ORCID Profile
0000-0003-3985-1622
Current Organisations
The University of Canberra
,
New South Wales Institute of Sport
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Public Library of Science (PLoS)
Date: 15-03-2017
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2012
Publisher: Public Library of Science (PLoS)
Date: 21-07-2016
Publisher: Springer Science and Business Media LLC
Date: 23-12-2011
DOI: 10.1007/S00421-011-2281-9
Abstract: It has been proposed that an even-pacing strategy is optimal for events lasting 0.05). The results of this study show that, for a time- and work-matched 20-km time trial, an even-paced strategy results in attenuated perturbations in the physiological response and lower perception of effort in comparison to self- and variable-paced strategies.
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.JSAMS.2013.08.005
Abstract: To examine the validity and inter-unit reliability of 10 Hz GPS for measuring instantaneous velocity during maximal accelerations. Experimental. Two 10 Hz GPS devices secured to a sliding platform mounted on a custom built monorail were towed whilst sprinting maximally over 10 m. Displacement of GPS devices was measured using a laser s ling at 2000 Hz, from which velocity and mean acceleration were derived. Velocity data was pooled into acceleration thresholds according to mean acceleration. Agreement between laser and GPS measures of instantaneous velocity within each acceleration threshold was examined using least squares linear regression and Bland-Altman limits of agreement (LOA). Inter-unit reliability was expressed as typical error (TE) and a Pearson correlation coefficient. Mean bias ± 95% LOA during accelerations of 0-0.99 ms(-2) was 0.12 ± 0.27 ms(-1), decreasing to -0.40 ± 0.67 ms(-1) during accelerations >4 ms(-2). Standard error of the estimate ± 95% CI (SEE) increased from 0.12 ± 0.02 ms(-1) during accelerations of 0-0.99 ms(-2) to 0.32 ± 0.06 ms(-1) during accelerations >4 ms(-2). TE increased from 0.05 ± 0.01 to 0.12 ± 0.01 ms(-1) during accelerations of 0-0.99 ms(-2) and >4 ms(-2) respectively. The validity and reliability of 10 Hz GPS for the measurement of instantaneous velocity has been shown to be inversely related to acceleration. Those using 10 Hz GPS should be aware that during accelerations of over 4 ms(-2), accuracy is compromised.
Publisher: Informa UK Limited
Date: 04-06-2019
DOI: 10.1080/02640414.2018.1482526
Abstract: Prior research indicates that providing participants with positive augmented feedback tends to enhance motor learning and performance, whereas the opposite occurs with negative feedback. However, the majority of studies were conducted with untrained participants performing unfamiliar motor tasks and so it remains unclear if elite athletes completing familiar tasks respond in a similar fashion. Thus, this study investigated the effects of three different versions of false-performance feedback on punching force (N), pacing (force over time) and ratings of perceived exertion (RPE) in 15 elite amateur male boxers. Athletes completed a simulated boxing bout consisting of three rounds with 84 maximal effort punches delivered to a punching integrator on four separate days. Day one was a familiarisation session in which no feedback was provided. In the following three days athletes randomly received false-positive, false-negative and false-neutral feedback on their punching performance between each round. No statistical or meaningful differences were observed in punching forces, pacing or RPE between conditions (P > 0.05 ≤ 2%). These null results could stem from the elite status of the athletes involved, the focus on performance rather than learning, or they may indicate that false feedback has a less potent effect on performance than previously thought.
Publisher: Human Kinetics
Date: 10-2016
Abstract: The aim of the current study was to determine if a single ParvoMedics TrueOne 2400 metabolic cart provides valid and reliable measurement of RMR in comparison with the criterion Douglas Bag method (DB). Ten endurance-trained participants completed duplicate RMR measurements on 2 consecutive days using the ParvoMedics system in exercise mode, with the same expirate analyzed using DB. Typical error (TE) in mean RMR between the systems was 578.9 kJ or 7.5% ( p = .01). In comparison with DB, the ParvoMedics system over-estimated RMR by 946.7 ± 818.6 kJ. The bias between systems resulted from ParvoMedics V E(STPD) values. A regression equation was developed to correct the bias, which reduced the difference to -83.3 ± 631.9 kJ. TE for the corrected ParvoMedics data were 446.8 kJ or 7.2% ( p = .70). On Day 1, intraday reliability in mean RMR for DB was 286.8 kJ or 4.3%, ( p = .54) and for ParvoMedics uncorrected , 359.3 kJ or 4.4%, ( p = .35), with closer agreement observed on Day 2. Interday reliability for DB was 455.3 kJ or 6.6% ( p = .61) and for ParvoMedics uncorrected , 390.2 kJ or 6.3% ( p = .54). Similar intraday and interday TE was observed between ParvoMedics uncorrected and ParvoMedics corrected data. The ParvoMedics TrueOne 2400 provided valid and reliable RMR values compared with DB when the V E(STPD) error was corrected. This will enable widespread monitoring of RMR using the ParvoMedics system in a range of field-based settings when DB is not available.
Publisher: Springer Science and Business Media LLC
Date: 05-2011
DOI: 10.1007/S00421-011-1974-4
Abstract: The aim of the study was to assess the reproducibility of pacing strategy, physiological and perceptual responses during simulated 20-km cycling time trials. Seventeen well-trained male cyclists ([Formula: see text] = 4.70 ± 0.33 L min(-1)) completed three 20-km time trials on a Velotron Pro cycle ergometer within a maximum duration of 14 days. During all trials power output, cadence and respiratory exchange were recorded throughout, rating of perceived exertion and affective response were recorded every 2-km and capillary blood was s led and assayed for the determination of lactate concentration every 4-km. Power output data was assigned to 1-km 'bins' and expressed relative to the mean to quantify pacing strategy. Reproducibility of the pacing strategy and the whole trial mean responses was subsequently quantified using typical error (TE) with 90% confidence intervals. The pacing strategy adopted was similar across repeat trials, though there was a higher degree of variability at the start and end of the trial (TE = 6.6 and 6.8% for the first and last 1-km), and a trend for a progressively blunted start on repeat trials. The reproducibility of performance, cardiorespiratory and perceptual measures was good (TE range 1.0-4.0%), but blood lactate exhibited higher variability (TE = 17.7%). The results demonstrate the performance, perceptual and physiological response to self-paced 20-km time trials is reproducible in well-trained cyclists. Future research should acknowledge that variability in pacing strategy at the start and end of a self-paced bout is likely regardless of any intervention employed.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2008
Publisher: Human Kinetics
Date: 04-2015
Abstract: Previous literature has presented pacing data of groups of competition finalists. The aim of this study was to analyze the pacing patterns displayed by medalists and nonmedalists in international competitive 400-m swimming and 1500-m running finals. Split times were collected from 48 swimming finalists (four 100-m laps) and 60 running finalists (4 laps) in international competitions from 2004 to 2012. Using a cross-sectional design, lap speeds were normalized to whole-race speed and compared to identify variations of pace between groups of medalists and nonmedalists. Lap-speed variations relative to the gold medalist were compared for the whole field. In 400-m swimming the medalist group demonstrated greater variation in speed than the nonmedalist group, being relatively faster in the final lap ( P .001 moderate effect) and slower in laps 1 ( P = .03 moderate effect) and 2 ( P .001 moderate effect). There were also greater variations of pace in the 1500-m running medalist group than in the nonmedalist group, with a relatively faster final lap ( P = .03 moderate effect) and slower second lap ( P = .01 small effect). Swimming gold medalists were relatively faster than all other finalists in lap 4 ( P = .04), and running gold medalists were relatively faster than the 5th- to 12th-placed athletes in the final lap ( P = .02). Athletes who win medals in 1500-m running and 400-m swimming competitions show different pacing patterns than nonmedalists. End-spurtspeed increases are greater with medalists, who demonstrate a slower relative speed in the early part of races but a faster speed during the final part of races than nonmedalists.
Publisher: Human Kinetics
Date: 11-2016
Abstract: The purpose of this study was to compare the pacing profiles between distance- and duration-based trials of short and long duration. Thirteen trained cyclists completed 2 time-based (6 and 30 min) and 2 distance-based (4 and 20 km) self-paced cycling time trials. Participants were instructed to complete each trial with the highest average power output. Ratings of perceived exertion (RPEs) were measured throughout the trials. Average power output was not different between the 4-km and 6-min trials (324 ± 46 vs 325 ± 45 W P = .96) or between the 20-km and 30-min trials (271 ± 44 vs 267 ± 38 W P = .24). Power output was greater on commencement of the distance-based trials when short and long trials were analyzed together. Furthermore, the rate of decline in power output over the 1st 40% of the trial was greater in the 20-km trial than in the 30-min trial ( P = .01) but not different between the 4-km and the 6-min trials ( P = .13). RPE was greater in the 4-km trial than in the 6-min trial but not different between the 20-km and 30-min trials. These findings indicate that athletes commenced distance-based time trials at relatively higher power outputs than a similar time-based trial. Such findings may result from discrete differences in our ability to judge or predict an exercise endpoint when performing time- and distance-based trials.
