Multiple-sprint sport exercise and carbohydrate-protein ingestion in humans

The aim of the present thesis was to examine the potential for acute carbohydrate-protein (CHO-P) ingestion to enhance performance and recovery from exercise designed to simulate the demands of multiple-sprint sports (MSSs). Chapter 3 of the thesis explored the inter- and intra-day reliability and concurrent validity of non-motorised treadmill ergometry (NMT) for the assessment of short-distance sprint performance [i.e. 10-30 m). There were no significant mean differences between NMT variables recorded on the same day or between days. Ratio limits of agreement indicated that the best agreement was in 20 [1.02 */-=- 1.09) and 30 m [1.02 */* 1.07) sprint times, peak [1.00 */T 1.06) and mean (0.99 */+ 1.07) running speed and step length (0.99 */-=- 1.09) and frequency (1.01 */+ 1.06). The poorest agreement was observed for time to peak running speed (1.10 */* 1.47). Significant differences were observed between NMT and over-ground sprint times across all distances, with times being lower (faster) by approximately 25-30% over-ground. The correlations between NMT and over-ground variables were generally modest (r5 = 0.44 - 0.67), and optimal for time to cover 30 m on Day 2 (rs = 0.8). Chapter 4 sought to examine the efficacy of CHO-P ingestion during 4 h of recovery from the Loughborough Intermittent Shuttle Test (LIST) when compared to CHO matched for energy (ISOEN) or CHO (ISOCHO) in a typical CHO beverage. There were significant increases over time in muscle soreness, and reductions in extensor and flexor peak torque (by approximately 9%, 9% and 8%, and 13 %, 13% and 11% at 60 deg-s-1) and jump performance (10%, 7% and 5%) with the ingestion of CHO-P, ISOEN and ISOCHO, respectively. Beverage type x time interactions were not significant for any of these variables, indicating that changes in each variable were similar for all groups. Decrements in sprint performance assessed on the NMT were typically small and not different between beverage types (<4%), although sprint times over 20 and 30 m remained elevated for 48 h post-exercise. Accordingly, Chapter 4 provided no clear evidence for a benefit of ingesting CHO-P in the hours after exercise to enhance recovery of muscle function and selected performance variables following MSS activity. Chapters 5 and 6 of the thesis aimed to examine the effect of CHO-P ingestion during simulated MSS exercise. In Chapter 5, it was observed that sprint times, HR and gut fullness increased over the course of the LIST, with no influence of consuming each of the different beverages. In contrast, there was a main effect of time (P < 0.001), and drink (P = 0.042) observed for RPE, which was lower (P < 0.001) during the LIST in the CHO-P condition (16.9 ± 1.4) than in either the ISOCHO (17.8 ± 1.1) or ISOEN (17.7 ± 1.3). However, time to exhaustion was not different (P = 0.29) between CHO-P (468.3 ± 268.5 s), ISOCHO (443.4 ± 286.3 s) and ISOEN (446.2 ± 282.08 s), although these times did equate to a non-significant mean improvement of 4% in the CHO-P trial. Chapter 6 demonstrated that during a modified version of the LIST with two self-regulated blocks of exercise intensity, participants had a higher average speed (8.1 ± 0.3 cf. 7.9 ± 0.5 knvlr1) during the final (self-regulated) 15 min block of the LIST in the CHO-P condition compared to CHO. Whilst the mechanisms for such an improvement are not certain, the attenuated rise in RPE observed in Chapter 5, and increased blood urea concentration observed in Chapter 6, with CHO-P ingestion may suggest altered central fatigue and/or increased protein oxidation enhances performance during MSSs

The physiological, perceptual and neuromuscular responses of team sport athletes to a running and cycling high intensity interval training session

