Nicholas J O'Dwyer

Nicholas J O'Dwyer
The University of Sydney · Discipline of Exercise and Sport Science

PhD

About

114
Publications
22,480
Reads
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Citations
Introduction
Nicholas J O'Dwyer is with the Discipline of Exercise and Sport Science, The University of Sydney and the School of Exercise Science, Sport and Health, Charles Sturt University. Nicholas does research in motor control and learning, energetics of skill acquisition, multi-joint coordination, neurological disorders of movement, and the relation between cognition and physical activity.
Skills and Expertise
Additional affiliations
September 2012 - July 2015
Charles Sturt University
Position
  • Professor (Associate)
September 2012 - July 2015
Charles Sturt University
Position
  • Professor (Associate)
January 1996 - September 2012
The University of Sydney
Position
  • Professor (Associate)

Publications

Publications (114)
Article
Background: Movement competency screens (MCSs) are commonly used by coaches and clinicians to assess injury risk. However, there is conflicting evidence regarding MCS reliability. Purpose: This study aimed to: (i) determine the inter- and intra-rater reliability of a sport specific field-based MCS in novice and expert raters using different view...
Article
Background: There is evidence that physical activity (PA), sitting time, and obesity may impact cognition, but few studies have examined this in young women. Methods: Healthy women (18-35 y), without conditions that impair cognition, were recruited for this cross-sectional study. Participants completed anthropometric and validated computerized c...
Article
Full-text available
Purpose Early adulthood is a high-risk time for weight gain; however, young women with obesity are difficult to recruit to weight management programs. To encourage participation and retention, it is important to understand what young women want from these programs. The purpose of the study was to explore participants’ perspectives on the features o...
Article
Full-text available
Omega-3 polyunsaturated fatty acids (n-3 PUFAs) are essential for healthy development and protect against metabolic disease. However, individuals with obesity may be pre-disposed to experiencing lower n-3 PUFA status than normal-weight individuals. This cross-sectional study examined the relationship between the omega-3 index (O3I), body mass index...
Article
Fast bowling is categorised into four action types: side-on, front-on, semi-open and mixed; however, little biomechanical comparison exists between action types in junior fast bowlers. This study investigated whether there are significant differences between action-type mechanics in junior fast bowlers. Three-dimensional kinematic and kinetic analy...
Article
Background: Despite increased interest in combining learning and physical activity (PA), the academic and PA benefits of active learning are uncertain. Methods: A systematic search of 5 databases for studies combining learning math with PA in primary/elementary schools was conducted. Academic benefit was evaluated by pre-post intervention math s...
Article
This study examined differences across skill levels in the kinematics of a complex, whole-body, asymmetrical, cyclical dance sequence, the 'Alternate Basic' in Cha-Cha-Cha, to determine whether observed differences were consistent with Bernstein's (1967) model of development of coordination. Bernstein proposed that with novel motor skills, beginner...
Article
Objectives: This study evaluated the benefit of physically-active lessons for learning maths multiplication-tables. The impact of the intervention on general numeracy, physical activity (PA), aerobic fitness, body mass index (BMI) and school-day moderate to vigorous PA (MVPA) was also assessed. Design: Randomised controlled cross-over trial. Method...
Article
Objectives: This study evaluated the benefit of physically-active lessons for learning maths multiplication-tables. The impact of the intervention on general numeracy, physical activity (PA), aerobic fitness, body mass index (BMI) and school-day moderate to vigorous PA (MVPA) was also assessed. Design: Randomised controlled cross-over trial. Me...
Article
Full-text available
Background: Research indicates that low omega-3 polyunsaturated fatty acid (n-3 PUFA) may be associated with decreased cognitive function. This study examined the association between n-3 PUFA status and cognitive function in young Australian women. Methods: This was a secondary outcome analysis of a cross-sectional study that recruited 300 healt...
Article
Due to the redundant degrees of freedom (DOF) and nonlinearity of reactional kinetic elements within the human motor apparatus, controlling the complex dynamics of the human muscu-loskeletal system presents considerable difficulties. Based on this challenge, Bernstein (1967) viewed skill development as the process whereby the central nervous system...
Article
Aim Recruiting young women to weight management research programs is difficult. The purpose of this study was to gain insights into the barriers and motivators that influence participation and to explore effective methods of recruitment from the perspective of young women with obesity living in both urban and regional areas. Methods Semi‐structure...