Publisher: Human Kinetics
Date: 02-2017
Abstract: High altitude exposure can increase resting metabolic rate (RMR) and induce weight loss in obese populations, but there is a lack of research regarding RMR in athletes at moderate elevations common to endurance training c s. The present study aimed to determine whether 4 weeks of classical altitude training affects RMR in middle-distance runners. Ten highly trained athletes were recruited for 4 weeks of endurance training undertaking identical programs at either 2200m in Flagstaff, Arizona (ALT, n = 5) or 600m in Canberra, Australia (CON, n = 5). RMR, anthropometry, energy intake, and hemoglobin mass (Hb mass ) were assessed pre- and posttraining. Weekly run distance during the training block was: ALT 96.8 ± 18.3km CON 103.1 ± 5.6km. A significant interaction for Time*Group was observed for absolute (kJ.day -1 ) (F-statistic, p-value: F (1,8) =13.890, p = .01) and relative RMR (F (1,8) =653.453, p = .003) POST-training. No significant changes in anthropometry were observed in either group. Energy intake was unchanged (mean ± SD of difference, ALT: 195 ± 3921kJ, p = .25 CON: 836 ± 7535kJ, p = .75). A significant main effect for time was demonstrated for total Hb mass (g) (F (1,8) =13.380, p = .01), but no significant interactions were observed for either variable [Total Hb mass (g): F (1,8) =1.706, p = .23 Relative Hb mass (g.kg -1 ): F (1,8) =0.609, p = .46]. These novel findings have important practical application to endurance athletes routinely training at moderate altitude, and those seeking to optimize energy management without compromising training adaptation. Altitude exposure may increase RMR and enhance training adaptation,. During training c s at moderate altitude, an increased energy intake is likely required to support an increased RMR and provide sufficient energy for training and performance.
Publisher: Springer Science and Business Media LLC
Date: 02-10-2013
DOI: 10.1007/S00421-013-2734-4
Abstract: Previous research has suggested that the optimal pacing strategy for self-paced exercise lasting >4 min is a uniform distribution of work, but this posit is not well established for prolonged endurance events. This study examined the utility of even pacing during 20 km cycling time trials (TTs). Fifteen well-trained male cyclists ([Formula: see text]O2max = 4.80 ± 0.38 L min(-1)) completed three best effort self-paced (SP) simulated 20 km TTs, followed by two even-paced trials. In one even-paced trial, participants cycled to exhaustion (EPtlim) at a fixed intensity equivalent to their best SP performance. In the other EP trial, participants were instructed to maintain this target intensity for a distance of 20 km, but the actual intensity was free to vary depending on the effort and cadence of the cyclist (EP-maintained). Cardiorespiratory, blood lactate and perceptual (RPE and affect) measures were assessed throughout. Nine out of fifteen cyclists failed the EPtlim task, completing 51-83 % (10.3-15.3 km) of the work done in their SP trial. Failure as a result of even pacing was associated with a faster rise in blood lactate, attainment of a higher relative intensity during SP and a moderate fast starting strategy. This failure was independent of the nature of the even-paced task. By adopting an uneven, parabolic distribution of work, cyclists in this study were able to achieve an average intensity during self-paced exercise in excess of their maximum sustainable power output. A subsequent matched even-paced bout resulted in cumulative metabolic stress that could not be managed by moment-to-moment changes in power output. These results challenge the notion that strict even pacing is optimal for endurance time trial events.
Publisher: Walter de Gruyter GmbH
Date: 04-2016
Abstract: This study aimed to determine the effects of a short-term, strength training intervention, typically undertaken by club-standard rowers, on 2,000 m rowing performance and strength and power development. Twenty-eight male rowers were randomly assigned to intervention or control groups. All participants performed baseline testing involving assessments of muscle soreness, creatine kinase activity (CK), maximal voluntary contraction (leg-extensors) (MVC), static-squat jumps (SSJ), counter-movement jumps (CMJ), maximal rowing power strokes (PS) and a 2,000 m rowing ergometer time-trial (2,000 m) with accompanying respiratory-exchange and electromyography (EMG) analysis. Intervention group participants subsequently performed three identical strength training (ST) sessions, in the space of five days, repeating all assessments 24 h following the final ST. The control group completed the same testing procedure but with no ST. Following ST, the intervention group experienced significant elevations in soreness and CK activity, and decrements in MVC, SSJ, CMJ and PS ( p 0.01). However, 2,000 m rowing performance, pacing strategy and gas exchange were unchanged across trials in either condition. Following ST, significant increases occurred for EMG ( p 0.05), and there were non-significant trends for decreased blood lactate and anaerobic energy liberation (p = 0.063 – 0.086). In summary, club-standard rowers, following an intensive period of strength training, maintained their 2,000 m rowing performance despite suffering symptoms of muscle damage and disruption to muscle function. This disruption likely reflected the presence of acute residual fatigue, potentially in type II muscle fibres as strength and power development were affected.
Publisher: Springer Science and Business Media LLC
Date: 06-09-2022
DOI: 10.1007/S11332-022-00997-Y
Abstract: This study aimed to investigate the reliability of surface electromyography (EMG) assessed at seven muscles during three repeated 2000 m rowing ergometer sessions. Twelve male well-trained rowers participated in a repeated measures design, performing three 2000 m rowing ergometer sessions interspersed by 3–7 days (S1, S2, S3). Surface electrodes were attached to the gastrocnemius, biceps femoris, gluteus maximus, erector spinae, vastus medialis, rectus abdominis and latissimus dorsi for EMG analysis. No differences existed between 2000 m sessions for EMG litude for any of the seven muscles ( p = 0.146–0.979). Mean coefficient of variation of EMG for 6 of 7 muscles was ‘acceptable’ (12.3–18.6%), although classed as ‘weak’ for gastrocnemius (28.6%). Mean intra-class correlation coefficient values across muscles ranged from ‘moderate’ to ‘very large’ (0.31–0.89). Within-session EMG activation rates of vastus medialis were greater during 0–500 m and 1500–2000 m segments, compared with 500–1000 m and 1000–1500 m ( p 0.05). Values for biceps femoris and gluteus maximus were significantly higher during 1500–2000 m compared to 500–1000 m and 1000–1500 m ( p 0.05). The general pattern was for higher activation rates during 0–500 m and 1500–2000 m compared to 500–1000 m and 1000–1500 m. However, there were no between-sessions differences in EMG for any of the 500 m segments ( p 0.05). Reliability of EMG values over repeated 2000 m sessions was generally ‘acceptable’. However, EMG was seemingly not sensitive enough to detect potential changes in neural activation between-sessions, with respect to changes in pacing strategy.
Publisher: Frontiers Media SA
Date: 05-12-2016
Publisher: Springer Science and Business Media LLC
Date: 11-01-2011
DOI: 10.1007/S00421-010-1818-7
Abstract: Although pacing-related research is widely reported, no studies have described the consistency of pacing strategies or their associated energetic contributions. This study aimed to investigate the consistency of pacing and energetic outlay by establishing the typical within and between trial variations during simulated 4,000 m time trials. Fifteen well-trained male cyclists performed three, 4,000 m time trials with 3-7 days separating each trial. Power output, cadence, heart rate, respiratory exchange and iEMG of the vastus lateralis were recorded continuously throughout each trial. To examine within-trial variability, the data were assigned to 10% bins. Rating of perceived exertion and affective response were recorded every 400 m and a capillary blood s le was collected and assayed for blood lactate concentration every 800 m. Mean typical error across trials 1-3 for all variables was low (range 2.1-6.3%) and lower between trials 2-3 for all variables with the exception of cadence. There were no between-trial differences in pacing strategy however, typical error for each 10% bin was lower between trials 2-3 than trials 1-2. Anaerobic contribution to power was greatest during the first and last 10% of each trial (p > 0.05). In conclusion, well-trained cyclists demonstrated a high degree of consistency in terms of the pacing strategy they adopted which coincided with similar levels of energy distribution and perceived exertion. A laboratory simulated 4-km cycling trial is a reliable test that may be used to monitor performance and pacing strategy.
