ORCID Profile
0000-0001-7907-3752
Current Organisations
Netball South Australia / Adelaide Thunderbirds
,
University of South Australia
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Publisher: Asociacion Espanola de Analisis del Rendimiento Deportivo
Date: 21-06-2023
DOI: 10.55860/AGRH6754
Abstract: This systematic review and meta-analysis evaluated the validity of tests / markers of athletic readiness to predict physical performance in elite team and in idual sport athletes. Ovid MEDLINE, Embase, Emcare, Scopus and SPORT Discus databases were searched from inception until 15 March 2023. Included articles examined physiological and psychological tests / markers of athletic readiness prior to a physical performance measure. 165 studies were included in the systematic review and 27 studies included in the meta-analysis. 20 markers / tests of athletic readiness were identified, of which five were meta-analysed. Countermovement jump (CMJ) jump height had a large correlation with improved 10m sprint speed / time (r = 0.69 p = .00), but not maximal velocity (r = 0.46 p = .57). Non-significant correlations were observed for peak power (r = 0.13 p = .87) and jump height (r = 0.70 p = .17) from squat jump, and 10m sprint speed / time. CMJ jump height (r = 0.38 p = .41) and salivary cortisol (r = -0.01 p = .99) did not correlate with total distance. Sub-maximal exercise heart rate (r = -0.65 p = .47) and heart rate variability (r = 0.66 p = .31) did not correlate with Yo-Yo Intermittent Recovery Test 1 performance. No correlation was observed between blood C-reactive protein and competition load (r = 0.33 p = .89). CMJ jump height can predict sprint and acceleration qualities in elite athletes. The validity of the other readiness tests / markers meta-analysed warrants further investigation.
Publisher: Springer Science and Business Media LLC
Date: 08-1999
Abstract: In this study we investigated the effect of pedal cadence on the cycling economy, accumulated oxygen deficit (AOD), maximal oxygen consumption (VO2max) and blood lactate transition thresholds of ten high-performance junior endurance cyclists [mean (SD): 17.4 (0.4) years 183.8 (3.5) cm, 71.56 (3.75) kg]. Cycling economy was measured on three ergometers with the specific cadence requirements of: 90-100 rpm for the road dual chain ring (RDCR90-100 rpm) ergometer, 120-130 rpm for the track dual chain ring (TDCR120-130 rpm) ergometer, and 90-130 rpm for the track single chain ring (TSCR90-130 rpm) ergometer. AODs were then estimated using the regression of oxygen consumption (VO2) on power output for each of these ergometers, in conjunction with the data from a 2-min supramaximal paced effort on the TSCR90-130 rpm ergometer. A regression of VO2 on power output for each ergometer resulted in significant differences (P<0.001) between the slopes and intercepts that produced a lower AOD for the RDCR90-100 rpm [2.79 (0.43) l] compared with those for the TDCR120-130 rpm [4.11 (0.78) l] and TSCR90-130 rpm [4.06 (0.84) l]. While there were no statistically significant VO2max differences (P = 0.153) between the three treatments [RDCR90-100 rpm: 5.31 (0.24) l x min(-1) TDCR120-130 rpm 5.33 (0.25) 1 x min(-1) TSCR90-130 rpm: 5.44 (0.27) l x min(-1)], all pairwise comparisons of the power output at which VO2max occurred were significantly different (P<0.001). Statistically significant differences were identified between the RDCR90-100 rpm and TDCR120-130 rpm tests for power output (P = 0.003) and blood lactate (P = 0.003) at the lactate threshold (Thla-), and for power output (P = 0.005) at the in idual anaerobic threshold (Thiat). Our findings emphasise that pedal cadence specificity is essential when assessing the cycling economy, AOD and blood lactate transition thresholds of high-performance junior endurance cyclists.
Publisher: Springer Science and Business Media LLC
Date: 28-04-2021
DOI: 10.1186/S40798-021-00301-1
Abstract: There is extensive research investigating the match demands of players in the Australian Football League (AFL). This systematic literature review and meta-regression sought to analyse the evolution of in-game demands in AFL matches from 2005 to 2017, focusing on the relationship between volume and intensity. A systematic search of Ovid MEDLINE, Embase, Emcare, Scopus, SPORTDiscus, and Cochrane Library databases was conducted. Included studies examined the physical demands of AFL matches utilising global positioning system (GPS) technology. Meta-regression analysed the shift in reported volume (total distance and total match time) and intensity (metres per minute [m.min −1 ], sprint duration and acceleration) metrics for overall changes, across quarters and positional groups (forwards, nomadics and defenders) from 2005 to 2017 inclusive and for each year between 2005 and 2007, 2007 and 2010, 2010 and 2012, and 2012 and 2015/2017 breakpoints. Distance ( p = 0.094), m.min −1 ( p = 0.494), match time ( p = 0.591), time over 18 km·h −1 ( p = 0.271), and number of accelerations greater than 4 km·h −1 ( p = 0.498) and 10 km·h −1 ( p = 0.335) in 1 s did not change from 2005 to 2017. From 2005 to 2007 volume decreased (− 6.10 min of match time p = 0.010) and intensity increased (6.8 m.min −1 increase p = 0.023). Volume and intensity increased from 2007 to 2010, evidenced by increases in total distance (302 m p = 0.039), time over 18 km·h −1 (0.31 min p = 0.005), and number of accelerations greater than 4 km·h −1 (41.1 p = 0.004) and 10 km·h −1 (3.6 p = 0.005) in 1 s. From 2010 to 2012, intensity decreased, evidenced by reductions in metres per minute (− 4.3 p = 0.022), time over 18 km·h −1 (− 0.93 min p 0.001), and number of accelerations greater than 4 km·h −1 (− 104.4 p 0.001) and 10 km·h −1 (− 8.3 p 0.001) in 1 s, whilst volume stabilised with no changes in distance ( p = 0.068) and match time ( p = 0.443). From 2012 to 2015/2017 volume remained stable and intensity increased with time over 18 km·h −1 (0.27 min p = 0.008) and number of accelerations greater than 4 km·h −1 (31.6 p = 0.016) in 1 s increasing. Changes in volume and intensity of AFL match demands are defined by discrete periods from 2007 to 2010 and 2010 to 2012. The interaction of rule and interpretation changes and coaching strategies play a major role in these evolutionary changes. In turn, modified game styles impact player game demands, training, and selection priorities. Standardisation and uniformity of GPS data reporting is recommended due to inconsistencies in the literature.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2017
Publisher: Informa UK Limited
Date: 09-11-2017
DOI: 10.1080/14763141.2017.1391326
Abstract: Magnetic-inertial measurement units (MIMUs) are becoming more prevalent in sports biomechanics and may be a viable tool to evaluate kinematic parameters. This study examined the accuracy of a MIMU to estimate orientation angles under static conditions and dynamically from a squash racket during a forehand drive shot. A MIMU was mounted onto a goniometer and moved through 0-90°, with static data collected at 10° increments during 10 repetitions of all three axes. Typical error analyses showed the MIMU to be very reliable (TE ≤ 0.03°). MIMU accuracy was determined via intraclass correlation coefficients (ICC) (r > 0.999, p < 0.001). An ordinary least products regression showed no proportional bias and minimal fixed bias for all axes. Dynamic accuracy was assessed by comparing MIMU and optical motion capture data of squash racket swing kinematics. A MIMU was fixed onto a racket and 10 participants each hit 10 forehand shots. Mean orientation angle error at ball impact was <0.50° and ICC showed very high correlations (r ≥ 0.988, p < 0.001) for all orientations. Swing phase root mean squared errors were ≤2.20°. These results indicate that a MIMU could be used to accurately and reliably estimate selected racket swing kinematics.
