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Biomedical subjects

S Legg

Publications and source records attributed to S Legg.

15 recordsLinked to original sources
PubMed1999

The physical demands of Olympic yacht racing.

The primary purpose of this study was to quantify the up wards forces of the feet on the hiking strap and the forces in the mainsheet of four Olympic classes of racing dinghies (Europe, Laser. Finn and 470) during realistic on-water sailing in varying wind conditions. The secondary aim of the study was to measure the joint angles adopted by the sailors and boat heel angles. The tertiary aim was to identify events and sailing conditions associated with large or patterned force production. Forces in the hiking strap and mainsheet of four classes of Olympic sailing dinghies were measured on eleven New Zealand sailors during simulated on-water racing in a range of wind conditions. Up-wind hiking strap forces reached an average of 73-87% of predicted maximal voluntary contraction (pred MVC), with peak forces exceeding 100% pred MVC. Mainsheet forces reached 25-35% pred MVC, with peak forces reaching 40-50% pred MVC. Off-wind hiking strap and mainsheet forces were considerably lower than up-wind forces. Ankle and hip joint angles increased and knee joint angles decreased with increasing wind speed during up-wind sailing. Large forces occurred in the hiking strap and mainsheet when boats reached the tops of wave during up-wind sailing in high wind speeds and when a gust of wind hit the boat. During off-wind sailing large forces were observed in the mainsheet when surfing down waves. It is recommended that the intensities and joint angles found in this study be used as a basis for the development of class specific off-water physical conditioning programmes.

Biomechanical Phenomena↗
PubMed1999

Temporal patterns of physical activity in Olympic dinghy racing.

BACKGROUND: The objective of the present study was to determine the temporal patterns of physical activity in four classes of Olympic racing dinghy. METHODS EXPERIMENTAL DESIGN: Descriptive. SETTING: A field (on-water) study. PARTICIPANTS: Nineteen elite New Zealand sailors (fifteen male and four female). INTERVENTION: Not applicable. MEASURES: The temporal pattern (duration and frequency) and nature of the physical activities of each sailor during each leg of simulated races were recorded on video tape and subsequently systematically quantified and categorised using notational analysis. The accumulated percentage of total leg time spent sitting (upright or leaning backwards), hiking (upright or fully extended) whilst trimming and whilst pumping the mainsheet and for the time spent on rig adjustments, tacking and gybing were calculated for both up-wind and off-wind sailing. RESULTS: When sailing up-wind, the most time was spent hiking upright (average 29-66% of total leg time) while trimming the mainsheet. During off-wind sailing, sailors spent the most time sitting upright while trimming the mainsheet (average 29-55% total leg time). Hiking upright while trimming the mainsheet was executed the greatest number of times (average 15.8-23.9) when sailing up-wind and sitting upright while trimming was executed the most times (average 3.5-7.4) when sailing off-wind. The most lengthy continuous activity was hiking upright while trimming the mainsheet when sailing up-wind (9-18 seconds) and sitting upright while trimming the mainsheet when sailing off-wind (17-34 seconds). CONCLUSIONS: The most physically demanding aspect of Olympic yacht racing is hiking. It occurs for the majority of up-wind legs when the wind starts to exceed approximately 8 knots. The only respite that the sailor gets from hiking is during tacking, rig adjustments or sitting in-board for brief periods when the wind is low. Sustained hiking tends to last for no more than approximately 20 seconds before the sailor changes to either a more extended or more upright hiking posture. The physical demands during off-wind sailing are generally less, except for a greater requirement for power in the arms and shoulders to pump the mainsheet in order to assist the dinghy in accelerating down waves. The findings of the present study are directly applicable to the design of sailing specific physical conditioning programmes for Olympic class sailors.

Female↗
PubMed1998

Sharing in nursing governance: creating opportunities for change.

Shared governance has created a radical shift in the management and systems thinking of organisations by empowering employees through increased accountability, ownership and decision making. This paper outlines the process of introducing the concept of shared governance to the nursing division of a large not-for-profit private hospital in Victoria. The objectives for change and the philosophy of shared governance are explained so as to clarify the reasons for selection of the shared governance model. The steps involved in planning for the introduction of the change process, implementation and integration of the model at both organisational departmental levels, and the actual structure of the working model of shared governance are described.

Decision Making, Organizational↗
PubMed1995

Effects of mild hypoxia on perceptual-motor performance: a signal-detection approach.

Twelve healthy male subjects were required to make speeded judgements concerning the orientation of visual stimuli while breathing air at reduced partial pressure in a hypobaric chamber at altitudes of 7000 and 12,000 ft. A control condition was also conducted at sea level, and subjects received practice on the task at sea level prior to the commencement of the experiment. Significantly slower response times were obtained at 7000 and 12,000 ft relative to sea level. A signal-detection analysis showed that accuracy of judgement was significantly poorer at 12,000 ft, but oxygen deprivation has no systematic effect on response criterion.

Adult↗
PubMed1995

Effects of exposure to simulated altitudes on visual fields, contrast sensitivity, and dazzle recovery.

Previous studies have shown that visual performance may be impaired at altitudes above 12,000 ft when supplementary oxygen is not used. What is not known is whether there may be subtle changes in visual function at altitudes to which airline cabins are usually pressurized. In this study, we measured spatial and temporal contrast sensitivity, central visual field thresholds, and macular photostress recovery time in 12 male subjects at sea level and at simulated altitudes of 7000 ft and 12,000 ft. Our results showed insignificant changes in spatial and temporal contrast sensitivity, central visual field thresholds and dazzle recovery time with respect to simulated altitudes.

Adult↗
PubMed1990

Memory factors in age-related differences in simple reasoning.

Adults in their 50s were compared with adults in their late teens or 20s in the accuracy of relatively simple reasoning decisions involving varying amounts of information. Because the magnitude of the age differences in decision accuracy was independent of the amount of information relevant to the decision, it was suggested that adults in their 20s and 50s do not differ in the effectiveness of integrating information across multiple premises. However, the 2 groups differed in the accuracy of trials involving only a single relevant premise, and thus it was inferred that 1 factor contributing to reasoning differences within the age range from 20 to 60 may be a failure to encode, or retain, relevant information.

Adult↗
PubMed1987

Fine needle aspiration cytology in breast disease management--a 4 year experience.

At the Queen Victoria Medical Centre between 1981 and 1984, 2920 fine needle aspirates of the breast were examined with an overall diagnostic accuracy of 97% and a sensitivity of 80%. This high diagnostic accuracy combined with the ease and complication-free nature of the procedure has meant that fine needle aspiration (FNA) has become an important part of the investigation and management of breast disease within the breast service of the Queen Victoria Medical Centre.

Australia↗
PubMedDate not supplied

Planning nursing resources.

In the UK the health service is undergoing radical changes to become more responsive to local needs, consumer feedback and modern medical technology. To keep up with this constantly changing health care environment, nurse resource planning must be flexible and responsive. Below, an outline of some of the information, tools and skills required to formulate nursing resource plans.

Education, Nursing↗