Publications by authors named "Liam D Harper"

Higher carbohydrate availability, achieved through combined intake of glucose and fructose, has been shown to enhance endurance performance. This study examined the effects of higher carbohydrate doses containing a fructose-glucose mixture (1:2 ratio) compared with lower doses containing only glucose on performance during a 120-min simulated soccer match. Fifteen semiprofessional soccer players (seven males and eight females) completed two 120-min soccer-specific exercise sessions in a randomized and crossover design.

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Background: Professional soccer teams are often required to compete with ≤ 4 days recovery between matches. Since congested schedules reduce recovery time between matches, players are possibly at an increased injury risk. To date, there are no published systematic reviews on the impact of match congestion on injuries during professional male soccer.

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Soccer is a fast-growing area of research, demonstrated by a 10-fold increase in the number of PubMed articles derived from the search term 'soccer' between 2001 and 2021. The scope of contemporary soccer-related articles ranges from match-play observations to laboratory evaluations of performance. The activity profile of soccer match-play is variable and techniques to collect data within matches are limited.

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: The extra-time (ET) period of soccer is competed during fixture congested schedules with often limited recovery time between matches. The aim of this study was to assess muscle damage recovery following 90- and 120-min (i.e.

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Purpose: To assess the training load, energy expenditure, dietary intake, and sleep quality and quantity of junior tennis players during a tennis training camp.

Methods: Ten junior academy tennis players (14 [1] y) completed a 6-day camp with daily morning and afternoon training. Players wore accelerometer watches to measure activity energy expenditure and sleep.

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Research has demonstrated that the extra-time (ET) period of soccer negatively impacts recovery. However, it is not known to what extent recovery practices are being adapted by practitioners following ET and where gaps exist between research and practice. Therefore, this study explored soccer practitioner perceptions of recovery practices following ET matches.

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Collagen peptide supplementation (COL), in conjunction with exercise, may be beneficial for the management of degenerative bone and joint disorders. This is likely due to stimulatory effects of COL and exercise on the extracellular matrix of connective tissues, improving structure and load-bearing capabilities. This systematic review aims to evaluate the current literature available on the combined impact of COL and exercise.

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Exercise-induced muscle damage (EIMD) is associated with oxidative stress and inflammation, muscle soreness, and reductions in muscle function. Cocoa flavanols (CF) are (poly)phenols with antioxidant and anti-inflammatory effects and thus may attenuate symptoms of EIMD. The purpose of this narrative review was to collate and evaluate the current literature investigating the effect of CF supplementation on markers of exercise-induced oxidative stress and inflammation, as well as changes in muscle function, perceived soreness, and exercise performance.

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During a 7-day training and/or competition period, macronutrient intake and distribution was assessed using food diaries, supported by remote food photography and 24-hr multiple pass recalls of youth tennis players categorised by under 12s, under 14s and under 16+ age groups (n = 27). Total energy did not differ between age groups nor type of day (training [TD], competition day [CD]), irrespective of a significant increase in body mass reported in the older players (U16+; p < 0.05).

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Purpose: To survey soccer practitioners' recovery strategy: (1) use, (2) perceived effectiveness, and (3) factors influencing their implementation in professional soccer.

Methods: A cross-sectional convenience sample of professional soccer club/confederation practitioners completed a web-based survey (April to July 2020). Pearson chi-square and Fisher exact tests with Cramer V (φ - c) assessed relationships and their strength, respectively, between the perceived effectiveness and frequency of strategy use.

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Purpose: To examine practitioners', coaches', and athletes' perceptions of evidence-based practice (EBP) in professional sport in Australia.

Methods: One hundred thirty-eight participants (practitioners n = 67, coaches n = 39, and athletes n = 32) in various professional sports in Australia each completed a group-specific online questionnaire. Questions focused on perceptions of research, the contribution of participants' own experience in implementing knowledge to practice, sources, and barriers for accessing and implementing EBP, preferred methods of feedback, and the required qualities of practitioners.

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Whilst the assessment of body composition is routine practice in sport, there remains considerable debate on the best tools available, with the chosen technique often based upon convenience rather than understanding the method and its limitations. The aim of this manuscript was threefold: (1) provide an overview of the common methodologies used within sport to measure body composition, specifically hydro-densitometry, air displacement plethysmography, bioelectrical impedance analysis and spectroscopy, ultra-sound, three-dimensional scanning, dual-energy X-ray absorptiometry (DXA) and skinfold thickness; (2) compare the efficacy of what are widely believed to be the most accurate (DXA) and practical (skinfold thickness) assessment tools and (3) provide a framework to help select the most appropriate assessment in applied sports practice including insights from the authors' experiences working in elite sport. Traditionally, skinfold thickness has been the most popular method of body composition but the use of DXA has increased in recent years, with a wide held belief that it is the criterion standard.

