title: Biomechanics and subjective measures of recreational male runners in three shoes running outdoors: A randomised crossover study

authors: Hébert-Losier, Kim

subjects: comfort

abstract: We compared biomechanical and subjective data from outdoor running in: habitual (OWN), Saucony Endorphin Racer 2 minimal (FLAT) and Nike Vaporfly 4% (VP4) shoes. We also explored relationships between comfort measures and the collected data. Eighteen male recreational runners ran three 1.5-km trials outdoors, once per shoe. The first 1.1 km was run at a self-selected comfortable (slower) speed, and last 400 m at perceived 5-km race pace (faster). A GPS-enabled smartwatch, 15-m Optojump system, high-speed camera and tibial accelerometer collected biomechanical data. Subjective data on comfort, shoe properties and overall running experience were collected using visual analogue scales (VAS) and rankings. Cadence, leg stiffness and vertical stiffness were greater in FLAT than both OWN and VP4 at the slower speed (trivial to small ES). At both speeds, footstrike angles were smaller in FLAT (small to large ES), while propulsion phase was shorter in VP4 (moderate to large ES). FLAT was ranked as the least comfortable at the slower speed and most likely to cause injury, whereas OWN as the most comfortable and least likely to cause injury. Comfort was not significantly different at the faster speed between shoes. Comfort measures were more strongly correlated to subjective than biomechanical data. The two experimental shoes generally had non-significant or small effects on running biomechanics versus OWN. As VP4 are more like traditional than minimal shoes, these were perceived as more comfortable. Running speed appeared to affect subjective measures. Speed should be considered when prescribing and selecting shoes.

text: Biomechanics and subjective measures of recreational male runners in three shoes running outdoors: A randomised crossover study We compared biomechanical and subjective data from outdoor running in: habitual (OWN), Saucony Endorphin Racer 2 minimal (FLAT) and Nike Vaporfly 4% (VP4) shoes. We also explored relationships between comfort measures and the collected data. Eighteen male recreational runners ran three 1.5-km trials outdoors, once per shoe. The first 1.1 km was run at a self-selected comfortable (slower) speed, and last 400 m at perceived 5-km race pace (faster). A GPS-enabled smartwatch, 15-m Optojump system, high-speed camera and tibial accelerometer collected biomechanical data. Subjective data on comfort, shoe properties and overall running experience were collected using visual analogue scales (VAS) and rankings. Cadence, leg stiffness and vertical stiffness were greater in FLAT than both OWN and VP4 at the slower speed (trivial to small ES). At both speeds, footstrike angles were smaller in FLAT (small to large ES), while propulsion phase was shorter in VP4 (moderate to large ES). FLAT was ranked as the least comfortable at the slower speed and most likely to cause injury, whereas OWN as the most comfortable and least likely to cause injury. Comfort was not significantly different at the faster speed between shoes. Comfort measures were more strongly correlated to subjective than biomechanical data. The two experimental shoes generally had non-significant or small effects on running biomechanics versus OWN. As VP4 are more like traditional than minimal shoes, these were perceived as more comfortable. Running speed appeared to affect subjective measures. Speed should be considered when prescribing and selecting shoes.

year: 2023

title: Redox cycling of colloidal macro- and micro-nutrients in a monomictic lake

