Andrew Kilding

Auckland University of Technology | AUT · Sports Performance Research Institute New Zealand (SPRINZ)

Muscle glycogen state and carbohydrate (CHO) supplementation before and during exercise may impact responses to high-intensity interval training (HIIT). This study determined cardiorespiratory, substrate metabolism, muscle oxygenation, and performance when completing HIIT with or without CHO supplementation in a muscle glycogen depleted state. On t...

This study quantified and compared the collision and non-collision match characteristics across age categories (i.e. U12, U14, U16, U18, Senior) for both amateur and elite playing standards from Tier 1 rugby union nations (i.e. England, South Africa, New Zealand). Two-hundred and one male matches (5911 min ball-in-play) were coded using computerise...

Highlights: Acute manipulation of muscle glycogen availability using an exercise and dietary manipulation protocol did not affect subsequent high intensity running performance across a range of running distances.Reduced muscle glycogen resulted in a marked increase in fat oxidation in low glycogen condition but no changes in running economy or cri...

Purpose To determine the effect of prolonged exercise on moderate-to-heavy intensity transition power output and heart rate. Methods Fourteen endurance-trained cyclists and triathletes took part in the present investigation (13 males, 1 female, V·O2peak 59.9 ± 6.8 mL.kg−1.min⁻¹). Following a characterisation trial, participants undertook a five-st...

Purpose: The three-minute all-out test (3MT), when performed on a laboratory ergometer in a linear mode, can be used to estimate the heavy-severe-intensity transition, or maximum metabolic steady state (MMSS), using the end-test power output. As the 3MT only requires accurate measurement of power output and time, it is possible the 3MT could be us...

Background: Multiple factors influence substrate oxidation during exercise including exercise duration and intensity, sex, and dietary intake before and during exercise. However, the relative influence and interaction between these factors is unclear. Objectives: Our aim was to investigate factors influencing the respiratory exchange ratio (RER)...

Background Contemporary sports nutrition guidelines recognize that endurance athletes should periodize their daily carbohydrate (CHO) intake according to the demands of their training and competitive schedule. However, objective assessments of the dietary CHO periodization practices adopted by endurance athletes during prolonged training periods ar...

Background The 5ʹ adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a cellular energy sensor that is activated by increases in the cellular AMP/adenosine diphosphate:adenosine triphosphate (ADP:ATP) ratios and plays a key role in metabolic adaptations to endurance training. The degree of AMPK activation during exercise can be influen...

Purpose Whole-body fat oxidation during exercise can be measured non-invasively during athlete profiling. Gaps in understanding exist in the relationships between fat oxidation during incremental fasted exercise and skeletal muscle parameters, endurance performance, and fat oxidation during prolonged fed-state exercise. Methods Seventeen endurance...

The primary aim of this study was to examine if biomarker and/or self-reported data could predict upper respiratory tract symptom (URTS) risk in elite field hockey players. The secondary aim was to investigate the effect of the additional stressor ‘repeated heat exposure’ on measures of thermoregulation and immunity. A prospective cohort repeated m...

Traditional movement economy (ME) measures the energetic cost of in-line running. However, it is debatable whether such a measure is representative of movement efficiency for team sport athletes who are required to run and change direction repeatedly. This study evaluated ME during both in-line running and runs with directional changes and provided...

Endurance athletes are frequently exposed to environmental heat stress during training. We investigated whether exposure to 33°C during training would improve endurance performance in temperate conditions and stimulate mitochondrial adaptations. Seventeen endurance-trained males were randomly assigned to perform a 3-week training intervention in 18...

Profiling physiological attributes is an important role for applied exercise physiologists working with endurance athletes. These attributes are typically assessed in well-rested athletes. However, as has been demonstrated in the literature and supported by field data presented here, the attributes measured during routine physiological-profiling as...