Publisher: BMJ
Date: 26-11-2013
Publisher: Human Kinetics
Date: 09-2023
Abstract: Purpose : To investigate the effects of a training c with heat and/or hypoxia sessions on hematological and thermoregulatory adaptations. Methods : Fifty-six elite male rugby players completed a 2-week training c with 5 endurance and 5 repeated-sprint sessions, rugby practice, and resistance training. Players were separated into 4 groups: CAMP trained in temperate conditions at sea level, HEAT performed the endurance sessions in the heat, ALTI slept and performed the repeated sprints at altitude, and H + A was a combination of the heat and altitude groups. Results : Blood volume across all groups increased by 140 mL (95%CI, 42–237 P = .006) and plasma volume by 97 mL (95%CI 28–167 P = .007) following the training c . Plasma volume was 6.3% (0.3% to 12.4%) higher in HEAT than ALTI ( P = .034) and slightly higher in HEAT than H + A (5.6% [−0.3% to 11.7%] P = .076). Changes in hemoglobin mass were not significant ( P = .176), despite a ∼1.2% increase in ALTI and H + A and a ∼0.7% decrease in CAMP and HEAT. Peak rectal temperature was lower during a postc heat-response test in HEAT (0.3 °C [0.1–0.5] P = .010) and H + A (0.3 °C [0.1–0.6] P = .005). Oxygen saturation upon waking was lower in ALTI (3% [2% to 5%] P .001) and H + A (4% [3% to 6%] P .001) than CAMP and HEAT. Conclusion : Although blood and plasma volume increased following the c , sleeping at altitude impeded the increase when training in the heat and only marginally increased hemoglobin mass. Heat training induced adaptations commensurate with partial heat acclimation however, combining heat training and altitude training and confinement during a training c did not confer concomitant hematological adaptations.
Publisher: BMJ
Date: 26-11-2013
Publisher: Springer Science and Business Media LLC
Date: 16-12-2008
DOI: 10.1007/S00421-008-0953-X
Abstract: This study assessed the relationship between haemoglobin mass (Hb(mass)) and maximum oxygen consumption (VO(2max)) in adolescents over 1 year. Twenty-three subjects (11-15 years) participated 12 undertook ~12 months of cycle training (cyclists) and 11 were sedentary (controls). Hb(mass) and VO(2max) were measured approximately every 3 months. At baseline there was a high correlation (r = 0.82, P < 0.0001) between relative VO(2max) (ml kg(-1) min(-1)) and relative Hb(mass) (g kg(-1)). During 12 months there was a significant increase in relative VO(2max) of the cyclists but not the controls however, there was no corresponding increase in relative Hb(mass) of either group. The correlation between percent changes in relative VO(2max) and relative Hb(mass) was not significant for cyclists (r = 0.31, P = 0.33) or controls (r = 0.42, P = 0.19). Training does not increase relative Hb(mass) in adolescents consistent with a strong hereditary role for Hb(mass) and VO(2max). Hb(mass) may be used to identify adolescents who have a high VO(2max).
Publisher: American Physiological Society
Date: 04-2008
DOI: 10.1152/JAPPLPHYSIOL.00719.2007
Abstract: The purpose of this study was to investigate the suggestion in a recent meta-analysis that variability in hemoglobin mass increases when time between measurements increases from days to months. Hemoglobin mass of six active men was measured with the carbon monoxide method every 1–6 days for 100–114 days (42 ± 3 measurements, mean ± SD). Measurement error for each in idual's series was estimated from the standard deviation of consecutive pairwise changes and compared with his total error (standard deviation of all values). Linear trends and periodicities in each series were quantified by regression and spectral analysis. Series with known random error and periodicity were also simulated and analyzed. There were clear differences in the pairwise error of measurement between subjects (range 1.4–2.7%). For five men, there was little difference between the total and pairwise errors their mean ratio (1.06, 90% confidence limits 0.96–1.17) was less than ratios for simulated sinusoidal series with random error of 2%, litude of 2%, and periods of 20–100 days (ratios 1.13–1.21). Spectral analysis clearly revealed such periodicities in the simulated series but not in the series of these subjects. The sixth man, who had donated blood 12 days before commencing measurements, showed errors, trend, and periodicity consistent with gradual restoration of hemoglobin mass. Measurement error of hemoglobin mass does not increase over 100 days. Consequently, hemoglobin mass may be suitable for long-term monitoring of small changes that might occur with training or erythropoietin abuse, taking into consideration the small differences between athletes in errors and trends.
