title: Predicting responses to a heat acclimation protocol in trained triathletes

authors: Miller, Liam

abstract: Chapter One reviews the differences between performing in temperate and hot and humid environments. When compared to performance in temperate environments, heat-stressful environments acutely alter physiology heart rate, sweat rate, both core and skin temperature, plasma volume and local blood flow. Heat acclimation (HA) protocol introduced prior to competition in varying ways specific to the competition type has been shown to have large impacts on eventual performance, often summarised through heat response tests (HRT) or adaptations of thermoregulatory physiology. Individual responses to HA have been proven to vary between individuals with little evidence presented to explain why such variation occurs. In Chapter Two, 10 endurance-trained competitive triathletes (aged 33.6 ± 10.6 years, 8 males and 2 females; VO2 max 56.9 ± 11.1) completed a 14-day, cycling-based HA protocol (36 °C, 65% relative humidity). Participants completed two HRTs (Day 1 & Day 13), composed of 20 minutes at a steady state intensity immediately followed by a 30-kilometer time trial. Between these HRTs were seven HA sessions. Performance in the 30-kilometer time trial significantly increased as a result of the HA protocol (p = 0.037). Two regression models for predicting performance outcomes were generated using stepwise regression analysis. A ‘best overall fit’ model using baseline VO2, sweat loss, and sweat sodium composition explains 53% of the variability of performance improvement (R2 = 0.53), and a ‘best practical fit’ model using baseline VO2 and sweat loss explains 49% of the variability of performance improvement (R2 = 0.49). Both models are statistically significant (p = 0.017; p = 0.023). The ‘best practical fit’ model interprets that those with low baseline VO2 but greater sweat loss in the first HRT demonstrated the best performance improvement, whereas those with high baseline VO2 and low sweat loss do not see much performance improvement. Chapter Three investigates the validity of the Kenzen™ wearable core temperature sensor. Ten participants engaged in two HRTs each (20 minutes at a steady state intensity immediately followed by a 30-kilometer time trial) whilst wearing a Kenzen™ device and a rectally inserted thermometer. Bland-Altman plots were used in conjunction with a direct comparison of the differences of the measures to determine validity. The Kenzen™ device is accurate between the range of 37-38 °C, but once core temperature measured rectally reaches 38.5 °C, the validity of the Kenzen™ device comes into question (when rectal temperature ≥ 39 °C, mean difference = 0.79 °C). The difference in measurements suggests that the Kenzen™ is not valid once moderate hyperthermia is reached (38.5 °C). Chapter Four presents a summary of the previous chapters. There is evidence to suggest that predicting variation in HA success is possible, potentially even more so with some refinement of the model through additional thermoregulatory measurement or protocol modification. The validity of wearable core temperature technology does not currently appear suitable in high-performance athletic environments where athletes are expected to reach core temperatures defined as hyperthermic, as most wearable sensors do not seem valid compared to gold standard measures. It is likely that the technology will advance as the popularity of such wearables increases.

