) identifies high impact forces as a major factor to be considered when investigating the causal nature of running injuries. Research into the type of shoe and ground reaction forces has been equivocal. Nigg and Bahlsen (1988) have stated that shoes with the hardest mid soles elicit the lowest maximal vertical forces. Conversely other research has indicated that shoe hardness is related to higher (vertical) loading rates. Listed above are a number of factors involved in the prediction of running injuries. Further research is needed to discover the causative factors involved in etiology of sport medicine running injuries. An analysis of running shoes, in particular the vertical ground reaction forces, may account for dynamic patterns of gait. Running at different levels of perceived exertion may elicit clues as to the biomechanics patterns that may be injurious to runners. For example, the gait of a runner at the beginning of the run may be markedly different from the gait at the end of the run. Variables such as intensity and distance will greatly affect the athlete's form as they become more tired. Thus, the number of running injuries (2/3 of Clarke's population) as a result of improper training may be the function of bad form (gait mechanics). An analysis under different levels of exertion will identify patterns of pressure with the foot that may have implications for the construction and design of athletic footwear as well as training methods for runners. This study was an attempt to understand the dynamic of in-shoe vertical ground reaction forces within the shoe under differing levels of perceived exertion. Research in the area of running shoe forces may lead to the development of a better product that will decrease the rate and type of running injuries

Variable rate spraying in varied micro-meteorological conditions

This study evaluated effects of crosswind on the variable rate sprayer application treatments spray coverage and deposition on different citrus canopy sizes.  The axial-fan airblast sprayer retrofitted with variable liquid- and air-assist rates was field-tested with different crosswind conditions on small (about 2 m tall and < 1.5 m wide) and medium-sized (about 3 m tall and < 2.5 m wide) canopies.  Crosswinds of 1.3, 2.7, and 4.0 ms-1 on the canopies being sprayed were generated using the stationary conical air shaker as the air blower unit.  Water sensitive papers (WSPs) were used to collect droplet deposits and image processing software was used to analyze the WSPs scanned at 600 dpi.  Percent spray coverage on the WSPs was found to be one of the most suited parameters to evaluate the effectiveness of spray application treatments.  Overall, the variable rate spray application treatments had comparable spray coverage on respective canopies (front, middle, and across WSP locations in the canopy) during all crosswind conditions.  For both types of canopies, spray coverage was higher on the canopy front and decreased as the spray penetrated inside (i.e. canopy middle) and across.  Due to coalescing, larger droplets (Dv,0.5 [volume median diameter] = 838 to 2,624 µm) were formed on the WSPs located on canopy front, whereas coalescing reduced as the spray penetrated inside (Dv,0.5 = 391 to 1,625 µm on canopy middle) and across the canopy (Dv,0.5 = 307 to 508 µm).    Keywords: airblast sprayer, adjustable air-assistance, crosswind, spray coverage, citru

A Model To Measure Supination And Pronation Of The Foot Over Different Levels Of Physiological Stress Using An In-Shoe Force Monitoring System

The purpose of this study was to create a diagnostic model of supination and pronation of the foot using vertical ground reaction forces. A size adjustable capacitive transducer retaining 960 individual pressure cells was used to assess orthopaedic parameters of gait cyale timing and vertical ground reaction forces. A pilot sample of five males were used for this model. The subjects were exposed to six experimental conditions. These being; a) a walk, b) jog, c) walk on treadmill, and d) three levels of perceived exertion (mild, moderate and hard running). Perceived exertion was measured with the Borg (RPE) scale. All subjects were measured in the same brand of athletic shoe to control for intershoe differences. The ptonation/supination model was determined by medial/lateral force and timing measurements of the calcaneus, forefoot prominence, arch, the first and fifth metatarsal heads and the toe off (end of gait cycle). Results indicated bi-Iateral differences in the medial and lateral force measurements of the calcaneus. Timing in this area was slightly different. Medial to lateral timing pronation was evidenced in the treadmill walking and moderate running condition. As well, the loading of the first and fifth metatarsal heads as a percentage of the gait cycle did not change over the running conditions. The preliminary results of five subjects provides for limited support of a vertical ground reaction model to assess pronation and supination. Further research with techniques such as high speed photography will allow for clarification of this model

Obtenção de anticorpos policlonais contra proteínas presentes em plantas afetadas pela anomalia declínio dos citros Production of antibodies against proteins expressed in plants affected by citrus blight

O declínio dos citros, uma anomalia de etiologia desconhecida, continua sendo um dos entraves para o setor citrícola, uma vez que não existem medidas de prevenção e controle para as plantas acometidas pela anomalia. Para a caracterização e estudo da anomalia, muita ênfase tem sido dada à mudança na expressão gênica de plantas afetadas, que culmina no acúmulo de proteínas. Proteínas totais extraídas dos vasos do xilema de raízes de plantas afetadas pela anomalia, quando separadas por eletroforese no sistema SDS-PAGE 12,5%, apresentam um perfil eletroforético contendo proteínas com massas moleculares de cerca de 21, 23, 31 e 42 kDa, sendo que plantas consideradas sadias apresentam proteínas de 21, 31 e 42 kDa. Com este trabalho objetivou-se obter anticorpos contra essas proteínas, bem como a titulação adequada para os mesmos. Duas inoculações subcutâneas foram realizadas em coelhos, espaçadas de 15 dias, ambas usando cerca de 120 µg de proteína isolada, sendo que cada coelho recebeu uma proteína específica, visando à produção de anticorpos. A primeira sangria foi realizada aos 21 dias após a primeira inoculação e as demais semanalmente. A técnica Western Blotting foi realizada para a confirmação da especificidade dos anticorpos, bem como para determinação das respectivas titulações. O título 1:1500 foi aquele que proporcionou maior especificidade para as proteínas de 21, 23 e 31 kDa. Para a proteína de 42 kDa a melhor titulação foi de 1:3000. Estes anticorpos poderão ser utilizados em estudos para caracterização dessas proteínas.<br>Citrus blight, an abnormality of unknown etiology, is a major problem in citrus production, since there are no prevention and control measures to be taken. In order to characterize this abnormality, changes in genetic expression of the affected plants have exhaustedly been studied. Crude proteec extract obtained from the root xylem of the abnormal plants, when separated by SDS-PAGE 12,5%, display a profile with 21, 23, 31 and 42 kDa proteins. This work aimed the production of antibodies against those proteins, as well as their ideal dilution for use. Two subcutaneous inoculations were done in rabbits, within a 15-day interval, both with approximately 120mg of the isolated protein, with each rabbit receiving shots with a specific protein, for the production of the antibodies. A First bleeding was performed 21 days after the first inoculation and afterwards, weekly. Western blotting was carried out to confirm the presence of the antibodies and their respective dilutions. The 1:1500 dilution provided the best specificity for the 21, 23 and 31 kDa proteins, whereas for the 26 and 42 kDa proteins, the best dilution was at 1:3000