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The Effects of Repeated-Sprint Training on Physical Fitness and Physiological Adaptation in Athletes: A Systematic Review and Meta-Analysis. Sports Med 2024; 54:953-974. [PMID: 38041768 DOI: 10.1007/s40279-023-01959-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2023] [Indexed: 12/03/2023]
Abstract
BACKGROUND Repeated-sprint training (RST) is a common training method for enhancing physical fitness in athletes. To advance RST prescription, it is important to understand the effects of programming variables on physical fitness and physiological adaptation. OBJECTIVES This study (1) quantifies the pooled effects of running RST on changes in 10 and 20 m sprint time, maximal oxygen consumption (VO2max), Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) distance, repeated-sprint ability (RSA), countermovement jump (CMJ) height and change of direction (COD) ability in athletes, and (2) examines the moderating effects of program duration, training frequency, weekly volume, sprint modality, repetition distance, number of repetitions per set and number of sets per session on changes in these outcome measures. METHODS Pubmed, SPORTDiscus and Scopus databases were searched for original research articles up to 04 July 2023, investigating RST in healthy, able-bodied athletes, between 14 and 35 years of age, and a performance calibre of trained or above. RST interventions were limited to repeated, maximal running (land-based) sprints of ≤ 10 s duration, with ≤ 60 s recovery, performed for 2-12 weeks. A Downs and Black checklist was used to assess the methodological quality of the included studies. Eligible data were analysed using multi-level mixed-effects meta-analysis, with standardised mean changes determined for all outcomes. Standardised effects [Hedges G (G)] were evaluated based on coverage of their confidence (compatibility) intervals (CI) using a strength and conditioning specific reference value of G = 0.25 to declare an improvement (i.e. G > 0.25) or impairment (i.e. G < - 0.25) in outcome measures. Applying the same analysis, the effects of programming variables were then evaluated against a reference RST program, consisting of three sets of 6 × 30 m straight-line sprints performed twice per week for 6 weeks (1200 m weekly volume). RESULTS 40 publications were included in our investigation, with data from 48 RST groups (541 athletes) and 19 active control groups (213 athletes). Across all studies, the effects of RST were compatible with improvements in VO2max (G 0.56, 90% CI 0.32-0.80), YYIR1 distance (G 0.61, 90% CI 0.43-0.79), RSA decrement (G - 0.61, 90% CI - 0.85 to - 0.37), linear sprint times (10 m: G - 0.35, 90% CI - 0.48 to - 0.22; 20 m: G - 0.48, 90% CI - 0.69 to - 0.27), RSA average time (G - 0.34, 90% CI - 0.49 to - 0.18), CMJ height (G 0.26, 90% CI 0.13-0.39) and COD ability (G - 0.32, 90% CI - 0.52 to - 0.12). Compared with the reference RST program, the effects of manipulating training frequency (+ 1 session per week), program duration (+ 1 extra training week), RST volume (+ 200 m per week), number of reps (+ 2 per set), number of sets per session (+ 1 set) or rep distance (+ 10 m per rep) were either non-substantial or comparable with an impairment in at least one outcome measure per programming variable. CONCLUSIONS Running-based RST improves speed, intermittent running performance, VO2max, RSA, COD ability and CMJ height in trained athletes. Performing three sets of 6 × 30 m sprints, twice per week for 6 weeks is effective for enhancing physical fitness and physiological adaptation. Additionally, since our findings do not provide conclusive support for the manipulation of RST variables, further work is needed to better understand how programming factors can be manipulated to augment training-induced adaptations. STUDY REGISTRATION Open Science Framework registration https://doi.org/10.17605/OSF.IO/RVNDW .
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Reliability of Measures of Lower-Body Strength and Speed in Academy Male Adolescent Soccer Players. J Strength Cond Res 2024; 38:e96-e103. [PMID: 38416449 PMCID: PMC10880938 DOI: 10.1519/jsc.0000000000004639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
ABSTRACT Ferguson, J, Gibson, NV, Weston, M, and McCunn, R. Reliability of measures of lower body strength and speed in academy male adolescent soccer players. J Strength Cond Res 38(3): e96-e103, 2024-The Nordbord and ForceFrame represent a practical and time efficient means of assessing eccentric hamstring and isometric adductor strength in the large number of squads and players associated with youth soccer academies, yet measurement reliability in this population is unexamined. Therefore, over a period of 4 days, with no less than 24 hours and no more than 48 hours between trials, 37 players (age: 14.7 ± 0.8 years, stature: 168.7 ± 7.8 cm, mass: 57.7 ± 9.1 kg, and maturity offset: 0.8 ± 0.9 years) were assessed for eccentric hamstring strength (force, torque), isometric adductor strength (long and short lever positions), and 30-m sprint (5, 10, and 20-m splits), using the Nordbord, ForceFrame, and electronic timing gates, respectively, on 3 separate occasions. Relative reliability (intraclass correlation coefficient) was rated as good for all Nordbord (range: 0.86-0.89) and ForceFrame (0.78-0.85) measures and ranged from moderate (0.53) to excellent (0.93) for the speed measures, improving with increased distance. Absolute reliability (standard error of the measurement [%SEM]) ranged from 7 to 8% (Nordbord), 3 to 11% (ForceFrame), and 1 to 4% (sprints). Our data provide the first Nordbord and ForceFrame reliability estimates in adolescent soccer academy players. To interpret test sensitivity, practitioners are encouraged to interpret our estimates of absolute reliability against meaningful change values derived from personal experience and evidence-based knowledge and not against absolute or standardized thresholds.
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Inconsistent Effect of Psychometric-Scale Familiarization on the Relationship Between Ratings of Perceived Exertion and External Load Measures in Elite Youth Soccer Players. Int J Sports Physiol Perform 2023; 18:1254-1262. [PMID: 37648250 DOI: 10.1123/ijspp.2022-0428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 04/29/2023] [Accepted: 07/10/2023] [Indexed: 09/01/2023]
Abstract
OBJECTIVES To examine the moderating effect of familiarization on the relationship between external load and ratings of perceived exertion (RPEs) in elite youth soccer players. METHODS Thirty-five elite male youth soccer players were monitored over a 31-week period. Players had no previous experience using the centiMax scale (arbitrary units [AU]). The final sample included familiarized (blackness test; n = 20) and nonfamiliarized players (n = 15) with the Borg centiMax scale. Players recorded a global RPE and differential RPEs (dRPE) for breathlessness (RPE-B) and leg-muscle exertion (RPE-L) 15 to 30 minutes following training sessions and competitive matches. Separate multivariable-adjusted random-effects generalized additive models with restricted maximum likelihood quantified familiarization versus no-familiarization differences in actual perceived exertion score (in AU) by number of accelerations, decelerations, and high-speed running distance (in meters) as predictor variables, respectively. RESULTS Players improved their blackness test score from 39% to 78%. For explorations by number of accelerations, familiarization effects were not practically relevant for the RPE and RPE-B variables. The width and sign of the effects for the RPE-L variable at 30 efforts of 10 AU (95% CI, 4-16 AU) suggested that scores were lower for players who underwent familiarization versus players who did not. Familiarization effects were not practically relevant for any RPE variable irrespective of the number of deceleration efforts and high-speed running distance covered. CONCLUSION Improved performance on the blackness test did not have a moderating effect on the relationship between proxy measures of external load and RPEs.
