A comparison of methods to estimate anaerobic capacity: Accumulated oxygen deficit and W' during constant and all-out work-rate profiles.

This document is the Pre-Print version of an article first published by Taylor & Francis Group in Journal of Sports Sciences, on December 2016, available online at:http://www.tandfonline.com/doi/full/10.1080/02640414.2016.1267386. The Accepted Manuscript version is under embargo. Embargo end date: 26 June 2018.This study investigated (i) whether the accumulated oxygen deficit (AOD) and curvature constant of the power-duration relationship (W') are different during constant work-rate to exhaustion (CWR) and 3-min all-out (3MT) tests and (ii) the relationship between AOD and W' during CWR and 3MT. Twenty-one male cyclists (age: 40 ± 6 years; maximal oxygen uptake [V̇O2max]: 58 ± 7 ml · kg-1 · min-1) completed preliminary tests to determine the V̇O2-power output relationship and V̇O2max. Subsequently, AOD and W' were determined as the difference between oxygen demand and oxygen uptake and work completed above critical power, respectively, in CWR and 3MT. There were no differences between tests for duration, work, or average power output (P ≥ 0.05). AOD was greater in the CWR test (4.18 ± 0.95 vs. 3.68 ± 0.98 L; P = 0.004), whereas W' was greater in 3MT (9.55 ± 4.00 vs. 11.37 ± 3.84 kJ; P = 0.010). AOD and W' were significantly correlated in both CWR (P < 0.001, r = 0.654) and 3MT (P < 0.001, r = 0.654). In conclusion, despite positive correlations between AOD and W' in CWR and 3MT, between-test differences in the magnitude of AOD and W', suggest that both measures have different underpinning mechanisms.Peer reviewe

The variation in pressures exerted by commercially available compression garments

Commercially available compression garments (CGs) demonstrate the enhanced recovery from exercise in some, but not all studies. It is possible that in some cases the degree of compression pressure (ComP) exerted is not sufficient to produce any physiological benefit. The aim of this investigation was to identify the levels of ComP exerted by commercially available CGs. This study was composed of two parts. In part A 50 healthy, physically active individuals (n=26 male, n=24 female) were fitted with CGs according to manufacturer’s guidelines. ComP was measured in participants standing in the anatomical position with a pressure measurement device inserted between the skin and the garment. Data were compared to ‘ideal’ pressure values proposed in the literature. In part B ComP in three different brands of CG were compared in a population of 29 men who all wore a medium sized garment. A one way ANOVA indicated that there was a significant difference (P0.05) between observed and ideal pressures in the calf of the male population. No significant differences in pressure (P>0.05) were observed between CG brands at the quadriceps or calf. In conclusion a large number of individuals may not be experiencing an adequate ComP from CG, and this is true for all 3 of the major brands of CGs tested in this investigation

Selective cortical adaptations associated with neural efficiency in visuospatial tasks – the comparison of electroencephalographic profiles of expert and novice artists

Visuospatial cognition encapsulates an individual's ability to efficiently navigate and make sense of the multimodal cues from their surroundings, and therefore has been linked to expert performance across multiple domains, including sports, performing arts, and highly skilled tasks, such as drawing (Morrone and Minini, 2023). As neural efficiency posits a task-specific functional reorganization facilitated by long-term training, the present study employs a visuospatial construction task as a means of investigating the neurophysiological adaptations associated with expert visuospatial cognitive performance. Electroencephalogram (EEG) data acquisitions were used to evaluate the event-related changes (ER%) and statistical topographic maps of nine expert versus nine novice artists. The expert artists displayed overall higher global ER% compared to the novices within task-active intervals. Significant increases in relative ER% were found in the theta (t (10) = 3.528, p = 0.003, CI = [27.3,120.9]), lower-alpha (t (10) = 3.751, p = 0.002, CI = [28.2,110.5]), upper-alpha (t (10) = 3.829, p = 0.002, CI = [50.2,189.8]), and low beta (t (10) = 4.342, p < 0.001, CI = [37.0,114.9]) frequency bands, when comparing the experts to the novice participants. These results were particularly found in the frontal (t (14) = 2.014, p = 0.032, CI = [7.7,245.4]) and occipital (t (14) = 2.647, p = 0.010, CI = [45.0,429.7]) regions. Further, a significant decrease in alpha ER% from lower to upper activity (t (8) = 4.475, p = 0.001, CI = [21.0, 65.8]) was found across cortical regions in the novice group. Notably, greater deviation between lower and upper-alpha activity was found across scalp locations in the novice group, compared to the experts. Overall, the findings demonstrate potential local and global EEG-based indices of selective cortical adaptations within a task requiring a high degree of visuospatial cognition, although further work is needed to replicate these findings across other domains