Publisher: Elsevier BV
Date: 02-2011
DOI: 10.1016/J.JELEKIN.2010.06.001
Abstract: Core strengthening and stability exercises are fundamental for any conditioning training program. Although surface electromyography (sEMG) is used to quantify muscle activity there is a lack of research using this method to investigate the core musculature and core stability. Two types of data reduction are commonly used for sEMG peak and average rectified EMG methods. Peak EMG has been infrequently reported in the literature with regard to the assessment of core training while even fewer studies have incorporated average rectified EMG data (ARV). The aim of the study was to establish the repeatability of peak and average rectified EMG data during core training exercises and their interrelationship. Ten male highly trained athletes (inter-subject repeatability group age, 18 ± 1.2 years height, 176.5 ± 3.2 cm body mass, 71 ± 4.5 kg) and one female highly trained athlete (intra-subject repeatability group age 27 years old height 180 cm weight 53 kg) performed five maximal voluntary isometric contractions (MVIC) and five core exercises, chosen to represent a range of movement and muscle recruitment patterns. Peak EMG and ARV EMG were calculated for eight core muscles (rectus abdominis, RA external oblique, EO internal oblique, IO multifidis, MF latissimus dorsi, LD longissimus, LG gluteus maximus, GM rectus femoris, RF) using sEMG. Average coefficient of variation (CV%) for peak EMG across all the exercises and muscles was 45%. This is in comparison to 35% for the ARV method, which was found to be a significant difference (P 0.70 RA, EO, MF, GM, LG) between peak and ARV EMG suggesting, that for these core muscles, the two methods provide a similar evaluation of muscle activity. However, for other muscles (IO, RF, LD) the relationship was found to range from poor to moderate (R=0.10-0.70). The relationship between peak and ARV EMG was also affected by exercise type. Dynamic low and high-threshold exercises and asymmetrical low-threshold exercises had a moderate correlation between the variables (R=0.74-0.81), while the static exercise showed a poor correlation (R=0.46). It can be concluded that there are similarities between the two EMG variables, however due to the effect of type of exercise and muscle on the EMG data, both methods should be included in any future EMG study on the core musculature and core stability exercises.
Publisher: Human Kinetics
Date: 03-2015
Abstract: To quantify the effects of a 12-wk isolated core-training program on 50-m front-crawl swim time and measures of core musculature functionally relevant to swimming. Twenty national-level junior swimmers (10 male and 10 female, 16 ± 1 y, 171 ± 5 cm, 63 ± 4 kg) participated in the study. Group allocation (intervention [n = 10], control [n = 10]) was based on 2 preexisting swim-training groups who were part of the same swimming club but trained in different groups. The intervention group completed the core training, incorporating exercises targeting the lumbopelvic complex and upper region extending to the scapula, 3 times/wk for 12 wk. While the training was performed in addition to the normal pool-based swimming program, the control group maintained their usual pool-based swimming program. The authors made probabilistic magnitude-based inferences about the effect of the core training on 50-m swim time and functionally relevant measures of core function. Compared with the control group, the core-training intervention group had a possibly large beneficial effect on 50-m swim time (–2.0% 90% confidence interval –3.8 to –0.2%). Moreover, it showed small to moderate improvements on a timed prone-bridge test (9.0% 2.1–16.4%) and asymmetric straight-arm pull-down test (23.1% 13.7–33.4%), and there were moderate to large increases in peak EMG activity of core musculature during isolated tests of maximal voluntary contraction. This is the first study to demonstrate a clear beneficial effect of isolated core training on 50-m front-crawl swim performance.
Publisher: Springer Science and Business Media LLC
Date: 10-03-2011
DOI: 10.1007/S00421-011-1878-3
Abstract: Rowers regularly undertake rowing training within 24 h of performing bouts of strength training however, the effect of this practice has not been investigated. This study evaluated the impact of a bout of high-intensity strength training on 2,000 m rowing ergometer performance and rowing-specific maximal power. Eight highly trained male club rowers performed baseline measures of five separate, static squat jumps (SSJ) and countermovement jumps (CMJ), maximal rowing ergometer power strokes (PS) and a single 2,000 m rowing ergometer test (2,000 m). Subsequently, participants performed a high-intensity strength training session consisting of various multi-joint barbell exercises. The 2,000 m test was repeated at 24 and 48 h post-ST, in addition SSJ, CMJ and PS tests were performed at these time points and also at 2 h post-ST. Muscle soreness, serum creatine kinase (CK) and lactate dehydrogenase (LDH) were assessed pre-ST and 2, 24 and 48 h post-ST. Following the ST, there were significant elevations in muscle soreness (2 and 24 h, P < 0.01), CK (2, 24 and 48 h, P < 0.01), and LDH (2 h, P < 0.05) in comparison to baseline values. There were significant decrements across all time points for SSJ, CMJ and PS, which ranged between 3 and 10% (P < 0.05). However, 2,000 m performance and related measurements of heart rate and blood lactate were not significantly affected by ST. In summary, a bout of high-intensity strength training resulted in symptoms of muscle damage and decrements in rowing-specific maximal power, but this did not affect 2,000 m rowing ergometer performance in highly trained rowers.
Publisher: Elsevier BV
Date: 04-2008
DOI: 10.1016/J.RESP.2008.02.001
Abstract: We tested the hypothesis that priming exercise would speed V(O2) kinetics during treadmill running. Eight subjects completed a square-wave protocol, involving two bouts of treadmill running at 70% of the difference between the running speeds at lactate threshold (LT) and V(O2) max, separated by 6-min of walking at 4 km h(-1), on two occasions. Oxygen uptake was measured breath-by-breath and subsequently modelled using non-linear regression techniques. Heart rate and blood lactate concentration were significantly elevated prior to the second exercise bout compared to the first. However, V(O2) kinetics was not significantly different between the first and second exercise bouts (mean+/-S.D., phase II time constant, Bout 1: 16+/-3s vs. Bout 2: 16+/-4s V(O2) slow component litude, Bout 1: 0.24+/-0.10 L min(-1)vs. Bout 2: 0.20+/-0.12 L min(-1) mean response time, Bout 1: 34+/-4s vs. Bout 2: 34+/-6s P>0.05 for all comparisons). These results indicate that, contrary to previous findings with other exercise modalities, priming exercise does not alter V(O2) kinetics during high-intensity treadmill running, at least in physically active young subjects. We speculate that the relatively fast V(O2) kinetics and the relatively small V(O2) slow component in the control ('un-primed') condition negated any enhancement of V(O2) kinetics by priming exercise in this exercise modality.
Publisher: Human Kinetics
Date: 07-2014
Abstract: To assess the reliability and stability of 400-m swimming and 1500-m running competitions to establish the number of s les needed to obtain a stable pacing profile. Coaches, athletes, and researchers can use these methods to ensure that sufficient data are collected before training and race strategies are constructed or research conclusions are drawn. Lap times were collected from 5 world and European ch ionship finals between 2005 and 2011, resulting in the capture of data from 40 swimmers and 55 runners. A cumulative mean for each lap was calculated, starting with the most recent data, and the number of races needed for this to stabilize to within 1% was reported. Typical error for each lap was calculated for athletes who had competed in more than 1 final. International swimmers demonstrated more reproducible performances than runners in 3 of the 4 laps of the race ( P .01). Variance in runners’ lap times significantly decreased by 1.7–2.7% after lap 1, whereas variance in swimmers’ lap times tended to increase by 0.1–0.5% after lap 1. To establish a stable profile, at least ten 400-m swimmers and forty-four 1500-m runners must be included. A stable race profile was observed from the analysis of 5 events for 1500-m running and 3 events for 400-m swimming. Researchers and athletes can be more certain about the pacing information collected from 400-m swimming than 1500-m running races, as the swimming data are less variable, despite both events being of similar duration.
Publisher: SAGE Publications
Date: 08-2013
DOI: 10.2466/06.30.PMS.117X11Z3
Abstract: This study examined the effect of low- and high-intensity running on cognitive thoughts (an in idual's “inner dialogue”) and its relationship to ratings of perceived exertion (RPE). Cognitive thoughts and RPE of eight runners were collected during a 40-min. treadmill run at either a low (50% peak running speed) or a high (70% peak running speed) exercise intensity. Runners were asked to place their thoughts into one of 10 themed categories, which incorporated a broad association/dissociation classification (Schomer, 1986, 1987). At a low intensity and RPE (6–10), runners reported more dissociative thoughts, while at a high intensity and RPE (16–20) they reported more associative thoughts. Further, although the runners may report a particular RPE, the inner dialogue and description of perceived exertion and fatigue may be markedly different. These findings suggest that an athlete's “internal dialogue” is intensity dependent, and may relate to the more urgent need to self-monitor physical changes and sensations during high-intensity running.
