Determining the barriers to the use of post-match fatigue monitoring in the rugby codes: A Concept Mapping study.

Topics in Exercise Science and Kinesiology Volume 5: Issue 1, Article 3, 2024. The rugby codes (i.e., rugby union, rugby league, rugby sevens [termed ‘rugby’]) are team-sports that impose complex physical demands upon players which in-turn, leads to domain-specific fatigue (e.g., neuromuscular, cardio-autonomic). Quantifying post-match fatigue through various methods and metrics is important to monitor player fatigue status, which influences training readiness. The specific and general barriers limiting the use of post-match fatigue monitoring in rugby are not presently known. Therefore, the aims of this study were to identify specific and general barriers (clusters of specific barriers) to the use of post-match fatigue monitoring methods and metrics in rugby across the domains of neuromuscular performance, cardio-autonomic, tissue biomarker, and self-reported fatigue, and which of these specific barriers were considered important to overcome and feasible to overcome. An international cohort of subject matter experts (SME) in rugby completed a two-round online questionnaire survey (Round One; n = 42, Round Two; n = 13), with the responses collected and analysed using Concept Mapping. Specific barrier statements were generated based on the SME responses to Round One, which were structured and then rated by the SME for importance to overcome and feasibility to overcome in Round Two. Five clusters of specific barriers (representing the general barriers) were determined based on analyses of the SME responses: 1. ‘Budget and Equipment’, 2. ‘Data and Testing Considerations’, 3. ‘Player and Coach Perceptions’, 4. ‘Test Appropriateness’, and 5. ‘Time and Space’. For both importance to overcome and feasibility to overcome, the ‘Data and Testing Considerations’ had the highest overall rating and contained the largest number of specific barriers which rated highly. These findings should be considered when identifying which post-match fatigue monitoring methods and metrics to implement in rugby, and potentially other sports

Latent variable dose-response modelling of external training load measures and musculoskeletal responses in elite rugby league players

Establishing dose-response relationships between training load and fatigue can help the planning of training. The aim was to establish the relative importance of external training load measurements to relate to the musculoskeletal response on a group and individual player level. Sixteen elite male rugby league players were monitored across three seasons. Two- to seven-day exponential weighted averages (EWMA) were calculated for total distance, and individualised speed thresholds (via 30-15 Intermittent Fitness Test) derived from global positioning systems. The sit and reach, dorsiflexion lunge, and adductor squeeze tests represented the musculoskeletal response. Partial least squares and repeated measures correlation analyses established the relative importance of training load measures and then investigated their relationship to the collective musculoskeletal response for individual players through the construction of latent variables. On a group level, 2- and 3-day EWMA total distance had the highest relative importance to the collective musculoskeletal response (

The validity and reliability of global positioning systems in team sport: A brief review

The use of global positioning systems (GPS) has increased dramatically over the last decade. Using signals from orbiting satellites, the GPS receiver calculates the exact position of the device and the speed at which the device is moving. Within team sports GPS devices are used to quantify the external load experienced by an athlete, allowing coaches to better manage trainings loads and potentially identify athletes who are overreaching or overtraining. This review aims to collate all studies that have tested either (or both) the validity or reliability of GPS devices in a team sport setting, with a particular focus on (a) measurements of distance, speed, velocities, and accelerations across all sampling rates and (b) accelerometers, player/body load and impacts in accelerometer-integrated GPS devices. A comprehensive search of the online libraries identified 22 articles that fit search criteria. The literature suggests that all GPS units, regardless of sampling rate, are capable of tracking athlete's distance during team sport movements with adequate intraunit reliability. One Hertz and 5Hz GPS units have limitations in their reporting of distance during high-intensity running, velocity measures, and short linear running (particularly those involving changes of direction), although these limitations seem to be overcome during measures recorded during team sport movements. Ten Hertz GPS devices seem the most valid and reliable to date across linear and team sport simulated running, overcoming many limitations of earlier models, whereas the increase to 15Hz GPS devices have had no additional benefit

High-intensity Interval Training in Team Sports: Testing, Monitoring and Prescription