This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1007/s00421-022-05053-8Purpose: The acute physiological, perceptual and neuromuscular responses to volume-matched running and cycling high intensity interval training (HIIT) were studied in team sport athletes. Methods: In a randomized cross-over design, 11 male team sport players completed 3 x 6 min (with 5 min between sets) repeated efforts of 15 s exercising at 120% speed (s"V" ̇O2max) or power (p"V" ̇O2max) at VO2max followed by 15 s passive recovery on a treadmill or cycle ergometer, respectively. Results: Absolute mean "V" ̇O2 (ES [95%CI] = 1.46 [0.47-2.34], p 90% VO2max during the HIIT was higher for running compared to cycling (ES [95%CI] = 1.21 [0.26-2.07], p = 0.015). Overall differential RPE (dRPE) (ES [95%CI] = 0.55 [-0.32-1.38], p = 0.094) and legs dRPE (ES [95%CI] = -0.65 [-1.48-0.23], p = 0.111) were similar whereas breathing dRPE (ES [95%CI] = 1.01 [0.08-1.85], p = 0.012) was higher for running. Maximal isometric knee extension force was unchanged after running (ES [95%CI] = -0.04 [-0.80-0.8], p = 0.726) compared to a moderate reduction after cycling (ES [95%CI] = -1.17 [-2.02- -0.22], p = 0.001). Conclusion: Cycling HIIT in team sport athletes is unlikely to meet the requirements for improving run-specific metabolic adaptation but might offer a greater lower limb neuromuscular load

Importance of GNSS data quality assessment with novel control criteria in professional soccer match- play

This is an Accepted Manuscript of an article published by Taylor & Francis in International Journal of Performance Analysis in Sport on 06/07/2021, available online: https://doi.org/10.1080/24748668.2021.1947017This study assessed the quality of Global Navigation Satellite System (GNSS) signal during professional football match-play in different stadia with the application of a novel Data Quality Control Criteria (DQCC). DQCC was applied to GPS-files from match-play, derived using 10 Hz GNSS devices for 27 professional soccer players across a season to assess external load measures accounting for poor positioning quality (%) and horizontal dilution of precision. Performances were categorised on playing position as Wide or Central to assess proximity to stand cover on GNSS signal quality. An average reduction in total distance (11.2%), high-speed running distance (6.4%), sprint distance (7.0%), accelerations (10.3%) and decelerations (10.0%) (all P <0.01) was observed upon DQCC application. In worst cases, 90% of an external variable was affected by poor quality signal. Signal quality was worse for wide positioned players than centrally positioned (positioning quality 2.6% lower (P <0.01)), resulting in a larger reduction of external variables upon DQCC application. Large stands in football stadia affect the data quality of GNSS and is exacerbated for players positioned closer to stand cover. Viewing only data with acceptable Position Quality and HDOP meaningfully reduces measured external loads, which has implications for the application of match data

Energy expenditure, metabolic power and high speed activity during linear and multi-directional running

Objectives: The purpose of the study was to compare measures of energy expenditure derived from indirect calorimetry and micro-technology, as well as high power and high speed activity during linear and multi-directional running. Design: Repeated measures Methods: Twelve university standard team sport players completed a linear and multi-directional running condition. Estimated energy expenditure, as well as time at high speed (> 14.4 km.h-1) and high power (> 20 W.kg-1) were quantified using a 10 Hz micro-technology device and compared with energy expenditure derived from indirect calorimetry. Results: Measured energy expenditure was higher during the multi-directional condition (9.0 ± 2.0 cf. 5.9 ± 1.4 kcal.min-1), whereas estimated energy expenditure was higher during the linear condition (8.7 ± 2.1 cf. 6.5 ± 1.5 kcal.min-1). Whilst measures of energy expenditure were strongly related (r > 0.89, p < 0.001), metabolic power underestimated energy expenditure by 52% (95% LoA: 20-93%) and 34% (95% LoA: 12-59%) during the multi-directional and linear condition, respectively. Time at high power was 41% (95% LoA: 4-92%) greater than time at high speed during the multi-directional condition, whereas time at high power was 5% (95% LoA: -17-9%) lower than time at high speed during the linear condition. Conclusions: Estimated energy expenditure and time at high metabolic power can reflect changes in internal load. However, micro-technology cannot be used to determine the energy cost of intermittent running

Sex-related changes in physical performance, wellbeing and neuromuscular function of elite Touch players during a four-day international tournament.