text: Predicting responses to a heat acclimation protocol in trained triathletes Chapter One reviews the differences between performing in temperate and hot and humid environments. When compared to performance in temperate environments, heat-stressful environments acutely alter physiology heart rate, sweat rate, both core and skin temperature, plasma volume and local blood flow. Heat acclimation (HA) protocol introduced prior to competition in varying ways specific to the competition type has been shown to have large impacts on eventual performance, often summarised through heat response tests (HRT) or adaptations of thermoregulatory physiology. Individual responses to HA have been proven to vary between individuals with little evidence presented to explain why such variation occurs. In Chapter Two, 10 endurance-trained competitive triathletes (aged 33.6 ± 10.6 years, 8 males and 2 females; VO2 max 56.9 ± 11.1) completed a 14-day, cycling-based HA protocol (36 °C, 65% relative humidity). Participants completed two HRTs (Day 1 & Day 13), composed of 20 minutes at a steady state intensity immediately followed by a 30-kilometer time trial. Between these HRTs were seven HA sessions. Performance in the 30-kilometer time trial significantly increased as a result of the HA protocol (p = 0.037). Two regression models for predicting performance outcomes were generated using stepwise regression analysis. A ‘best overall fit’ model using baseline VO2, sweat loss, and sweat sodium composition explains 53% of the variability of performance improvement (R2 = 0.53), and a ‘best practical fit’ model using baseline VO2 and sweat loss explains 49% of the variability of performance improvement (R2 = 0.49). Both models are statistically significant (p = 0.017; p = 0.023). The ‘best practical fit’ model interprets that those with low baseline VO2 but greater sweat loss in the first HRT demonstrated the best performance improvement, whereas those with high baseline VO2 and low sweat loss do not see much performance improvement. Chapter Three investigates the validity of the Kenzen™ wearable core temperature sensor. Ten participants engaged in two HRTs each (20 minutes at a steady state intensity immediately followed by a 30-kilometer time trial) whilst wearing a Kenzen™ device and a rectally inserted thermometer. Bland-Altman plots were used in conjunction with a direct comparison of the differences of the measures to determine validity. The Kenzen™ device is accurate between the range of 37-38 °C, but once core temperature measured rectally reaches 38.5 °C, the validity of the Kenzen™ device comes into question (when rectal temperature ≥ 39 °C, mean difference = 0.79 °C). The difference in measurements suggests that the Kenzen™ is not valid once moderate hyperthermia is reached (38.5 °C). Chapter Four presents a summary of the previous chapters. There is evidence to suggest that predicting variation in HA success is possible, potentially even more so with some refinement of the model through additional thermoregulatory measurement or protocol modification. The validity of wearable core temperature technology does not currently appear suitable in high-performance athletic environments where athletes are expected to reach core temperatures defined as hyperthermic, as most wearable sensors do not seem valid compared to gold standard measures. It is likely that the technology will advance as the popularity of such wearables increases.

year: 2023

title: Using micro-mechanical modelling to predict short-fibre composite properties in computer-aided design of sporting equipment

authors: Ewart, Paul

subjects: flexural modulus

abstract: Computer-aided design (CAD) of sporting equipment requires knowledge of the mechanical properties of proposed materials. The mechanical properties of composite materials are often not as simple to obtain as those of conventional materials, in which case micro-mechanical modelling could be used in conjunction with CAD software. A micro-mechanical model was used to predict the flexural modulus of composite materials, based on the assumption of partial interfacial adhesion between composite components. It was found that the partial adhesion model was both practical and consistently accurate. The partial adhesion model accounted for adhesion between components by considering an ‘effective shear value’ at the interface. The model was compared to experimental data for glass, wood and carbon-fibre reinforced polyethylene. It was shown that the adhesion coefficient ranged between 0.1 for carbon fibre, 0.5 for glass fibre and 0.8 for the wood fibre composites. It was shown that using micro-mechanical modelling to predict composite mechanical properties, as opposed to simulating the comprehensive composites structure, computer processing time and file size can be reduced with little compromise in simulation accuracy.

text: Using micro-mechanical modelling to predict short-fibre composite properties in computer-aided design of sporting equipment Computer-aided design (CAD) of sporting equipment requires knowledge of the mechanical properties of proposed materials. The mechanical properties of composite materials are often not as simple to obtain as those of conventional materials, in which case micro-mechanical modelling could be used in conjunction with CAD software. A micro-mechanical model was used to predict the flexural modulus of composite materials, based on the assumption of partial interfacial adhesion between composite components. It was found that the partial adhesion model was both practical and consistently accurate. The partial adhesion model accounted for adhesion between components by considering an ‘effective shear value’ at the interface. The model was compared to experimental data for glass, wood and carbon-fibre reinforced polyethylene. It was shown that the adhesion coefficient ranged between 0.1 for carbon fibre, 0.5 for glass fibre and 0.8 for the wood fibre composites. It was shown that using micro-mechanical modelling to predict composite mechanical properties, as opposed to simulating the comprehensive composites structure, computer processing time and file size can be reduced with little compromise in simulation accuracy.