Aerobic fitness and repeated high-intensity efforts have been shown to be a determinant in the performance of team sports, especially in the ability to finish a match, to cover a distance, to repeat and recover between sprints and explosive movements (e.g. accelerations, changes of direction; COD) and to reduce the deterioration in some technical skill. Due to this, coaches must appropriately develop these capacities to adequately prepare athletes for match-play demands. High-intensity interval training is considered an effective and time efficient means to optimise individual physiological adaptation. However, the best processes which examine these qualities (physical testing protocols), prescribe training and monitor the response of this training requires attention, particularly in team sport athletes that possess heterogenous physical attributes. Therefore, this thesis aimed to examine a valid and reliable approach to assess the training outcome as well as prescribe and monitor the training process in rugby league athletes

Normative values, longitudinal trends and usefulness of adductor dynamometry to detect fatigue in professional rugby league players

In rugby league change-of-direction, kicking and running are essential. As such, hip and groin soreness and injuries are common. Dynamometry tests are regularly used to assess adductor strength and monitor groin pain. Test results appear sensitive to changes in acute and chronic training loads (TL), providing further evidence to monitor fatigue. This study aimed to examine the typical error of measurement (TE) and smallest worthwhile change (SWC) of the adductor squeeze test at 60° as well as provide positional differences, normative values and longitudinal trends across a National Rugby League (NRL) season. METHODS: Thirty-three players competing in the NRL (26.3 ± 3.6 yr, 100.6 ± 8.7 kg) were broken into their positional groups (Outside Backs, Adjustables and Forwards) and tested at the beginning of pre-season to limit any TL induced fatigue. Using a hand-held dynamometer, adductor squeeze scores for the 60° test (lying supine with legs bent at 60°) were collected twice, with two minutes separating the test-retest. Intra-individual means were used to calculate positional normative means. Effects sizes (ES) and 95% confidence intervals (CI) were used to describe the magnitude of difference between positional groups, interpreted as; ES 2.1 very large. TE and SWC were calculated with 95% CI to examine reliability and usefulness. To remove variance in individual norms, all data was converted to intra-individual Z-Scores with the squad mean reported across the competitive season. RESULTS: TE (14.4; CI: 11.6 - 19.0) was similar to SWC (14.1; CI: 11.4 - 18.7) of the squad indicating the test is 'satisfactory'. Adjustables had lowest mean squeeze scores (225.8 ± 59.8 N; n=9) behind Forwards (256.5 ± 77.2 N; n=15) and Outside Backs (265.0 ± 67.9 N; n=9). Moderate and small ES were observed (0.6 ± 0.9 and 0.4 ± 0.8; ES ± CI) when comparing Outside Backs and Forwards with Adjustables, respectively. However, all CI overlapped zero and therefore differences were deemed unclear between positional groups. Observation throughout the competition season showed distinct periods of decreased adductor strength output (Figure 1). DISCUSSION: The current findings deem the 60° adductor dynamometry test 'satisfactory' for use in elite rugby league players. Additionally, any change ≥15 N may be practically considered a 'real' change. The longitudinal periods of decreased strength appear related to specific time periods, demonstrating that groin strength is sensitive to changes in TL, however the detailed extent of this relationship requires further examination. PRACTICAL APPLICATION: The current findings provide practitioners a value of 'real' change when using adductor dynamometry tests in rugby league athletes. This may assist performance staff to monitor changes in the ability of the pelvis to produce force that may indicate fatigue or potential for injury

Individualised submaximal shuttle run test: A comparison of elite and recreational athletes heart rate responses and relationships with fitness

