ORCID Profile
0000-0003-1901-6910
Current Organisation
University of South Australia
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Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.JSAMS.2015.12.008
Abstract: The study examined the change in fitness test performance of elite junior Australian football cohorts tested over the span of seven years. Annual cross-sectional observation study. A total of 1714 elite junior male Australian football players were eligible for the study and completed annual late pre-season fitness testing between 2009 and 2015. The testing comprised anthropometric (height, mass, and skinfolds) and performance tests (standing vertical jump, left and right foot running vertical jumps, 5- and 20-m sprinting, agility, and shuttle run test). A linear regression analysed the performance change for each test over time for two analyses: (1) the entire cohort, and (2) a stratified analysis of 'high' (top 20% of players) and 'low' (bottom 20% of players) performers for each performance test. There was a moderate (f(2)=0.20) improvement in the standing vertical jump for the entire cohort. Small (f(2)≥0.03) changes occurred for the right and left foot running vertical jumps, agility, and shuttle run, whilst trivial/small (f(2)≤0.02) changes were observed for skinfolds, 5- and 20-m sprinting for the entire cohort. The most notable difference in the stratified analysis was that the 'low' performance groups had a greater improvement in the shuttle run, and 5- and 20-m sprinting. Findings indicate a small overall annual improvement in fitness test performance of elite junior cohorts over time that seems to permeate through both 'high' and 'low' performers for most tests. The results might suggest an increase in the professionalism of players and junior developmental pathways.
Publisher: Elsevier BV
Date: 05-2012
DOI: 10.1016/J.JSAMS.2011.12.002
Abstract: To implement an injury recording protocol in a junior elite Australian Football competition and determine the injury profile of this population. Longitudinal cohort study. Players from an elite Under 18 Australian Football competition were tracked throughout one football season in terms of participation or non-participation in the football competition. Injury reporting forms were collected for all players who were not available for selection as a result of injury. The cohort consisted of 532 players who provided consent for inclusion in the study (100% of players in the competition). There were 256 injuries sustained during the season. Results were standardised to a 40 man team to allow comparison with results from the Australian Football League. The injury incidence was 17.1 new injuries per club (95% CI 14.1-19.4), and prevalence 63.3 missed matches per club (95% CI 59.1-67.1). The category "Ankle joint injuries" was the most commonly reported (n=34) and "Collision with another player" was the main injury mechanism (n=75). The most commonly injured region in junior elite Australian Football was the ankle and collision with another player was the most common injury mechanism. As with previous reports on junior Australian Football, injury incidence was low in comparison to the senior elite competition. Defining the injury profile guides injury prevention strategies. Analysis of injury in junior elite football may provide a unique opportunity to affect both junior and senior injury rates.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 17-10-2023
DOI: 10.1249/MSS.0000000000003062
Abstract: High-impact loads have been linked with running injuries. Fatigue has been proposed to increase impact loads, but this relationship has not been rigorously examined, including the associated role of muscle strength, power, and endurance. This study aimed to investigate the effect of fatigue on impact loading in runners and the role of muscle function in mediating changes in impact loading with fatigue. Twenty-eight trained endurance runners performed a fixed-intensity time to exhaustion test at 85% of V̇O 2max . Tibial accelerations were measured using leg-mounted inertial measurement units and s led every minute until volitional exhaustion. Tests of lower limb muscle strength, power, and endurance included maximal isometric strength (soleus, knee extensors, and knee flexors), single leg hop for distance, and the one leg rise test. Changes in peak tibial acceleration (PTA, g ) were compared between time points throughout the run (0%, 25%, 50%, 75%, and 100%). Associations between the change in PTA and lower limb muscle function tests were assessed (Spearman’s rho [ r s ]). PTA increased over the duration of the fatiguing run. Compared with baseline (0%) (mean ± SD, 9.1 g ± 1.6 g ), there was a significant increase at 75% (9.9 g ± 1.7 g , P = 0.001) and 100% (10.1 g ± 1.8 g , P 0.001), with no change at 25% (9.6 g ± 1.6 g , P = 0.142) or 50% (9.7 g ± 1.7 g , P = 0.053). Relationships between change in PTA and muscle function tests were weak and not statistically significant ( r s = −0.153 to 0.142, all P 0.05). Peak axial tibial acceleration increased throughout a fixed-intensity run to exhaustion. The change in PTA was not related to performance in lower limb muscle function tests.