Publisher: Informa UK Limited
Date: 25-07-2017
DOI: 10.1080/02640414.2016.1210196
Abstract: The potential relationship between physical activity and endogenous pain modulatory capacity remains unclear. Therefore, the aim of the current study was to compare the pain modulatory responses of athletes and non-athletes. Conditioned pain modulation (CPM) was assessed in 15 athletes and 15 non-athletes at rest. Participation was restricted to pain-free males between 18 and 40 years of age. To measure CPM capacity, a sequential CPM testing protocol was implemented, whereby a test stimulus (pressure pain threshold [PPT]) was presented before and immediately after a conditioning stimulus (4-min cold-pressor test). Pain intensity ratings were obtained at 15-s intervals throughout the cold-pressor task using a numerical rating scale. Athletes demonstrated higher baseline PPTs compared to non-athletes (P = .03). Athletes also gave lower mean (P < .001) and maximum (P < .001) pain intensity ratings in response to the conditioning stimulus. The conditioning stimulus had a stronger inhibitory effect on the test stimulus in athletes, showing enhanced CPM in athletes compared to non-athletes (P < .05). This finding of enhanced CPM in athletes helps clarify previous mixed findings. Potential implications for exercise performance and injury are discussed.
Publisher: Georg Thieme Verlag KG
Date: 08-02-2016
Abstract: We investigated whether performance gains achieved with deception persisted after the deception was revealed, and whether pacing strategy changed. 14 trained cyclists completed 4 simulated 4-km time trials (TT) on a cycle ergometer comprising familiarization and baseline trials (BAS), followed by "unaware" (of deception, UAW) and "aware" (of deception, AW) trials on separate days. In the UAW trial, participants competed against an on-screen avatar set at 102% of their baseline trial mean power output (Pmean) believing it was set at 100% of BAS Pmean. 24 h prior to the AW trial, participants were informed of the deception in the UAW trial. 4 participants did not improve in the UAW trial compared to BAS. 10 participants improved time to completion (TTC) and Pmean in the UAW and AW trials compared to BAS (p 0.05) for these participants. In summary, deception did not improve performance in all participants. However, participants whose time trial performance improved following deception could retain their performance gains once the deception was revealed, demonstrating a similar pacing strategy and RPE response.
Publisher: Elsevier BV
Date: 04-2016
DOI: 10.1016/J.JSAMS.2015.04.012
Abstract: The lengthy competition transition phases commonly experienced by competitive swimmers may mitigate the benefits of the pool warm-up. To combat this, we examined the impact of additional passive and active warm-up strategies on sprint swimming performance. Counterbalanced, repeated-measures cross-over study. Sixteen junior competitive swimmers completed a standardised pool warm-up followed by a 30min transition and 100m freestyle time-trial. Swimmers completed four different warm-up strategies during transition: remained seated wearing a conventional tracksuit top and pants (Control), wore an insulated top with integrated heating elements (Passive), performed a 5min dryland-based exercise circuit (Dryland), or a combination of Passive and Dryland (Combo). Swimming time-trial performance, core and skin temperature and perceptual variables were monitored. Time variables were normalised relative to Control. Both Combo (-1.05±0.26% mean±90% confidence limits, p=0.00) and Dryland (-0.68±0.34% p=0.02) yielded faster overall time-trial performances, with start times also faster for Combo (-0.37±0.07% p=0.00) compared to Control. Core temperature declined less during transition with Combo (-0.13±0.25°C p=0.01) and possibly with Dryland (-0.24±0.13°C p=0.09) compared to Control (-0.64±0.16°C), with a smaller reduction in core temperature related to better time-trial performance (R(2)=0.91 p=0.04). Dryland-based exercise circuits completed alone and in combination with the application of heated tracksuit jackets during transition can significantly improve sprint swimming performance. Attenuation in the decline of core temperature and a reduction in start time appear as likely mechanisms.
Publisher: Human Kinetics
Date: 10-2016
Abstract: Targeted passive heating and completion of dryland-based activation exercises within the warm-up can enhance sprint freestyle performance. The authors investigated if these interventions would also elicit improvements in sprint breaststroke swimming performance. Ten national and internationally competitive swimmers (~805 FINA ( Fédération internationale de natation ) 2014 scoring points 6 men, mean ± SD 20 ± 1 y 4 women, 21 ± 3 y) completed a standardized pool warm-up (1550 m) followed by a 30-min transition phase and a 100-m breaststroke time trial. In the transition phase, swimmers wore a conventional tracksuit and remained seated (control) or wore tracksuit pants with integrated heating elements and performed a 5-min dryland-based exercise routine (combo) in a crossover design. Performance in the 100-m time trial (control: 68.6 ± 4.0 s, combo: 68.4 ± 3.9 s, P = .55) and start times to 15 m (control: 7.3 ± 0.6 s combo: 7.3 ± 0.6 s P = .81) were not different between conditions. It was unclear ( P = .36) whether combo (–0.12°C ± 0.19°C [mean ± 90% confidence limits]) elicited an improvement in core temperature maintenance in the transition phase compared with control (–0.31°C ± 0.19°C). Skin temperature immediately before commencement of the time trial was higher (by ~1°C, P = .01) within combo (30.13°C ± 0.88°C [mean ± SD]) compared with control (29.11°C ± 1.20°C). Lower-body power output was not different between conditions before the time trial. Targeted passive heating and completion of dryland-based activation exercises in the transition phase does not enhance sprint breaststroke performance despite eliciting elevated skin temperature immediately before time trial commencement.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2014
Publisher: Elsevier BV
Date: 08-2021
Publisher: Springer Science and Business Media LLC
Date: 23-09-2015
DOI: 10.1007/S40279-015-0376-X
Abstract: It is widely accepted that warming-up prior to exercise is vital for the attainment of optimum performance. Both passive and active warm-up can evoke temperature, metabolic, neural and psychology-related effects, including increased anaerobic metabolism, elevated oxygen uptake kinetics and post-activation potentiation. Passive warm-up can increase body temperature without depleting energy substrate stores, as occurs during the physical activity associated with active warm-up. While the use of passive warm-up alone is not commonplace, the idea of utilizing passive warming techniques to maintain elevated core and muscle temperature throughout the transition phase (the period between completion of the warm-up and the start of the event) is gaining in popularity. Active warm-up induces greater metabolic changes, leading to increased preparedness for a subsequent exercise task. Until recently, only modest scientific evidence was available supporting the effectiveness of pre-competition warm-ups, with early studies often containing relatively few participants and focusing mostly on physiological rather than performance-related changes. External issues faced by athletes pre-competition, including access to equipment and the length of the transition/marshalling phase, have also frequently been overlooked. Consequently, warm-up strategies have continued to develop largely on a trial-and-error basis, utilizing coach and athlete experiences rather than scientific evidence. However, over the past decade or so, new research has emerged, providing greater insight into how and why warm-up influences subsequent performance. This review identifies potential physiological mechanisms underpinning warm-ups and how they can affect subsequent exercise performance, and provides recommendations for warm-up strategy design for specific in idual and team sports.
Publisher: Georg Thieme Verlag KG
Date: 21-11-2014
Abstract: This study examined the acceleration demands associated with changing direction and the subsequent physiological consequences of acceleration during running at 3 submaximal speeds. 10 male professional footballers completed four 600 m running bouts at 3 speeds (2.50, 3.25 & 4.00 m·s(-1)). Each bout was in the format of either: i) 3 laps of a 200 m track (CON), ii) ten 60 m shuttles (S60), iii) twenty 30 m shuttles (S30), or iv) thirty 20 m shuttles (S20). Peak heart rate (HRPEAK), blood lactate concentration (BLa) and RPE (Borg CR-10) were recorded for each bout. A single change of direction required 1.2, 1.5 and 2.0 s of acceleration at running speeds of 2.50, 3.25 and 4.00 m s(-1) respectively. An increase in time spent accelerating produced a linear increase in BLa (r=0.43-0.74) and RPE (r=0.81-0.93) at all speeds. Acceleration increases linearly with change of direction frequency during submaximal shuttle running. Increased time spent accelerating elicits proportional increases in perceived exertion, BLa and HRPEAK. The current study further underlines the need to consider acceleration when quantifying training load during activities involving numerous changes of direction.