Publisher: Wiley
Date: 27-07-2017
DOI: 10.1002/DTA.2219
Abstract: The haematological module of the Athlete's Biological Passport (ABP) has significantly impacted the prevalence of blood manipulations in elite sports. However, the ABP relies on a number of concentration-based markers of erythropoiesis, such as haemoglobin concentration ([Hb]), which are influenced by shifts in plasma volume (PV). Fluctuations in PV contribute to the majority of biological variance associated with volumetric ABP markers. Our laboratory recently identified a panel of common chemistry markers (from a simple blood test) capable of describing ca 67% of PV variance, presenting an applicable method to account for volume shifts within anti-doping practices. Here, this novel PV marker was included into the ABP adaptive model. Over a six-month period (one test per month), 33 healthy, active males provided blood s les and performed the CO-rebreathing method to record PV (control). In the final month participants performed a single maximal exercise effort to promote a PV shift (mean PV decrease -17%, 95% CI -9.75 to -18.13%). Applying the ABP adaptive model, in idualized reference limits for [Hb] and the OFF-score were created, with and without the PV correction. With the PV correction, an average of 66% of [Hb] within-subject variance is explained, narrowing the predicted reference limits, and reducing the number of atypical ABP findings post-exercise. Despite an increase in sensitivity there was no observed loss of specificity with the addition of the PV correction. The novel PV marker presented here has the potential to improve the ABP's rate of correct doping detection by removing the confounding effects of PV variance.
Publisher: Georg Thieme Verlag KG
Date: 07-09-2013
Abstract: The purpose of this study was to quantify match play intensity distribution in young soccer players in relation to age, playing position and physical fitness. Distance covered and heart rate were measured (global positioning system) on 103, highly-trained young players (Under13 to Under 18) during 42 international club games. Maximal sprinting speed (MSS), estimated maximal aerobic speed (MAS) and maximal heart rate (HRmax) were assessed via field test measures. Distance covered and heart rate (HR) were categorized into 5 intensity zones relative to MSS and MAS and HR(max), respectively. Intensity distribution was significantly influenced by both age and playing position with younger groups, wide-midfielders and strikers covering the greatest distance above the MAS. There was a significant, negative, large-to-very large correlation (r= -0.52-0.74) between MAS and the distance run at speeds above MAS for all positions except strikers. HR responses were not different across age groups and playing positions. Distance covered below MAS were lower in the second half for all positions (P<0.05 0.08<η(2) 0.1 0.00<η(2)<0.03). This reduction in distance covered below MAS was not related to a player's physical capacity. Except for strikers, a superior aerobic fitness level was unlikely to affect total distance covered but was associated with a reduced in idual running demand during the game.
Publisher: Springer Science and Business Media LLC
Date: 04-1999
Abstract: Investigation of the impact of environmental stimuli such as altitude exposure on hemoglobin mass currently rely on invasive techniques that require venous blood s ling. This study assessed the feasibility of lancet skin pricks as an alternative to venepuncture to estimate hemoglobin mass with the carbon monoxide (CO) dilution technique, with the intent of making the technique accessible to technicians without phlebotomy training. Sixteen healthy volunteers rebreathed CO via a small-volume rebreathing apparatus. Blood was s led simultaneously with a glass syringe (VEN) from a superficial forearm vein and with a capillary tube from either a lanced fingertip or earlobe (CAP). As a control, VEN blood was then aliquoted into capillary tubes (CONTROL-CAP). S les were assayed for carboxy-hemoglobin (HbCO) using a diode-array spectrophotometer. Mean %HbCO was higher in CAP than VEN (bias 0.3+/-0.2%HbCO, p < 0.01), but VEN and CONTROL-CAP were not different (p = 0.55). Compared to VEN, Hb mass derived from CAP s les was overestimated by 1.7% (15+/-22 g Hb, p = 0.01). CAP s les to estimate Hb mass demonstrated a technical error of measurement of 2.7%, which is comparable to the 1.9% reported previously with VEN s les. We conclude that using CAP s les gives a reliable measure of %HbCO, and will make the estimation of Hb mass with the CO-technique accessible to technicians without phlebotomy training.
Publisher: Physical Education and Sport Faculty
Date: 31-07-2023
Publisher: Informa UK Limited
Date: 03-2011
DOI: 10.1080/02640414.2010.536248
Abstract: We investigated age-related differences in the relationships among acceleration, maximum running speed, and repeated-sprint performance in 61 highly trained young male soccer players (Under 14, n = 14 Under 16, n = 22 Under 18, n = 25). We also examined the possible influence of anthropometry (stature, body mass, fat-free mass) and biological maturation (age at peak height velocity) on performance in those three sprint-running qualities. Players were tested for 10-m sprint (acceleration), flying 20-m sprint (maximum running speed), and 10 × 30-m sprint (repeated-sprint performance) times. Correlations between acceleration, maximum running speed, and repeated-sprint performance were positive and large to almost perfect (r = 0.55-0.96), irrespective of age group. There were age-based differences both in absolute performance in the three sprint-running qualities (Under 18 > Under 16 > Under 14 P < 0.001) and when body mass and fat-free mass were statistically controlled (P 0.05). The large correlations among acceleration, maximum running speed, and repeated-sprint performance in all age groups, as well as the disappearance of between-group differences when adjusted for estimated biological maturity, suggest that these physical qualities in young highly trained soccer players might be considered as a general quality, which is likely to be related to qualitative adaptations that accompany maturation.
Publisher: Human Kinetics
Date: 10-2021
Abstract: Purpose: To investigate whether including heat and altitude exposures during an elite team-sport training c induces similar or greater performance benefits. Methods: The study assessed 56 elite male rugby players for maximal oxygen uptake, repeated-sprint cycling, and Yo-Yo intermittent recovery level 2 (Yo-Yo) before and after a 2-week training c , which included 5 endurance and 5 repeated-sprint cycling sessions in addition to daily rugby training. Players were separated into 4 groups: (1) control (all sessions in temperate conditions at sea level), (2) heat training (endurance sessions in the heat), (3) altitude (repeated-sprint sessions and sleeping in hypoxia), and (4) combined heat and altitude (endurance in the heat, repeated sprints, and sleeping in hypoxia). Results: Training increased maximal oxygen uptake (4% [10%], P = .017), maximal aerobic power (9% [8%], P .001), and repeated-sprint peak (5% [10%], P = .004) and average power (12% [14%], P .001) independent of training conditions. Yo-Yo distance increased (16% [17%], P .001) but not in the altitude group ( P = .562). Training in heat lowered core temperature and increased sweat rate during a heat-response test ( P .05). Conclusion: A 2-week intensified training c improved maximal oxygen uptake, repeated-sprint ability, and aerobic performance in elite rugby players. Adding heat and/or altitude did not further enhance physical performance, and altitude appears to have been detrimental to improving Yo-Yo.