Publisher: Routledge
Date: 03-09-2018
Publisher: Springer Science and Business Media LLC
Date: 18-05-2019
DOI: 10.1007/S40279-019-01126-5
Abstract: Studies investigating the association between the Functional Movement Screen (FMS) and sports injury risk have reported mixed results across a range of athlete populations. The purpose of this systematic review was to identify whether athlete age, sex, sport type, injury definition and mechanism contribute to the variable findings. Systematic review and meta-analysis. A systematic search was conducted in October 2018 using PubMed, EBSCOhost, Scopus, EmBase and Web of Science databases. Studies were included if they were peer reviewed and published in English language, included athletes from any competition level, performed the FMS at baseline to determine risk groups based on FMS composite score, asymmetry or pain, and prospectively observed injury incidence during training and competition. Study eligibility assessment and data extraction was performed by two reviewers. Random effects meta-analyses were used to determine odds ratio (OR), sensitivity and specificity with 95% confidence intervals. Sub-group analyses were based on athlete age, sex, sport type, injury definition, and injury mechanism. Twenty-nine studies were included in the FMS composite score meta-analysis. There was a smaller effect for junior (OR = 1.03 [0.67-1.59] p = 0.881) compared to senior athletes (OR = 1.80 [1.17-2.78] p = 0.008) and for male (OR = 1.79 [1.08-2.96] p = 0.024) compared to female (OR = 1.92 [0.43-8.56] p = 0.392) athletes. FMS composite scores were most likely to be associated with increased injury risk in rugby (OR = 5.92 [1.67-20.92] p = 0.006), and to a lesser extent American football (OR = 4.41 [0.94-20.61] p = 0.059) and ice hockey (OR = 3.70 [0.89-15.42] p = 0.072), compared to other sports. Specificity values were higher than sensitivity values for FMS composite score. Eleven studies were included in the FMS asymmetry meta-analysis with insufficient study numbers to generate sport type subgroups. There was a larger effect for senior (OR = 1.78 [1.16-2.73] p = 0.008) compared to junior athletes (OR = 1.21 [0.75-1.96] p = 0.432). Sensitivity values were higher than specificity values for FMS asymmetry. For all FMS outcomes, there were minimal differences across injury definitions and mechanisms. Only four studies provided information about FMS pain and injury risk. There was a smaller effect for senior athletes (OR = 1.28 [0.33-4.96] p = 0.723) compared to junior athletes (OR = 1.71 [1.16-2.50] p = 0.006). Specificity values were higher than sensitivity values for FMS pain. Athlete age, sex and sport type explained some of the variable findings of FMS prospective injury-risk studies. FMS composite scores and asymmetry were more useful for estimating injury risk in senior compared to junior athletes. Effect sizes tended to be small except for FMS composite scores in rugby, ice hockey and American football athletes. CRD42018092916.
Publisher: Elsevier BV
Date: 11-2019
Publisher: Elsevier BV
Date: 04-2022
DOI: 10.1016/J.JSAMS.2021.10.014
Abstract: Identify how modified Lower-Quarter Y-Balance Test (mYBT-LQ) and Upper-Quarter Balance Test (mYBT-UQ) scores relate to injury risk and measures of physical performance in elite adolescent Australian Football (AF) athletes. Prospective cohort study. Pre-season mYBT-LQ, mYBT-UQ, and physical performance measures (speed, jump height, and agility) were obtained in 257 elite adolescent male AF athletes. Injury status was tracked across the 18-game season to determine the relationship between mYBT scores and injury risk based on time-to-event analysis. Cross-sectional analysis of mYBT-LQ scores and performance measures determined the relationships between these variables. There were no significant associations between injury risk and any single mYBT parameter. However, athletes with high posteromedial asymmetry and good agility performance (top 25% of the cohort) had moderately increased injury risk with and tended to without a previous injury history (Hazard Ratio = 3.26 [95% Confidence Interval: 1.01, 10.54 p = 0.048] and 2.69 [95% Confidence Interval = 0.92, 7.82 p = 0.069], respectively). There were significant correlations between faster agility times and higher composite limb-length normalised mYBT-LQ (r = -0.210 CI = -0.324, -0.090), limb-length normalised average posteromedial reach score (r = -0.227 CI = -0.340, -0.108), and limb-length normalised average posterolateral reach score (r = -0.250: CI = -0.361, -0.132). In isolation, the mYBT is not useful for identifying injury risk in junior AF athletes, and only small correlations between mYBT-LQ and physical performance variables were identified. However, high mYBT-LQ posteromedial asymmetry is associated with increased injury risk for athletes with good agility performance. This should be considered within athlete preparation programs.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-03-2021