Publisher: Public Library of Science (PLoS)
Date: 09-03-2017
Publisher: Human Kinetics
Date: 04-2016
Abstract: To investigate if swimming performance is better in a relay race than in the corresponding in idual race. The authors analyzed 166 elite male swimmers from 15 nations in the same competition (downloaded from www.swimrankings.net ). Of 778 observed races, 144 were Olympic Games performances (2000, 2004, 2012), with the remaining 634 performed in national or international competitions. The races were 100-m (n = 436) and 200-m (n = 342) freestyle events. Relay performance times for the 2nd–4th swimmers were adjusted (+ 0.73 s) to allow for the “flying start.” Without any adjustment, mean in idual relay performances were significantly faster for the first 50 m and overall time in the 100-m events. Furthermore, the first 100 m of the 200-m relay was significantly faster ( P .001). During relays, swimmers competing in 1st position did not show any difference compared with their corresponding in idual performance ( P .16). However, swimmers competing in 2nd–4th relay-team positions demonstrated significantly faster times in the 100-m ( P .001) and first half of the 200-m relays than in their in idual events ( P .001, ES: 0.28–1.77). However, when finishing times for 2nd–4th relay team positions were adjusted for the flying start no differences were detected between relay and in idual race performance for any event or split time ( P .17). Highly trained swimmers do not swim (or turn) faster in relay events than in their in idual races. Relay exchange times account for the difference observed in in idual vs relay performance.
Publisher: American Physiological Society
Date: 09-2014
DOI: 10.1152/JAPPLPHYSIOL.00242.2014
Abstract: Plasma volume (PV) can be modulated by altitude exposure (decrease) and periods of intense exercise (increase). Cycle racing at altitude combines both stimuli, although presently no data exist to document which is dominant. Hemoglobin mass (Hbmass), hemoglobin concentration ([Hb]), and percent reticulocytes (%Retics) of altitude (ALT n = 9) and sea-level (SL n = 9) residents were measured during a 14-day cycling race, held at 1,146–4120 m, as well as during a simulated tour near sea level (SIM n = 12). Hbmass was assessed before and on days 9 and 14 of racing. Venous blood was collected on days 0, 3, 6, 10, and 14. PV was calculated from Hbmass and [Hb]. A repeated-measures ANOVA was used to assess the impact of racing at altitude over time, within and between groups. [Hb] decreased significantly in all groups over time ( P 0.0001) with decreases evident on the third day of racing. %Retics increased significantly in SL only ( P 0.0001), with SL values elevated at day 6 compared with prerace ( P = 0.02), but were suppressed by the end of the race ( P = 0.0002). Hbmass significantly increased in SL after 9 ( P = 0.0001) and 14 ( P = 0.008) days of racing and was lower at the end of the race than midrace ( P = 0.018). PV increased in all groups ( P 0.0001). Multiday cycle racing at altitude induces hemodilution of a similar magnitude to that observed during SL racing and occurs in nonacclimatized SL residents, despite an altitude-induced increase in Hbmass. Osmotic regulatory mechanisms associated with intense exercise appear to supersede acute enhancement of oxygen delivery at altitude.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2011
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.JSAMS.2012.12.005
Abstract: This study examined distances covered at low (1-2 ms(-2)), moderate (2-3 ms(-2)) and high (>3 ms(-2)) acceleration (L(ACC), M(ACC) and H(ACC) respectively) and deceleration (L(DEC), M(DEC), and H(DEC) respectively) during competitive football games. Temporal and transient patterns of acceleration and deceleration were also examined. Observational, repeated measures. Thirty-six professional male professional footballers were monitored using a 10 Hz non-differential global positioning system (NdGPS). Match data was organised into six 15 min periods (P1: 1-15 min, P2: 16-30 min, P3: 31-45 min, P4: 46-60 min, P5: 61-75 min, and P6: 76-90 min) for analysis of temporal patterns, and into eighteen 5 min periods for analysis of transient patterns. ANOVA with Bonferroni post hoc tests were used to identify significant (p<0.05) differences between periods. Distance covered at L(ACC), M(ACC), H(ACC), L(DEC), M(DEC), and H(DEC) was 424±75 m, 242±25 m, 178±38 m, 365±54 m, 210±23 m and 162±29 m respectively. Between period decrements ranged from 8.0% to 13.2% from P1 to P3, 9.2% to 16.3% from P4 to P6, and from 14.9% to 21.0% from P1 to P6. Following PEAK H(ACC) (148% of mean 5 min H(ACC)), H(ACC) at 5POST was 10.4% lower than mean (p<0.01). Time-dependent reductions in distances covered suggest that acceleration and deceleration capability are acutely compromised during match play. Further, the occurrence of transient fatigue may be supported by the findings that HACC and HDEC performance following PEAK was approximately 10% lower than mean values.
Publisher: Human Kinetics
Date: 05-2017
Abstract: An exercise bout completed several hours prior to an event may improve competitive performance later that same day. To examine the influence of morning exercise on afternoon sprint-swimming performance. Thirteen competitive swimmers (7 male, mean age 19 ± 3 y 6 female, mean age 17 ± 3 y) completed a morning session of 1200 m of variedintensity swimming (SwimOnly), a combination of varied-intensity swimming and a resistance-exercise routine (SwimDry), or no morning exercise (NoEx). After a 6-h break, swimmers completed a 100-m time trial. Time-trial performance was faster in SwimOnly (1.6% ± 0.6, mean ± 90% confidence limit, P .01) and SwimDry (1.7% ± 0.7%, P .01) than in NoEx. Split times for the 25- to 50-m distance were faster in both SwimOnly (1.7% ± 1.2%, P = .02) and SwimDry (1.5% ± 0.8%, P = .01) than in NoEx. The first 50-m stroke rate was higher in SwimOnly (0.70 ± 0.21 Hz, mean ± SD, P = .03) and SwimDry (0.69 ± 0.18 Hz, P = .05) than in NoEx (0.64 ± 0.16 Hz). Before the afternoon session, core (0.2°C ± 0.1°C [mean ± 90% confidence limit], P = .04), body (0.2°C ± 0.1°C, P = .02), and skin temperatures (0.3°C ± 0.3°C, P = .02) were higher in SwimDry than in NoEx. Completion of a morning swimming session alone or together with resistance exercise can substantially enhance sprint-swimming performance completed later the same day.
Publisher: Informa UK Limited
Date: 02-2004
DOI: 10.1080/02640410310001641467
Abstract: Performances often vary between the heats and finals of breaststroke swimming competitions possibly because the swimmers try to conserve their energy, or for other tactical reasons. Additionally, coaches might advise either a 'positive' or 'even' pace race strategy during the final. The effect of such pacing changes on metabolism (blood lactate, heart rate, ventilation), ratings of perceived exertion, stroke kinematics and turning times have not been investigated. Nine male competitive breaststroke swimmers swam three paced (Aquapacer) 200-m trials, 48 h apart and in random order, at 98%, 100% and at an attempted 102% of their maximal 200-m time-trial speed. Responses in metabolic variables were similar between the 98% and 100% trials, but higher post-exercise blood lactate concentrations and respiratory exchange ratios were observed following the 102% trial. As the pace of trials increased, stroke rate was found to increase proportionately with stroke count. However, during the latter stages of the 100% trial, a disproportionate increase in the stroke count was observed, which led to a significant pacing error. This feature was more obvious in the 102% trial, where participants demonstrated 'positive pacing' and reported higher ratings of perceived exertion than for the 98% trial. During the early stages of the trials, turning times were initially shorter the faster the pace of the trial however, as the trials progressed, this pattern was found to reverse. We conclude that a slight reduction in pace during near maximal breaststroke swimming altered kinematic but not post-exercise metabolic responses, while an increase in pace led to positive pacing and an increase in both kinematic responses and anaerobic metabolism.
Publisher: SAGE Publications
Date: 08-2012
DOI: 10.2466/25.07.05.PMS.115.4.213-227
Abstract: This study examined the effect of introducing either a male or female observer on the ratings of perceived exertion (RPE) and affect of male runners during a moderate intensity running task. 10 moderately active men completed three 20-min. moderate intensity running trials at 60% of their peak treadmill running speed. Each participant completed three trials in random order: control, male-observed, and female-observed, where either the male or female observer joined the trial after 10 min. of the trial had elapsed, during which RPE and affect were monitored. The introduction of a female observer caused a significant decrease in RPE, whereas the introduction of a male observer caused a significant increase in RPE compared to the control trial. Affect was higher in the presence of both a male and female observer compared to control. It was concluded that there is a social, interpersonal, psychological dimension to RPE during exercise.