Article
Full-text available
According to the World Health Organisation, drowning fatalities are a neglected public health issue ranked as the third most frequent cause of unintentional death by injury. Data used to record drowning incidents are acknowledged as inaccurate. Recommendations on drowning prevention based on these data are currently not informed by accurate, detail...
Article
Usage of accelerometers within player tracking devices in sport to quantify load, vertical ground reaction force (vGRF) or energy expenditure is contrary to placement guidelines. This study aimed to determine whether trunk-mounted accelerometers were a valid and reliable method to estimate thoracic segment or centre of gravity (COG) acceleration or...
Article
At face value, the term 'synergy' provides a unifying concept within a fractured field that encompasses complementary neural, computational and behavioral approaches. However, the term is not used synonymously by different researchers, but has substantially different meanings depending on the research approach. With so many operational definitions...
Article
Full-text available
Introduction: Studies of cerebral haemodynamics have shown changes with increased exercise intensity, but the patterns have been highly variable and reliable associations with cognitive performance have not been identified. The aim of this study was to examine whether exercise-induced changes in oxygenated haemoglobin (O2Hb) led to changes in conc...
Article
Background: Physically active learning that combines physical activity with core curriculum areas is emerging in school-based health interventions. This study investigates the effectiveness of learning an important numeracy skill of times tables (TT) while concurrently engaging in aerobic activity compared with a seated classroom approach. Method...
Article
Full-text available
Iron is an essential micronutrient for human health and inadequate intake may result in iron deficiency (ID) or iron deficiency anaemia (IDA). Unlike other recent studies investigating iron status in young women, this cross-sectional study analysed dietary intake and biochemical data from healthy young (18-35 years) women (n = 299) to determine the...
Article
Full-text available
Women of reproductive age are at increased risk for iron deficiency (ID) and iron deficiency anemia (IDA), with both implicated in decreased cognitive function (CF). Obesity may complicate this association via inflammatory-mediated ferritin elevation. This cross-sectional study examined the association between hematological iron status (iron replet...
Article
Full-text available
Limited research addresses links between obesity and cognitive function in young adults. Objective . To investigate the relationship between obesity and cognitive function in young women. Methods . This cross-sectional study recruited healthy, young (18–35 y) women of normal (NW: BMI = 18.5–24.9 kg·m ⁻² ) or obese (OB: BMI ≥ 30.0 kg·m ⁻² ) weight....
Article
We suspected that the observed inconsistency of sex differences in drop-landing motor skills might be due to the confounding factor of prior experience. Thus, in this study, we explored the role of experience in shaping male and female surfboard riders' motor skill kinematics during drop landings while surfboard riding. We recruited 42 participants...
Article
Full-text available
Due to the high incidence of lumbar spine injury in fast bowlers, international cricket organisations advocate limits on workload for bowlers under 19 years of age in training/matches. The purpose of this study was to determine whether significant changes in either fast bowling technique or movement variability could be detected throughout a 10-ove...
Article
This study examined whether laterality frequency, team familiarity, and game experience affected preferred Kicking Foot Identification in professional Australian Football players. Using a repeated-measures experimental design, 13 and 10 players, respectively, identified the kicking foot of 30 teammates and 30 opponents using static images in a rand...
Article
Abstract?Snap-kicks? in Australian Football (AF) occur when players can potentially score but are facing away from the goal, necessitating a kick across the body or over the opposite shoulder. In games, situations arise for both right- and left-foot snaps, but players often strive to use their preferred rather than non-preferred foot. We consider w...
Article
Objectives: To investigate whether exercise, proposed to enhance neuroplasticity and potentially cognitive function (CF) and academic performance (AP), may be beneficial during adolescence when important developmental changes occur. Design: Systematic review evaluating the impact of acute or chronic exercise on CF and AP in adolescents (13-18 ye...
Article
In dance, the goals of actions are not always clearly defined. Investigations into the perceived quality of dance actions and their relation to biomechanical motion should give insight into the performance of dance actions and their goals. The purpose of this review was to explore and document current literature concerning dance perception and its...
Article
Objectives: There is increasing evidence that physical activity (PA) positively affects cognitive function (CF). Existing research has focussed on this association in children and the elderly, with less research available in young to middle-aged adults who constitute a substantial proportion of the population. Design: A systematic review investi...
