Liam D. Harper

Minimal muscle damage after a marathon and no influence of beetroot juice on inflammation and recovery

This study examined whether beetroot juice (BTJ) would attenuate inflammation and muscle damage following a marathon. Using a double blind, independent group design, 34 runners (each having completed ca. ∼16 previous marathons) consumed either BTJ or an isocaloric placebo (PLA) for 3 days following a marathon. Maximal isometric voluntary contractions (MIVC), countermovement jumps (CMJ), muscle soreness, serum cytokines, leucocytosis, creatine kinase (CK), high sensitivity C-reactive protein (hs-CRP), and aspartate aminotransferase (AST) were measured pre, post, and 2 days after the marathon. CMJ and MIVC were reduced after the marathon (P < 0.05), but no group differences were observed (P > 0.05). Muscle soreness was increased in the day after the marathon (BTJ; 45 ± 48 vs. PLA; 46 ± 39 mm) and had returned to baseline by day 2, irrespective of supplementation (P = 0.694). Cytokines (interleukin-6; IL-6, interleukin-8, tumour necrosis factor-α) were increased immediately post-marathon but apart from IL-6 had returned to baseline values by day 1 post. No interaction effects were evident for IL-6 (P = 0.213). Leucocytes increased 1.7-fold after the race and remained elevated 2 days post, irrespective of supplement (P < 0.0001). CK peaked at 1 day post marathon (BTJ: 965 ± 967, and PLA: 1141 ± 979 IU·L-1) and like AST and hs-CRP, was still elevated 2 days after the marathon (P < 0.05); however, no group differences were present for these variables. Beetroot juice did not attenuate inflammation or reduce muscle damage following a marathon, possibly because most of these indices were not markedly different from baseline values in the days after the marathon.

The independent effects of match location, match result and the quality of opposition on subjective wellbeing in under 23 soccer players: a case study

ABSTRACT This study examined if subjective wellbeing in soccer players was affected by match location, match result and opposition quality before a match (PRE), 1 day after (POST-1), and 3 days after a match (POST-3). Eleven professional male soccer players from the under 23 squad playing in the Premier League 2 division completed a wellbeing questionnaire before and after 17 matches. Match training load (session-rating perceived exertion) was not different, regardless of the location, result, or quality of opposition faced (P > 0.05). Subjective wellbeing was not different at PRE (P > 0.05); however, at POST-1 and POST-3, stress and mood were ≥20% lower after playing away from home or losing (P < 0.05). Stress, mood and sleep were ≥12% worse after playing against a higher-level opposition at POST-1. Coaches need to be aware that match location, match result and the quality of the opposition can influence post-match wellbeing, irrespective of match load.

The influence of a 12% carbohydrate-electrolyte beverage on self-paced soccer-specific exercise performance

OBJECTIVES To assess the physiological and performance effects of a 12% carbohydrate-electrolyte beverage consumed at practically applicable time-points (i.e., before each half) throughout simulated soccer match-play. DESIGN Randomised, counterbalanced, crossover. METHODS Fed players (n=15) performed 90-min of soccer-specific exercise (including self-paced exercise at the end of each half). Players consumed carbohydrate-electrolyte (CHO; 60g×500ml-1, Na+ 205mg×500ml-1), placebo-electrolyte (PL) or water (Wat) beverages at the end of the warm-up (250ml) and half-time (250ml plus ad-libitum water). Blood was drawn before each half and every 15-min during exercise. Physical (15-m sprinting, countermovement jumps, self-paced distance, acceleration/deceleration count), technical (dribbling) and cognitive (memory, attention, decision-making) performance was assessed. Ratings of perceived exertion (RPE) and abdominal discomfort were measured. RESULTS Against Wat and PL, CHO increased (all p<0.05) mean accelerations >1.5m·s-2 during self-paced exercise (>+25%) and dribbling speed from 60-min onwards (>+3%). Mean sprinting speed improved (+2.7%) in CHO versus Wat. Blood glucose increased before and during each half in CHO versus PL and Wat (all p<0.05). A 27% decline in glycaemia occurred at 60-min in CHO. RPE was comparable between trials. Cognition reduced post-exercise (p<0.05); this decline was not attenuated by CHO. Abdominal discomfort increased during exercise but was similar between trials. CONCLUSIONS Using more realistic fluid ingestion timings than have been examined previously, consuming a 12% carbohydrate-electrolyte beverage increased blood glucose, self-paced exercise performance, and improved dribbling speed in the final 30-min of exercise compared to water and placebo. Carbohydrates did not attenuate post-exercise reductions in cognition.

Investigating the Nutritional and Recovery Habits of Tennis Players

In this study, the nutritional and recovery habits of tennis players pre-, during, and post-match-play were investigated. Seventy tennis players completed a bespoke nutrition and recovery habits questionnaire, with questions related to the following areas: match preparation, intra-match nutritional habits, situation dependent variables, and post-match nutrition and recovery. On match day-1, the consumption of balanced meals consisting of carbohydrate (CHO), fat and protein, with some micronutrient considerations were reported by 51% of players. On match-days, CHOs were prioritised prior to match-play with CHO dominant meals consumed by the majority of players. During matches, all players adopted a nutritional strategy, with water (94%), banana(s) (86%) and sports drinks (50%) commonly used. Carbohydrate rich nutritional aids, including sports drinks (80%) and energy gels (26%) were utilised more readily during long matches (>2 h). The day after match-play, 39% of players reported the consumption of “nothing specific”. Multiple post-match recovery strategies were adopted by 80% of players, with foam rolling (77%), ice baths (40%), protein shake intake (37%) and hot baths (26%) most used. Findings indicate highly variable eating and recovery habits in tennis players pre-, during and post-match-play, with scope for improved practices.

