• The development of a novel rugby league match simulation protocol

      Twist, Craig; Nicholas, Ceri; Lamb, Kevin L.; Sykes, Dave (University of Liverpool (University of Chester)University of Chester, 2011-12)
      The effectiveness of recovery interventions following prolonged multiple sprint team sports matches has rarely been studied despite the potential for exercise-induced muscle damage to adversely affect training in the days following games. The lack of research related to this topic is probably owing to the wide variability that exists in the movement demands of players between matches and the impact that this has on the subsequent rate and magnitude of recovery which makes it difficult to detect meaningful differences when conducting research with small sample sizes. Therefore, the purpose of this thesis was to develop a rugby league-specific match simulation protocol that replicates the movement demands, physiological responses and subsequent recovery from matches in order to study the effectiveness of recovery interventions. Hence, two time-motion analysis studies were conducted using a semi-automated image recognition system to inform the development of the rugby league match simulation protocol (RLMSP). Whilst mean total distance covered over the duration of the match was 8,503 m, ball in play and stoppage work-to-rest ratios were 1:6.9 and 1:87.4, respectively, for all players. Furthermore, a significant decline in high and very high intensity running locomotive rates were observed between the initial and final 20 min periods of the match. Thus a RLMSP was devised to replicate the overall movement demands, intra-match fatigue and recovery from a senior elite rugby league match. Not only was there a low level of variability in the movement demands during the RLMSP over consecutive trials, but with the exception of creatine kinase, the rate and magnitude of recovery following the RLMSP was similar to that that has been published following competitive matches. Therefore, the RLMSP devised in this thesis may be a more appropriate research tool for assessing the effectiveness of recovery interventions following match related exercise than following actual match play.
    • Multiple-sprint sport exercise and carbohydrate-protein ingestion in humans

      Nicholas, Ceri; Twist, Craig; Lamb, Kevin L.; Highton, Jamie M. (University of ChesterUniversity of Chester, 2012-03)
      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.