Publisher: Elsevier BV
Date: 03-2014
DOI: 10.1016/J.RESP.2013.12.015
Abstract: Dietary inorganic nitrate supplementation causes physiological effects which may enhance exercise tolerance. However it is not known whether nitrate might alter cognitive function during exercise. In a double-blind, cross-over study, sixteen subjects ingested either nitrate-rich beetroot juice or a placebo and completed a continuous cycle exercise test involving 20min stages at 50% and 70% V˙O2peak and a final stage at 90% V˙O2peak until volitional exhaustion. Cognitive tasks were completed before, during and after exercise. In the dietary nitrate condition: plasma [nitrite] increased (p<0.01), systolic blood pressure decreased (p<0.05) and there was a trend for a reduced oxygen uptake at 50% V˙O2peak. Tissue oxygenation improved across exercise intensities and exercise tolerance was greater at 90% V˙O2peak (p<0.05). Rating of perceived exertion, energy levels and cognitive performance were similar between conditions with mental fatigue being evident from 70% V˙O2peak onwards (p<0.05). Dietary nitrate supplementation enhanced short-term endurance exercise performance with concomitant mental fatigue but did not improve cognitive performance post-fatigue.
Publisher: Springer Science and Business Media LLC
Date: 09-04-2013
DOI: 10.1007/S40279-013-0044-Y
Abstract: Effective regulation of pace enables the majority of runners to complete competitive endurance events without mishap. However, some runners do experience exercise-induced collapse associated with postural hypotension, which in rare cases results from life-threatening conditions such as cardiac disorders, cerebral events, heat stroke and hyponatraemia. Despite the experience of either catastrophic system failure or extreme peripheral muscle fatigue, some runners persist in attempting to reach the finish line, and this often results in a sequence of dynamic changes in posture and gait that we have termed the 'Foster collapse positions'. The initial stage involves an unstable gait and the runner assumes the 'Early Foster' collapse position with hips slightly flexed and their head lowered. This unstable gait further degrades into a shuffle referred to as the 'Half Foster' collapse position characterized by hip flexion of approximately 90° with the trunk and head parallel to the ground. At this point, the muscles of postural support and the co-ordination of propulsion begin to be compromised. If the condition worsens, the runner will fall to the ground and assume the 'Full Foster' collapse position, which involves crawling forwards on knees and elbows towards the finish line, with their trunk angled such that the head is at a lower angle than the hips. Upon reaching the finish line, or sometimes before that, the runner may collapse and remain prone until recovering either with or without assistance or medical treatment. The Foster collapse positions are indicative of a final, likely primordial, protective mechanism designed to attenuate postural hypotension, cardiac 'pump' insufficiency or cerebral blood flow deficiency. Continuing to attempt to reach the finish line in this impaired state is also perhaps indicative of a high psychological drive or a variety of neurological and psychological pathologies such as diminished sensitivity to interoceptive feedback, unrealistic situational appraisal or extreme motivational drives. A better understanding of the physiological, neurological and psychological antecedents of the Foster collapse sequence remains an important issue with practical implications for runner safety and theoretical understanding of collapses during exercise.
Publisher: SAGE Publications
Date: 03-2012
DOI: 10.1260/1747-9541.7.1.109
Abstract: This study evaluated the impact of a high-intensity strength training session on rowing sprint performance. Ten male club rowers performed a baseline counter-movement jump (CMJ) and a 250 m rowing ergometer sprint (250 m). Twenty-four hours after baseline, participants performed a high-intensity strength training session (ST) consisting of multi-joint barbell exercises. At 24 h, 48 h and 72 h post-ST, CMJ and 250 m were repeated alongside assessment of plasma creatine kinase (CK) and perceived muscle soreness. At 24 h post-ST 250 m performance decreased significantly (90% CI: 0.3 – 0.7 s), but returned to pre-test values at 48 h. There was a significant decrease in CMJ height at 48 h post ST (90% CI: −0.7 – −4.1 cm). Perceived muscle soreness was significantly greater than baseline at all assessed time points following ST ( p 0.05). There was a significant increase in CK from baseline to 24 h (90% CI: 146 – 390 U/L). High-intensity strength training was observed to adversely affect 250 m rowing ergometer performance after 24 h and coincided with transient muscle damage.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2015
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2016
DOI: 10.1519/JSC.0000000000001443
Abstract: McGowan, CJ, Pyne, DB, Raglin, JS, Thompson, KG, and Rattray, B. Current warm-up practices and contemporary issues faced by elite swimming coaches. J Strength Cond Res 30(12): 3471–3480, 2016—A better understanding of current swimming warm-up strategies is needed to improve their effectiveness. The purpose of this study was to describe current precompetition warm-up practices and identify contemporary issues faced by elite swimming coaches during competition. Forty-six state-international level swimming coaches provided information through a questionnaire on their prescription of volume, intensity, and recovery within their pool and dryland-based competition warm-ups, and challenges faced during the final stages of event preparation. Coaches identified four key objectives of the precompetition warm-up: physiological (elevate body temperature and increase muscle activation), kinesthetic (tactile preparation, increase “feel” of the water), tactical (race-pace rehearsal), and mental (improve focus, reduce anxiety). Pool warm-up volume ranged from ∼1300 to 2100 m, beginning with 400–1000 m of continuous, low-intensity (∼50–70% of perceived maximal exertion) swimming, followed by 200–600 m of stroke drills and 1–2 sets (100–400 m in length) of increasing intensity (∼60–90%) swimming, concluding with 3–4 race or near race-pace efforts (25–100 m ∼90–100%) and 100–400 m easy swimming. Dryland-based warm-up exercises, involving stretch cords and skipping, were also commonly prescribed. Coaches preferred swimmers complete their warm-up 20–30 minutes before race start. Lengthy marshalling periods (15–20+ minutes) and the time required to don racing suits ( minutes) were identified as complicating issues. Coaches believed that the pool warm-up affords athletes the opportunity to gain a tactile feel for the water and surrounding pool environment. The combination of dryland-based activation exercises followed by pool-based warm-up routines seems to be the preferred approach taken by elite swimming coaches preparing their athletes for competition.
Publisher: Human Kinetics
Date: 07-2015
Abstract: To investigate the variation in training demands, physical performance, and player well-being across a women’s soccer season. Seventeen elite female players wore GPS tracking devices during every training session (N = 90) throughout 1 national-league season. Intermittent high-speed-running capacity and 5-, 15-, and 25-m-sprint testing were conducted at the beginning of preseason, end of preseason, midseason, and end of season. In addition, subjective well-being measures were selfreported daily by players over the course of the season. Time over 5 m was lowest at the end of preseason (mean 1.148 s, SE 0.017 s) but then progressively deteriorated to the end of the season ( P .001). Sprint performance over 15 m improved by 2.8% ( P = .013) after preseason training, while 25-m-sprint performance peaked at midseason, with a 3.1% ( P = .05) improvement from the start of preseason, before declining at the end of season ( P = .023). Training demands varied between phases, with total distance and high-speed distance greatest during preseason before decreasing ( P .001) during the early- and late-season phases. Endurance capacity and well-being measures did not change across training phases. Monitoring training demands and subsequent physical performance in elite female soccer players allow coaches to ensure that training periodization goals are being met and related positive training adaptations are being elicited.
Publisher: Public Library of Science (PLoS)
Date: 02-12-2015
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2009
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2011
Publisher: Human Kinetics
Date: 09-2014
Abstract: Nitrate supplementation improves endurance exercise and single bouts of high-intensity activity, but its effect on repeated sprints is unclear. This study is the first to investigate the effects of acute dietary nitrate supplementation during a high-intensity intermittent-sprint test to exhaustion. Team-sport athletes (9 male, age 22.3 ± 2.1 y, VO 2max 57.4 ± 8.5 mL · kg −1 · min −1 7 female, age 20.7 ± 1.3 y, VO 2max 47.2 ± 8.5 mL · kg −1 · min −1 ) were assigned to a double-blind, randomized, crossover design. Participants consumed 70 mL of concentrated beetroot juice containing a minimum of 0.3 g of nitrate (NT) or 70 mL of placebo (PL) 2 h before a repeated-sprint protocol involving repeated 8-s sprints with 30-s recovery on a cycle ergometer to exhaustion. Fewer sprints (NT = 13 ± 5 vs PL = 15 ± 6, P = .005, d = 0.41) and less total work (NT = 49.2 ± 24.2 kJ vs PL = 57.8 ± 34.0 kJ, P = .027, d = 0.3) were completed in NT relative to PL. However there was no difference in overall mean power output or the mean power output for each in idual 8-s sprint. These findings suggest that dietary nitrate is not beneficial for improving repeated-sprint performance, at least when such sprints are near-maximal and frequent in nature. The lack of an effect of nitrate at near-maximal oxygen uptake supports the suggestion that at greater exercise intensities nitrate does not have an ergogenic effect.