DOI: 10.1519/JSC.0000000000003903
Abstract: Bennett, H, Fuller, J, Milanese, S, Jones, S, Moore, E, and Chalmers, S. The relationship between movement quality and physical performance in elite adolescent Australian football players. J Strength Cond Res 36(10): 2824–2829, 2022—The assessment of movement quality is commonplace in competitive sport to profile injury risk and guide exercise prescription. However, the relationship between movement quality scores and physical performance measures is unclear. Moreover, whether improvements in these measures are associated remain unknown. Over a 4-year period, 918 in idual elite adolescent Australian Rules Footballers completed the Functional Movement Screen (FMS) and physical performance testing (5- and 20-m sprint, vertical jump, planned agility, and 20-m shuttle run test), allowing the analysis of relationships between FMS parameters and performance measures. In addition, 235 athletes completed testing over 2 consecutive years, allowing the analysis of relationships between changes in these outcomes. Small associations were observed between FMS composite score, hurdle step performance, in-line lunge performance, trunk stability push-up performance, rotary stability, and measures of speed, power, agility, and aerobic fitness (ρ = 0.071–0.238). Across consecutive seasons, significant improvements were observed in the deep squat subtest ( d = 0.21), FMS composite score ( d = 0.17), and 5- ( d = 0.16) and 20-m sprint times ( d = 0.39). A negative association between change in rotary stability and change in jump height (ρ = −0.236) from one season to the next was detected. Results suggest FMS scores have limited relationships with measures of performance in footballers. To optimize athletic performance, once acceptable movement capabilities have been established, training should not prioritize improving movement quality over improvements in strength, power, and change of direction ability.
Publisher: Informa UK Limited
Date: 02-01-2023
Publisher: Wiley
Date: 07-05-2020
DOI: 10.1111/SMS.13686
Publisher: Human Kinetics
Date: 05-2022
Abstract: Purpose: Determine the impact of preseason and between-seasons changes in in idual physical performance on injury risk in elite junior Australian football players and if injuries sustained during a season impact subsequent-season performance improvement. Methods: This prospective cohort study assessed in idual performance measures (sprint speed, jump, agility, and aerobic endurance) during preseason over 4 consecutive seasons. Injury status (injured/not injured) was tracked weekly to determine the relationship between in idual performance and in-season injury occurrence. Mixed models were used to determine the relationship between physical performance and injury, and the effect of injury on physical performance improvement. Results: A total of 206 players played 2 consecutive seasons and were included (17.6 y, 181.9 cm, 75.7 kg). Faster players during preseason experienced higher injury incidence (injuries/season) during that playing season (incidence rate ratio = 0.127 P = .034). Injury incidence was not influenced by between-seasons change in any performance measure. Players injured during their first season maintained their aerobic fitness, which declined in noninjured players ( d = 0.39 P = .013). Players who sustained a lower-limb injury during their first season saw smaller improvements in sprint speed than players who did not get injured ( d = 0.39 P = .035). Conclusion: Faster players experience higher injury incidence than slower players and may require specific prevention interventions. Players who experience a lower-limb injury during the playing season do not improve sprint speed between seasons to the same extent as players who do not get injured, highlighting the need for targeted high-speed running ability development as part of rehabilitation.
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.JSAMS.2019.04.009
Abstract: The study examined if three feasible strategies involving additional in-play cooling periods attenuate the core (rectal) temperature rise during simulated football matches. Four counterbalanced experimental trials in an environmental chamber set to 35 °C ambient temperature, 55% relative humidity, and 30 °C WBGT. Twelve healthy well-trained football players completed a regular simulated match (REG), regular simulated match with additional 3-min cooling periods at the 30-min mark of each half inclusive of chilled water consumption (COOL The difference in rectal temperature change was significantly lower in the COOL All three cooling interventions attenuated core body thermal strain during simulated matches. The laboratory-based study supports the use of brief in-play cooling periods as a means to attenuate the rise in core temperature during matches in hot and humid conditions.
