I am a Senior Physiologist in the Physiology department of the Australian Institute of Sport and working with our Olympic and Paralympic Winter high performance programs. I received my doctorate in 2008 from Edith Cowan University following a series of studies investigating exercise-induced muscle damage and the influence of contraction velocity. I been fortunate to be an Australian Olympic team member at two Olympic Winter games (2010 and 2014) working across the sliding sports of luge, bobsleigh and skeleton. My research focus is on applied sports research that leads to practical solutions to problems that are limiting an athlete’s performance or their development into elite athletes. Primarily this is in the broad area of muscle physiology and includes neuromuscular fatigue and adaptation, exercise induced muscle damage, applied physiology of strength and conditioning, tendon and muscle response to training, postural control and balance, athlete and special population characterization.
There is uncertainty as to which knee angle during a squat jump (SJ) produces maximal jump perfor... more There is uncertainty as to which knee angle during a squat jump (SJ) produces maximal jump performance. Importantly, understanding this information will aid in determining appropriate ratios for assessment and monitoring of the explosive characteristics of athletes. This study compared SJ performance across different knee angles-90º, 100º, 110º, 120º, 130º, and a self-selected depth-for jump height and other kinetic characteristics. For comparison between SJ and an unconstrained dynamic movement, participants also performed a countermovement jump from a self-selected depth. Thirteen participants (Mage = 25.4 ± 3.5 years, Mheight = 1.8 ± 0.06 m, Mweight = 79.8 ± 9.5 kg) were recruited and tested for their SJ performance. In the SJ, maximal jump height (35.4 ± 4.6 cm) was produced using a self-selected knee angle (98.7 ± 11.2°). Differences between 90°, 100°, and self-selected knee angles for jump height were trivial (ES ± 90% CL = 90°-100° 0.23 ± 0.12, 90°-SS -0.04 ± 0.12, 100°-SS -0...
Training in front of mirrors is common, yet little is known about how the use of mirrors effects ... more Training in front of mirrors is common, yet little is known about how the use of mirrors effects muscle force production. Accordingly, we investigated how performing in front of a mirror influences performance in single and multi-joint tasks, and compared the mirror condition to the established performance effects of internal focus (IF) and external focus (EF) instructions in a two part experiment. In the single-joint experiment 28 resistance-trained participants (14 males and 14 females) completed two elbow flexion maximal voluntary isometric contractions under four conditions: mirror, IF, EF and neutral instructions. During these trials, surface EMG activity of the biceps and triceps were recorded. In the multi-joint experiment the same participants performed counter-movement jumps on a force plate under the same four conditions. Single-joint experiment: EF led to greater normalized force production compared to all conditions (P≤0.02, effect-size range [ES] = 0.46-1.31). No differ...
While self-controlled practice has been shown to enhance motor learning with various populations ... more While self-controlled practice has been shown to enhance motor learning with various populations and novel tasks, it remains unclear if such effects would be found with athletes completing familiar tasks. Study 1 used a single case-study design with a world-champion kickboxer. We investigated whether giving the athlete a choice over the order of punches would affect punching velocity and impact force. Separated by 1 min of rest, the athlete completed 2 rounds of 12 single, maximal effort punches (lead straight, rear straight, lead hook and rear hook) delivered to a punching integrator in a counterbalanced order over six testing days. In one round the punches were delivered in a predetermined order while in the second round the order was self-selected by the athlete. In the choice condition, the world champion punched with greater velocities (6-11 %) and impact forces (5-10 %). In Study 2, the same testing procedures were repeated with 13 amateur male kickboxers over 2 testing days. ...