Publisher: Human Kinetics
Date: 07-2014
Abstract: To examine the physiological and performance responses to a heat-acclimatization c in highly trained professional team-sport athletes. Eighteen male Australian Rules Football players trained for 2 wk in hot ambient conditions (31–33°C, humidity 34–50%). Players performed a laboratory-based heat-response test (24-min walk + 24 min seated 44°C), a YoYo Intermittent Recovery Level 2 Test (YoYoIR2 indoor, temperate environment, 23°C) and standardized training drills (STD outdoor, hot environment, 32°C) at the beginning and end of the c . The heat-response test showed partial heat acclimatization (eg, a decrease in skin temperature, heart rate, and sweat sodium concentration, P .05). In addition, plasma volume (PV, CO rebreathing, +2.68 [0.83 4.53] mL/kg) and distance covered during both the YoYoIR2 (+311 [260 361] m) and the STD (+45.6 [13.9 77.4] m) increased postc ( P .01). None of the performance changes showed clear correlations with PV changes ( r .24), but the improvements in running STD distance in hot environment were correlated with changes in hematocrit during the heat-response test ( r = –.52, 90%CI [–.77 –.12]). There was no clear correlation between the performance improvements in temperate and hot ambient conditions ( r .26). Running performance in both hot and temperate environments was improved after a football training c in hot ambient conditions that stimulated heat acclimatization. However, physiological and performance responses were highly in idual, and the absence of correlations between physical-performance improvements in hot and temperate environments suggests that their physiological basis might differ.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2015
Publisher: BMJ
Date: 26-11-2013
Publisher: BMJ
Date: 26-11-2013
Publisher: Elsevier BV
Date: 09-1998
DOI: 10.1016/S1440-2440(98)80011-X
Abstract: Haemoglobin mass (Hb mass), maximum oxygen consumption (VO2max), simulated 4000 m in idual pursuit cycling performance (IP4000), and haematological markers of red blood cell (RBC) turnover were measured in 8 male cyclists before and after (A) 31 d of altitude training at 2690 m. The dependent variables were measured serially after altitude on d A3-4, A8-9 and A20-21. There was no significant change in Hb mass over the course of the study and VO2max at d A9 was significantly lower than the baseline value (79.3 +/- 0.7 versus 81.4 +/- 0.6 ml x kg(-1) x min(-1), respectively). No increase in Hb mass or VO2max was probably due to initial values being close to the natural physiological limit with little scope for further change. When the IP4000 was analysed as a function of the best score on any of the three test days after altitude training there was a 4% improvement that was not reflected in a corresponding change in VO2max or Hb mass. RBC creatine concentration was significantly reduced after altitude training, suggesting a decrease in the average age of the RBC population. However, measurement of reticulocyte number and serum concentrations of erythropoietin, haptoglobin and bilirubin before and after altitude provided no evidence of increased RBC turnover. The data suggest that for these elite cyclists any benefit of altitude training was not from changes in VO2max or Hb mass, although this does not exclude the possibility of improved anaerobic capacity.
Publisher: Springer Science and Business Media LLC
Date: 20-09-2007
DOI: 10.1007/S00421-007-0554-0
Abstract: Athletes regularly compete at 2,000-3,000 m altitude where peak oxygen consumption (VO2peak) declines approximately 10-20%. Factors other than VO2peak including gross efficiency (GE), power output, and pacing are all important for cycling performance. It is therefore imperative to understand how all these factors and not just VO2peak are affected by acute hypobaric hypoxia to select athletes who can compete successfully at these altitudes. Ten well-trained, non-altitude-acclimatised male cyclists and triathletes completed cycling tests at four simulated altitudes (200, 1,200, 2,200, 3,200 m) in a randomised, counter-balanced order. The exercise protocol comprised 5 x 5-min submaximal efforts (50, 100, 150, 200 and 250 W) to determine submaximal VO2 and GE and, after 10-min rest, a 5-min maximal time-trial (5-minTT) to determine VO2peak and mean power output (5-minTT(power)). VO2peak declined 8.2 +/- 2.0, 13.9 +/- 2.9 and 22.5 +/- 3.8% at 1,200, 2,200 and 3,200 m compared with 200 m, respectively, P < 0.05. The corresponding decreases in 5-minTT(power) were 5.8 +/- 2.9, 10.3 +/- 4.3 and 19.8 +/- 3.5% (P < 0.05). GE during the 5-minTT was not different across the four altitudes. There was no change in submaximal VO2 at any of the simulated altitudes, however, submaximal efficiency decreased at 3,200 m compared with both 200 and 1,200 m. Despite substantially reduced power at simulated altitude, there was no difference in pacing at the four altitudes for athletes whose first trial was at 200 or 1,200 m whereas athletes whose first trial was at 2,200 or 3,200 m tended to mis-pace that effort. In conclusion, during the 5-minTT there was a dose-response effect of hypoxia on both VO2peak and 5-minTT(power) but no effect on GE.
Publisher: Wiley
Date: 19-12-2016
DOI: 10.1002/AJH.24577
Abstract: Plasma volume and red cell mass are key health markers used to monitor numerous disease states, such as heart failure, kidney disease, or sepsis. Nevertheless, there is currently no practically applicable method to easily measure absolute plasma or red cell volumes in a clinical setting. Here, a novel marker for plasma volume and red cell mass was developed through analysis of the observed variability caused by plasma volume shifts in common biochemical measures, selected based on their propensity to present with low variations over time. Once a month for 6 months, serum and whole blood s les were collected from 33 active males. Concurrently, the CO-rebreathing method was applied to determine target levels of hemoglobin mass (HbM) and blood volumes. The variability of 18 common chemistry markers and 27 Full Blood Count variables was investigated and matched to the observed plasma volume variation. After the removal of between-subject variations using a Bayesian model, multivariate analysis identified two sets of 8 and 15 biomarkers explaining 68% and 69% of plasma volume variance, respectively. The final multiparametric model contains a weighting function to allow for isolated abnormalities in single biomarkers. This proof-of-concept investigation describes a novel approach to estimate absolute vascular volumes, with a simple blood test. Despite the physiological instability of critically ill patients, it is hypothesized the model, with its multiparametric approach and weighting function, maintains the capacity to describe vascular volumes. This model has potential to transform volume management in clinical settings. Am. J. Hematol. 92:62-67, 2017. © 2016 Wiley Periodicals, Inc.