Publisher: Wiley
Date: 22-01-2018
DOI: 10.1111/SMS.13021
Abstract: An indicator of movement quality and potential injury risk during Functional Movement Screen (FMS) testing is the presence of asymmetry when comparing the left and right sides of the body. The aim of the study was to investigate the reproducibility of the injury risk model proposed in our previous research (Chalmers et al. 2017 derivation study) that showed an increased injury risk for elite junior Australian football players demonstrating ≥2 asymmetrical FMS subtests. We used a direct replication design. Players underwent pre-season FMS testing, and an injury surveillance system monitored 277 male participants during the subsequent regular season competition. Designated club officials monitored the weekly competition participation of players. The definition of an injury was "a trauma or medical condition which caused a player to miss a competitive game". Cox proportional hazards regression models were used to investigate the relationship between asymmetry and number of games played before first injury (ie, survival time). The level of reproducibility was determined according to statistical significance, effect size, and subjective assessment. Demonstrating asymmetry during FMS testing was not associated with a significant increase in prospective injury risk in the replication study (P > .05). Moreover, effect sizes (hazard ratios) from the derivation dataset were not within the 95% confidence intervals of the respective asymmetry predictor in the replication dataset. Subjectively, researchers were in agreement that the findings from the derivation data were not successfully reproduced. Clinicians and researchers should be cautious about using FMS asymmetry findings to derive injury risk for junior football players.
Publisher: Elsevier BV
Date: 04-2017
DOI: 10.1016/J.JTHERBIO.2017.01.011
Abstract: Heat acclimation over consecutive days has been shown to improve aerobic-based performance. Recently, it has been suggested that heat training can improve performance in a temperate environment. However, due to the multifactorial training demands of athletes, consecutive-day heat training may not be suitable. The current study aimed to investigate the effect of brief (8×30min) intermittent (every 3-4 days) supplemental heat training on the second lactate threshold point (LT
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.JTHERBIO.2018.01.012
Abstract: The effects of pre cooling on endurance performance are widely known. In contrast, the approach of cooling during endurance exercise in combination with pre-exercise cooling has been poorly understood. The purpose of the present study was to determine whether the effects of precooling and cooling during exercise enhance exercise performance compared to the ingestion of a thermo-neutral beverage (20 °C) or precooling alone in cycling performance. This was an experimental study using a randomised crossover design in which 7 cyclists underwent three trials comprising of 45 min steady state cycling (SS) at 70% VO
Publisher: Elsevier BV
Date: 06-2018
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.JSAMS.2016.05.003
Abstract: The purpose of this study was to describe the prevalence of dysfunctional, asymmetrical, and painful movement in junior Australian Football players using the Functional Movement Screen (FMS). Cross-sectional study. Elite junior male Australian Football players (n=301) aged 15-18 years completed pre-season FMS testing. The FMS consists of 7 sub-tests: deep squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, trunk stability push-up (TSPU) and rotary stability. The shoulder mobility, TSPU, and rotary stability tests were combined with an accompanying clearing test to assess pain. Each sub-test was scored on an ordinal scale from 0 to 3 and summed to give a composite score out of 21. Composite scores ≤14 were operationally defined as indicating dysfunctional movement. Players scoring differently on left and right sides were considered asymmetrical. Players reported whether they missed any games due to injury in the preceding 22 game season. Sixty percent of players (n=182) had composite scores ≤14, 65% of players (n=196) had at least one asymmetrical sub-test, and 38% of players (n=113) had at least one painful sub-test. Forty-two percent of players (n=126) missed at least one game in the previous season due to injury. Previous injury did not influence composite score (p=0.951) or asymmetry (p=0.629). Players reporting an injury during the previous season were more likely to experience pain during FMS testing (odds ratio 1.97, 95% confidence interval 1.23-3.18 p=0.005). Junior Australian Football players demonstrate a high prevalence of dysfunctional, asymmetrical, and painful movement during FMS testing.