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Pain relief in interventional radiology. Clin Radiol 2023; 78:239. [PMID: 36868972 DOI: 10.1016/j.crad.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 02/09/2023] [Indexed: 02/19/2023]
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Atom-Specific Probing of Electron Dynamics in an Atomic Adsorbate by Time-Resolved X-Ray Spectroscopy. PHYSICAL REVIEW LETTERS 2022; 129:276001. [PMID: 36638285 DOI: 10.1103/physrevlett.129.276001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 06/14/2022] [Accepted: 11/18/2022] [Indexed: 06/17/2023]
Abstract
The electronic excitation occurring on adsorbates at ultrafast timescales from optical lasers that initiate surface chemical reactions is still an open question. Here, we report the ultrafast temporal evolution of x-ray absorption spectroscopy (XAS) and x-ray emission spectroscopy (XES) of a simple well-known adsorbate prototype system, namely carbon (C) atoms adsorbed on a nickel [Ni(100)] surface, following intense laser optical pumping at 400 nm. We observe ultrafast (∼100 fs) changes in both XAS and XES showing clear signatures of the formation of a hot electron-hole pair distribution on the adsorbate. This is followed by slower changes on a few picoseconds timescale, shown to be consistent with thermalization of the complete C/Ni system. Density functional theory spectrum simulations support this interpretation.
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Abstract
The purpose of this study was to present reference standards for physical performance test outcomes relevant to elite female soccer players. We analysed mixed-longitudinal data (n = 1715 observations) from a sample of 479 elite youth and senior players as part of the English Football Association's national development programme (age range: 12.7 to 36.0 years). Semi-parametric generalized additive models for location, scale and shape (GAMLSS) estimated age-related reference centiles for 5-m sprinting, 30-m sprinting, countermovement jump (CMJ) height, and Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1) performance. The estimated reference centiles indicated that the median of the distribution of physical performance test scores varied non-linearly with advancing chronological age, improving until around 25 years for each performance variable. These are the first reference ranges for performance test outcomes in elite English female soccer players. These data can assist practitioners when interpreting physical test performance outcomes to track an individual's progress over time and support decision-making regarding player recruitment and development.
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Symmetry-resolved CO desorption and oxidation dynamics on O/Ru(0001) probed at the C K-edge by ultrafast X-ray spectroscopy. J Chem Phys 2022; 157:164705. [DOI: 10.1063/5.0114399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report on carbon monoxide desorption and oxidation induced by 400 nm femtosecond laser excitation on the O/Ru(0001) surface probed by time-resolved X-ray absorption spectroscopy (TR-XAS) at the carbon K-edge. The experiments were performed under constant background pressures of CO (6x10-8 Torr) and O2 (3x10-8 Torr). Under these conditions, we detect two transient CO species with narrow 2π* peaks, suggesting little 2π* interaction with the surface. Based on polarization measurements, we find that these two species have opposing orientations: (1) CO favoring a more perpendicular orientation and (2) CO favoring a more parallel orientation with respect to the surface. We also directly detect gas-phase CO2 using a mass spectrometer and observe weak signatures of bent adsorbed CO2 at slightly higher X-ray energies than the 2π* region. These results are compared to previously reported TR-XAS results at the O K-edge where the CO background pressure was three times lower (2x10-8 Torr) while maintaining the same O2 pressure. At the lower CO pressure, in the CO 2π* region, we observed adsorbed CO and a distribution of OC-O bond lengths close to the CO oxidation transition state, with little indication of gas-like CO. The shift towards 'gas-like' CO species may be explained by the higher CO exposure, which blocks O adsorption, decreasing O coverage and increasing CO coverage. These effects decrease the CO desorption barrier through dipole-dipole interaction, while simultaneously increasing the CO oxidation barrier.
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EP04.01-013 Frailty Index Predicts Treatment Outcomes in Older Adults with Lung Cancer. J Thorac Oncol 2022. [DOI: 10.1016/j.jtho.2022.07.425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Efficacy of Plasmapheresis and Intravenous Immunoglobulin on the Reduction of Donor Specific Antibodies in Heart Transplant Recipients. J Heart Lung Transplant 2022. [DOI: 10.1016/j.healun.2022.01.304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Relationship of Noninvasive Detection of Allograft Rejection and Injury (Donor-Derived Cell Free DNA and Gene Expression Profiling) and Tissue-Based Molecular Microscopic Diagnosis After Heart Transplantation. J Heart Lung Transplant 2022. [DOI: 10.1016/j.healun.2022.01.272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Abstract
![]()
Using time-resolved
wide-angle X-ray scattering, we investigated
the early stages (10 μs–1 ms) of crystallization of supercooled
water, obtained by the ultrafast heating of high- and low-density
amorphous ice (HDA and LDA) up to a temperature T = 205 K ± 10 K. We have determined that the crystallizing phase
is stacking disordered ice (Isd), with
a maximum cubicity of χ = 0.6, in agreement with predictions
from molecular dynamics simulations at similar temperatures. However,
we note that a growing small portion of hexagonal ice (Ih) was also observed, suggesting that within our timeframe, Isd starts annealing into Ih. The onset of crystallization, in both amorphous ice, occurs
at a similar temperature, but the observed final crystalline fraction
in the LDA sample is considerably lower than that in the HDA sample.
We attribute this discrepancy to the thickness difference between
the two samples.
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Fast reconstruction of centre of mass and foot kinematics during a single-legged horizontal jump: A point-cloud processing approach. J Biomech 2022; 135:111015. [DOI: 10.1016/j.jbiomech.2022.111015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 12/23/2021] [Accepted: 02/17/2022] [Indexed: 10/19/2022]
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Abstract
ABSTRACT Kyprianou, E, Di Salvo, V, Lolli, L, Al Haddad, H, Villanueva, AM, Gregson, W, and Weston, M. To measure peak velocity in soccer, let the players sprint. J Strength Cond Res 36(1): 273-276, 2022-Expressing externals loads relative to a player's individual capacities has potential to enhance understanding of dose-response. Peak velocity is an important metric for the individualization process and is usually measured during a sprint test. Recently, however, peak velocity was reported to be faster during soccer matches when compared with a 40-m sprint test. With the aim of developing the practice of individualized training prescription and match evaluation, we examined whether the aforementioned finding replicates in a group of elite youth soccer players across a broader range of soccer activities. To do this, we compared the peak velocities of 12 full-time male youth soccer players (age 16.3 ± 0.8 years) recorded during a 40-m sprint test with peak velocity recorded during their routine activities (matches, sprints, and skill-based conditioning drills: small-sided games [SSG], medium-sided games [MSG], large-sided games [LSG]). All activities were monitored with 10-Hz global positioning systems (Catapult Optimeye S5, version 7.32) with the highest speed attained during each activity retained as the instantaneous peak velocity. Interpretation of clear between-activity differences in peak velocity was based on nonoverlap of the 95% confidence intervals for the mean difference between activities with sprint testing. Peak velocity was clearly faster for the sprint test (8.76 ± 0.39 m·s-1) when compared with matches (7.94 ± 0.49 m·s-1), LSG (6.94 ± 0.65 m·s-1), MSG (6.40 ± 0.75 m·s-1), and SSG (5.25 ± 0.92 m·s-1), but not sprints (8.50 ± 0.36 m·s-1). Our data show the necessity for 40-m sprint testing to determine peak velocity.