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: The aim of this study was to investigate thigh musculature excitation and torque generation in response to soccer-specific exercise incorporating an extra-time (ET) period. : Twelve semiprofessional soccer players performed 120-min treadmill-based soccer-specific exercise. Surface electromyography (EMG) signals for the rectus femoris (EMG) and biceps femoris (EMG) were measured as the mean response across a pre-determined 10-second sprint bout during each 15-min block of exercise.

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Background: Fixture congestion (defined as a minimum of two successive bouts of match-play, with an inter-match recovery period of < 96 h) is a frequent and contemporary issue in professional soccer due to increased commercialisation of the sport and a rise in the number of domestic and international cup competitions. To date, there is no published systematic review or meta-analysis on the impact of fixture congestion on performance during soccer match play.

Objective: We sought to conduct a systematic review and meta-analysis of the literature related to the effects of fixture congestion on physical, technical, and tactical performance in professional soccer match-play.

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Biological maturation can be defined as the timing and tempo of progress to achieving a mature state. The estimation of age of peak height velocity (PHV) or percentage of final estimated adult stature attainment (%EASA) is typically used to inform the training process in young athletes. In youth soccer, maturity-related changes in anthropometric and physical fitness characteristics are diverse among individuals, particularly around PHV.

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Polyphenol consumption has become a popular method of trying to temper muscle damage. Cocoa flavanols (CF) have attracted attention due to their high polyphenol content and palatability. As such, this study will investigate whether an acute dose of CF can aid recovery following exercise-induced muscle damage.

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The present study assessed changes in academy soccer players' perception of mental fatigue (MF) across a competitive season, investigating the relationship between MF and other subjective measures of wellness. Ten players completed a modified Brief Assessment of Mood (BAM+) questionnaire that included the question: "How mentally fatigued do you feel"? on match-day (MD) and one (MD+1), two (MD+2) and three (MD+3) days post-match (35 matches). Players reported their MF, along with other subjective measures (sleep, muscle soreness, fatigue and motivation).

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Objective: Soccer match-play is typically contested over 90 min; however, in some cup and tournament scenarios, when matches are tied, they proceed to an additional 30 min, which is termed "extra-time" (ET). This systematic review sought to appraise the literature available on 120-min of soccer-specific exercise, with a view to identifying practical recommendations and future research opportunities.

Methods: The review was conducted according to the PRISMA guidelines.

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Research has demonstrated that induced mental fatigue impairs soccer-specific technical, tactical and physical performance in soccer players. The findings are limited by the lack of elite players and low ecological validity of the tasks used to induce mental fatigue, which do not resemble the cognitive demands of soccer. The current study collected survey data from English academy soccer players (n = 256; age groups - U14 - U23), with questions comprising of five themes (descriptors of physical and mental fatigue, travel, education, match-play and fixture congestion).

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Purpose: To examine the prevalence of disordered eating (DE) in elite male and female soccer players and the influence of perfectionism.

Methods: Using a cross-sectional design, elite male (n = 137) and female (n = 70) soccer players and non-athlete controls (n = 179) completed the clinical perfectionism questionnaire (CPQ-12) and the eating attitudes test (EAT-26) to assess perfectionism and DE risk, respectively.

Results: Male soccer players had higher EAT-26 scores than controls (10.

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: The purpose of the study is to investigate biomechanical and physiological responses to soccer-specific exercise incorporating an extra-time period (ET) and assess the test-retest reliability of these responses. : Twelve soccer players performed 120 min of soccer-specific exercise. Tri-axial (PL) and uni-axial PlayerLoad™ in the vertical (PL), anterior-posterior (PL), and medial-lateral (PL) planes were monitored using a portable accelerometer.

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The aim of this investigation was to profile the physiological, physical, and biomechanical responses during walking football. A total of 17 male participants (aged 66 ± 6 years) participated. Heart rate; blood lactate; accelerometer variables (biomechanical load [PlayerLoad™], changes of direction); and rating of perceived exertion were measured.

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Fullagar, HHK, Harper, LD, Govus, A, McCunn, R, Eisenmann, J, and McCall, A. Practitioner perceptions of evidence-based practice in elite sport in the United States of America. J Strength Cond Res 33(11): 2897-2904, 2019-Practitioners' perceptions regarding the use and effectiveness of research evidence in sport is not well understood.

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This study examined the influence of injury, match selection and training load on mental wellbeing (MW) in a squad of professional soccer players. Using a longitudinal design, twenty-five male soccer players (age, 20 ± 1 years, height, 1.80 ± 5.

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The purpose of the study was to examine the perspectives of both academics and practitioners in relation to forming applied collaborative sport science research within team sports. Ninety-three participants who had previously engaged in collaborative research partnerships within team sports completed an online survey which focused on motivations and barriers for forming collaborations using blinded sliding scale (0-100) and rank order list. Research collaborations were mainly formed to improve the team performance (Academic: 73.

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