Publisher: Elsevier BV
Date: 07-2017
DOI: 10.1016/J.JSAMS.2016.12.076
Abstract: The Functional Movement Screen (FMS) is a popular screening tool, however, the postulated relationship between prospective injury and FMS scoring remains sparsely explored in adolescent athletes. The aim of the study was to examine the association between pre-season FMS scores and injuries sustained during one regular season competition in elite adolescent Australian football players. Prospective cohort study. 237 elite junior Australian football players completed FMS testing during the late pre-season phase and had their weekly playing status monitored during the regular season. The definition of an injury was 'a trauma which caused a player to miss a competitive match'. The median composite FMS score was 14 (mean=13.5±2.3). An apriori analysis revealed that the presence of ≥1 asymmetrical sub-test was associated with a moderate increase in the risk of injury (hazard ratio=2.2 [1.0-4.8] relative risk=1.9 p=0.047 sensitivity=78.4% specificity=41.0%). Notably, post-hoc analysis identified that the presence of ≥2 asymmetrical sub-tests was associated with an even greater increase in risk of prospective injury (hazard ratio=3.7 [1.6-8.6] relative risk=2.8 p=0.003 sensitivity=66.7% specificity=78.0%). Achieving a composite score of ≤14 did not substantially increase the risk of prospective injury (hazard ratio=1.1 [0.5-2.1] p=0.834). Junior Australian football players demonstrating asymmetrical movement during pre-season FMS testing were more likely to sustain an injury during the regular season than players without asymmetry. Findings suggest that the commonly reported composite FMS threshold score of ≤14 was not associated with injury in elite junior AF players.
Publisher: Elsevier BV
Date: 07-2013
DOI: 10.1016/J.JSAMS.2012.09.005
Abstract: Australian Football (AF) is a collision sport containing high injury rates in junior competition. Successful performance at the elite junior level not only requires superior specific football knowledge and skills, but also well developed fitness qualities. However, no studies have examined the link between physical fitness qualities and injury in AF. Prospective cohort. Injury data were collected through the use of a Player Movement Record (PMR) and a standardized Injury Report Form (IRF). Fitness test data was collected during the pre-season of the 2010 and 2011 seasons. 382 players consented to participate in the study. The cohort experienced an injury incidence rate of 24.29/standardized club (40 players/club). A faster 5-m sprint was associated with 'injury status' (p=0.016) and a 'knee' region (p≤0.001) injury. A faster planned agility score was associated with an increased risk of a 'hip/groin/thigh' region (p=0.010) injury, and specifically a 'quadriceps strain' (p=0.005). A lower 20-m shuttle run was associated with an increased risk of a 'shin/ankle/foot' (p=0.045) injury. Increased injury severity was associated with a higher left foot running vertical jump (VJ) (p=0.040), and faster 5-m sprint (p=0.043). Lower aerobic endurance, faster 5-m acceleration and greater planned agility were associated with an increased risk of various injury types in elite junior AF players. Furthermore, a higher left foot running VJ and faster 5-m acceleration were associated with injury severity. These results may largely relate to a greater work capacity placing a higher load upon the musculoskeletal system in contact and non-contact situations.
Publisher: Informa UK Limited
Date: 02-10-2017
Publisher: Frontiers Media SA
Date: 23-12-2021
DOI: 10.3389/FPHYS.2021.785399
Abstract: Open-water swim racing in warm water is associated with significant physiological strain. However, existing international policy that governs safe participation during competition relies only on a fixed water temperature threshold for event cancellation and has an unclear biophysical rationale. The current policy does not factor other environmental factors or race distance, nor provide a stratification of risk (low, moderate, high, or extreme) prior to the threshold for cancellation. Therefore, the primary aim of this Perspectives article is to highlight considerations for the development of modernized warm-water competition policies. We highlight current accounts (or lack thereof) of thermal strain, cooling interventions, and performance in warm-water swimming and opportunities for advancement of knowledge. Further work is needed that systematically evaluate real-world thermal strain and performance during warm water competition (alongside reports of environmental conditions), novel preparatory strategies, and in-race cooling strategies. This could ultimately form a basis for future development of modernized policies for athlete cohorts that stratifies risk and mitigation strategies according to important environmental factors and race-specific factors (distance).