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The between-week reliability of neuromuscular, endocrine, and mood markers in soccer players and the repeatability of the movement demands during small-sided games. J Sports Med Phys Fitness 2021; 62:1440-1448. [PMID: 34881555 DOI: 10.23736/s0022-4707.21.12993-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Establishing the reliability and repeatability of both the movement demands and the consequential responses of athletes applied settings is important. Therefore, the primary aim of this study was to assess the between- week reliability of potential fatigue monitoring methods in soccer players. Secondary aims were to establish the repeatability of the movement demands and the changes in monitoring variables from the same small-sided game (SSG) protocol programmed on consecutive weeks. METHODS Twelve semi-professional soccer players (age, 21±2 years; mass, 80.1±6.8kg; height, 1.81±0.06m) performed the same SSG protocol (4vs4+goalkeepers; 6x7-min, 2-min inter-set recovery) separated by 7 days. Movement demands were monitored using global positioning systems (GPS), with countermovement jump (CMJ), saliva (testosterone and cortisol), and brief assessment of mood (BAM+) collected immediately pre and post SSG training. RESULTS Results suggest that CMJ variables and hormonal markers have good between-week reliability when measuring athletes at rest (CV, 2.1-7.7%; ICC, 0.82-0.98), however BAM+ did not (CV, 23.5%; ICC, 0.47). GPS variables presented low to high repeatability during SSG training, with reliability statistics varying between metrics (CV, 4.4-62.4%; ICC, 0.30-0.81). In detecting responses from pre- to post-SSG training, CMJ and hormonal markers showed moderate to very-high reliability (ICC, 0.68-0.99), whilst BAM + did not (ICC, 0.12). CONCLUSIONS The findings from this study suggest CMJ and hormonal markers provide good between-week reliability, yet caution should be applied when using short subjective questionnaires. Additionally, some movement demands may not be repeatable when programming the same SSG session on separate occasions.
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Distribution of External Load During Acquisition Training Sessions and Match Play of a Professional Soccer Team. J Strength Cond Res 2021; 35:3453-3458. [PMID: 31469765 DOI: 10.1519/jsc.0000000000003363] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/20/2023]
Abstract
ABSTRACT Castillo, D, Raya-González, J, Weston, M, and Yanci, J. Distribution of external load during acquisition training sessions and match play of a professional soccer team. J Strength Cond Res 35(12): 3453-3458, 2021-The aim of this study was to use global position systems to analyze the external loads of the 3 different acquisition training sessions (ATS) with competitive matches in professional soccer players over a 6-week period. Sixteen professional soccer players participated in the study, which analyzed the distribution of external load during the training microcycle of a professional soccer team. The 3 types of ATS undertaken by the players were as follows: ATS1 (strength), ATS2 (endurance), and ATS3 (speed). The total distance covered, the distance covered at above 14 km·h-1, the distance covered >21 km·h-1, the number of high accelerations (>3 m·s-2), and player load were recorded. The results showed that external loads were consistently higher during matches when compared with all training sessions (range of effect sizes: 1.06-3.38). Between training session comparisons revealed higher external loads during ATS1 and ATS2, when compared with ATS3 (range of effect sizes: 0.60-2.41). The only external load variable that differed between ATS1 and ATS2 was the distance covered >21 km·h-1, which was higher for ATS1. Our findings suggest that technical staff should consider the physical demands of weekly periodization to understand the training process regarding optimizing player physical performance.
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Ultrafast Adsorbate Excitation Probed with Subpicosecond-Resolution X-Ray Absorption Spectroscopy. PHYSICAL REVIEW LETTERS 2021; 127:016802. [PMID: 34270277 DOI: 10.1103/physrevlett.127.016802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 05/07/2021] [Indexed: 06/13/2023]
Abstract
We use a pump-probe scheme to measure the time evolution of the C K-edge x-ray absorption spectrum from CO/Ru(0001) after excitation by an ultrashort high-intensity optical laser pulse. Because of the short duration of the x-ray probe pulse and precise control of the pulse delay, the excitation-induced dynamics during the first picosecond after the pump can be resolved with unprecedented time resolution. By comparing with density functional theory spectrum calculations, we find high excitation of the internal stretch and frustrated rotation modes occurring within 200 fs of laser excitation, as well as thermalization of the system in the picosecond regime. The ∼100 fs initial excitation of these CO vibrational modes is not readily rationalized by traditional theories of nonadiabatic coupling of adsorbates to metal surfaces, e.g., electronic frictions based on first order electron-phonon coupling or transient population of adsorbate resonances. We suggest that coupling of the adsorbate to nonthermalized electron-hole pairs is responsible for the ultrafast initial excitation of the modes.
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Brief Exercise at Work (BE@Work): A Mixed-Methods Pilot Trial of a Workplace High-Intensity Interval Training Intervention. Front Sports Act Living 2021; 3:699608. [PMID: 34278300 PMCID: PMC8282817 DOI: 10.3389/fspor.2021.699608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 05/31/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction: The efficacy of high-intensity interval training (HIIT) for improving markers of physical fitness and cardiometabolic health is promising. The workplace is one non-laboratory setting where the effectiveness of HIIT could be explored. The aim of this study was to undertake a mixed-methods exploratory pilot trial of a workplace HIIT intervention named Brief Exercise at Work (BE@Work). Methods: Fifty-four healthy employees (mean ± standard deviation [SD] age 46 ± 10 years) from two workplaces in Northeast England were allocated to 8 weeks of thrice-weekly workplace HIIT based on boxing, stair climbing and stepping, comprising 4-7 60 s high-intensity intervals interspersed with 75 s rest (n = 30), or a no-intervention control (n = 24). The primary outcome was the change SD of predicted maximal oxygen consumption (VO2max). Markers of physical fitness, cardiometabolic health and mental well-being were also measured at baseline and follow-up. Participant perceptions of the intervention were explored in post-intervention focus groups (n = 9). Results: Mean (±SD) session attendance was 82% (±15%). Mean peak heart rate across the intervention was 87% of age-predicted maximal heart rate with a within- and between-subject SD of 5.5% and 3.7%, respectively. The SD of changes in predicted VO2max was 6.6 mL·kg-1·min-1 across both groups, which can be used to inform sample size estimations for a future full trial. The control-adjusted mean increase (95% confidence interval) in predicted VO2max was 3.9 (-0.2 to 8.1) mL·kg-1·min-1, corresponding to a Cohen's D of 0.47. We also observed preliminary evidence of small to moderate effects in favour of the intervention group for non-dominant leg extensor muscle power, markers of health-related quality of life, well-being and perceived stress and small to moderate effects in favour of the controls in perceived pain, physical activity and high-density lipoprotein cholesterol. During HIIT, focus group participants reported physiological responses they perceived as unpleasant or tiring (e.g., breathlessness, local muscular fatigue), but also that they felt alert and energised afterwards. Conclusion: The findings of this exploratory pilot trial support the implementation of a definitive randomised controlled trial to quantify the effectiveness of a workplace HIIT intervention.