ABSTRACT BSTRACT Research has identified a plethora of physiological, biochemical, psychological ... more ABSTRACT BSTRACT Research has identified a plethora of physiological, biochemical, psychological and performance markers that help inform coaching staff about when an athlete is in a state of fatigue or recovery. However use of such markers in the regular high performance training environment remains undocumented. To establish current best practice methods for training monitoring, 100 participants involved in coaching or sport science support roles in a variety of high performance sports programs were invited to participate in an online survey. The response rate was 55% with results indicating 91% of respondents implemented some form of training monitoring system. A majority of respondents (70%) indicated there was an equal focus between load quantification and the monitoring of fatigue and recovery within their training monitoring system. Interestingly, 20% of participants indicated the focus was solely on load quantification, while 10% solely monitored the fatigue/recovery process. Respondents reported that the aims of their monitoring systems were to prevent overtraining (22%), reduce injuries (29%), monitor the effectiveness of training programs (27%), and ensure maintenance of performance throughout competitive periods (22%). A variety of methods were used to achieve this, based mainly on experiential evidence rather than replication of methods used in scientific publications. Of the methods identified for monitoring fatigue and recovery responses, self-report questionnaires (84%) and practical tests of maximal neuromuscular performance (61%) were the most commonly utilised.
Research indicates that instructing athlete's to focus on bodily movements (internal focus of... more Research indicates that instructing athlete's to focus on bodily movements (internal focus of attention [IFA]) may hinder performance, whereas instructing them to focus on the movement outcome (external focus of attention [EFA]) often enhances performance. Despite the importance of instructions in striking combat sports, limited research has examined the influence of IFA and EFA on performance in well-trained combat athletes. This study investigated the effects of different instructional cues on punching velocity (m · s(-1)) and normalised impact forces (N · kg(-1)) among intermediate (n = 8) and expert (n = 7) competitive boxers and kickboxers. Athletes completed three rounds of 12 maximal effort punches delivered to a punching integrator on three separate days. Day one was a familiarisation session with only control instructions provided. In the following two days athletes randomly received IFA, EFA or control instructions prior to each of the three rounds. Athletes punching w...
Non-local muscle fatigue (NLMF) is characterized by muscle performance impairments in a contralat... more Non-local muscle fatigue (NLMF) is characterized by muscle performance impairments in a contralateral or remote non-exercised muscle(s) following a fatiguing protocol of a different muscle group(s). This topic is of interest as it affords insights into physiological determinants of muscle fatigue and may provide practical applications concerning the order of exercises in training and rehabilitation programs. A literature review was conducted using Web of Science, PubMed, and Google Scholar databases to evaluate the NLMF effects and possible underlying mechanisms. Overall, 35 studies with 58 outcome measures that met the inclusion criteria were identified. The literature is conflicting with approximately half of the studies reporting NLMF effects (32 of 58 measurements). However, on closer examination 76% of outcome measures of the lower limbs reported NLMF effects (23 of 30 measurements) compared to only 32% in the upper body (9 of 28 measurements). Thus, it appears that NLMF effect...
This study aimed to (1) profile a professional boxer (23 years and 80 kg) with boxing-specific, m... more This study aimed to (1) profile a professional boxer (23 years and 80 kg) with boxing-specific, muscle function, aerobic capacity and body composition tests, and (2) quantify how these measures varied during an 8-week preparation phase leading to, and post a state-Title Bout fought in the 76.2-kg class. A series of boxing-specific and muscle function tests were completed on 11 occasions: 9 prior and twice after the bout, each separated by approximately 2 weeks. The boxing test included 36 maximal punches (9 of each: lead and rear straights, lead and rear hooks) to a punching integrator measuring forces and velocity. Muscle function tests included countermovement jump, drop-jumps, isometric mid-thigh pull and isometric bench-press. Body composition was assessed using skin-fold measurements on three occasions and one dual energy X-ray absorptiometry scan. Aerobic capacity was assessed using 2 VO2 max tests. Leading up to the bout, performance decreased in isometric mid-thigh pull (8%)...