Publisher: Human Kinetics
Date: 04-2017
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2016
Publisher: Human Kinetics
Date: 07-2017
Abstract: This study aimed to identify the minimum increment duration required to accurately assess 2 distinct lactate thresholds. A total of 21 elite rowers (12 women and 9 men) participated in this study, and each performed 8 or 9 rowing tests comprising 5 progressive incremental tests (3-, 4-, 5-, 7-, or 10-min steps) and at least three 30-min constant-intensity maximal lactate steady-state assessments. Power output (PO) at lactate threshold 1 was higher in the 3- and 4-min incremental tests. No other measures were different for lactate threshold 1. The PO at the second lactate threshold was different between most tests and was higher than the PO at maximal lactate steady state, except for the 10-min incremental test. Lactate threshold 2 oxygen consumption was higher in the 3-, 4-, and 5-min tests, but heart rate (HR) and rating of perceived exertion were not different between tests. Peak PO in the incremental tests was inversely related to the step durations ( r 2 = .86, P ≤ .02). Peak oxygen consumption was higher in the shorter (≤5 min) than the longer (≥7 min) incremental tests, whereas peak HR was not different between tests. These data suggest that for the methods used in this study, incremental exercise tests with step durations ≤7 min overestimate maximal lactate steady-state exercise intensity, peak physiological values are best determined using incremental tests with step durations ≤4 min, and HR measures are not affected by step duration, and therefore, prescription of training HRs can be made using any of these tests.
Publisher: Wiley
Date: 16-07-2012
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2011
Publisher: Briefland
Date: 04-08-2018
DOI: 10.5812/ASJSM.59620
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2006
Publisher: Human Kinetics
Date: 09-2002
Abstract: A randomized, double-blind, placebo controlled design was used in which 13 elite female rowers, all of whom had competed at World Ch ionships, were supplemented with 60 g · day −1 of either bovine colostrum (BC n = 6) or concentrated whey protein powder (WP n = 7) during 9 weeks of pre-competition training. All subjects undertook the study as a group and completed the same training program. Prior to, and after 9 weeks of supplementation and training, subjects completed an incremental rowing test (ROW1) on a rowing ergometer consisting of 3 3 4-min submaximal workloads and a 4-min maximal effort (4max), each separated by a 1-min recovery period. The rowing test was repeated after a 15-min period of passive recovery (ROW2). The 4max for ROW1 provided a measure of performance, and the difference between the 4max efforts of ROW1 and ROW2 provided an index of recovery. Blood lactate concentrations and pH measured prior to exercise and at the end of each workload were used to estimate blood buffer capacity (b). Food intake was recorded daily for dietary analysis. There were no differences in macronutrient intakes ( p .56) or training volumes ( p .99) between BC and WP during the study period. Rowing performance (distance rowed and work done) during 4max of ROW2 was less than ROW1 at baseline ( p .05) but not different between groups ( p .05). Performance increased in both rows by Week 9 ( p .001), with no difference between groups ( p .75). However, the increase was greatest in ROW2 ( p .05), such that by Week 9 there was no longer a difference in performance between the two rows in either group ( p .05). b was not different between groups for ROW1 at baseline (BC 38.3 ± 5.0, WP 38.2 ± 7.2 slykes p .05) but was higher in BC by Week 9 (BC 40.8 ± 5.9, WP 33.4 ± 5.3 slykes p .05). b for ROW2 followed the same pattern of change as for ROW1. We conclude that supplementation with BC improves b, but not performance, in elite female rowers. It was not possible to determine whether b had any effect on recovery.
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.JSAMS.2012.12.003
Abstract: To examine the usefulness of selected physiological and perceptual measures to monitor fitness, fatigue and running performance during a pre-season, 2-week training c in eighteen professional Australian Rules Football players (21.9±2.0 years). Observational. Training load, perceived ratings of wellness (e.g., fatigue, sleep quality) and salivary cortisol were collected daily. Submaximal exercise heart rate (HRex) and a vagal-related heart rate variability index (LnSD1) were also collected at the start of each training session. Yo-Yo Intermittent Recovery level 2 test (Yo-YoIR2, assessed pre-, mid- and post-c , temperate conditions) and high-speed running distance during standardized drills (HSR, >14.4 km h(-1), 4 times throughout, outdoor) were used as performance measures. There were significant (P<0.001 for all) day-to-day variations in training load (coefficient of variation, CV: 66%), wellness measures (6-18%), HRex (3.3%), LnSD1 (19.0%), but not cortisol (20.0%, P=0.60). While the overall wellness (+0.06, 90% CL (-0.14 0.02) AU day(-1)) did not change substantially throughout the c , HRex decreased (-0.51 (-0.58 -0.45)% day(-1)), and cortisol (+0.31 (0.06 0.57) nmol L(-1)day(-1)), LnSD1 (+0.1 (0.04 0.06) ms day(-1)), Yo-YoIR2 performance (+23.7 (20.8 26.6) m day(-1), P<0.001), and HSR (+4.1 (1.5 6.6) m day(-1), P<0.001) increased. Day-to-day ΔHRex (r=0.80, 90% CL (0.75 0.85)), ΔLnSD1 (0.51 (r=0.40 0.62)) and all wellness measures (0.28 (-0.39 -0.17)<r<0.25 (0.14 0.36)) were related to Δtraining load. There was however no clear relationship between Δcortisol and Δtraining load. ΔYo-YoIR2 was correlated with ΔHRex (r=0.88 (0.84 0.92)), ΔLnSD1 (r=0.78 (0.67 0.89)), Δwellness (r=0.58 (0.41 0.75), but not Δcortisol. ΔHSR was correlated with ΔHRex (r = -0.27 (-0.48 -0.06)) and Δwellness (r=0.65 (0.49 0.81)), but neither with ΔLnSD1 nor Δcortisol. Training load, HRex and wellness measures are the best simple measures for monitoring training responses to an intensified training c cortisol post-exercise and LnSD1 did not show practical efficacy here.