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Inter-methodological quantification of the target change for performance test outcomes relevant to elite female soccer players. SCI MED FOOTBALL 2021; 6:248-261. [DOI: 10.1080/24733938.2021.1942538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Getting Sucker Punched by Depdc5 Really Hurts. Epilepsy Curr 2021; 20:378-380. [PMID: 34025259 PMCID: PMC7818211 DOI: 10.1177/1535759720956992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
[Box: see text]
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Heart Transplant Recipients with pAMR1 (H+) and pAMR2 Rejection Have the Same Amount of Myocardial Injury by Molecular Microscope. J Heart Lung Transplant 2021. [DOI: 10.1016/j.healun.2021.01.1847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Initial fitness, maturity status, and total training explain small and inconsistent proportions of the variance in physical development of adolescent footballers across one season. Res Sports Med 2021; 30:283-294. [PMID: 33650436 DOI: 10.1080/15438627.2021.1888106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
To investigate how initial fitness, maturity status, and training time explain changes in physical performance across one season. Eighty-eight adolescent male footballers, representing four age categories (Under 15 [n = 12], Under 14 [n = 21], Under 13 [n = 25], Under 12 [n = 30]), were tested using physical performance tests (20 m sprint, change of direction, squat jump and yo-yo intermittent recovery test level 1 [YYIRTL1]) and maturity offset at the season start (Test 1) and end (Test 2). Multiple regression determined the proportion of variance in test score changes, explained by three predictor variables: initial fitness (i.e., Test 1), maturity offset change, and training time. With combined categories, predictor variables explained 0.051 to 0.297 of the variance in physical performance score changes. Analysing age categories separately, predictor variables explained 0.047 to 0.407 (20 m sprint), 0.202 to 0.626 (change of direction), 0.336 to 0.502 (squat jump), and 0.196 to 0.777 (YYIRTL1) of variance in test score changes. Of the limited differences in relative predictor contribution, Test 1 was the strongest predictor of test score change. Initial fitness, maturity status change, and training time explain small and inconsistent proportions of variance in adolescent footballers' physical development across one season.
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Variability in the Study Quality Appraisals Reported in Systematic Reviews on the Acute:Chronic Workload Ratio and Injury Risk. Sports Med 2021; 50:2065-2067. [PMID: 32852751 DOI: 10.1007/s40279-020-01333-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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A Novel Method to Maintain the Sample Position and Pressure in Differentially Pumped Systems Below the Resolution Limit of Optical Microscopy Techniques. APPLIED SPECTROSCOPY 2021; 75:137-144. [PMID: 32597682 PMCID: PMC7859668 DOI: 10.1177/0003702820942798] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/17/2020] [Indexed: 06/11/2023]
Abstract
We present a new method to maintain constant gas pressure over a sample during in situ measurements. The example shown here is a differentially pumped high-pressure X-ray photoelectron spectroscopy system, but this technique could be applied to many in situ instruments. By using the pressure of the differential stage as a feedback source to change the sample position, a new level of consistency has been achieved. Depending on the absolute value of the sample-to-aperture distance, this technique allows one to maintain the distance within several hundred nanometers, which is below the limit of typical optical microscopy systems. We show that this method is well suited to compensate for thermal drift. Thus, X-ray photoelectron spectroscopy data can be acquired continuously while the sample is heated and maintaining constant pressure over the sample. By implementing a precise manipulator feedback system, pressure variations of less than 5% were reached while the temperature was varied by 400 ℃. The system is also shown to be highly stable under significant changes in gas flow. After changing the flow by a factor of two, the pressure returned to the set value within 60 s.
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Experimental observation of the liquid-liquid transition in bulk supercooled water under pressure. Science 2021; 370:978-982. [PMID: 33214280 DOI: 10.1126/science.abb9385] [Citation(s) in RCA: 88] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 08/11/2020] [Accepted: 10/06/2020] [Indexed: 01/30/2023]
Abstract
We prepared bulk samples of supercooled liquid water under pressure by isochoric heating of high-density amorphous ice to temperatures of 205 ± 10 kelvin, using an infrared femtosecond laser. Because the sample density is preserved during the ultrafast heating, we could estimate an initial internal pressure of 2.5 to 3.5 kilobar in the high-density liquid phase. After heating, the sample expanded rapidly, and we captured the resulting decompression process with femtosecond x-ray laser pulses at different pump-probe delay times. A discontinuous structural change occurred in which low-density liquid domains appeared and grew on time scales between 20 nanoseconds to 3 microseconds, whereas crystallization occurs on time scales of 3 to 50 microseconds. The dynamics of the two processes being separated by more than one order of magnitude provides support for a liquid-liquid transition in bulk supercooled water.
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The neuromuscular, physiological, endocrine and perceptual responses to different training session orders in international female netball players. Eur J Sport Sci 2021; 22:314-325. [PMID: 33393427 DOI: 10.1080/17461391.2020.1869837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
AbstractThe 20 h responses of International female netball players to training days requiring two sessions (netball and strength, separated by two hours) ordered alternatively were examined. Eleven players completed strength followed by netball training two hours later (STR-NET), with the order reversed (NET-STR) on a separate day. Well-being, neuromuscular performance (jump height [JH], peak power output [PPO], peak velocity [PV]) and endocrine function (testosterone, cortisol concentrations) were measured before sessions one (PreS1) and two (PreS2), immediately after sessions one (IPS1) and two (IPS2), and 20 h post session one (20P). Session and differential ratings of perceived exertion (upper-body, cognitive/technical [RPE-T], lower-body, breathlessness) were collected, and accelerometry and heart rate measured netball load. Identification of clear between-order differences was based on the nonoverlap of the 95% confidence interval (95%CI) for mean differences relative to baseline. Compared to PreS1, greater increases in JH (percentage difference between trials; 95%CI: 9%; 4-14%), PPO (5%; 2-8%), PV (3%; 1-5%) and cortisol concentration (45%; 1-88%), and a greater decrease for testosterone/cortisol ratio (-35%; -72 to -2%) occurred at PreS2 in NET-STR. At 20P, greater decreases in JH (10%; 5-15%), PPO (4%; 1-8%) and PV (4%; 2-6%) were observed following STR-NET. No differences existed for well-being, whilst RPE-T was greater (15 AU; 3-26 AU) for strength training during NET-STR. Session order influenced neuromuscular and endocrine responses in International female netball players, highlighting session ordering as a key consideration when planning training.
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Differential Ratings of Perceived Match and Training Exertion in Girls' Soccer. Int J Sports Physiol Perform 2020; 15:1315-1323. [PMID: 32947260 DOI: 10.1123/ijspp.2019-0595] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 12/01/2019] [Accepted: 01/06/2020] [Indexed: 11/18/2022]
Abstract
PURPOSE To understand the validity of differential ratings of perceived exertion (dRPE) as a measure of girls' training and match internal loads. METHODS Using the centiMax scale (CR100), session dRPE for breathlessness (sRPE-B) and leg muscle exertion (sRPE-L) were collected across a season of training (soccer, resistance, and fitness) and matches from 33 players (15 [1] y). Differences and associations between dRPE were examined using mixed and general linear models. The authors' minimal practical important difference was 8 arbitrary units (AU). RESULTS Mean (AU [SD] ∼16) sRPE-B and sRPE-L were 66 and 61 for matches, 51 and 49 for soccer, 86 and 67 for fitness, and 45 and 58 for resistance, respectively. Session RPE-B was rated most likely harder than sRPE-L for fitness (19 AU; 90% confidence limits: ±7) and most likely easier for resistance (-13; ±2). Match (5; ±4) and soccer (-3; ±2) differences were likely to most likely trivial. The within-player relationships between sRPE-B and sRPE-L were very likely moderate for matches (r = .44; 90% confidence limits: ±.12) and resistance training (.38; ±.06), likely large for fitness training (.51; ±.22), and most likely large for soccer training (.56; ±.03). Shared variance ranged from 14% to 35%. CONCLUSIONS Practically meaningful differences between dRPE following physical training sessions coupled with low shared variance in all training types and matches suggest that sRPE-B and sRPE-L represent unique sensory inputs in girls' soccer players. The data provide evidence for the face and construct validity of dRPE as a measure of internal load in this population.