Purpose: To investigate the acute effect of repeated-sprint activity (RSA) on change-of-direction economy (assessed using shuttle running economy [SRE]) in soccer players and explore neuromuscular and cardiorespiratory characteristics that may modulate this effect. Methods: Eleven young elite male soccer players (18.5 [1.4] y old) were tested on...

Nutritional intake can influence exercise metabolism and performance, but there is a lack of research comparing protein-rich pre-exercise meals with endurance exercise performed both in the fasted state and following a carbohydrate-rich breakfast. The purpose of this study was to determine the effects of three pre-exercise nutrition strategies on m...

This study examined possible predictors of upper respiratory tract symptom (URTS) episodes in elite rugby union and league players (n = 51) during intensive pre-season training. Baseline saliva and blood samples were collected in the first week of pre-season training for analysis of salivary secretory immunoglobulin A (SIgA) and cytomegalovirus. Th...

This study aimed to evaluate the effect of high-intensity interval training shock microcycles (HIITSM) on endurance, running economy and change of direction economy in female soccer players. Nineteen sub-elite female soccer players were randomised to two groups: HIITSM (10 HIIT sessions over 13 days) or HIITTRAD (4 HIIT sessions over 13 days) inter...

Acute exposure to heat, such as that experienced by people arriving into a hotter or more humid environment, can compromise physical and cognitive performance as well as health. In military contexts heat stress is exacerbated by the combination of protective clothing, carried loads, and unique activity profiles, making them susceptible to heat illn...

The primary variables influencing the adaptive response to a bout of endurance training are exercise duration and exercise intensity. However, altering the availability of nutrients before and during exercise can also impact the training response by modulating the exercise stimulus and/or the physiological and molecular responses to the exercise-in...

RESEARCH QUESTIONS 1. What are the movement patterns and physiological demands of match day performance for high-performance netball umpires? 2. Is there variance in the movement patterns and physiological demands between higher and lower ranked umpires?

Objectives To identify periods of increased risk for upper respiratory tract symptom (URTS) episodes, and examine whether biomarkers and/or self-reported lifestyle and wellness data can predict URTS risk in elite rugby union players. Design Prospective, longitudinal and repeated-measures study. Methods Salivary secretory immunoglobulin A (SIgA),...

Objective: The purpose of this study was to determine the self-reported beliefs and practices relating to pre-exercise nutrition intake among endurance athletes of varying ages and competitive levels and examine differences based on sex, competitive level, and habitual dietary pattern. Method: An anonymous online survey was circulated internatio...

Athletes may choose to perform exercise in the overnight-fasted state for a variety of reasons related to convenience, gut comfort, or augmenting the training response, but it is unclear how many endurance athletes use this strategy. We investigated the prevalence and determinants of exercise performed in the overnight-fasted state among endurance...

Soccer is a complex and exhaustive team-sport requiring a high level of tactical, technical, and physical ability to succeed. During a competitive match, a random combination of explosive and powerful activities, together with technical and tactical gestures, is performed in an intermittent manner over a 90-minute game. This review presents a detai...

Purpose: To evaluate the reliability of new change-of-direction-economy tests (assessing energetic efficiency when performing continuous shuttle runs) compared with common running-economy tests in soccer players Methods: Sixteen subelite, male soccer players were recruited to perform a testing battery involving running economy (RE), 10-m shuttle-r...

To compare demands of national netball umpires between levels of competition, 22 Netball New Zealand high-performance umpires participated in this investigation. These included from highest to lowest standard: 9 × semi-professional ANZ Championships (ANZC); 6 × National A Squad (NZA); and 7 × National Development Squad (DEV). Physical (global posit...

Dolci, F, Kilding, AE, Chivers, P, Piggott, B, and Hart, NH. High-intensity interval training shock microcycle for enhancing sport performance: A brief review. J Strength Cond Res XX(X): 000-000, 2019-High-intensity interval training (HIIT) is a powerful strategy to develop athletes' fitness and enhance endurance performance. Traditional HIIT inter...