Publisher: Elsevier BV
Date: 04-2023
Publisher: Elsevier BV
Date: 10-2019
Publisher: Informa UK Limited
Date: 20-06-2022
DOI: 10.1080/02640414.2022.2089803
Abstract: This systematic review and meta-analysis aimed to synthesise and clarify the effect of running-induced fatigue on impact loading during running. Eight electronic databases were systematically searched until April 2021. Studies that analysed impact loading over the course of a run, in adult runners free of medical conditions were included. Changes in leg stiffness, vertical stiffness, shock attenuation, peak tibial accelerations, peak ground reaction forces (GRF) and loading rates were extracted. Subgroup analyses were conducted depending on whether participants were required to run to exhaustion. Thirty-six studies were included in the review, 25 were included in the meta-analysis. Leg stiffness decreased with running-induced fatigue (SMD -0.31, 95% CI -0.52, -0.08, moderate evidence). Exhaustive and non-exhaustive subgroups were different for peak tibial acceleration (Chi
Publisher: Elsevier BV
Date: 08-2013
DOI: 10.1016/J.PTSP.2013.06.001
Abstract: Summarise the progress of junior Australian football (AF) injury research in line with the six stages of the 'Translating Research into Injury Prevention Practice' (TRIPP) model, in order to direct future research for the area. Systematically searched narrative review. Bibliographic research databases (Medline, PubMed, Scopus, and SPORTDiscus™) were used to search for original studies in which injuries in junior AF players were investigated. 18 studies (NHMRC levels of evidence ranging from NHMRC II-IV) addressed junior AF injuries within the TRIPP model. Injury surveillance (stage 1) was represented by five studies, aetiology and mechanism of injury (stage 2) was represented by various contributions from 12 studies, and injury prevention (stages 3-6) was represented by five papers. All papers addressing TRIPP stage 1 suffered from methodological discrepancies and inconsistencies in the data that are reported. Hence, a consistent injury definition and ongoing injury surveillance remains a priority. Injury research at the junior level of AF is predominantly situated at stage 2 of the TRIPP process. It can be postulated that most junior AF injury prevention programs are based upon senior AF research and anecdotal evidence due to the paucity of studies addressing stages 3-6.
Publisher: Journal of Orthopaedic & Sports Physical Therapy (JOSPT)
Date: 02-2020
Abstract: To describe the location and severity of pain during Functional Movement Screen (FMS) testing in junior Australian football players and to investigate its effect on FMS composite score and injury risk. Prospective cohort study. Junior male Australian football players (n = 439) completed preseason FMS testing. Pain location and severity (on a 0-to-10 numeric pain-rating scale [NPRS]) were assessed for painful subtests. The FMS composite score was calculated using 3 scoring approaches: "traditional," a score of zero on painful subtests "moderate," a score of zero on painful subtests if an NPRS pain severity was greater than 4 and "raw," did not adjust painful FMS subtest scores. Players were monitored throughout the competitive season and considered injured when 1 or more matches were missed due to injury. One hundred seventy players reported pain during FMS testing. The pain-scoring approach affected mean composite score values (raw, 14.9 moderate, 14.5 traditional, 13.6 Pain was common during FMS testing in junior Australian football players and had a notable effect on the FMS composite score, but minimal effect on subsequent injury risk.
Publisher: Human Kinetics
Date: 10-2015
Abstract: The purpose of this study was to test the reliability and validity of 2 standardized methods for calculating speed at the second lactate-threshold point (LT 2 ) based on the preexisting D max (LT D ) and modified D max (LT MOD ) procedures. 13 trained male road runners and triathletes completed 2 incremental laboratory running tests to determine LT 2 , followed by separate time trials (5, 10, 15 km) on an outdoor running track. Two new methods were proposed for calculating the speed at LT 2 : (1) the single standardized lactate threshold (LT SDs ) and (2) the paired standardized lactate threshold (LT SDp ) for quantifying changes over time. The LT SDs and LT SDp methods had high relative (ICC ≥ .98) and absolute (CV ≤ 1.9%) reliability in identifying the speed at LT 2 . The speed at LT2 according to the LT SDs and LT SDp methods had a strong correlation and was not different to the performance speed during the 10- and 15-km time trials (≤2.3% ρ c 0.8 P .05). The following natural logbased formula was created to estimate the percentage of LT 2 speed (using the LT SDs method) that could be sustained for events ~15–75 min: y = –7.256(ln x ) + 157.64, where y = %LT 2 speed, x = time-trial performance (s), and ln = natural log. The standardized methods are reliable for determining LT 2 . The LT SDs and LT SDp methods for calculating the speed at LT 2 from a near-maximal incremental test calculated speeds similar to those exhibited in 10- and 15-km running time trials. A prediction equation for estimating the percentage of LT 2 that can be sustained for events of ~15–75 min was generated.