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A survey of talent identification and development processes in the youth academies of professional soccer clubs from around the world. J Sports Sci 2020; 38:1269-1278. [DOI: 10.1080/02640414.2020.1752440] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Effects of Workplace-Based Physical Activity Interventions on Cardiorespiratory Fitness: A Systematic Review and Meta-Analysis of Controlled Trials. Sports Med 2020; 49:1255-1274. [PMID: 31115827 DOI: 10.1007/s40279-019-01125-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Cardiorespiratory fitness is a strong predictor of all-cause mortality. Physical activity of at least moderate intensity can improve cardiorespiratory fitness. Workplaces may provide a relatively controlled setting in which to improve cardiorespiratory fitness through physical activity. Limited work has been conducted to quantify the impact of delivering physical activity in the workplace on cardiorespiratory fitness. OBJECTIVE The objective of this systematic review was to quantify the effects of workplace physical activity interventions on peak oxygen consumption (VO2peak) and explore study and participant characteristics as putative moderators. METHODS Seven databases were searched up to September 2018. Search terms included "workplace", "physical activity" and "intervention". Inclusion criteria were controlled trials where physical activity of at least moderate intensity was delivered in the workplace and compared to controls or non-active comparators; and cardiorespiratory fitness measured by actual or predicted VO2peak. Risk of bias was assessed using the PEDro scale. A random-effects meta-analysis was conducted with between-study variation quantified and then explored for putative predictors with a meta-regression. Pooled estimate uncertainty was expressed as 90% confidence intervals (CIs) and assessed against our threshold value for clinical relevance of 1 mL·kg-1·min-1. RESULTS The final dataset consisted of 25 estimates of VO2peak from 12 trials. The pooled mean differences between intervention and control arms was a beneficial improvement of 2.7 mL·kg-1·min-1 (90% CI 1.6-3.8). The 95% prediction interval ranged from a reduction in VO2peak of - 1.1 to an improvement of 6.5 mL·kg-1·min-1. Between-study heterogeneity (τau) was ± 1.6 mL·kg-1·min-1. The meta-regression showed longer interventions (3.2 mL·kg-1·min-1; 90% CI 1.6-3.8) to have an additive effect and studies with a low risk of bias (- 2.5 mL·kg-1·min-1; 90% CI - 4.0 to - 1.0), and participants of greater baseline VO2peak (- 1.6 mL·kg-1·min-1; 90% CI - 3.6 to 0.4), and age (- 1.4 mL·kg-1·min-1; 90% CI - 3.2 to 0.3) having a lesser effect. Participant sex (percentage female) had an additive effect on VO2peak (0.4 mL·kg-1·min-1; 90% CI - 1.6 to 2.4). CONCLUSIONS Workplace-based physical activity interventions consisting of at least moderate-intensity activity improve cardiorespiratory fitness. At the present time, we surmise that no single group of employees (e.g. older employees or less fit individuals) can be definitively identified as standing to benefit more from workplace physical activity interventions than others. This demonstrates the potential utility of workplace physical activity interventions for improving cardiorespiratory fitness in a broad range of healthy employees. Protocol registration: PROSPERO (registration number: 42017057498).
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Changes in quadriceps femoris muscle perfusion following different degrees of cold-water immersion. J Appl Physiol (1985) 2020; 128:1392-1401. [PMID: 32352343 DOI: 10.1152/japplphysiol.00833.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We examined the influence of graded cold-water immersion (CWI) on global and regional quadriceps muscle perfusion with positron emission tomography (PET) and [15O]H2O. In 30 healthy men [33 ± 8 yr; 81 ± 10 kg; 184 ± 5 cm; percentage body fat: 13 ± 5%; peak oxygen uptake (V̇o2peak): 47 ± 8 mL·kg-1·min-1] quadriceps perfusion, thigh and calf cutaneous vascular conductance (CVC), intestinal, muscle, and local skin temperatures, thermal comfort, mean arterial pressure, and heart rate were assessed before and after 10 min of CWI at 8°C, 15°C, or 22°C. Global quadriceps perfusion did not change beyond a clinically relevant threshold (0.75 mL·100 g·min-1) in any condition and was similar between conditions {range of differences [95% confidence interval (CI)]: 0.1 mL·100 g·min-1 (-0.9 to 1.2 mL·100 g·min-1) to 0.9 mL·100 g·min-1 (-0.2 to 1.9 mL·100 g·min-1)}. Muscle perfusion was greater in vastus intermedius (VI) compared with vastus lateralis (VL) (2.2 mL·100 g·min-1; 95% CI 1.5 to 3.0 mL·100 g·min-1) and rectus femoris (RF) (2.2 mL·100 g·min-1; 1.4 to 2.9 mL·100 g·min-1). A clinically relevant increase in VI muscle perfusion after immersion at 8°C and a decrease in RF muscle perfusion at 15°C were observed. A clinically relevant increase in perfusion was observed in VI in 8°C compared with 22°C water (2.3 mL·100 g·min-1; 1.1 to 3.5 mL·100 g·min-1). There were no clinically relevant between-condition differences in thigh CVC. Our findings suggest that CWI (8-22°C) does not reduce global quadriceps muscle perfusion to a clinically relevant extent; however, colder water increases (8°C) deep muscle perfusion and reduces (15°C) superficial muscle (RF) perfusion in the quadriceps muscle.NEW & NOTEWORTHY Using positron emission tomography, we report for the first time muscle perfusion heterogeneity in the quadriceps femoris in response to different degrees of cold-water immersion (CWI). Noxious CWI temperatures (8°C) increase perfusion in the deep quadriceps muscle, whereas superficial quadriceps muscle perfusion is reduced in cooler (15°C) water. Therefore, these data have important implications for the selection of CWI approaches used in the treatment of soft tissue injury, while also increasing our understanding of the potential mechanisms underpinning CWI.