Accepted author manuscript version reprinted, by permission, from International Journal of Sports Physiology and Performance, 2020, 15(8): 1138–1146, https://doi.org/10.1123/ijspp.2019-0594. © Human Kinetics, Inc.Purpose: To examine the within- and between-sex physical performance, wellbeing and neuromuscular function responses across a four-day international touch rugby (Touch) tournament. Methods: Twenty females and twenty-one males completed measures of wellbeing (fatigue, soreness, sleep, mood, stress) and neuromuscular function (countermovement jump (CMJ) height, peak power output (PPO) and peak force (PF)) during a 4-day tournament with internal, external and perceptual loads recorded for all matches. Results: Relative and absolute total, low- (females) and high-intensity distance was lower on day 3 (males and females) (ES = -0.37 to -0.71) compared to day 1. Mean heart rate was possibly to most likely reduced during the tournament (except day 2 males) (ES = -0.36 to -0.74), whilst RPE-TL was consistently higher in females (ES = 0.02 to 0.83). The change in mean fatigue, soreness and overall wellbeing were unclear to most likely lower (ES = -0.33 to -1.90) across the tournament for both sexes, with greater perceived fatigue and soreness in females on days 3-4 (ES = 0.39 to 0.78). Jump height and PPO were possibly to most likely lower across days 2-4 (ES = -0.30 to -0.84), with greater reductions in females (ES = 0.21 to 0.66). Wellbeing, CMJ height, and PF were associated with changes in external, internal and perceptual measures of load across the tournament (2 = -0.37 to 0.39). Conclusions: Elite Touch players experience reductions in wellbeing, neuromuscular function and running performance across a 4-day tournament, with notable differences in fatigue and running between males and females, suggesting sex-specific monitoring and intervention strategies are necessary

The internal and external responses to a forward-specific rugby league simulation protocol performed with and without physical contact

As accepted for publication in International Journal of Sports Physiology and PerformanceIt is important to understand to what extent physical contact changes the internal and external load during rugby simulations that aim to replicate the demands of match play. Accordingly, this study examined the role of physical contact on the physiological and perceptual demands during and immediately after a simulated rugby league match. Nineteen male rugby players completed a ‘contact’ (CON) and a ‘non-contact’ (NCON) version of the rugby league match simulation protocol (RLMSP-i) in a randomized crossover design with one week between trials. Relative distance covered (ES = 1.27; ±0.29), low intensity activity (ES = 1.13; ±0.31), high-intensity running (ES = 0.49; ±0.34), heart rate (ES = 0.52; ±0.35), blood lactate concentration (ES = 0.78; ±0.34), RPE (ES = 0.72; ±0.38) and session RPE (ES = 1.45; ±0.51) were all higher in the CON compared to the NCON trial. However, peak speeds were lower in the CON trial (ES = -0.99; ±0.40) despite unclearreductions in knee extensor (ES = 0.19; ±0.40) and knee flexor (ES = 0.07; ±0.43) torque. Muscle soreness was also greater after CON compared to the NCON trial (ES = 0.97; ±0.55). The addition of physical contact to the movement demands of a simulated rugby league match increases many of the external and internal demands, but also results in players slowing their peak running speed during sprints. These findings highlight the importance of including contacts in simulation protocols and training practices designed to replicate the demands of real match play

Passive heat maintenance after an initial warm-up improves high intensity activity during an interchange rugby league match simulation protocol.

This is an Accepted Manuscript of an article published by Lippincott, Williams & Wilkins in Journal of Strength and Conditioning Research on publication 01/01/2019, available online: https//doi.org/10.1519/JSC.0000000000003061This study examined using passive heat maintenance to maintain core temperature after a warm-up and its effect on first half running performance in rugby players. Thirteen male rugby players completed this randomized crossover study. Tympanic temperature was taken before a warm-up and then after a further 15 minutes passive recovery either with (PHM) or without (CON) a passive heat maintenance garment. Participants then completed 23 min of the rugby league match simulation protocol (RLMSP-i). Differences in tympanic temperature were unclear between CON and PHM before (35.7 ± 1.3 cf. 36.0 ± 1.1oC; ES = 0.20) and during exercise (34.5 ± 0.1 cf. 35.2 ± 0.1oC; ES = 0.26-0.35). High-intensity running (ES = 0.27) and peak sprint speed were higher (ES = 0.46-0.56) during the PHM compared to the CON trial. Time spent above 20 W.kg-1 also increased in the first quartile of PHM compared to CON trial (ES = 0.18). All other between trial comparisons of performance were unclear. HRmean (ES = 0.38) was higher in PHM compared to CON, while differences in RPEmean (ES = -0.19) were unclear. There are small to large increases in high intensity work performed during a playing bout when rugby players wear a PHM garment after a warm-up. Rugby players should consider PHM during extended periods of time between a warm-up and starting a match