authors: Saeed, Huma

subjects: Anoxia

abstract: Lakes are more than just water bodies as they play an essential role in the cycling of nutrients and carbon, with impacts at the local and global scale. This study selected Lake Ngapouri, a small monomictic lake in the Waikiti Valley, Taupo Volcanic Zone, New Zealand, which receives a considerable amount of nutrients and organic carbon input from the surrounding pastures. The study was designed to investigate the cycling of nutrients and dissolved organic carbon in lake Ngapouri, with a focus on processes occurring at the colloidal size level under varying thermal and redox conditions. 
To achieve the objectives of the study, a year-long sampling campaign was designed involving field and laboratory measurements of the lake's water column. The lake's physicochemical characteristics were determined via high-resolution depth profiles and paried  with a detailed set of depth-resolved geochemical measurements. Analysis for reduced Fe (II) was used to control for oxidative loss during transportation and storage of samples, and generally demonstrated very good protocols and minimal sample alteration. 
This work comprises a comparison of components in colloidal and dissolved size ranges, determined by ultrafiltration under a zero grade N2 atmosphere, and in situ measurements by diffusive gradients in thin films (DGT). Colloids from the lake were additionally analyzed using transmission electron microscopy (TEM), atomic force microscopy (AFM), fluorescence spectroscopy, and a suite of complementary methods. 
Results show considerable changes in the physicochemical properties of the lake over the hydrological year. Isothermal conditions prevailed through the water column during austral autumn and winter, with thermal stratification becoming established as the summer progressed. Dissolved oxygen concentration followed the thermal pattern, and thus vertically divided the water column into three distinct zones during summer. These zones are referred to as 1) Epilimnion (0-5m measuring from the surface) with uniform thermal and dissolved oxygen concentration, 2) transition zone with varying temperature and dissolved oxygen concentration referred to as metalimnion (6-13m), and 3) hypolimnion (15-20m) marked with cold water and reduced oxygen concentration in comparison to the upper two compartments. The pH of the water column stayed circumneutral during this study. The implications of the lake's variation in thermal and redox status on the cycling of macro and micronutrients are discussed in data chapters.  
The third chapter of this thesis addresses the role of suspended iron hydroxides in phosphorus cycling. The spatial and temporal distribution of iron and phosphorus was clearly coupled and was strongly influenced by sediment releases of both elements in anaerobic bed sediments. Both iron and phosphorus were predominantly colloidal and displayed an increasing degree of lability (to DGT) as hypolimnetic anoxia deepened. The implications of this finding are that iron-based colloids can mediate phosphorus cycling even under anaerobic conditions, and might therefore influence iron and phosphorus bioavailability within the water column. 
The fourth chapter of this thesis explores the evolution, seasonal production, and consumption of dissolved organic matter (DOM) in the water column of Lake Ngapouri. Both the quality and quantity of DOM influence the turnover of DOM in the lake system, and this influence was explored using the constituent molecules' fluorescent properties. The resulting excitation-emission matrices (EEM's) were analyzed using parallel factor analysis (PARAFAC), identifying two humic-like fluorophores and one protein-like fluorophore in both colloidal and dissolved size fractions. DOM in the lake showed marked seasonality with greater production and turnover during the summer season. This study shows that the concentration of humic-like DOM was ~3.5 times lower and less variable than protein-like DOM. The proteinaceous material in the low molecular weight fraction cycled actively in the anaerobic hypolimnetic water during summer, consistent with the contemporaneous dissimilatory reduction of manganese, iron, and sulphur. 
Chapter 5 of this thesis examines the spatial and temporal distribution of trace elements (iron (Fe), manganese (Mn), zinc (Zn), copper(Cu), chromium (Cr), cobalt (Co), nickel (Ni), and cadmium (Cd)) in Lake Ngapouri, and the degree to which binding to colloidal surfaces and DOM influence trace element bioavailability. DGT-lability was thus used as a proxy the available metal for biological uptake. In general, the DGT-labile fraction was much lower than a total load of respective trace metal, indicating the significance of adsorption, precipitation, and complexation reactions for trace metal availability for biological uptake. Broadly, the study groups trace metals into two distinct categories: strongly redox cycled, and controlled by organic complexation. This work shows that colloidal association is often, but not always a predictor of lower bioavailability with important implications for our understanding of metal micronutrients in aquatic systems. 
The contributions from this study are significant for studies of the bioavailability of macro and micronutrients which exhibit strong adsorption behavior. The redox state of lakes affects the formation, complexation character, and stability of various mineral colloids. Colloids clearly should be considered as an important intermediary phase with the potential to affect nutrient availability and with implications for lake restoration and management initiatives.