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A Mismatch Made in Medicine: Potential Implications of HLA DQ Epitope Mismatching Following Heart Transplantation. J Heart Lung Transplant 2020. [DOI: 10.1016/j.healun.2020.01.1125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Vulnerabilities in a Dominant Receptor Subunit. Epilepsy Curr 2020; 20:97-98. [PMID: 32064923 PMCID: PMC7160872 DOI: 10.1177/1535759720904359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
[Box: see text]
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The effect of training order on neuromuscular, endocrine and mood response to small-sided games and resistance training sessions over a 24-h period. J Sci Med Sport 2020; 23:866-871. [PMID: 32061525 DOI: 10.1016/j.jsams.2020.01.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 01/23/2020] [Accepted: 01/31/2020] [Indexed: 10/25/2022]
Abstract
OBJECTIVES This study examined the acute effect of small-sided-game (SSG) and resistance training sequence on neuromuscular, endocrine and mood response over a 24-h (h) period. DESIGN Repeated measures. METHODS Fourteen semi-professional soccer players performed SSG-training (4vs4+goalkeepers; 6×7-min, 2-min inter-set recovery) followed by resistance training 2h later (back-squat, Romanian deadlift, barbell-hip-thrust; 4×4 repetitions, 4-min inter-set recovery; 85% 1 rep-max) (SSG+RES), and on a separate week reversed the session order (RES+SSG). Physical demands of SSG's were monitored using global positioning systems (GPS) and ratings of perceived exertion (RPE). Countermovement-jump (CMJ; peak power output; jump height) and brief assessment of mood were collected before (pre), during (0h) and after (+24h) both protocols. Salivary testosterone and cortisol concentrations were obtained at the same time-points but with the inclusion of a measure immediately prior to the second training session (+2h). RESULTS GPS outputs and RPE were similar between SSG-training during both protocols. Between-protocol comparisons revealed no significant differences at +24h in CMJ performance, mood, and endocrine markers. Testosterone was higher at 0h during RES+SSG in comparison to SSG+RES (moderate-effect; +21.4±26.7pgml-1; p=0.010), yet was similar between protocols by +2h. CONCLUSIONS The order of SSG and resistance training does not appear to influence the physical demands of SSG's with sufficient recovery between two sessions performed on the same day. Session order did not influence neuromuscular, endocrine or mood responses at +24h, however a favourable testosterone response from the resistance first session may enhance neuromuscular performance in the second session of the day.
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Time-resolved observation of transient precursor state of CO on Ru(0001) using carbon K-edge spectroscopy. Phys Chem Chem Phys 2020; 22:2677-2684. [PMID: 31531435 DOI: 10.1039/c9cp03677f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The transient dynamics of carbon monoxide (CO) molecules on a Ru(0001) surface following femtosecond optical laser pump excitation has been studied by monitoring changes in the unoccupied electronic structure using an ultrafast X-ray free-electron laser (FEL) probe. The particular symmetry of perpendicularly chemisorbed CO on the surface is exploited to investigate how the molecular orientation changes with time by varying the polarization of the FEL pulses. The time evolution of spectral features corresponding to the desorption precursor state was well distinguished due to the narrow line-width of the C K-edge in the X-ray absorption (XA) spectrum, illustrating that CO molecules in the precursor state rotated freely and resided on the surface for several picoseconds. Most of the CO molecules trapped in the precursor state ultimately cooled back down to the chemisorbed state, while we estimate that ∼14.5 ± 4.9% of the molecules in the precursor state desorbed into the gas phase. It was also observed that chemisorbed CO molecules diffused over the metal surface from on-top sites toward highly coordinated sites. In addition, a new "vibrationally hot precursor" state was identified in the polarization-dependent XA spectra.
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KCC2 Much Chloride Might Not Be the Only Problem. Epilepsy Curr 2019; 20:43-44. [PMID: 31826658 PMCID: PMC7020531 DOI: 10.1177/1535759719890333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
KCC2 Regulates Neuronal Excitability and Hippocampal Activity via Interaction With Task-3 Channels Goutierre M, Al Awabdh S, Donneger F, et al. Cell Rep. 2019;28(1):91-103.e7. doi:10.1016/j.celrep.2019.06.001. PMID: 31269453. KCC2 regulates neuronal transmembrane chloride gradients and thereby controls GABA signaling in the brain. KCC2 downregulation is observed in numerous neurological and psychiatric disorders. Paradoxical, excitatory GABA signaling is usually assumed to contribute to abnormal network activity underlying the pathology. We tested this hypothesis and explored the functional impact of chronic KCC2 downregulation in the rat dentate gyrus. Although the reversal potential of GABAA receptor currents is depolarized in KCC2 knockdown neurons, this shift is compensated by depolarization of the resting membrane potential. This reflects downregulation of leak potassium currents. We show KCC2 interacts with TASK-3 (KCNK9) channels and is required for their membrane expression. Increased neuronal excitability upon KCC2 suppression altered dentate gyrus rhythmogenesis, which could be normalized by chemogenetic hyperpolarization. Our data reveal KCC2 downregulation engages complex synaptic and cellular alterations beyond GABA signaling which perturb network activity, thus offering additional targets for therapeutic intervention.
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No association between perceived exertion and session duration with hamstring injury occurrence in professional football. Scand J Med Sci Sports 2019; 30:523-530. [PMID: 31663176 DOI: 10.1111/sms.13591] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 09/30/2019] [Accepted: 10/28/2019] [Indexed: 11/27/2022]
Abstract
Training and competition loads have emerged as modifiable composite risk factors of non-contact injury. Hamstring strains are the most common injuries in football with substantial burden on the individual player and club. Nevertheless, robust evidence of a consistent load-hamstring injury relationship in professional football is lacking. Using available data from the Qatar Stars League over three competitive seasons, this study investigated the separate and combined effects of perceived exertion and session duration on hamstring injury occurrence in a sample of 30 outfield football players. Load variables were calculated into 7-day, 14-day, 21-day, 28-day periods of data, and week-to-week changes for average ratings of perceived exertion (RPE; au) score and session-RPE (s-RPE; session-duration × score), plus the cumulative training and match minutes and s-RPE, respectively. Conditional logistic regression models estimated load-injury relationships per 2-within-subject standard deviation increments in each candidate variable. Associations were declared practically important based on the location of the confidence interval in relation to thresholds of 0.90 and 1.11 defining small beneficial and harmful effects, respectively. The uncertainty for the corrected odds ratios show that typically high within-subject increments in each candidate variable were not practically important for training- and match-related hamstring injury (95% confidence intervals range: 0.85 to 1.16). We found limited exploratory evidence regarding the value of perceived exertion and session duration as etiological factors of hamstring injury in Middle-East professional football. Monitoring remains valuable to inform player load management strategies, but our exploratory findings suggest its role for type-specific injury risk determination appears empirically unsupported.
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Harmful association of sprinting with muscle injury occurrence in professional soccer match-play: A two-season, league wide exploratory investigation from the Qatar Stars League. J Sci Med Sport 2019; 23:134-138. [PMID: 31591064 DOI: 10.1016/j.jsams.2019.08.289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 08/23/2019] [Accepted: 08/29/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVES To investigate the impact of physical efforts performed in the period preceding activity as a potential risk factor of muscle injury during match-play within a sample of professional soccer players. DESIGN Observational cohort study. METHODS Match load (running [>14.4-19.8km/h], high-speed running [>19.8-25.2km/h], sprinting [>25.2km/h], leading and explosive sprint type) averaged in 1-min and 5-min periods prior to an event or non event for 29 professional outfield soccer players. Conditional logistic and Poisson regression models estimated the relationship between load and injury for a 2 within-subject standard deviation in match load or 1-action increment in the number of sprinting activities, respectively. Associations were deemed beneficial or harmful based on non-overlap of the 95% confidence intervals against thresholds of 0.90 and 1.11, respectively. RESULTS An increment in sprinting distance [+2-SDs=11m] covered over a 1-min period (odds ratio [OR]: 1.22, 95%CI, 1.12 to 1.33) increased the odds of muscle injury. CONCLUSIONS Our study provides novel exploratory evidence that the volume of sprinting during competitive soccer match-play has a harmful association with muscle injury occurrence.