ABSTRACT The aim of this study was to determine the individual effects of acute sodium bicarbonat... more ABSTRACT The aim of this study was to determine the individual effects of acute sodium bicarbonate (NaHCO3) supplementation on elite short track speed skating relay race simulation. Material and Method. Double-blinded balanced, cross-over investigation required two teams of 4 athletes from the Australian National Short Track Speed Skating Program to participate in 2 simulated relay races 72 h apart. Each athlete performed 7 maximal speed skating sprints at a work:rest ratio of ~1:4. Each athlete ingested either 0.3g.kg-1 per body mass of NaHCO3 or lactose placebo (P) 75 min prior to each race. Plasma blood lactate concentration (Bla) was recorded 10min pre- and 2 min post- race simulation. Race lap times and changes in Bla were log transformed and analyzed using paired sample t-tests between NaHCO3 and P. Data were also, analysed to evaluate individual response. Magnitudes of differences between conditions were interpreted using effect sizes (ES) and 90% confidence limits (CL). Results. Post-race simulation, Bla concentration demonstrated a very large increase from baseline for both groups. P demonstrated substantially faster performance for overall (ES: 0.98, CL: -0.13 to 1.82), mean lap (ES: 1.59, CL: 0.22 to 2.95), and fastest lap time (ES: 1.26, CL: 0.02 to 2.50) compared to NaHCO3. Interpretation of the individual analysis indicates that NaHCO3 results in a greater magnitude of individual variation for total (ES: 1.05, CL: -0.40 to 1.54), mean (ES: 2.04, CL: 0.71 to 2.79), and fastest lap time (ES: 1.85, CL: 0.64 to 2.54) than P. Conclusion. These findings indicate responses to acute NaHCO3 supplementation may be individual.
Micro-sensors were used to quantify macro kinematics of classical cross-country skiing techniques... more Micro-sensors were used to quantify macro kinematics of classical cross-country skiing techniques and measure cycle rates and cycle lengths during on-snow training. Data were collected from seven national level participants skiing at two submaximal intensities while wearing a micro-sensor unit (MinimaxX(™)). Algorithms were developed identifying double poling (DP), diagonal striding (DS), kick-double poling (KDP), tucking (Tuck), and turning (Turn). Technique duration (T-time), cycle rates, and cycle counts were compared to video-derived data to assess system accuracy. There was good reliability between micro-sensor and video calculated cycle rates for DP, DS, and KDP, with small mean differences (Mdiff% = -0.2 ± 3.2, -1.5 ± 2.2 and -1.4 ± 6.2) and trivial to small effect sizes (ES = 0.20, 0.30 and 0.13). Very strong correlations were observed for DP, DS, and KDP for T-time (r = 0.87-0.99) and cycle count (r = 0.87-0.99), while mean values were under-reported by the micro-sensor. Incorrect Turn detection was a major factor in technique cycle misclassification. Data presented highlight the potential of automated ski technique classification in cross-country skiing research. With further refinement, this approach will allow many applied questions associated with pacing, fatigue, technique selection and power output during training and competition to be answered.
There is uncertainty as to which knee angle during a squat jump (SJ) produces maximal jump perfor... more There is uncertainty as to which knee angle during a squat jump (SJ) produces maximal jump performance. Importantly, understanding this information will aid in determining appropriate ratios for assessment and monitoring of the explosive characteristics of athletes. This study compared SJ performance across different knee angles-90º, 100º, 110º, 120º, 130º, and a self-selected depth-for jump height and other kinetic characteristics. For comparison between SJ and an unconstrained dynamic movement, participants also performed a countermovement jump from a self-selected depth. Thirteen participants (Mage = 25.4 ± 3.5 years, Mheight = 1.8 ± 0.06 m, Mweight = 79.8 ± 9.5 kg) were recruited and tested for their SJ performance. In the SJ, maximal jump height (35.4 ± 4.6 cm) was produced using a self-selected knee angle (98.7 ± 11.2°). Differences between 90°, 100°, and self-selected knee angles for jump height were trivial (ES ± 90% CL = 90°-100° 0.23 ± 0.12, 90°-SS -0.04 ± 0.12, 100°-SS -0...
Training in front of mirrors is common, yet little is known about how the use of mirrors effects ... more Training in front of mirrors is common, yet little is known about how the use of mirrors effects muscle force production. Accordingly, we investigated how performing in front of a mirror influences performance in single and multi-joint tasks, and compared the mirror condition to the established performance effects of internal focus (IF) and external focus (EF) instructions in a two part experiment. In the single-joint experiment 28 resistance-trained participants (14 males and 14 females) completed two elbow flexion maximal voluntary isometric contractions under four conditions: mirror, IF, EF and neutral instructions. During these trials, surface EMG activity of the biceps and triceps were recorded. In the multi-joint experiment the same participants performed counter-movement jumps on a force plate under the same four conditions. Single-joint experiment: EF led to greater normalized force production compared to all conditions (P≤0.02, effect-size range [ES] = 0.46-1.31). No differ...