Many endurance athletes perform specific blocks of training in hot environments in “heat stress training camps.” It is not known if physiological threshold heart rates measured in temperate conditions are reflective of those under moderate environmental heat stress. A total of 16 endurance-trained cyclists and triathletes performed incremental exer...

This review has outlined the existing literature relating to activity profiles in elite netball umpires. In particular, the physical (distance travelled), physiological (heart rate), and technical (movement classifications) characteristics have been described. The limited available literature report that on average elite netball umpires travel appr...

Hyperthermia stimulates endogenous carbohydrate metabolism during exercise; however, it is not known if exercise intensity impacts the metabolic effect of heat stress. In the first study of this two-part investigation, endurance-trained male cyclists performed incremental exercise assessments in 18 and 35°C (60 % rH). The stimulatory effect of heat...

Recent evidence indicates that the modern-day men’s 800 m runner requires a speed capability beyond that of previous eras. In addition, the appreciation of different athlete subgroups (400–800, 800, 800–1500 m) implies a complex interplay between the mechanical (aerial or terrestrial) and physiological characteristics that enable success in any ind...

A common practice amongst endurance athletes is to purposefully train in hot environments during a ‘heat stress camp’. However, combined exercise-heat stress poses threats to athlete wellbeing, and therefore heat stress training has the potential to induce maladaptation. This case study describes the monitoring strategies used in a successful three...

Keeping athletes healthy will be important for optimal athletic performance at the 2020 Tokyo Summer Olympic and Paralympic Games. Athletes will be exposed to several stressors during the preparatory and competition phases of the Summer Games that have the potential to depress immunity and increase illness risk. This mini-review provides an overvie...

This study sought to examine time course changes in maximal oxygen consumption (VO2max) confirmed with verification testing following 12 weeks of standardized vs. individualized exercise training. Participants (N=39) were randomly allocated to differing exercise intensity prescription groups: ventilatory threshold (individualized) or % heart rate r...

Background Running economy represents a complex interplay of physiological and biomechanical factors that are able to adapt chronically through training, or acutely through other interventions such as changes in footwear. The Nike Vaporfly (NVF) shoe was designed for marathon running on the roads and has been shown to improve running economy by ~ 4...

This study examined the dose‐response effects of caffeine on saliva secretory immunoglobulin A (SIgA) responses to prolonged submaximal running. In a double‐blind randomized crossover design, 12 endurance trained male runners (age: 29 ± 3, VO2peak 62.7 ± 5.1 mL·kg⁻¹·min⁻¹, mean ± SD) ran for 70 min at 80% VO2peak 60 min after ingesting 0 (PLA), 2 (...

Purpose The anaerobic speed reserve (ASR) defined as the speed range from vVO 2 max to maximal sprint speed (MSS) has recently been shown to be an important tool for middle-distance coaches to meet event surge demands and inform on the complexity of athlete profiles. To enable field application of ASR, the relationship between gun-to tape 1500 m av...

The aim of this study was to determine the effect of ischemic preconditioning (IPC) on several measures of aerobic function and 4-km cycling time-trial performance. An acute cross-over design was adopted involving eight well-trained cyclists (age 27.0 ± 7.0 years) who completed incremental and square-wave exercise tests for determination of peak O2...

This study sought to investigate the efficacy of standardized versus individualized exercise intensity prescription on metabolic syndrome (MetS) severity following a 12-week exercise intervention. A total of 38 experimental participants (47.8 ± 12.2 yr, 170.7 ± 8.0 cm, 82.6 ± 18.7 kg, 26.9 ± 6.7 mL·k −1 ·min −1) were randomized to one of two exerci...

Introduction: Despite knowledge of cardiorespiratory fitness (CRF) training responders and nonresponders, it is not well understood how the exercise intensity prescription affects the incidence of response. The purpose of this study was to determine CRF training responsiveness based on cohort-specific technical error after 12 wk of standardized or...