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The neuromuscular, endocrine and mood responses to a single versus double training session day in soccer players. J Sci Med Sport 2019; 23:69-74. [PMID: 31526664 DOI: 10.1016/j.jsams.2019.08.291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 05/17/2019] [Accepted: 08/29/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVES This study profiled the 24h neuromuscular, endocrine and mood responses to a single versus a double training day in soccer players. DESIGN Repeated measures. METHODS Twelve semi-professional soccer players performed small-sided-games (SSG's; 4 vs 4+goalkeepers; 6×7-min, 2-min inter-set recovery) with neuromuscular (peak-power output, PPO; jump height, JH), endocrine (salivary testosterone, cortisol), and mood measures collected before (pre) and after (0h, +24h). The following week, the same SSG protocol was performed with an additional lower body strength training session (back-squat, Romanian deadlift, barbell hip thrust; 4×4 repetitions, 4-min inter-set recovery; 85% 1 rep-max) added at 2h after the SSG's. RESULTS Between-trial comparisons revealed possible to likely small impairments in PPO (2.5±2.2Wkg-1; 90% Confidence Limits: ±2.2Wkg-1), JH (-1.3; ±2.0cm) and mood (4.6; ±6.1AU) in response to the double versus single sessions at +24h. Likely to very likely small favourable responses occurred following the single session for testosterone (-15.2; ±6.1pgml-1), cortisol (0.072; ±0.034ugdl-1) and testosterone/cortisol ratio (-96.6; ±36.7AU) at +24h compared to the double session trial. CONCLUSIONS These data highlight that performance of two training sessions within a day resulted in possible to very likely small impairments of neuromuscular performance, mood score and endocrine markers at +24h relative to a single training session day. A strategy of alternating high intensity explosive training days containing multiple sessions with days emphasising submaximal technical/tactical activities may be beneficial for those responsible for the design and delivery of soccer training programs.
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High-intensity endurance capacity assessment as a tool for talent identification in elite youth female soccer. J Sports Sci 2019; 38:1313-1319. [PMID: 31451097 DOI: 10.1080/02640414.2019.1656323] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Talent identification and development programmes have received broad attention in the last decades, yet evidence regarding the predictive utility of physical performance in female soccer players is limited. Using a retrospective design, we appraised the predictive value of performance-related measures in a sample of 228 youth female soccer players previously involved in residential Elite Performance Camps (age range: 12.7-15.3 years). With 10-m sprinting, 30-m sprinting, counter-movement jump height, and Yo-Yo Intermittent Recovery Test Level 1 (IR1) distance as primary predictor variables, the Akaike Information Criterion (AIC) assessed the relative quality of four penalised logistic regression models for determining future competitive international squads U17-U20 level selection. The model including Yo-Yo IR1 was the best for predicting career outcome. Predicted probabilities of future selection to the international squad increased with higher Yo-Yo IR1 distances, from 4.5% (95% confidence interval, 0.8 to 8.2%) for a distance lower than 440 m to 64.7% (95% confidence interval, 47.3 to 82.1%) for a score of 2040 m. The present study highlights the predictive utility of high-intensity endurance capacity for informing career progression in elite youth female soccer and provides reference values for staff involved in the talent development of elite youth female soccer players.
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Using differential ratings of perceived exertion to assess agreement between coach and player perceptions of soccer training intensity: An exploratory investigation. J Sports Sci 2019; 37:2783-2788. [PMID: 31423944 DOI: 10.1080/02640414.2019.1653423] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We aimed to assess the coach-player agreement of subjective soccer training loads via differential ratings of perceived exertion (dRPE). The coach initially underwent quantifiable familiarisation (blackness test) with the Borg CR100 scale. Data were collected from 16 semi-professional soccer players across seven consecutive training sessions. For the measurement of subjective training load, the coach and players provided dRPE (CR100) for legs (RPE-L), breathlessness (RPE-B) and technical exertion (RPE-T). Coach-prescribed dRPE were recorded prior to training, with coach observed and player reported dRPE collected post training. Statistical equivalence bounds for agreement between coach (prescribed and observed) and player reported dRPE scores were 4 arbitrary units on the CR100 and we used a probability outcome of likely (≥75%) to infer realistic equivalence. Following three familiarisation sessions, the coach improved their blackness test score from 39% to 83%. Coach observed and player reported RPE-T scores were likely equivalent, with all other comparisons not realistically equivalent. Since training prescription is coach-led, our data highlight the importance of accurate internal load measurement and feedback in soccer. The improved accuracy and precision of coach intensity estimation after three attempts at the blackness test suggests that this method could be worthwhile to researchers and practitioners employing dRPE.
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Abstract
To examine responses to an International netball tournament, female athletes (n= 11) played three matches over consecutive days. External (accelerometry) and internal (heart rate; HR, session; sRPE, and differential; dRPE, rating of perceived exertion) load measures quantified match intensity. On match-day mornings, and three days after match 3, well-being (brief assessment of mood; BAM+), biochemical (creatine kinase concentration; CK), neuromuscular (jump height; JH, peak power output; PPO) and endocrine function (salivary cortisol; C, testosterone; T, concentrations) were assessed. External load was similar between matches whereas dRPE and sRPE were greatest for match 3. Following match 1, CK increased, whereas BAM+, JH, C and T decreased. Following two matches, BAM+, PPO, and T decreased with CK increasing versus baseline. Following consecutive matches, CK (likely moderate; 27.9% ± 19.5%) and C (possibly moderate; 43.3% ± 46.8%) increased, whilst BAM+ (possibly moderate; -20.6% ± 24.4%) decreased. Three days post-tournament BAM+, T, PPO, and JH decreased. Mid-court elicited higher mean HR (possibly moderate; 3.7% ± 3.8%), internal and external intensities (possibly very large; 85.7% ± 49.6%) compared with goal-based positions. Consecutive matches revealed a dose-response relationship for well-being and physiological function; a response evident three days post-tournament.
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High-Intensity Interval Training: A Potential Exercise Countermeasure During Human Spaceflight. Front Physiol 2019; 10:581. [PMID: 31191330 PMCID: PMC6541112 DOI: 10.3389/fphys.2019.00581] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 04/25/2019] [Indexed: 12/30/2022] Open
Abstract
High-intensity interval training (HIT) is an effective approach for improving a range of physiological markers associated with physical fitness. A considerable body of work has demonstrated substantial improvements in cardiorespiratory fitness following short-term training programmes, while emerging evidence suggests that HIT can positively impact aspects of neuromuscular fitness. Given the detrimental consequences of prolonged exposure to microgravity on both of these physiological systems, and the potential for HIT to impact multiple components of fitness simultaneously, HIT is an appealing exercise countermeasure during human spaceflight. As such, the primary aim of this mini review is to synthesize current terrestrial knowledge relating to the effectiveness of HIT for inducing improvements in cardiorespiratory and neuromuscular fitness. As exercise-induced fitness changes are typically influenced by the specific exercise protocol employed, we will consider the effect of manipulating programming variables, including exercise volume and intensity, when prescribing HIT. In addition, as the maintenance of HIT-induced fitness gains and the choice of exercise mode are important considerations for effective training prescription, these issues are also discussed. We conclude by evaluating the potential integration of HIT into future human spaceflight operations as a strategy to counteract the effects of microgravity.