EEG-based neurophysiological indices for expert psychomotor performance – a review

A primary objective of current human neuropsychological performance research is to define the physiological correlates of adaptive knowledge utilization, in order to support the enhanced execution of both simple and complex tasks. Within the present article, electroencephalography-based neurophysiological indices characterizing expert psychomotor performance, will be explored. As a means of characterizing fundamental processes underlying efficient psychometric performance, the neural efficiency model will be evaluated in terms of alpha-wave-based selective cortical processes. Cognitive and motor domains will initially be explored independently, which will act to encapsulate the task-related neuronal adaptive requirements for enhanced psychomotor performance associating with the neural efficiency model. Moderating variables impacting the practical application of such neuropsychological model, will also be investigated. As a result, the aim of this review is to provide insight into detectable task-related modulation involved in developed neurocognitive strategies which support heightened psychomotor performance, for the implementation within practical settings requiring a high degree of expert performance (such as sports or military operational settings)

Injury incidence, severity and type across the menstrual cycle in female footballers:A prospective three season cohort study

AbstractPurpose The aim of the study was to assess the influence of menstrual cycle phase on injury incidence, severity and type in elite female professional footballers over three seasons.Methods Time-loss injuries and menstrual cycle data were prospectively recorded for 26 elite female football players across three seasons. The menstrual cycle was categorised into four phases using a standardised model: menstruation (phase 1; P1), remainder of follicular phase (phase 2; P2), early luteal (phase 3; P3), and pre-menstrual phase (phase 4; P4). Injury incidence rates (IRR) and ratios (IIRR) were calculated for overall injuries, injury severity, type, contact vs non-contact and game/training.Results 593 cycles across 13,390 days were tracked during the study and 74 injuries from 26 players were eligible for analysis. When comparing IRR between phases (reference: P1), overall injury rates were highest in P4 (IIRR: 2.30 [95% CI: 0.99-5.34; p = 0.05]). When examining rates by injury severity and type, IRR were also highest in P4 for ≤7 days’ time-loss (4.40 [0.93-20.76; p = 0.06]), muscle-specific (6.07 [1.34-27.43; p = 0.02]) and non-contact (3.05 [1.10-8.50; p = 0.03]) injuries. Muscle-specific (IIRR P3:P1: 5.07 [1.16-22.07; p = 0.03]) and ≤ 7 days’ time-loss (4.47 [1.01-19.68; p = 0.05]) injury risk was also significantly higher in P3. Muscle injuries were the most prevalent sub-type (n = 41). No anterior cruciate ligament injuries were recorded across the monitoring period.Conclusions Injury risk was significantly elevated during the luteal phase of the menstrual cycle (P3 and P4) among elite female professional footballers. Further research is urgently needed to better understand the influence of the menstrual cycle on injury risk and to develop interventions to mitigate risk

Acute and long-term sleep measurements produce opposing results on sleep quality in 8 and 12 hour shift patterns in law enforcement officers