While self-controlled practice has been shown to enhance motor learning with various populations ... more While self-controlled practice has been shown to enhance motor learning with various populations and novel tasks, it remains unclear if such effects would be found with athletes completing familiar tasks. Study 1 used a single case-study design with a world-champion kickboxer. We investigated whether giving the athlete a choice over the order of punches would affect punching velocity and impact force. Separated by 1 min of rest, the athlete completed 2 rounds of 12 single, maximal effort punches (lead straight, rear straight, lead hook and rear hook) delivered to a punching integrator in a counterbalanced order over six testing days. In one round the punches were delivered in a predetermined order while in the second round the order was self-selected by the athlete. In the choice condition, the world champion punched with greater velocities (6-11 %) and impact forces (5-10 %). In Study 2, the same testing procedures were repeated with 13 amateur male kickboxers over 2 testing days. ...
ABSTRACT BSTRACT Research has identified a plethora of physiological, biochemical, psychological ... more ABSTRACT BSTRACT Research has identified a plethora of physiological, biochemical, psychological and performance markers that help inform coaching staff about when an athlete is in a state of fatigue or recovery. However use of such markers in the regular high performance training environment remains undocumented. To establish current best practice methods for training monitoring, 100 participants involved in coaching or sport science support roles in a variety of high performance sports programs were invited to participate in an online survey. The response rate was 55% with results indicating 91% of respondents implemented some form of training monitoring system. A majority of respondents (70%) indicated there was an equal focus between load quantification and the monitoring of fatigue and recovery within their training monitoring system. Interestingly, 20% of participants indicated the focus was solely on load quantification, while 10% solely monitored the fatigue/recovery process. Respondents reported that the aims of their monitoring systems were to prevent overtraining (22%), reduce injuries (29%), monitor the effectiveness of training programs (27%), and ensure maintenance of performance throughout competitive periods (22%). A variety of methods were used to achieve this, based mainly on experiential evidence rather than replication of methods used in scientific publications. Of the methods identified for monitoring fatigue and recovery responses, self-report questionnaires (84%) and practical tests of maximal neuromuscular performance (61%) were the most commonly utilised.
Research indicates that instructing athlete's to focus on bodily movements (internal focus of... more Research indicates that instructing athlete's to focus on bodily movements (internal focus of attention [IFA]) may hinder performance, whereas instructing them to focus on the movement outcome (external focus of attention [EFA]) often enhances performance. Despite the importance of instructions in striking combat sports, limited research has examined the influence of IFA and EFA on performance in well-trained combat athletes. This study investigated the effects of different instructional cues on punching velocity (m · s(-1)) and normalised impact forces (N · kg(-1)) among intermediate (n = 8) and expert (n = 7) competitive boxers and kickboxers. Athletes completed three rounds of 12 maximal effort punches delivered to a punching integrator on three separate days. Day one was a familiarisation session with only control instructions provided. In the following two days athletes randomly received IFA, EFA or control instructions prior to each of the three rounds. Athletes punching w...
Non-local muscle fatigue (NLMF) is characterized by muscle performance impairments in a contralat... more Non-local muscle fatigue (NLMF) is characterized by muscle performance impairments in a contralateral or remote non-exercised muscle(s) following a fatiguing protocol of a different muscle group(s). This topic is of interest as it affords insights into physiological determinants of muscle fatigue and may provide practical applications concerning the order of exercises in training and rehabilitation programs. A literature review was conducted using Web of Science, PubMed, and Google Scholar databases to evaluate the NLMF effects and possible underlying mechanisms. Overall, 35 studies with 58 outcome measures that met the inclusion criteria were identified. The literature is conflicting with approximately half of the studies reporting NLMF effects (32 of 58 measurements). However, on closer examination 76% of outcome measures of the lower limbs reported NLMF effects (23 of 30 measurements) compared to only 32% in the upper body (9 of 28 measurements). Thus, it appears that NLMF effect...