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A novel approach to assessing validity in sports performance research: integrating expert practitioner opinion into the statistical analysis. SCI MED FOOTBALL 2019. [DOI: 10.1080/24733938.2019.1617433] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
We report on atom-specific activation of CO oxidation on Ru(0001) via resonant X-ray excitation. We show that resonant 1s core-level excitation of atomically adsorbed oxygen in the co-adsorbed phase of CO and oxygen directly drives CO oxidation. We separate this direct resonant channel from indirectly driven oxidation via X-ray induced substrate heating. Based on density functional theory calculations, we identify the valence-excited state created by the Auger decay as the driving electronic state for direct CO oxidation. We utilized the fresh-slice multi-pulse mode at the Linac Coherent Light Source that provided time-overlapped and 30 fs delayed pairs of soft X-ray pulses and discuss the prospects of femtosecond X-ray pump X-ray spectroscopy probe, as well as X-ray two-pulse correlation measurements for fundamental investigations of chemical reactions via selective X-ray excitation.
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The reliability of a modified 505 test and change-of-direction deficit time in elite youth football players. SCI MED FOOTBALL 2018. [DOI: 10.1080/24733938.2018.1526402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Neuromuscular, Biochemical, Endocrine, and Mood Responses to Small-Sided Games' Training in Professional Soccer. J Strength Cond Res 2018; 32:2569-2576. [DOI: 10.1519/jsc.0000000000002424] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Differential training loads and individual fitness responses to pre-season in professional rugby union players. J Sports Sci 2018; 36:2438-2446. [DOI: 10.1080/02640414.2018.1461449] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Development of an Exergame to Deliver a Sustained Dose of High-Intensity Training: Formative Pilot Randomized Trial. JMIR Serious Games 2018; 6:e4. [PMID: 29588271 PMCID: PMC5893890 DOI: 10.2196/games.7758] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 09/15/2017] [Accepted: 12/19/2017] [Indexed: 12/22/2022] Open
Abstract
Background Sport science can play a critical role in reducing health inequalities. The inverse relationship between life expectancy, cardiorespiratory fitness, and socioeconomic status could be addressed by performing high-intensity training (HIT), delivered in a class salient and accessible approach. Commercially available exergames have shown encouraging compliance rates but are primarily designed for entertainment purposes rather than focusing on health-related outcomes. A serious game tailored toward delivering an exercise stimulus, while reducing the aversive protocols associated with HIT, could be beneficial to engage and improve health outcomes in socially deprived males. Objective The aims of this study were to develop an exergame capable of delivering HIT and evaluate the effect on selected health outcomes in men recruited in regions of socioeconomic deprivation. Methods We conducted an exploratory trial in our target population, and participants were allocated to intervention (n=14) or control groups (n=10) by third-party minimization. The intervention was a 6-week training program consisting of three sessions of exergaming per week. The sessions involved a structured warm-up, then brief intermittent repetitions in the form of boxing rounds (10 s, 20 s, and 30 s) against their peers with a work/rest ratio of 0.25. Results Retention to the intervention was 87.5% (21/24). Over the duration of the intervention, session attendance was 67.5% (170/252); repetition mean and peak heart rates (% of maximal) and session ratings of perceived exertion (AU, arbitrary units) were 86.3 (5.4%), 89.9 (6.1%), and 7.5 (2.2 AU), respectively. The effect of the intervention, when compared with the control, was a likely small beneficial improvement in predicted maximum oxygen consumption (VO2 max, 3.0; 90% confidence limits ±2.6%). Effects on body mass, waist circumference, and blood pressure were either trivial or unclear. Conclusions Over the 6-week intervention, the exergame delivered a consistent and sustained dose of HIT, with some beneficial effects on aerobic fitness in the target population. Trial Registration ClinicalTrials.gov NCT03477773; https://clinicaltrials.gov/ct2/show/NCT03477773 (Archived by WebCite at http://www.webcitation.org/6yDLgVs35)
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Match Physical Performance of Elite Female Soccer Players During International Competition. J Strength Cond Res 2018; 31:2379-2387. [PMID: 27467514 DOI: 10.1519/jsc.0000000000001575] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Datson, N, Drust, B, Weston, M, Jarman, IH, Lisboa, P, and Gregson, W. Match physical performance of elite female soccer players during international competition. J Strength Cond Res 31(9): 2379-2387, 2017-The purpose of this study was to provide a detailed analysis of the physical demands of competitive international female soccer match play. A total of 148 individual match observations were undertaken on 107 outfield players competing in competitive international matches during the 2011-2012 and 2012-2013 seasons, using a computerized tracking system (Prozone Sports Ltd., Leeds, England). Total distance and total high-speed running distances were influenced by playing position, with central midfielders completing the highest (10,985 ± 706 m and 2,882 ± 500 m) and central defenders the lowest (9,489 ± 562 m and 1,901 ± 268 m) distances, respectively. Greater total very high-speed running distances were completed when a team was without (399 ± 143 m) compared to with (313 ± 210 m) possession of the ball. Most sprints were over short distances with 76% and 95% being less than 5 and 10 m, respectively. Between half reductions in physical performance were present for all variables, independent of playing position. This study provides novel findings regarding the physical demands of different playing positions in competitive international female match play and provides important insights for physical coaches preparing elite female players for competition.
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The Influence of Playing Position and Contextual Factors on Soccer Players' Match Differential Ratings of Perceived Exertion: A Preliminary Investigation. Sports (Basel) 2018; 6:sports6010013. [PMID: 29910317 PMCID: PMC5969182 DOI: 10.3390/sports6010013] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 02/08/2018] [Accepted: 02/10/2018] [Indexed: 11/18/2022] Open
Abstract
(1) Background: Differential RPE (dRPE) separates scores for breathlessness (RPE-B), leg muscle exertion (RPE-L) and technical/cognitive exertion (RPE-T). Limited information for dRPE is available in soccer match play, yet these measurements may help inform practitioners training and recovery strategies. This preliminary study investigated the effects of playing position and contextual factors on elite soccer players’ dRPE. (2) Methods: Thirty-two male English Premier League players recorded dRPE scores 15–30 min post-match for RPE-B, RPE-L, and RPE-T. Data were analysed using linear mixed models, with magnitude-based inferences subsequently applied. (3) Results: Overall, the mean ± SD for the dRPE were 63 ± 23 arbitrary units (au) (RPE-B), 67 ± 22 au (RPE-L), and 60 ± 24 au (RPE-T). Full Backs reported substantially higher RPE-B, RPE-L and RPE-T when compared to all other positions. Substantially higher RPE-T scores were reported for matches played against Top teams compared to Bottom (10 au; 90% Confidence Interval 5 to 15 au) and Middle (10 au; 4 to 15 au) ranked teams. The effects of match result and location on dRPE were not substantial. (4) Conclusions: Positional differences were observed following soccer match play for RPE-B, RPE-L and RPE-T. Full backs had substantially higher dRPE then any other position, with all players reporting increased RPE-T when playing teams at the Top of the league. These findings can help practitioners monitor internal load responses and support the prescription of training and recovery sessions.
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