year: 2010

title: Exploring Māori and non-Māori mental health nurses' perceptions of Te Whare Tapa Whā: A mixed methods study looking at Māori and non-Māori mental health nurses' perceptions of Te Whare Tapa Whā within the Waikato region

authors: Teinakore, Samantha

subjects: Te Whare Tapa Whā

abstract: Background: Te Whare Tapa Whā is a well-recognised Māori model of health and wellbeing which is embraced within the health system in Aotearoa/ New Zealand. Although it can be applied in different specialties, the impacts generated from this model were first noticed in mental health, as this model was created by Mason Durie who is a psychiatrist. Research has shown this model provided an opportunity for Māori to have a voice in their health.
Objective: This study aims were to explore mental health nurses’ perceptions of the Māori Health model, Te Whare Tapa Whā, and how their beliefs and values may impact them implementing this model into their care.
Methods: A mixed methods approach was utilised for this study. Phase one was about gathering quantitative data, collecting statistical data through surveys. The first phase helped with the formulate interview schedule, which was the beginning of the next phase. Phase two was semi structured interviews which helped with the gathering of qualitative data. Data were analysed using descriptive statistics and thematic analysis.
Participants: Mental health nurses within the Waikato region were the participants for this research study. A survey was distributed to mental health nurses in the Waikato area and 53 responded. After the survey, semi structured one on one interviews were conducted with the researcher. Total of 8 interviews; (n = 6) Māori mental health nurses and (n = 2) Non-Māori mental health nurses.
Results: The survey showed that more than half the nurses had a positive perspective on Te Whare Tapa Whā and felt it was good for nursing care. They were able to identify barriers to implementation. There were mixed responses on feeling supported to use Te Whare Tapa Whā in the workplace. Four over-arching themes were identified from the interviews . These were; Māori, clinical practice, organisation level and individual factors.
Conclusion: Overall, all mental health nurses had a positive perception of Te Whare Tapa Whā and the impacts it can have on nursing care. Most identified barriers which can impact whether they can actually use it in practice. Māori and non-Māori nurses had different depths of knowledge, cultural worldviews and clinical practice experiences, creating complexities with implementation. These beliefs, perceptions and experiences were highlighted in this study.

text: Exploring Māori and non-Māori mental health nurses' perceptions of Te Whare Tapa Whā: A mixed methods study looking at Māori and non-Māori mental health nurses' perceptions of Te Whare Tapa Whā within the Waikato region Background: Te Whare Tapa Whā is a well-recognised Māori model of health and wellbeing which is embraced within the health system in Aotearoa/ New Zealand. Although it can be applied in different specialties, the impacts generated from this model were first noticed in mental health, as this model was created by Mason Durie who is a psychiatrist. Research has shown this model provided an opportunity for Māori to have a voice in their health.
Objective: This study aims were to explore mental health nurses’ perceptions of the Māori Health model, Te Whare Tapa Whā, and how their beliefs and values may impact them implementing this model into their care.
Methods: A mixed methods approach was utilised for this study. Phase one was about gathering quantitative data, collecting statistical data through surveys. The first phase helped with the formulate interview schedule, which was the beginning of the next phase. Phase two was semi structured interviews which helped with the gathering of qualitative data. Data were analysed using descriptive statistics and thematic analysis.
Participants: Mental health nurses within the Waikato region were the participants for this research study. A survey was distributed to mental health nurses in the Waikato area and 53 responded. After the survey, semi structured one on one interviews were conducted with the researcher. Total of 8 interviews; (n = 6) Māori mental health nurses and (n = 2) Non-Māori mental health nurses.
Results: The survey showed that more than half the nurses had a positive perspective on Te Whare Tapa Whā and felt it was good for nursing care. They were able to identify barriers to implementation. There were mixed responses on feeling supported to use Te Whare Tapa Whā in the workplace. Four over-arching themes were identified from the interviews . These were; Māori, clinical practice, organisation level and individual factors.
Conclusion: Overall, all mental health nurses had a positive perception of Te Whare Tapa Whā and the impacts it can have on nursing care. Most identified barriers which can impact whether they can actually use it in practice. Māori and non-Māori nurses had different depths of knowledge, cultural worldviews and clinical practice experiences, creating complexities with implementation. These beliefs, perceptions and experiences were highlighted in this study.

year: 2023