Publisher: Springer Science and Business Media LLC
Date: 09-06-2012
DOI: 10.1007/S00421-011-2014-0
Abstract: The aim of the present study was to verify the validity of using exercise heart rate (HRex), HR recovery (HRR) and post-exercise HR variability (HRV) during and after a submaximal running test to predict changes in physical performance over an entire competitive season in highly trained young soccer players. Sixty-five complete data sets were analyzed comparing two consecutive testing sessions (3-4 months apart) collected on 46 players (age 15.1 ± 1.5 years). Physical performance tests included a 5-min run at 9 km h(-1) followed by a seated 5-min recovery period to measure HRex, HRR and HRV, a counter movement jump, acceleration and maximal sprinting speed obtained during a 40-m sprint with 10-m splits, repeated-sprint performance and an incremental running test to estimate maximal cardiorespiratory function (end test velocity V (Vam-Eval)). Possible changes in physical performance were examined for the players presenting a substantial change in HR measures over two consecutive testing sessions (greater than 3, 13 and 10% for HRex, HRR and HRV, respectively). A decrease in HRex or increase in HRV was associated with likely improvements in V (Vam-Eval) opposite changes led to unclear changes in V (Vam-Eval). Moderate relationships were also found between in idual changes in HRR and sprint [r = 0.39, 90% CL (0.07 .64)] and repeated-sprint performance [r = -0.38 (-0.05 -0.64)]. To conclude, while monitoring HRex and HRV was effective in tracking improvements in V (Vam-Eval), changes in HRR were moderately associated with changes in (repeated-)sprint performance. The present data also question the use of HRex and HRV as systematic markers of physical performance decrements in youth soccer players.
Publisher: Elsevier BV
Date: 1988
Abstract: Functional residual capacity (FRC), residual volume (RV), vital capacity (VC), and total lung capacity (TLC) were measured in 162 men aged 18.9 to 78.6 years using a multiple breath helium dilution technique. Multiple regression equations were generated to predict these lung parameters from the best weighted combination (p less than or equal to 0.05) of age, mass, standing height, body surface area, sitting height, biacromial breadth, end-tidal chest girth, expanded chest girth, and chest expansion (FRC: R = .748, SEE = 504 ml RV: R = .725, SEE = 301 ml VC: R = .808, SEE = 537 ml TLC: R = .808, SEE = 551 ml RV/TLC: R = .778, SEE = 4.15 percent). The range of normality was defined as the predicted value +/- the 95 percent confidence interval (two-tailed test). Cross-validation of other FRC, RV, VC, and TLC equations in the literature indicated that they were unsuitable for use with our data.
Publisher: Wiley
Date: 08-04-2012
DOI: 10.1111/J.1600-0838.2011.01310.X
Abstract: A high hemoglobin mass (Hb(mass)) is associated with a high maximum aerobic power (VO(2max)), however, the extent to which Hb(mass) is influenced by training is currently unclear. Accordingly, this study monitored changes in Hb(mass) and VO(2max) in 12 previously untrained adults (aged 18-25 years) following 40 days of regular physical activity. Hb(mass) and VO(2max) were assessed at the start and end of a 40-day physical activity program, which comprised of approximately 40 min of daily, moderate-intensity physical activity. Relative VO(2max) increased by 11.3%, yet there was no significant change in relative Hb(mass) (1.7%) and body mass (0.2%) during the 40-day period. There was a significant correlation between Hb(mass) and VO(2max) at the start of the study (r=0.58, P=0.05), but not between the change in relative VO(2max) and the change in relative Hb(mass) (r=-0.07, P=0.83). Our results support the concept of relative stability in Hb(mass) with approximately 1 month of moderate-intensity physical activity suggesting that Hb(mass) may be used for talent identification and possibly for anti-doping purposes.
Publisher: EDP Sciences
Date: 28-02-2017
DOI: 10.1051/SM/2017001
Abstract: This study examined the validity of the Hunt Squash Accuracy Test (HSAT) for predicting within-game shot performance and tournament rank. Shots from eight male junior squash players performing the HSAT and tournament match-play were analysed. A typical-error analysis from repeated trials showed the HSAT to be very reliable (1.82%). HSAT rank had significant correlations ( p 0.05) to tournament rank ( r = 0.98) and tournament shot success ( r = 0.95). HSAT score showed significant correlations to the percentage of winning shots during match-play ( r = 0.88). HSAT shots with significant correlations to successful match-play shots were backhand-drive ( r = 0.92) and backhand-volley ( r = 0.97). These results suggest the HSAT is a valid method of assessing the accuracy and performance of junior squash players. It could potentially be used to track shot improvements and predict match-play performance.
Publisher: Frontiers Media SA
Date: 2012
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2016
Publisher: BMJ
Date: 19-11-2013
Publisher: BMJ
Date: 26-11-2013
Publisher: Informa UK Limited
Date: 03-2011
DOI: 10.1080/02640414.2010.546424
Abstract: The aim of this study was to examine the effect of age and spa treatment (i.e. combined sauna, cold water immersion, and jacuzzi) on match running performance over two consecutive matches in highly trained young soccer players. Fifteen pre- (age 12.8 ± 0.6 years) and 13 post- (15.9 ± 1 y) peak height velocity (PHV) players played two matches (Matches 1 and 2) within 48 h against the same opposition, with no specific between-match recovery intervention (control). Five post-PHV players also completed another set of two consecutive matches, with spa treatment implemented after the first match. Match running performance was assessed using a global positioning system with very-high-intensity running (> 16.1-19.0 km · h(-1)), sprinting distance (>19 km · h(-1)), and peak match speed determined. Match 2 very-high-intensity running was "possibly" impaired in post-PHV players (-9 ± 33% ± 90% confidence limits), whereas it was "very likely" improved for the pre-PHV players (+27 ± 22%). The spa treatment had a beneficial impact on Match 2 running performance, with a "likely" rating for sprinting distance (+30 ± 67%) and "almost certain" for peak match speed (+6.4 ± 3%). The results suggest that spa treatment is an effective recovery intervention for post-PHV players, while its value in pre-PHV players is questionable.