The occupational demands of law enforcement increase the risk of poor-quality sleep, putting officers at risk of adverse physical and mental health. This cross-sectional study aimed to characterise sleep quality in day workers, 8 and 12 h rotating shift pattern workers. One hundred eighty-six officers volunteered for the study (37 female, age: 41 ± 7). Sleep quality was assessed using the Pittsburgh sleep quality index, actigraphy and the Leeds sleep evaluation questionnaire. The maximal aerobic capacity (VO2max) was measured on a treadmill via breath-by-breath analysis. There was a 70% overall prevalence of poor sleepers based on Pittsburgh sleep quality index scores, where 8 h shifts exhibited the worst prevalence (92%, p = 0.029), however, there was no difference between age, gender, or role. In contrast, 12 h shifts exhibited the poorest short-term measures, including awakening from sleep (p = 0.039) and behaviour following wakefulness (p = 0.033) from subjective measures, and poorer total sleep time (p = 0.024) and sleep efficiency (p = 0.024) from the actigraphy. High VO2max predicted poorer wake after sleep onset (Rsq = 0.07, p = 0.05) and poorer sleep latency (p = 0.028). There was no relationship between the Pittsburgh sleep quality index scores and any of the short-term measures. The prevalence of poor sleepers in this cohort was substantially higher than in the general population, regardless of shift pattern. The results obtained from the long- and short-term measures of sleep quality yielded opposing results, where long-term perceptions favoured the 12 h pattern, but short-term subjective and objective measures both favoured the 8 h pattern

Modelling menstrual cycle length in athletes using state-space models

The ability to predict an individual’s menstrual cycle length to a high degree of precision could help female athletes to track their period and tailor their training and nutrition correspondingly. Such individualisation is possible and necessary, given the known inter‐individual variation in cycle length. To achieve this, a hybrid predictive model was built using data on 16,524 cycles collected from a sample of 2125 women (mean age 34.38 years, range 18.00–47.10, number of menstrual cycles ranging from 4 to 53). A mixed‐effect state‐space model was fitted to capture the within‐subject temporal correlation, incorporating a Bayesian approach for process forecasting to predict the duration (in days) of the next menstrual cycle. The modelling procedure was split into three steps (1) a time trend component using a random walk with an overdispersion parameter, (2) an autocorrelation component using an autoregressive moving‐average model, and (3) a linear predictor to account for covariates (e.g. injury, stomach cramps, training intensity). The inclusion of an overdispersion parameter suggested that 26.36% [23.68%, 29.17%] of cycles in the sample were overdispersed. The random walk standard deviation for a non‐overdispersed cycle is 27.41 ± 1.05 [1.00, 1.09] days while under an overdispersed cycle, the menstrual cycle variance increase in 4.78 [4.57, 5.00] days. To assess the performance and prediction accuracy of the model, each woman’s last observation was used as test data. The root mean square error (RMSE), concordance correlation coefficient and Pearson correlation coefficient (r) between the observed and predicted values were calculated. The model had an RMSE of 1.6412 days, a precision of 0.7361 and overall accuracy of 0.9871. In conclusion, the hybrid model presented here is a helpful approach for predicting menstrual cycle length, which in turn can be used to support female athlete wellness

Caffeine and Sprinting Performance: Dose Responses and Efficacy

The aims of this study were to evaluate the effects of caffeine supplementation on sprint cycling performance and to determine if there was a dose-response effect. Using a randomized, double-blind, placebo-controlled design, 17 well-trained men (age: 24 ± 6 years, height: 1.82 ± 0.06 m, and body mass(bm): 82.2 ± 6.9 kg) completed 7 maximal 10-second sprint trials on an electromagnetically braked cycle ergometer. Apart from trial 1 (familiarization), all the trials involved subjects ingesting a gelatine capsule containing either caffeine or placebo (maltodextrin) 1 hour before each sprint. To examine dose-response effects, caffeine doses of 2, 4, 6, 8, and 10 mg·kg bm−1 were used. There were no significant (p ≥ 0.05) differences in baseline measures of plasma caffeine concentration before each trial (grand mean: 0.14 ± 0.28 μg·ml−1). There was, however, a significant supplement × time interaction (p < 0.001), with larger caffeine doses producing higher postsupplementation plasma caffeine levels. In comparison with placebo, caffeine had no significant effect on peak power (p = 0.11), mean power (p = 0.55), or time to peak power (p = 0.17). There was also no significant effect of supplementation on pretrial blood lactate (p = 0.58), but there was a significant time effect (p = 0.001), with blood lactate reducing over the 50 minute postsupplementation rest period from 1.29 ± 0.36 to 1.06 ± 0.33 mmol·L−1. The results of this study show that caffeine supplementation has no effect on short-duration sprint cycling performance, irrespective of the dosage used