Conference Paper
Full-text available
Drowning fatalities are one of the 10 leading causes of death in every region of the world for people aged 1 to 24 years, according to the World Health Organisation’s inaugural World Drowning Report. While the fatal drowning toll is significantly lower in high income countries (HICs), it is still a substantial issue that has not been remediated by...
Poster
Background: Young women of reproductive age have higher iron requirements due to menstruation, and often restrict energy and iron rich foods due to weight concerns. They are therefore at a greater risk of iron deficiency (ID) and iron deficiency anaemia (IDA), both of which often go undiagnosed. Objectives: A non-invasive method of assessing risk o...
Presentation
Emerging evidence suggests that obesity may be detrimental to cognitive function [1—3]. A systematic review and meta-analysis was undertaken to evaluate differences in cognitive performance between overweight/obese (BMI ≥25.0 kgm−2) and healthy-weight (BMI 18. —24.9 kgm−2) adults. A systematic search conducted according to PRISMA guidelines across...
Article
We investigated the acquisition of skill in balancing a stick (52 cm, 34 g) on the fingertip in nine participants using three-dimensional motion analysis. After 3.5 hours practice over 6 weeks, the participants could more consistently balance the stick for longer durations with greatly reduced magnitude and speed of stick and finger movements. Irre...
Article
Full-text available
Wind instrumentalists require a sophisticated functioning of their respiratory system to control their air stream, which provides the power for optimal musical performance. The air supply must be delivered into the instrument in a steady and controlled manner and with enough power by the action of the expiratory musculature to produce the desired l...
Poster
Relationships Between Fitness on the Cognitive Function and Academic Performance of Sedentary Adolescent Schoolboys Joanna W. Li1, Helen O’Connor1, Tenzing Tsewang1, Hoi Lun Cheng1, Rhonda Orr1, Nicholas O’Dwyer2. 1The University of Sydney, Sydney, Australia. 2Charles Sturt University, Bathurst, Australia. (Sponsor: Mike Climstein, FACSM) (No relat...
Article
There are two issues in balancing a stick pivoting on a finger tip (or mechanically on a moving cart): maintaining the stick angle near to vertical and maintaining the horizontal position within the bounds of reach or cart track. The (linearised) dynamics of the angle are second order (although driven by pivot acceleration), and so, as in human sta...
Article
Surfing is one of the most popular sports among Australian athletes, yet data about the characteristics of its performers are sparse, most likely due to the difficulty of examining the skill during performance and the distance of the observer from the performer. To gain information about skilled surfers of both sexes, and how they differ from less...
Article
Full-text available
Most previous studies of associated reactions (ARs) in people with cerebral palsy have used observation scales, such as recording the degree of movement through observation. The sensitive quantitative method can detect ARs that are not amply visible. The aim of this study was to provide quantitative measures of ARs during a visual pursuit position...
Article
Full-text available
Walking is a complex task which includes hundreds of muscles, bones and joints working together to deliver smooth movements. With the complexity, walking has been widely investigated in order to identify the pattern of multi-segment movement and reveal the control mechanism. The degree of freedom and dimensional properties provide a view of the coo...
Article
ABSTRACT Principal component analysis is a powerful and popular technique for capturing redundancy in muscle activity and kinematic patterns. A primary limitation of the correlations or covariances between signals on which this analysis is based is that they do not account for dynamic relations between signals, yet such relations-such as that betwe...
Article
The effects on both joint mechanics and the neural stretch reflex of changes in amplitude of stretch ranging from within the region of short range stiffness up to 3% of resting muscle length were quantified. The level of activation of the primary agonist was held constant but there was a small but systematic increase in activation of the other flex...
Article
We studied 14 skilled subjects balancing a stick (a television antenna, 52 cm, 34 g) on their middle fingertip. Comprehensive three-dimensional analyses revealed that the movement of the finger was 1.75 times that of the stick tip, such that the balanced stick behaved more like a normal noninverted pendulum than the inverted pendulum common to engi...
Article
In quantitative gait analysis, two types of variability of kinematic waveforms with identifiably different sources may be distinguished: variability of the offset values (mean or DC values) of the waveforms and variability of the waveform patterns. Offset variability is influenced by the repeatability of the motor performance as well as by addition...