Publisher: BMJ
Date: 26-11-2013
Publisher: Human Kinetics
Date: 04-2017
Abstract: Monitoring the load placed on athletes in both training and competition has become a very hot topic in sport science. Both scientists and coaches routinely monitor training loads using multidisciplinary approaches, and the pursuit of the best methodologies to capture and interpret data has produced an exponential increase in empirical and applied research. Indeed, the field has developed with such speed in recent years that it has given rise to industries aimed at developing new and novel paradigms to allow us to precisely quantify the internal and external loads placed on athletes and to help protect them from injury and ill health. In February 2016, a conference on “Monitoring Athlete Training Loads—The Hows and the Whys” was convened in Doha, Qatar, which brought together experts from around the world to share their applied research and contemporary practices in this rapidly growing field and also to investigate where it may branch to in the future. This consensus statement brings together the key findings and recommendations from this conference in a shared conceptual framework for use by coaches, sport-science and -medicine staff, and other related professionals who have an interest in monitoring athlete training loads and serves to provide an outline on what athlete-load monitoring is and how it is being applied in research and practice, why load monitoring is important and what the underlying rationale and prospective goals of monitoring are, and where athlete-load monitoring is heading in the future.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2014
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2012
Publisher: Elsevier BV
Date: 2009
Publisher: MDPI AG
Date: 25-01-2023
Abstract: The growth of sport science technology is enabling more sporting teams to implement athlete monitoring practices related to performance testing and load monitoring. Despite the increased emphasis on youth athlete development, the lack of longitudinal athlete monitoring literature in youth athletes is concerning, especially for indoor sports such as basketball. The aim of this study was to evaluate the effectiveness of six different athlete monitoring methods over 10 weeks of youth basketball training. Fourteen state-level youth basketball players (5 males and 9 females 15.1 ± 1.0 years) completed this study during their pre-competition phase prior to their national basketball tournament. Daily wellness and activity surveys were completed using the OwnUrGoal mobile application, along with heart rate (HR) and inertial measurement unit (IMU) recordings at each state training session, and weekly performance testing (3x countermovement jumps [CMJs], and 3x isometric mid-thigh pulls [IMTPs]). All of the athlete monitoring methods demonstrated the coaching staff’s training intent to maintain performance and avoid spikes in workload. Monitoring IMU data combined with PlayerLoad™ data analysis demonstrated more effectiveness for monitoring accumulated load (AL) compared to HR analysis. All six methods of athlete monitoring detected similar trends for all sessions despite small-trivial correlations between each method (Pearson’s correlation: −0.24 r 0.28). The use of subjective monitoring questionnaire applications, such as OwnUrGoal, is recommended for youth sporting clubs, given its practicability and low-cost. Regular athlete education from coaches and support staff regarding the use of these questionnaires is required to gain the best data.
Publisher: Georg Thieme Verlag KG
Date: 18-07-2014
Abstract: The athlete biological passport for the fight against doping is currently based on longitudinal monitoring for abnormal changes in cellular blood parameters. Serum parameters related to altered erythropoiesis could be considered for inclusion in the passport. The aim of this study was to quantify the changes in such parameters in athletes during a period of intense exercise.12 highly trained cyclists tapered for 3 days before 6 days of simulated intense stage racing. Morning and afternoon blood s les were taken on most days and analysed for total protein, albumin, soluble transferrin receptor and ferritin concentrations. Plasma volume was determined via total haemoglobin mass measured by carbon-monoxide rebreathing. Percent changes in means from baseline and percent standard errors of measurement (analytical error plus intra-athlete variation) on each measurement occasion were estimated with mixed linear modelling of log-transformed measures. Means of all variables changed substantially in the days following the onset of racing, ranging from -13% (haemoglobin concentration) to +27% (ferritin). After the second day, errors of measurement were generally twice those at baseline. Plasma variables were affected by heavy exercise, either because of changes in plasma volume (total protein, albumin, haemoglobin), acute phase/inflammatory reactions (ferritin) or both (soluble transferrin receptor). These effects need to be taken into consideration when integrating a plasma parameter into the biological passport model for athletes.
Publisher: Georg Thieme Verlag KG
Date: 08-07-2010
Abstract: This study examined the occurrence and nature of repeated-sprint sequences (RSS) in highly-trained young soccer players, as a function of age, playing position and playing time. Time-motion analyses using a global positioning system (GPS) were performed on 99 highly-trained young soccer (U13, U14, U15, U16, U17 and U18) players during 42 international games. Sprint activities were defined as at least a 1-s run at intensities higher than 61% of the in idual peak running velocity RSS, as a minimum of 2 consecutive sprints interspersed with a maximum of 60 s. During the first half of games the younger teams had a greater number of RSS than the older teams (P U14>U16>U15>U18>U17. The younger players also performed more (e. g., U14 vs. U17: 2.8±0.3 vs. 2.6±0.3, P<0.05) and longer (e. g., U14 vs. U17: 2.8±0.5 vs. 2.6±0.5 s, P<0.05) sprints per sequence than the older players. RSS occurrence was also affected by playing position and decreased throughout the game in most age-groups (P<0.001). Both the occurrence and the nature of RSS are affected by age, position and playing time. Present results also question the importance of repeated-sprint ability as a crucial physical component of soccer performance in developing players.