Soccer is an intermittent team-sport, where performance is determined by a myriad of psychological, technical, tactical, and physical factors. Among the physical factors, endurance appears to play a key role into counteracting the fatigue-related reduction in running performance observed during soccer matches. One physiological determinant of endur...

Wearable resistance training involves added load attached directly to the body during sporting movements. The effects of load position during running are not yet fully established. Therefore, the purpose of this research was to determine spatio-temporal and kinetic characteristics during submaximal running using upper, lower and whole-body wearable...

Purpose:: In recent years (2011-2016), men's 800m championship running performances have required greater speed than previous eras (2000-2009). The "Anaerobic speed reserve" (ASR) may be a key differentiator of this performance, but profiles of elite 800m runners and its relationship to performance time have yet to be determined. Methods:: The A...

Ironman triathlons are ultra-endurance events of extreme duration. The performance level of those competing varies dramatically, with elite competitors finishing in ~ 8:00:00, and lower performing amateurs finishing in ~ 14-15:00:00. When applying appropriate values for swimming, cycling and running economies to these performance times, it is demon...

The purposes of this applied session are to provide a brief introduction on how pedalling style/technique can influence energy cost and joint loads, and then to perform a laboratorial based assessment (i.e. cycle ergometer) illustrating how changes from pushing to pulling technique could affect pedal forces and oxygen cost. A background of optimal...

Purpose: To determine the effect of different high-intensity interval training (IT) sessions on the post-exercise recovery response and time-course across varying recovery measures. Methods: Thirteen highly-trained rowers (♂= 10, ♀= 3; VO2peak 4.9 ± 0.7 L⋅min-1) completed three IT sessions on the rowing ergometer separated by seven days. Session...

Objectives: Elite team-sport athletes are frequently exposed to stressors that have the potential to depress immunity and increase infection risk. Therefore, the purpose of this review is to describe how team-sport stressors impact upon immune responses, along with exploring whether alterations in these markers have the potential to predict upper...

Aasgaard, M and Kilding, AE. Does man marking influence running outputs and intensity during small-sided soccer games? J Strength Cond Res XX(X): 000-000, 2018-Small-sided games (SSGs) are considered an effective training tool for physical development in soccer. Small-sided games can be modified in several ways to manipulate the physical demands to...

Using a short-duration step protocol and continuous indirect calorimetry, whole-body rates of fat and carbohydrate oxidation can be estimated across a range of exercise workloads, along with the individual maximal rate of fat oxidation (MFO) and the exercise intensity at which MFO occurs (Fatmax). These variables appear to have implications both in...

Background Even though cardiorespiratory fitness (CRF) training elicits numerous health benefits, not all individuals have positive training responses following a structured CRF intervention. It has been suggested that the technical error (TE), a combination of biological variability and measurement error, should be used to establish specific train...

Objectives: Given apparent consumer interest in calorie counting and arguably inadequate understanding of the differential effects of exercise modality despite equivalent caloric expenditure, we sought to quantify and compare the acute physiological responses within and between a BODYPUMP™ (BP) group-fitness class and steady-state cycling (CARDIO)...

Commentaries on Viewpoint: Resistance training and exercise tolerance during high-intensity exercise: moving beyond just running economy and muscle strength

Purpose: To determine the effects of heated resistance exercise on thermal strain, neuromuscular function and hormonal responses in power athletes. Methods: Sixteen (n = 8 female; 8 male) highly trained power athletes completed a combined strength and power resistance exercise session in hot (HOT ~30 °C) and temperate (CON ~20 °C) conditions. Hu...

As major sporting events are often held in hot environments, increased interest in ways of optimally heat acclimating athletes to maximise performance has emerged. Heat acclimation involves repeated exercise sessions in hot conditions that induce physiological and thermoregulatory adaptations that attenuate heat-induced performance impairments. Cur...

Tests of handgrip strength (HGS) and handgrip force (HGF) are commonly used across a number of sporting populations. Measures of HGS and HGF have also been utilized by practitioners and researchers to evaluate links with sports performance. This article, firstly evaluates the validity and reliability of various handgrip dynamometers (HGD) and HGF s...