text: Redox cycling of colloidal macro- and micro-nutrients in a monomictic lake Lakes are more than just water bodies as they play an essential role in the cycling of nutrients and carbon, with impacts at the local and global scale. This study selected Lake Ngapouri, a small monomictic lake in the Waikiti Valley, Taupo Volcanic Zone, New Zealand, which receives a considerable amount of nutrients and organic carbon input from the surrounding pastures. The study was designed to investigate the cycling of nutrients and dissolved organic carbon in lake Ngapouri, with a focus on processes occurring at the colloidal size level under varying thermal and redox conditions. 
To achieve the objectives of the study, a year-long sampling campaign was designed involving field and laboratory measurements of the lake's water column. The lake's physicochemical characteristics were determined via high-resolution depth profiles and paried  with a detailed set of depth-resolved geochemical measurements. Analysis for reduced Fe (II) was used to control for oxidative loss during transportation and storage of samples, and generally demonstrated very good protocols and minimal sample alteration. 
This work comprises a comparison of components in colloidal and dissolved size ranges, determined by ultrafiltration under a zero grade N2 atmosphere, and in situ measurements by diffusive gradients in thin films (DGT). Colloids from the lake were additionally analyzed using transmission electron microscopy (TEM), atomic force microscopy (AFM), fluorescence spectroscopy, and a suite of complementary methods. 
Results show considerable changes in the physicochemical properties of the lake over the hydrological year. Isothermal conditions prevailed through the water column during austral autumn and winter, with thermal stratification becoming established as the summer progressed. Dissolved oxygen concentration followed the thermal pattern, and thus vertically divided the water column into three distinct zones during summer. These zones are referred to as 1) Epilimnion (0-5m measuring from the surface) with uniform thermal and dissolved oxygen concentration, 2) transition zone with varying temperature and dissolved oxygen concentration referred to as metalimnion (6-13m), and 3) hypolimnion (15-20m) marked with cold water and reduced oxygen concentration in comparison to the upper two compartments. The pH of the water column stayed circumneutral during this study. The implications of the lake's variation in thermal and redox status on the cycling of macro and micronutrients are discussed in data chapters.  
The third chapter of this thesis addresses the role of suspended iron hydroxides in phosphorus cycling. The spatial and temporal distribution of iron and phosphorus was clearly coupled and was strongly influenced by sediment releases of both elements in anaerobic bed sediments. Both iron and phosphorus were predominantly colloidal and displayed an increasing degree of lability (to DGT) as hypolimnetic anoxia deepened. The implications of this finding are that iron-based colloids can mediate phosphorus cycling even under anaerobic conditions, and might therefore influence iron and phosphorus bioavailability within the water column. 
The fourth chapter of this thesis explores the evolution, seasonal production, and consumption of dissolved organic matter (DOM) in the water column of Lake Ngapouri. Both the quality and quantity of DOM influence the turnover of DOM in the lake system, and this influence was explored using the constituent molecules' fluorescent properties. The resulting excitation-emission matrices (EEM's) were analyzed using parallel factor analysis (PARAFAC), identifying two humic-like fluorophores and one protein-like fluorophore in both colloidal and dissolved size fractions. DOM in the lake showed marked seasonality with greater production and turnover during the summer season. This study shows that the concentration of humic-like DOM was ~3.5 times lower and less variable than protein-like DOM. The proteinaceous material in the low molecular weight fraction cycled actively in the anaerobic hypolimnetic water during summer, consistent with the contemporaneous dissimilatory reduction of manganese, iron, and sulphur. 
Chapter 5 of this thesis examines the spatial and temporal distribution of trace elements (iron (Fe), manganese (Mn), zinc (Zn), copper(Cu), chromium (Cr), cobalt (Co), nickel (Ni), and cadmium (Cd)) in Lake Ngapouri, and the degree to which binding to colloidal surfaces and DOM influence trace element bioavailability. DGT-lability was thus used as a proxy the available metal for biological uptake. In general, the DGT-labile fraction was much lower than a total load of respective trace metal, indicating the significance of adsorption, precipitation, and complexation reactions for trace metal availability for biological uptake. Broadly, the study groups trace metals into two distinct categories: strongly redox cycled, and controlled by organic complexation. This work shows that colloidal association is often, but not always a predictor of lower bioavailability with important implications for our understanding of metal micronutrients in aquatic systems. 
The contributions from this study are significant for studies of the bioavailability of macro and micronutrients which exhibit strong adsorption behavior. The redox state of lakes affects the formation, complexation character, and stability of various mineral colloids. Colloids clearly should be considered as an important intermediary phase with the potential to affect nutrient availability and with implications for lake restoration and management initiatives.

year: 2022

title: Aroha

authors: Maxwell, Te Kahautu

abstract: Waita Tira. Lyrics composed by Te Kahautu Maxwell, muscial score composed by Raharuha Mitai, Thomas Mitai, Renee Mitai. Performed by Ōpōtiki Mai Tawhiti (Kapa Haka group) (3mins)

Waiata ā Tira: Aroha
Whakaeke: Pinepine Te Kura
Mōteatea: Tērā te haeata
Waiata ā Ringa: Tiaho Mai
Poi: E ia, e ia
Haka: Ranginui
Whakawātea: Te Tiriti o Waitangi

text: Aroha Waita Tira. Lyrics composed by Te Kahautu Maxwell, muscial score composed by Raharuha Mitai, Thomas Mitai, Renee Mitai. Performed by Ōpōtiki Mai Tawhiti (Kapa Haka group) (3mins)

Waiata ā Tira: Aroha
Whakaeke: Pinepine Te Kura
Mōteatea: Tērā te haeata
Waiata ā Ringa: Tiaho Mai
Poi: E ia, e ia
Haka: Ranginui
Whakawātea: Te Tiriti o Waitangi

year: 2020-02-06