The Impact of 120 Minutes of Match-Play on Recovery and Subsequent Match Performance: A Case Report in Professional Soccer Players

The influence of a match including extra-time (ET) on subsequent 90 min match performance and recovery has not been investigated. Four professional soccer players played in three competitive matches in a 7-day period: matches one (MD1) and three (MD3) lasted 90 min and match 2 (MD2) lasted 120 min (i.e., included ET). Physical (total and high-intensity (HI) distance covered, accelerations and decelerations, and mechanical load) and technical performances (pass and dribble accuracy) were analyzed throughout match-play. Subjective measures of recovery and countermovement jump (CMJ) height were made 36–42 h post-match. Post-MD2, there were very or most likely harmful effects of ET on CMJ height (−6 ± 9%), muscle soreness (+18 ± 12%), and fatigue (+27 ± 4%) scores, and overall wellness score (−13 ± 5%) compared to post-MD1. Furthermore, there were very likely harmful effects on muscle soreness (+13 ± 14%), wellness scores (−8 ± 10%), and CMJ height (−6 ± 9%) post-MD3 vs. post-MD1. There was a possibly harmful effect of ET on HI distance covered during MD3, along with reductions in pass (−9.3%) and dribble (−12.4%) accuracy. An ET match negatively impacted recovery 36 h post-match. Furthermore, in some players, indices of performance in a 90 min match played 64 h following ET were compromised, with subsequent recovery also adversely affected.

Professional youth football academy injury data: collection procedures, perceived value, and use

ABSTRACT Purpose: There is a paucity of descriptive injury data relevant to professional academy football, with little to no evidence reporting how sports science/medicine staff within academies collect and use injury data. Materials and methods: An online survey relating to the perceptions surrounding injury data collection, its value and use was developed. Forty-seven applied practitioners working for different professional football academies completed the survey. Results: Injury data collection procedures conducted by appropriately trained medical staff are widespread among football academies. Injury data collection within academies was deemed worthwhile and important by 79% of practitioners. Similarly, 79% strongly agreed/agreed that using injury data for academic research is worthwhile. The engagement with and use of injury data by coaching staff appears to be relatively poor, with only 49% of practitioners stating coaches formally review data. Conclusions: Injury data are widely collected within academies and practitioners consider this information valuable. However, improving engagement with coaches and using the data for academic research could further improve applied practice. Practical implications: Applied practitioners should consider sharing injury data with both researchers and coaches. In doing so evidence-guided injury prevention interventions may be developed and subsequently applied in the field.

Small sided games in soccer – a systematic review

ABSTRACT The purpose of this paper was to systematically review and organise the literature on soccer SSGs, in order to ascertain the most frequently researched topics, characterise the methodologies employed, and systematise the evolution of the related research areas. A systematic review of Web of Science, Pubmed and SPORTDiscus databases was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. The following keywords were used: football and soccer, with each one associated with the terms: “small sided games”, SSG, “drill-based training”, “small sided”, “conditioned games” and “position games”. The search returned 394 records. After screening against set criteria, a total of 77 manuscripts were fully reviewed. The most common topics of analysis were (1) pitch area; (2) player number: (a) with/without a goalkeeper; (b) with floater(s) in/outside the pitch; (3) goal: (a) goal vs. scoring zone; (b) number of goals; (c) size of goals; (4) rules modification/task constraints (a) no. of ball touches; (b) offside rule; (c) others; (4) training regimen; (5) coach encouragement. This review provides valuable information on the complex relationship between technical, tactical and physiological interactions in SSGs and how the manipulation of these types of variables can improve the soccer training process.

Perspectives of applied collaborative sport science research within professional team sports

Abstract 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: 73.6 ± 23.3; Practitioner: 84.3 ± 16.0; effect size (ES = 0.54), small). Academics ranked journal articles’ importance significantly higher than practitioners did (Academic: Mrank = 53.9; Practitioner: 36.0; z = −3.18, p = .001, p < q). However, practitioners rated one-to-one communication as more preferential (Academic: Mrank = 41.3; Practitioner 56.1; z = −2.62, p = .009, p < q). Some potential barriers were found in terms of staff buy in (Academic: 70.0 ± 25.5; Practitioner: 56.8 ± 27.3; ES = 0.50, small) and funding (Academic: 68.0 ± 24.9; Practitioner: 67.5 ± 28.0; ES = 0.02, trivial). Both groups revealed low motivation for invasive mechanistic research (Academic: 36.3 ± 24.2; Practitioner: 36.4 ± 27.5; ES = 0.01, trivial), with practitioners have a preference towards ‘fast’ type research. There was a general agreement between academics and practitioners for forming research collaborations. Some potential barriers still exist (e.g. staff buy in and funding), with practitioners preferring ‘fast’ informal research dissemination compared to the ‘slow’ quality control approach of academics.

Correction to: A comparison of isomaltulose versus maltodextrin ingestion during soccer-specific exercise.

The article “A comparison of isomaltulose versus maltodextrin ingestion during soccer-specific exercise”, written by “Emma J. Stevenson, Anthony Watson, Stephan Theis, Anja Holz,·Liam D. Harper, Mark Russell”, was originally published Online First without open access. After publication in volume [117], issue [11], page.

Impact Of “extra-time” On Performance And Physiological Responses To Simulated Soccer Match-play: 2434 Board #6 June 3, 9

The physiological and performance responses to 90 min of soccer-specific exercise are well known. However, the responses to 120 min of soccer-specific exercise (i.e., inclusion of an extra-time period; ET) are unclear. This is despite the importance of ET in determining match outcomes in tournament match-play.