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.PHYSBEH.2015.05.035
Abstract: Nitrate derived from vegetables is consumed as part of a normal diet and is reduced endogenously via nitrite to nitric oxide. It has been shown to improve endothelial function, reduce blood pressure and the oxygen cost of sub-maximal exercise, and increase regional perfusion in the brain. The current study assessed the effects of dietary nitrate on cognitive performance and prefrontal cortex cerebral blood-flow (CBF) parameters in healthy adults. In this randomised, double-blind, placebo-controlled, parallel-groups study, 40 healthy adults received either placebo or 450 ml beetroot juice (~5.5 mmol nitrate). Following a 90 minute drink/absorption period, participants performed a selection of cognitive tasks that activate the frontal cortex for 54 min. Near-Infrared Spectroscopy (NIRS) was used to monitor CBF and hemodynamics, as indexed by concentration changes in oxygenated and deoxygenated-haemoglobin, in the frontal cortex throughout. The bioconversion of nitrate to nitrite was confirmed in plasma by ozone-based chemi-luminescence. Dietary nitrate modulated the hemodynamic response to task performance, with an initial increase in CBF at the start of the task period, followed by consistent reductions during the least demanding of the three tasks utilised. Cognitive performance was improved on the serial 3s subtraction task. These results show that single doses of dietary nitrate can modulate the CBF response to task performance and potentially improve cognitive performance, and suggest one possible mechanism by which vegetable consumption may have beneficial effects on brain function.
Publisher: Informa UK Limited
Date: 2002
DOI: 10.1080/026404102760000044
Abstract: Generally, swimmers pace themselves using their own judgement and the poolside clock during swimming training, fitness testing protocols or scientific investigation. The Aquapacer is a new pacing device that can be used to pace the swimming speed or stroke rate of the swimmer. The aims of this study were to determine if breaststroke swimmers could pace accurately during submaximal swimming using a poolside clock (Study 1) and the Aquapacer (Study 2), at swimming speeds at, just above and just below maximal 200 m time-trial speeds (using the Aquapacer, Study 3) and under three different race pacing conditions (using the Aquapacer, Study 4). Between 8 and 15 male national or club standard 200 m breaststroke swimmers participated in each of the studies. The swimmers in Study 2, despite being less well trained than the swimmers in Study 1 and part of a more heterogeneous group in terms of swimming performance, repeatedly demonstrated less random error in pacing, suggesting that the Aquapacer may be preferable to the poolside clock when swimmers are being required to pace accurately. The Aquapacer also enabled swimmers to pace accurately at race-specific swimming speeds (until fatigue precluded them from holding pace) (Study 3), and through a change in pace at race-specific speeds (Study 4), which suggests that it may be of use in entraining racing strategies.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2012
Publisher: Springer Science and Business Media LLC
Date: 24-06-2010
DOI: 10.1007/S00421-010-1548-X
Abstract: Interleukin-6 (IL-6) is a cytokine that can mediate numerous biological actions including fatigue. Circulating IL-6 increases during prolonged exercise, and furthermore, the signalling receptors sIL-6R and sgp130 are also increased. The variability of the response of these markers to exercise is unknown therefore, we examined the changes in these markers to a preloaded time trial bout of running. Nine males performed three identical trials where participants ran at 60% vVO2max for 2 h interspersed with 30 s at 90% vVO2max every 10 min, followed by a 5-km time trial. Blood s les were drawn at baseline, following the 2-h bout, post time trial, 1 h post time trial and the following morning. Results showed that between-subject variability (CVg) was greater than within-subject variation (CVi) for the three markers. IL-6, sIL-6R and sgp130 demonstrated a CVi of 15.3-25.5%, 15.0-17.6% and 6.2-9.4% variation, respectively, across the time points. When the data from the second and third trials were analysed independently, CVi was reduced which is supported by the time trial results for which CVi improve (4.7-2.4%). In conclusion, the results indicate that a large variation in response to exercise can be reduced following a habituation trial.
Publisher: Human Kinetics
Date: 11-2013
Abstract: The collection of retrospective lap times from video footage is a potentially useful research tool to analyze the pacing strategies in any number of competitive events. The aim of this study was to validate a novel method of obtaining running split-time data from publically available video footage. Videos of the 1500-m men’s final from the 2004 and 2008 Olympics, 2005 and 2009 World Ch ionships, and 2010 European Ch ionships were obtained from the YouTube Web site, and split times were collected from all competitors using frame-by-frame playback. The typical error of video split times ranged between 0.02 s and 0.11 s for the 4 laps when compared with official split times. Video finishing times were also similar to official finishing times (typical error of 0.04 s). The method was shown to be highly reliable with a typical error of 0.02 s when the same video was analyzed on 2 occasions separated by 8 mo. Video data of track races are widely available however, camera angles are not always perpendicular to the start/finish line, and some slower athletes may cross the line after the camera has panned away. Nevertheless, the typical errors reported here show that when appropriate camera angles are available this method is both valid and reliable.
Publisher: Human Kinetics
Date: 10-2016
Abstract: To investigate the physical and physiological response to different formats of various-sided games. Eighteen elite women’s soccer players wore 15-Hz global positioning system devices and heart-rate (HR) monitors during various-sided games (small, 4 vs 4 and 5 vs 5 medium, 6 vs 6 and 7 vs 7 large, 8 vs 8 and 9 vs 9). Players covered more relative sprinting distance during large-sided games than in small-sided ( P .001, d = 0.69) and medium-sided ( P .001, d = 0.54) games. In addition, a greater proportion of total acceleration efforts that had a commencement velocity m/s were observed in small-sided games (44.7% ± 5.5%) than in large-sided games (36.7% ± 10.6%) ( P = .018, d = 0.94). This was accompanied by a greater proportion of acceleration efforts with a final velocity equivalent to the sprint threshold in large-sided games (15.4% ± 7.7%) than in small-sided games (5.2% ± 2.5%) ( P .001, d = 1.78). The proportion of time spent in HR zone 4 ( % maximum HR) was greater during small-sided games (69.8% ± 2.5%) than in medium- (62.1% ± 2.8%, d = 2.90) and large-sided games (54.9% ± 3.1%) ( P .001, d = 5.29). The results from this study demonstrate that coaches can use small-sided games as an aerobic conditioning stimulus and to develop players’ explosiveness and repeat-sprint ability over short durations. Large-sided games can be used to maintain aerobic capacity and develop maximum speed over longer distances.
Publisher: Wiley
Date: 31-03-2017
DOI: 10.1111/SMS.12685
Abstract: The post-exercise hepcidin response during prolonged (>2 weeks) hypoxic exposure is not well understood. We compared plasma hepcidin levels 3 h after exercise [6 × 1000 m at 90% of maximal aerobic running velocity (vVO
Publisher: OMICS Publishing Group
Date: 2014
Publisher: Informa UK Limited
Date: 15-09-2017
DOI: 10.1080/02640414.2016.1223329
Abstract: This study investigated the effect of completing additional warm-up strategies in the transition phase between the pool warm up and the start of a race on elite sprint swimming performance. Twenty-five elite swimmers (12 men, 20 ± 3 years 13 women, 20 ± 2 years, performance standard ~807 FINA2014 points) completed a standardised pool warm up followed by a 30-min transition phase and a 100-m freestyle time trial. During the transition phase, swimmers wore a tracksuit jacket with integrated heating elements and performed a dry land-based exercise routine (Combo), or a conventional tracksuit and remained seated (Control). Start (1.5% ± 1.0%, P = 0.02 mean ± 90% confidence limits) and 100-m time trial (0.8% ± 0.4%, P < 0.01) performances were improved in Combo. Core temperature declined less (-0.2°C ± 0.1°C versus -0.5°C ± 0.1°C, P = 0.02) during the transition phase and total local (trapezius) haemoglobin concentration was greater before the time trial in Combo (81 µM ± 25 µM versus 30 µM ± 18 µM, P < 0.01 mean ± standard deviation) than in Control. Combining swimmers traditional pool warm up with passive heating via heated jackets and completion of dry land-based exercises in the transition phase improves elite sprint swimming performance by ~0.8%.