Publisher: Human Kinetics
Date: 11-2016
Abstract: Athletes often seek the minimum required time that might elicit a physiological or performance change. It is reasonable to suggest that heat training may improve aerobic-based performance in mild conditions. Therefore, rather than providing a traditional heat-exposure stimulus (ie, 7–10 × 60–100 min sessions), the current article details 2 studies that aimed to determine the effect of brief (≤240 min exposure) heat training on the second lactate threshold (LT 2 ) in mild conditions. Forty-one participants completed 5 (study 1, n = 18) or 4 (study 2, n = 23) perceptually regulated treadmill exercise training sessions in 35°C and 30% relative humidity (RH) (experimental group) or 19°C and 30% RH (control group). Preincremental and postincremental exercise testing occurred in mild conditions (19°C and 30% RH). Linear mixed-effects models analyzed the change in LT 2 . Heat training did not substantially change LT 2 in either study 1 (+1.2%, d = 0.38, P = .248) or study 2 (+1.9%, d = 0.42, P = .163). LT 2 was not substantially changed in the control group in study 1 (+1.3%, d = 0.43, P = .193), but a within-group change was evident in study 2 (+2.3%, d = 1.04, P = .001). Brief heat training was inadequate to improve the speed at LT 2 in mild conditions more than comparable training in mild conditions. The brief nature of the heattraining protocol did not allow adaptations to develop to the extent required to potentially confer a performance advantage in an environment that is less thermally stressful than the training conditions.
Publisher: Elsevier BV
Date: 08-2021
Publisher: BMJ
Date: 04-2020
DOI: 10.1136/BMJSEM-2020-000774
Abstract: We detail key considerations for the development of extreme heat policies in sport and exercise. Policies should account for the four environmental parameters (ambient temperature, humidity, air velocity, and mean radiant temperature) and two personal (activity and clothing) parameters that determine the prevailing thermoregulatory strain during exercise in the heat. Considerations for how to measure environmental stress and convey the level of risk are discussed. Finally, we highlight the need to include feasible cooling strategies that are relevant for the prevailing environmental conditions.
Publisher: Springer Science and Business Media LLC
Date: 10-05-2014
DOI: 10.1007/S40279-014-0178-6
Abstract: Studies have demonstrated that longer-term heat acclimation training (≥8 heat exposures) improves physical performance. The physiological adaptations gained through short-term heat acclimation (STHA) training suggest that physical performance can be enhanced within a brief timeframe. The aim of this systematic review was to determine if STHA training (≤7 heat exposures) can improve physical performance in healthy adults. MEDLINE, PubMed, and SPORTDiscus™ databases were searched for available literature. Studies were included if they met the following criteria: STHA intervention, performance measure outcome, apparently healthy participants, adult participants (≥18 years of age), primary data, and human participants. A modified McMaster critical appraisal tool determined the level of bias in each included study. Eight papers met the inclusion criteria. Studies varied from having a low to a high risk of bias. The review identified aerobic-based tests of performance benefit from STHA training. Peak anaerobic power efforts have not been demonstrated to improve. At the review level, this systematic review did not include tolerance time exercise tests however, certain professions may be interested in this type of exercise (e.g. fire-fighters). At the outcome level, the review was limited by the moderate level of bias that exists in the field. Only two randomized controlled trials were included. Furthermore, a limited number of studies could be identified (eight), and only one of these articles focused on women participants. The review identified that aerobic-based tests of performance benefit from STHA training. This is possibly through a number of cardiovascular, thermoregulatory, and metabolic adaptations improving the perception of effort and fatigue through a reduction in anaerobic energy release and elevation of the anaerobic threshold. These results should be viewed with caution due to the level of available evidence, and the limited number of papers that met the inclusion criteria of the review. STHA training can be applied in the team-sport environment during a range of instances within the competitive season. A mixed high-intensity protocol may only require five sessions with a duration of 60 min to potentially improve aerobic-based performance in trained athletes.
Publisher: Springer Science and Business Media LLC
Date: 14-09-2015
No related grants have been discovered for Samuel Chalmers.