Purpose: To assess the longitudinal evolution of tactical behaviours used to medal in Men's 800m (M800) Olympic Games (OG) or World Championship (WC) events in the recent competition era (2000-2016). Methods: Thirteen OG and WC events were characterised for first and second lap splits using available footage from YouTube. Positive pacing strateg...

Purpose: The aim of this study was to determine the effect of NO3(-) consumption on measures of perception, thermoregulation and cycling performance in hot conditions. Methods: Using a randomised, double-blind, crossover-design, 8 well-trained cyclists (mean ± SD: age: 25 ± 8 y, V̇O2peak: 64 ± 5 ml·kg(-1)·min(-1)) performed 2 separate trials, in...

Purpose: This study aimed to examine relationships between methods of lower-limb stiffness and their associations with running economy (RE) and maximal velocity (vmax) in middle-distance (MD) runners. Methods: Eleven highly-trained male MD runners performed a series of mechanical and physiological tests to determine maximal overground sprint spe...

Purpose: To establish the validity of smartphone photoplethysmography (PPG) and heart rate sensor in the measurement of heart rate variability (HRV). Methods: 29 healthy subjects were measured at rest during 5 min of guided breathing (GB) and normal breathing (NB) using Smartphone PPG, heart rate chest strap and electrocardiography (ECG). The ro...

We aimed to compare the effects of two different dosing durations of dietary nitrate (NO3-) supplementation on 1- and 4km cycling time-trial performance in highly-trained cyclists. In a double-blind crossover-design, nine highly-trained cyclists ingested 140ml of NO3--rich beetroot juice containing ~8.0mmol [NO3-], or placebo, for seven days. Parti...

Background There is individual variability to cardiorespiratory fitness (CRF) training, but the underlying cause is not well understood. Traditionally, a standardized approach to exercise prescription has utilized relative percentages of maximal heart rate, heart rate reserve (HRR), maximal oxygen uptake (VO2max), or VO2 reserve to establish exerci...

The manifestations of fatigue during fast bowling in cricket were systematically evaluated using subjective/perceptual reports by cricket experts and quantitative data published from scientific studies. Narratives by international players/team physiotherapists were sourced from the internet using criteria for opinion-based evidence. Research articl...

Purpose: To determine the effect of dietary nitrate (NO3(-)) supplementation on physiology and performance in well-trained cyclists following six to eight-days of NO3(-) supplementation. Methods: Eight competitive male cyclists (mean ± SD; age = 26 ± 8 y; body mass = 76.7 ± 6.9 kg; VO2peak = 63 ± 4 ml.kg(-1).min(-1)) participated in a double-bli...

Purpose : To examine the retention and re-acclimation responses during a periodized heat acclimation (HA) protocol in elite sailors preparing for the 2013 World Championships in Muscat, Oman (∼27-30°C, 40-60% RH). Methods : Two elite male Laser class sailors completed 5 consecutive days of HA (60 min per day in 35°C, 60% RH). Heat response tests (...

Purpose: To compare the physiological and performance effects of ad libitum cold fluid (CF) and ice slurry (IS) ingestion on cycling time-trial (TT) performance in the heat. Methods: Seven well-trained male triathletes and cyclists completed two maximal-effort 40-km cycling TT's in hot (35°C) and humid (60% rH) conditions. In randomised order, p...

The following match-­play data and fitness test results provide an insight into the physical demands of three levels of High Performance Netball umpiring. This information may assist in further understanding the demands of umpiring across the three different levels. Such data could be used to refine umpire specific training and goal setting for fut...

The aim of this study was to determine the effect of short duration intermittent hypoxic exposure (IHE) on physical performance in basketball players. Using a single-blind placebo-controlled group design, 14 trained basketball players were subjected to 15 days of passive short duration IHE (n 7), or normoxic control (CON, n 7), using a biofeedback...