Article
The authors investigated metabolic and attentional energy costs as participants (N = 6) practiced in-phase, antiphase, and 90 degrees -phase cycling (order counterbalanced) on independent bicycle ergometers, with resistance (40 W/ergometer) and frequency (40 rpm) held constant. Coordination stabilized and became more accurate for all 3 cycling mode...
Article
Voluntary eyelid closure and smiling were studied in 11 normal subjects and 11 patients with long-term unilateral facial nerve palsy (FNP). The conjugacy of eyelid movements shown previously for blinks was maintained for voluntary eye closures in normal subjects, with movement onset being synchronous in both eyes. Bilateral onset synchrony of the s...
Article
Understanding the relationship between the motor impairments and their impact on physical activity will allow rehabilitation after stroke to be based on scientific principles. The aims of this study were to determine: (i) the relative contribution of weakness and spasticity to contracture, and (ii) the relative contribution of all three impairments...
Article
In this study the systematic modulation of wrist flexor muscle activity by imposed joint movement was examined. Ten subjects maintained a constant contraction level (25% of the maximum; trial duration: 20 s) in flexor carpi radialis while their wrists were perturbed with 50 different quasi-sinusoidal signals (frequency range: 0.5–9.5 Hz; amplitude:...
Article
To improve smiling after long-term facial nerve palsy (FNP). Physiotherapy rehabilitation of an adapted (more symmetrical) smile was investigated in FNP subjects 1 year post-onset, using video self-modeling (video replay of only best adapted smiles) and implementation intentions (preplanning adapted smiles for specific situations). Prospective, bli...
Article
This study quantified the systematic effects on wrist joint mechanics of changes in amplitude of displacement ranging from within the region of short-range stiffness (0.2% of resting muscle length) up to 3% of resting muscle length. The joint mechanics were modelled using a second-order system from which estimates of joint stiffness, viscosity, ine...
Article
This paper presents empirical evidence suggesting that healthy humans can perform a two degree of freedom visuo-motor pursuit tracking task with the same response time delay as a one degree of freedom task. In contrast, the time delay of the response is influenced markedly by the nature of the motor synergy required to produce it. We suggest a conc...
Article
Kinematic (relative phase error), metabolic (oxygen consumption, heart rate) and attentional (baseline and cycling reaction times) variables were measured while participants practised a high energy-demanding, intrinsically unstable 90 degrees relative phase coordination pattern on independent bicycle ergometers. The variables were found to be stron...
Article
To investigate the extent of within-system reliability and between-system correlation for the "Sydney" and "Sunnybrook" systems of grading facial nerve paralysis, and to examine the interobserver reliability and agreement of the "House Brackmann" grading system. A fixed-effects reliability study in which 6 otolaryngologists viewed videotapes of pat...
Article
OBJECTIVE. To investigate the extent of within-system reliability and between-system correlation for the "Sydney" and "Sunnybrook" systems of grading facial nerve paralysis, and to examine the interobserver reliability and agreement of the "House Brackmann" grading system. STUDY DESIGN., A fixed-effects reliability study in which 6 otolaryngologist...
Article
Full-text available
Spasticity is defined/assessed in resting limbs, where increased stretch reflex activity and mechanical joint resistance are evident. Treatment with antispastic agents assumes that these features contribute to the movement disorder, although it is unclear whether they persist during voluntary contraction. To compare reflex amplitude and joint resis...
Article
Full-text available
To investigate the facial expression of emotion and quality of life in patients after long-term facial nerve paralysis. Cross-sectional. Facial nerve paralysis clinic. Twenty-four patients with facial nerve paralysis and 24 significant others (partner, relative, friend). Patients were assessed using Sunnybrook, Sydney, and House-Brackmann grading s...
Article
This paper reports an investigation of the magnitude and timing of the stretch reflex over the full range of activation of flexor carpi radialis. While it is well established that the magnitude of the reflex increases with the level of muscle activation, there have been few studies of reflex magnitude above 50% of maximum voluntary contraction (MVC...
Article
The major contributors to physical disability after stroke are considered to be the negative impairments of loss of dexterity (defined here as loss of the ability to co-ordinate muscle activity in the performance of any motor task) and loss of strength. The aims of this study were: (1) to determine the relative contributions of strength and dexteri...