This study aimed to (1) profile a professional boxer (23 years and 80 kg) with boxing-specific, m... more This study aimed to (1) profile a professional boxer (23 years and 80 kg) with boxing-specific, muscle function, aerobic capacity and body composition tests, and (2) quantify how these measures varied during an 8-week preparation phase leading to, and post a state-Title Bout fought in the 76.2-kg class. A series of boxing-specific and muscle function tests were completed on 11 occasions: 9 prior and twice after the bout, each separated by approximately 2 weeks. The boxing test included 36 maximal punches (9 of each: lead and rear straights, lead and rear hooks) to a punching integrator measuring forces and velocity. Muscle function tests included countermovement jump, drop-jumps, isometric mid-thigh pull and isometric bench-press. Body composition was assessed using skin-fold measurements on three occasions and one dual energy X-ray absorptiometry scan. Aerobic capacity was assessed using 2 VO2 max tests. Leading up to the bout, performance decreased in isometric mid-thigh pull (8%)...
ABSTRACT The aim of this study was to determine the individual effects of acute sodium bicarbonat... more ABSTRACT The aim of this study was to determine the individual effects of acute sodium bicarbonate (NaHCO3) supplementation on elite short track speed skating relay race simulation. Material and Method. Double-blinded balanced, cross-over investigation required two teams of 4 athletes from the Australian National Short Track Speed Skating Program to participate in 2 simulated relay races 72 h apart. Each athlete performed 7 maximal speed skating sprints at a work:rest ratio of ~1:4. Each athlete ingested either 0.3g.kg-1 per body mass of NaHCO3 or lactose placebo (P) 75 min prior to each race. Plasma blood lactate concentration (Bla) was recorded 10min pre- and 2 min post- race simulation. Race lap times and changes in Bla were log transformed and analyzed using paired sample t-tests between NaHCO3 and P. Data were also, analysed to evaluate individual response. Magnitudes of differences between conditions were interpreted using effect sizes (ES) and 90% confidence limits (CL). Results. Post-race simulation, Bla concentration demonstrated a very large increase from baseline for both groups. P demonstrated substantially faster performance for overall (ES: 0.98, CL: -0.13 to 1.82), mean lap (ES: 1.59, CL: 0.22 to 2.95), and fastest lap time (ES: 1.26, CL: 0.02 to 2.50) compared to NaHCO3. Interpretation of the individual analysis indicates that NaHCO3 results in a greater magnitude of individual variation for total (ES: 1.05, CL: -0.40 to 1.54), mean (ES: 2.04, CL: 0.71 to 2.79), and fastest lap time (ES: 1.85, CL: 0.64 to 2.54) than P. Conclusion. These findings indicate responses to acute NaHCO3 supplementation may be individual.
Micro-sensors were used to quantify macro kinematics of classical cross-country skiing techniques... more Micro-sensors were used to quantify macro kinematics of classical cross-country skiing techniques and measure cycle rates and cycle lengths during on-snow training. Data were collected from seven national level participants skiing at two submaximal intensities while wearing a micro-sensor unit (MinimaxX(™)). Algorithms were developed identifying double poling (DP), diagonal striding (DS), kick-double poling (KDP), tucking (Tuck), and turning (Turn). Technique duration (T-time), cycle rates, and cycle counts were compared to video-derived data to assess system accuracy. There was good reliability between micro-sensor and video calculated cycle rates for DP, DS, and KDP, with small mean differences (Mdiff% = -0.2 ± 3.2, -1.5 ± 2.2 and -1.4 ± 6.2) and trivial to small effect sizes (ES = 0.20, 0.30 and 0.13). Very strong correlations were observed for DP, DS, and KDP for T-time (r = 0.87-0.99) and cycle count (r = 0.87-0.99), while mean values were under-reported by the micro-sensor. Incorrect Turn detection was a major factor in technique cycle misclassification. Data presented highlight the potential of automated ski technique classification in cross-country skiing research. With further refinement, this approach will allow many applied questions associated with pacing, fatigue, technique selection and power output during training and competition to be answered.
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