Randomisation of simulated rugby match activity produces reliable movements and associated measures of subjective task load, cognitive and neuromuscular function

This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Sports Sciences on 2019-forthcoming, available online: https://doi.org/10.1080/02640414.2013.1646071The study assesses the test-retest reliability of movement and physiological measures during a simulated rugby match that employed activities performed in a random order. Twenty male rugby players (21.4 ± 2.1 y) completed two trials of a 2 x 23 min rugby movement simulation protocol during which the order of events was randomised, with 7-10 days between trials. Movement characteristics, heart rate (HR), RPE, maximum voluntary contraction (MVC), voluntary activation (VA%) of the quadriceps, Stroop test and subjective task load rating (NASA-TLX) were measured. The most reliable measures of external load was relative distance (typical error [TE] and CV% = 1.5-1.6 m.min-1 and 1.4-1.5%, respectively), with all other movement characteristics possessing a CV% 5%). Future studies can confidently examine changes in several perceptual, neuromuscular, physiological and movement measures related to rugby activity using stochastic movements

Influence of Knowledge of Task Endpoint on Pacing and Performance During Simulated Rugby League Match Play

As accepted for publicationPurpose: To examine the influence of knowledge of exercise duration on pacing and performance during simulated rugby league match play. Methods: Thirteen male university rugby players completed 3 simulated rugby league matches (RLMSP-i) on separate days in a random order. In a control trial, participants were informed that they would be performing 2 × 23-min bouts (separated by 20 min) of the RLMSP-i (CON). In a second trial, participants were informed that they would be performing 1 × 23-min bout of the protocol but were then asked to perform another 23-min bout (DEC). In a third trial, participants were not informed of the exercise duration and performed 2 × 23-min bouts (UN). Results: Distance covered and high-intensity running were higher in CON (4813 ± 167 m, 26 ± 4.1 m/min) than DEC (4764 ± 112 m, 25.2 ± 2.8 m/min) and UN (4744 ± 131 m, 24.4 m/min). Compared with CON, high-intensity running and peak speed were typically higher for DEC in bout 1 and lower in bout 2 of the RLMSP-i, while UN was generally lower throughout. Similarly, DEC resulted in an increased heart rate, blood lactate, and rating of perceived exertion than CON in bout 1, whereas these variables were lower throughout the protocol in UN. Conclusions: Pacing and performance during simulated rugby league match play depend on an accurate understanding of the exercise endpoint. Applied practitioners should consider informing players of their likely exercise duration to maximize running

Development of anthropometric characteristics in professional Rugby League players: Is there too much emphasis on the pre-season period?

This is an Accepted Manuscript of an article published by Taylor & Francis in European Journal of Sport Science on 04/12/2019, available online: http://www.tandfonline.com/doi/full/10.1080/17461391.2019.1695953Rugby League is a team sport requiring players to experience large impact collisions, thus requiring high amounts of muscle mass. Many players (academy and senior) strive to increase muscle mass during the pre-season, however, quantification of changes during this period have not been thoroughly investigated. We therefore assessed changes in body-composition using Dual X-Ray Absorptiometry (DXA) in eleven academy players over three successive pre-seasons and ninety-three senior players from four different European Super League clubs prior to, and at the end of, a pre-season training period. There was no meaningful change in lean mass of the academy players during any of the pre-season periods (year 1 = 72.3 ± 7.1–73.2 ± 7.2kg; ES 0.05, year 2 = 74.4 ± 6.9–75.5 ± 6.9kg; ES 0.07, year 3 = 75.9 ± 6.7–76.8 ± 6.6kg; ES 0.06) with small changes only occurring over the three-year study period (72.3–75.9kg; ES = 0.22). Senior players showed trivial changes in all characteristics during the pre-season period (total mass = 95.1–95.0kg; ES −0.01, lean mass = 74.6–75.1kg; ES 0.07, fat mass = 13.6–12.9kg; ES −0.17, body fat percentage = 14.8–14.1%; ES −0.19). These data suggest that academy players need time to develop towards profiles congruent with senior players. Moreover, once players reach senior level, body-composition changes are trivial during the pre-season and therefore teams may need to individualise training for players striving to gain muscle mass by reducing other training loads