Publisher: Human Kinetics
Date: 03-2016
Abstract: Exercise is known to result in hemodynamic changes in the bilateral prefrontal cortex. The aim of this study was to investigate hemodynamic changes in right and left hemispheres of the prefrontal cortex (PFC) during incremental cycling exercise. After 10 min rest, 9 participants (mean age 26.6 ± 2.5 y, mass 77.5 ± 9.7 kg, stature 1.79 ± 0.9 m) cycled at 100–150 W for 4 min. Thereafter, resistance was increased by 25 W every 4 min until exhaustion (EXH). Respiratory exchange and concentrations of oxy- ([HbO 2 ]), deoxy- ([(HHb]), and total hemoglobin ([Hb tot ]) in the PFC were continuously measured. Data were averaged for 60 s at rest and preceding ventilatory threshold 1 (VT 1 ), VT 2 , and volitional EXH and after 5 min recovery. Subjective ratings of affect were measured at VT 1 , VT 2 , VT 1 minus 25 W (VT 1 -25W), and VT 2 plus 25 W (VT 2 +25W). There were no between-hemispheres differences in [HbO 2 ] or [Hb tot ] at rest, VT 1 , or recovery or in [HHb] at any point. Right-hemisphere [HbO 2 ] and [Hb tot ] were significantly greater than left at VT 2 ( P = .01 and P = .02) and EXH ( P = .03 and P = .02). Affect was significantly greater at VT 1 -25W vs VT 2 and VT 2 +25W and at VT 1 and VT 2 vs VT 2 +25W ( P .01–.03). To the authors’ knowledge, this is the first study to describe an exercise-state-dependent change in PFC asymmetry during incremental exercise. The asymmetry detected coincided with a decrease in affect scores in agreement with the PFC-asymmetry hypothesis.
Publisher: Springer Science and Business Media LLC
Date: 26-11-2015
DOI: 10.1007/S00421-014-3052-1
Abstract: Mental fatigue can negatively impact on submaximal endurance exercise and has been attributed to changes in perceived exertion rather than changes in physiological variables. The impact of mental fatigue on maximal anaerobic performance is, however, unclear. Therefore, the aim of the present study was to induce a state of mental fatigue to examine the effects on performance, physiological and perceptual variables from subsequent tests of power, strength and anaerobic capacity. Twelve participants took part in the single-blind, randomised, crossover design study. Mental fatigue was induced by 90 min of the computer-based Continuous Performance Task AX version. Control treatment consisted of 90 min of watching emotionally neutral documentaries. Participants consequently completed countermovement jump, isometric leg extension and a 3-min all-out cycling tests. Results of repeated measures analysis of variance and paired t tests revealed no difference in any performance or physiological variable. Rating of perceived exertion tended to be greater when mentally fatigued (mental fatigue = 19 ± 1 vs control = 18 ± 1, p = 0.096, [Formula: see text] = .232) and intrinsic motivation reduced (mental fatigue = 11 ± 4 vs control = 13 ± 6, p = 0.063, d = 0.597) in the mental fatigue condition. Near identical responses in performance and physiological parameters between mental fatigue and control conditions suggest that peripheral mechanisms primarily regulate maximal anaerobic exercise. Whereas mental fatigue can negatively impact submaximal endurance exercise, it appears that explosive power, voluntary maximal strength and anaerobic work capacity are unaffected.
Publisher: PeerJ
Date: 02-03-2017
DOI: 10.7717/PEERJ.3028
Abstract: The ergogenic effects of analgesic substances suggest that pain perception is an important regulator of work-rate during fatiguing exercise. Recent research has shown that endogenous inhibitory responses, which act to attenuate nociceptive input and reduce perceived pain, can be increased following transcranial direct current stimulation of the hand motor cortex. Using high-definition transcranial direct current stimulation (HD-tDCS 2 mA, 20 min), the current study aimed to examine the effects of elevated pain inhibitory capacity on endurance exercise performance. It was hypothesised that HD-tDCS would enhance the efficiency of the endogenous pain inhibitory response and improve endurance exercise performance. Twelve healthy males between 18 and 40 years of age ( M = 24.42 ± 3.85) were recruited for participation. Endogenous pain inhibitory capacity and exercise performance were assessed before and after both active and sham (placebo) stimulation. The conditioned pain modulation protocol was used for the measurement of pain inhibition. Exercise performance assessment consisted of both maximal voluntary contraction (MVC) and submaximal muscular endurance performance trials using isometric contractions of the non-dominant leg extensors. Active HD-tDCS (pre-tDCS, −.32 ± 1.33 kg post-tDCS, −1.23 ± 1.21 kg) significantly increased pain inhibitory responses relative to the effects of sham HD-tDCS (pre-tDCS, −.91 ± .92 kg post-tDCS, −.26 ± .92 kg p = .046). Irrespective of condition, peak MVC force and muscular endurance was reduced from pre- to post-stimulation. HD-tDCS did not significantly influence this reduction in maximal force (active: pre-tDCS, 264.89 ± 66.87 Nm post-tDCS, 236.33 ± 66.51 Nm sham: pre-tDCS, 249.25 ± 88.56 Nm post-tDCS, 239.63 ± 67.53 Nm) or muscular endurance (active: pre-tDCS, 104.65 ± 42.36 s post-tDCS, 93.07 ± 33.73 s sham: pre-tDCS, 123.42 ± 72.48 s post-tDCS, 100.27 ± 44.25 s). Despite increasing pain inhibitory capacity relative to sham stimulation, active HD-tDCS did not significantly elevate maximal force production or muscular endurance. These findings question the role of endogenous pain inhibitory networks in the regulation of exercise performance.
Publisher: Georg Thieme Verlag KG
Date: 08-2000
DOI: 10.1055/S-2000-3829
Abstract: Swimming training is characterised by the use of early morning and evening training sessions. The purpose of the present study was to investigate if the physiological and kinematic responses to swimming a typical training set are affected by time of day. Seven male collegiate swimmers (age 22 +/- 4 years height 1.8 +/- 0.1 m mass 82.1 +/- 4.1 kg) completed a standardised 600 m warm up followed by a 10 x 100 m sub-maximal freestyle set twice a day (06:30-08:00 h and 16:30-20:00 h) on three separate days. Swimming speed was controlled precisely throughout (limits of agreement multiplied/ ided 1.00) using a new pacing device (Aquapacer, Challenge and Response, Inverurie, Scotland). Oral temperature (To), heart rate (HR), minute ventilation (VE), oxygen uptake (VO2), carbon dioxide expired (VCO2), respiratory exchange ratio (RER), capillary blood lactate (Bla), and glucose (BGL) were measured at rest and post exercise. Stroke rate (SR) and HR were measured during the first nine 100 m repetitions while rate of perceived exertion (RPE) was measured immediately after each 100 m. Significant diurnal variation was found at rest in To, HR, and VO2 on all three days and for VE and VCO2 on two of the days (P<0.05). During the training set no diurnal variation was evident in HR and SR responses or repetition times although RPE values were higher in morning trials compared to evening trials on two of the three days (P < 0.05). Post-exercise significant diurnal variation was found for To and blood glucose for two of the three days (P < 0.05). Therefore, although diurnal variation is evident at rest, there is no subsequent effect on physiological and kinematic responses during a sub-maximal training set following a standardised warm-up.
Publisher: Informa UK Limited
Date: 10-2011
DOI: 10.1080/00071668.2011.607429
Abstract: The influence of in-feed lactoferrin (Lf) on bird production, intestinal microbiota, mucosal immune system and gut microarchitecture was assessed in male Cobb 500 broiler chickens. Birds were given one of four diets from day of hatch: Control (basal diet with no additives), ZnB (basal diet + 50 mg/kg zinc bacitracin), Lf 250 mg/kg (basal diet + 250 mg/kg Lf) and Lf 500 mg/kg (basal diet + 500 mg/kg Lf) n = 24 birds/treatment. An apparent metabolisable energy study was performed between d 25-32. Lf did not affect growth rate or feed conversion in the period 0-21 d of age, nor performance or energy metabolism during the 7 d metabolism experiment which commenced at 25 d of age.The profiles of caecal microbial communities were significantly different in birds given ZnB compared with birds given a diet with no additives, or supplemented with 250 mg/kg Lf. Birds given 250 mg/kg Lf also had a different microbial profile compared with birds given 500 mg/kg Lf. In comparison to control birds, Lf treated birds showed some differences in the T cell proportions in caecal tonsil and spleen. No differences in ileal villus height, crypt depth or goblet cell proportions were observed amongst dietary treatments. Whilst Lf had little effect on the measured parameters, the use of an integrated approach to study the influence of novel feed additives may facilitate a greater understanding of the relationships between nutrition, gut health and bird performance.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Kevin Thompson.