ORCID Profile
0000-0001-7342-4240
Current Organisations
University of Technology Sydney
,
Rugby Australia
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Publisher: Human Kinetics
Date: 05-2019
Abstract: Purpose : To examine the collective independent influence of a range of in idual characteristics on physical and technical match performance during international rugby sevens matches. Methods : Data were collected from 20 international rugby sevens players from 1 team across 1 season. Activity profiles were measured using wearable microtechnology devices, and technical performance measures were collected from match video analysis. Subjective well-being measures were collected using a well-being questionnaire completed on the morning of main training days, and groin-squeeze assessments at 0° and 60° knee flexion were also conducted using a sphygmomanometer. Assessments of aerobic fitness were completed periodically across the season, including time to complete a 2-km run and final velocity during the 30:15 Intermittent Fitness Test ( V IFT ). A principal-components analysis was conducted to reduce the dimensionality of the physical and technical variables into single-factor values. Linear mixed models were then constructed to examine the collective influence of a range of in idual contextual variables on physical and technical performance factors. Results : Increased muscle soreness, stress, and V IFT were associated with trivial to small increases in physical and technical performance values, whereas trivial to small decreases were associated with higher perceived recovery, body weight, and groin squeeze (0° knee flexion). Conclusions : A range of well-being metrics are required to account for a significant portion of the variance in physical and technical performance. These factors may be manipulated by coaches or practitioners to achieve favorable physiological readiness that may lead to improved match performance.
Publisher: Human Kinetics
Date: 09-2023
Abstract: Purpose : This study investigated within- and between-matches blood lactate (La − ) responses across an international Rugby Sevens tournament (5 matches over 2 d) in male and female players. Methods : Earlobe blood s les were taken from 25 professional players around matches: before warm-up (PRE), immediately upon finishing match participation (POST), and 30 minutes postmatch (30 min). Results : POST [La − ] (mean [SD], range) for males was 10.3 (3.2 2.9–20.2) mmol·L −1 and for females was 9.1 (2.3 3.4–14.6) mmol·L −1 . Linear mixed-effects models revealed a decrease in POST [La − ] after match 5, compared to match 1. Increased PRE [La − ] was found before match 2 (+0.8 [0.6–1.1] mmol·L −1 ), match 3 (+0.8 [0.5–1.1] mmol·L −1 ), and match 5 (+0.6 [0.4–0.9] mmol·L −1 ) compared to match 1 (all P .001). The [La − ] remained elevated at 30 min, compared to PRE (+1.7 [1.4–2.0] mmol·L −1 , P .001), with ∼20% of values persisting mmol·L −1 . Higher POST was observed in males compared to females (+1.6 [0.1–3.2] mmol·L −1 , P = .042) however, no differences between sexes were found across 30 min or PRE [La − ]. No [La − ] differences between positions (backs and forwards) were identified. Conclusions : Lactate concentrations above 10 mmol·L −1 are required to effectively simulate the anaerobic demands of international Rugby Sevens matches. Practitioners are advised to in idualize anaerobic training prescription due to the substantial variability observed within positional groups. Additionally, improving athletes’ metabolic recovery capacity through training, nutrition, and recovery interventions may enhance physical preparation for subsequent matches within a day, where incomplete lactate clearance was observed.
Publisher: Informa UK Limited
Date: 27-04-2019
Publisher: Springer Science and Business Media LLC
Date: 08-2023
DOI: 10.1007/S40279-023-01892-3
Abstract: Hyperthermia (and associated health and performance implications) can be a significant problem for athletes and teams involved in intermittent sports. Quantifying the highest thermal strain (i.e. peak core body temperature [peak T c ]) from a range of intermittent sports would enhance our understanding of the thermal requirements of sport and assist in making informed decisions about training or match-day interventions to reduce thermally induced harm and/or performance decline. The objective of this systematic review was to synthesise and characterise the available thermal strain data collected in competition from intermittent sport athletes. A systematic literature search was performed on Web of Science, MEDLINE, and SPORTDiscus to identify studies up to 17 April 2023. Electronic databases were searched using a text mining method to provide a partially automated and systematic search strategy retrieving terms related to core body temperature measurement and intermittent sport. Records were eligible if they included core body temperature measurement during competition, without experimental intervention that may influence thermal strain (e.g. cooling), in healthy, adult, intermittent sport athletes at any level. Due to the lack of an available tool that specifically includes potential sources of bias for physiological responses in descriptive studies, a methodological evaluation checklist was developed and used to document important methodological considerations. Data were not meta-analysed given the methodological heterogeneity between studies and therefore were presented descriptively in tabular and graphical format. A total of 34 studies were selected for review 27 were observational, 5 were experimental (2 parallel group and 3 repeated measures randomised controlled trials), and 2 were quasi-experimental (1 parallel group and 1 repeated measures non-randomised controlled trial). Across all included studies, 386 participants (plus participant numbers not reported in two studies) were recruited after accounting for shared data between studies. A total of 4 studies (~ 12%) found no evidence of hyperthermia, 24 (~ 71%) found evidence of ‘modest’ hyperthermia (peak T c between 38.5 and 39.5 °C), and 6 (~ 18%) found evidence of ‘marked’ hyperthermia (peak T c of 39.5 °C or greater) during intermittent sports competition. Practitioners and coaches supporting intermittent sport athletes are justified to seek interventions aimed at mitigating the high heat strain observed in competition. More research is required to determine the most effective interventions for this population that are practically viable in intermittent sports settings (often constrained by many competing demands). Greater statistical power and homogeneity among studies are required to quantify the independent effects of wet bulb globe temperature, competition duration, sport and level of competition on peak T c , all of which are likely to be key modulators of the thermal strain experienced by competing athletes. This systematic review was registered on the Open Science Framework ( osf.io/vfb4s 0.17605/OSF.IO/EZYFA , 4 January 2021).
No related grants have been discovered for Mitchell Henderson.