Publisher: Springer Science and Business Media LLC
Date: 14-03-2010
DOI: 10.1007/S00421-010-1422-X
Abstract: Measurements of exercise heart rate (HR(ex)), HR recovery (HRR) and HR variability (HRV) are used as indices of training status. However, the day-to-day variability of these indices throughout a competitive soccer period is unknown. On 14 occasions during a 3-week competition c , 18 under 15 (U15) and 15 under 17 (U17) years soccer players performed a 5-min submaximal run, followed by a seated 5-min recovery period. HR(ex) was determined during the last 30 s of exercise, while HRR and HRV were measured during the first and last 3 min of the post-exercise recovery period, respectively. U15 players displayed greater HR(ex) (P = 0.02) and HRR (P = 0.004) compared with the U17 players, but there was no difference in HRV (P = 0.74). The mean coefficient of variation (CV) for HR(ex) was lower than that for HRV [3.4 (90% CL, 3.1, 3.7) vs. 10.7 (9.6, 11.9)%, P < 0.001] both were lower than that for HRR [13.3 (12.2, 14.3)%, P < 0.01]. In contrast to HR(ex) and HRR, the CV for HRV was correlated to maximal aerobic speed (r = -0.52, P = 0.002). There was no correlation between total activity time (training sessions + matches) and CV of any of the quantified variables. The variability of each of these measures and player fitness levels should be considered when interpreting changes in training status.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-2012
Publisher: Human Kinetics
Date: 05-2014
Abstract: The aims of the current study were to examine the magnitude of between-GPS-models differences in commonly reported running-based measures in football, examine between-units variability, and assess the effect of software updates on these measures. Fifty identical-brand GPS units (15 SPI-proX and 35 SPIproX2, 15 Hz, GPSports, Canberra, Australia) were attached to a custom-made plastic sled towed by a player performing simulated match running activities. GPS data collected during training sessions over 4 wk from 4 professional football players (N = 53 files) were also analyzed before and after 2 manufacturersupplied software updates. There were substantial differences between the different models (eg, standardized difference for the number of acceleration m/s 2 = 2.1 90% confidence limits [1.4, 2.7], with 100% chance of a true difference). Between-units variations ranged from 1% (maximal speed) to 56% (number of deceleration m/s 2 ). Some GPS units measured 2–6 times more acceleration/deceleration occurrences than others. Software updates did not substantially affect the distance covered at different speeds or peak speed reached, but 1 of the updates led to large and small decreases in the occurrence of accelerations (–1.24 –1.32, –1.15) and decelerations (–0.45 –0.48, –0.41), respectively. Practitioners are advised to apply care when comparing data collected with different models or units or when updating their software. The metrics of accelerations and decelerations show the most variability in GPS monitoring and must be interpreted cautiously.
Publisher: Georg Thieme Verlag KG
Date: 08-02-2012
Abstract: Haemoglobin mass (Hbmass) determination using CO rebreathing may assist to detect illegal blood doping practices, however variations in Hbmass with periods of intensive training and detraining must be quantified. This study aimed to determine the effect of a 30-day period of detraining on Hbmass in ultra-endurance triathletes. 9 male recreational triathletes (29-44 years) participated in the study. Hbmass was assessed using CO rebreathing 30 days and 10 days before an ultra-endurance triathlon and after ~10, 20 and 30 days of detraining following the race. V˙O2max was assessed 10 days before the race and also after the 30-day detraining period, which consisted of an 87% reduction in training hours. After 30-days of detraining there was a 3.1% decrease in mean Hbmass from 868±99 to 840±94 g, (p=0.03), and a 4.7% decrease in mean V˙O2max from 4.83±0.29 to 4.61±0.41 L/min as well as a 2.8% increase of body mass from 75.1±6.4 to 77.1±6.1 kg and a 28% increase in skinfold total from 43.9±14.2 to 55.1±14.0 mm. In idual decreases in Hbmass following detraining would need to be considered if using Hbmass for anti-doping purposes.
Publisher: BMJ
Date: 26-11-2013
Publisher: Springer Science and Business Media LLC
Date: 1987
DOI: 10.1007/BF00640643
Abstract: THE TITLE COMPOUND [SYSTEMATIC NAME: (2R,3R,4S,5R,6R)-2-(acet-oxy-meth-yl)-6-propoxytetra-hydro-2H-pyran-3,4,5-triyl triacetate], C(17)H(26)O(10), was formed by a Koenigs-Knorr reaction of 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide and n-propanol. The central ring adopts a chair conformation. The crystal does not contain any significant inter-actions such as hydrogen bonds.
Publisher: BMJ
Date: 26-11-2013
Publisher: Asociacion Espanola de Analisis del Rendimiento Deportivo
Date: 24-08-2023
DOI: 10.55860/LKVI1358
Abstract: Assess the influence of a 20% reduction in game time on the volume and intensity of elite AF players’ match activity profiles. GPS technology was used to analyse the movement demands of 45 AF players from the same AFL club during 43 matches across the 2019 and 2020 seasons. GPS data were categorised into measures of volume (total match time [TMT] and total distance [TD]) and intensity (metres per minute [m.min-1], high-intensity running [HIR] distance and m.min-1 [ km·h-1], and very-high intensity running [VHIR] distance and m.min-1 [ km·h-1]). Volume decreased in 2020 with reductions in TMT (effect size [ES] ± 95% confidence interval [CI] = -1.8 ± 0.2 p .001) and TD (ES = -1.8 ± 0.2 p .001) overall, across all positional groups, and quarters. Intensity increased, evidenced by increases in HIR m.min-1 (ES = 0.3 ± 0.1 p .001), and VHIR m.min-1 (ES = 0.3 ± 0.2 p = .006). HIR m.min-1 increased for midfielders (ES = 0.6 ± 0.3 p = .017). Defenders exhibited increases in HIR m.min-1 (ES = 0.2 ± 0.2 p = .007), and VHIR m.min-1 (ES = 0.4 ± 0.2 p = .010). Intensity of third quarters decreased at a greater rate in 2020 with reductions in m.min-1 (ES = -0.2 ± 0.1 p = .004) and HIR m.min-1 (ES = -0.2 ± 0.1 p = .037) compared to Q1. Systematic reductions in volume were found overall, across positional groups, and quarters. Average movement speed remained relatively stable overall, across quarters and positional groups. Increases in intensity were defined predominately by increases at high and very-high intensity speeds per minute, with defenders exhibiting the greatest increase in intensity and change to their match activity profiles. Longer quarter and three-quarter time breaks, and time between goals preserved intensity.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2014
Publisher: Elsevier BV
Date: 12-2003
Publisher: Frontiers Media SA
Date: 2011
Publisher: BMJ
Date: 26-11-2013
Publisher: Springer Science and Business Media LLC
Date: 1997
Publisher: Springer Science and Business Media LLC
Date: 08-1993
DOI: 10.1007/BF00376659
Abstract: Natural language processing (NLP) research combines the study of universal principles, through basic science, with applied science targeting specific use cases and settings. However, the process of exchange between basic NLP and applications is often assumed to emerge naturally, resulting in many innovations going unapplied and many important questions left unstudied. We describe a new paradigm of
No related grants have been discovered for Pitre C. Bourdon.