INTRODUCTION: Maximal exercise tests are an accepted method to monitor fitness, however given the exertion required to complete a maximal test, exposing an athlete to such assessment on a regular basis within a training setting seems inappropriate. Submaximal exercise tests may deliver a viable alternative for monitoring athletes physiological capabilities and responses to training, thus providing an appropriate tool to monitor athletes training status. It has been demonstrated that heart rate (HR) response to a given submaximal workload may differ depending on the level of fitness and training status. Typically, trained athletes will exhibit lower exercise heart rate (HRex) and faster heart rate recovery (HRR) rates than untrained or recreationally trained individuals. The purpose of this study was to compare elite and recreational athletes HR responses to an individualised submaximal shuttle run test (SSRIndiv) and examine the association of these results and levels of fitness. METHODS: Elite rugby league athletes (n=22; 23.2 ± 3.4 yr, 186.8 ± 5.4 cm, 100.2 ± 8.5 kg), competing in the National Rugby League (NRL) competition and recreationally trained males (n=14; 25.8 ± 6.3 yr, 183.3 ± 5.4 cm, 83.3 ± 8.1 kg) volunteered to participate. Each subject performed a 1500-m continuous time trial, 30-15 Intermittent Fitness Test (30-15IFT) and a SSRIndiv. Subjects undertook familiarisation of all tests. The SSRIndiv was conducted as a continuous 20-s shuttle run, prescribed as 75% of the average speed during the 1500-m time trial, corresponding to 60.0 ± 0.2% of the final velocity achieved during the 30-15IFT (VIFT). The average HR during the final 30-s of the SSRIndiv (HRex) was calculated along with HRR following 1-minute (HRR60) and 2-minutes (HRR120) of seated recovery, expressed as a percentage decrement to HRex. Differences between groups were examined using ES and 90% CI. The likelihood of the observed effect was established using a progressive magnitude based approach. The degree of association between level of fitness (VIFT and estimated VO2max from 30-15IFT) and HR responses during and following SSRIndiv was assessed using Pearson's coefficient correlation. RESULTS: Elite NRL athletes demonstrated a possibly lower HRex (ES = -0.67 ± 0.37 (CI)), possibly greater decrement in HRR60 (ES = 0.63 ± 0.39) and very likely decrement in HRR120 (ES = 1.41 ± 0.42) following the SSRIndiv when compared to recreational athletes. Trivial and unclear correlations were observed between VIFT and estimated VO2max and HRex, HRR60 and HRR120. DISCUSSION: Elite rugby league athletes recorded lower HRex and demonstrated faster HRR during and following the SSRIndiv, indicating greater levels of cardiorespiratory function. However, when comparing these results to levels of fitness there was no association. The differences in HR responses may be indicative of the superior trained state of the elite athletes, which is likely reflective of their habitual training stimulus. It may be speculated that the determinants of these differences in physiological function may not be directly measured through the 30-15IFT. PRACTICAL APPLICATIONS: These findings confirm elite athletes demonstrate greater physiological performance during submaximal running indicating superior training status, however this relationship with measures of fitness required further exploration

Defining and quantifying fatigue in the rugby codes.

The rugby codes (i.e., rugby union, rugby league, rugby sevens [termed 'rugby']) are team-sports that impose multiple complex physical, perceptual, and technical demands on players which leads to substantial player fatigue post-match. In the post-match period, fatigue manifests through multiple domains and negatively influences recovery. There is, however, currently no definition of fatigue contextualised to the unique characteristics of rugby (e.g., locomotor and collision loads). Similarly, the methods and metrics which practitioners consider when quantifying the components of post-match fatigue and subsequent recovery are not known. The aims of this study were to develop a definition of fatigue in rugby, to determine agreement with this common definition of fatigue, and to outline which methods and metrics are considered important and feasible to implement to quantify post-match fatigue. Subject matter experts (SME) undertook a two-round online Delphi questionnaire (round one; n = 42, round two; n = 23). SME responses in round one were analysed to derive a definition of fatigue, which after discussion and agreement by the investigators, obtained 96% agreement in round two. The SME agreed that fatigue in rugby refers to a reduction in performance-related task ability which is underpinned by time-dependent negative changes within and between cognitive, neuromuscular, perceptual, physiological, emotional, and technical/tactical domains. Further, there were 33 items in the neuromuscular performance, cardio-autonomic, or self-report domains achieved consensus for importance and/or feasibility to implement. Highly rated methods and metrics included countermovement jump force/power (neuromuscular performance), heart rate variability (cardio-autonomic measures), and soreness, mood, stress, and sleep quality (self-reported assessments). A monitoring system including highly-rated fatigue monitoring objective and subjective methods and metrics in rugby is presented. Practical recommendations of objective and subjective measures, and broader considerations for testing and analysing the resulting data in relation to monitoring fatigue are provided

Differences Between Relative and Absolute Speed and Metabolic Thresholds in Rugby League

Purpose: To compare relative and absolute speed and metabolic thresholds for quantifying match output in elite rugby league. Methods: Twenty-six professional players competing in the National Rugby League were monitored with global positioning systems (GPS) across a rugby-league season. Absolute speed (moderate-intensity running [MIRTh  >  3.6 m/s] and high-intensity running [HIRTh  >  5.2 m/s]) and metabolic ( > 20 W/kg) thresholds were compared with individualized ventilatory (first [VT1IFT] and second [VT2IFT]) thresholds estimated from the 30-15 Intermittent Fitness Test (30-15IFT), as well as the metabolic threshold associated with VT2IFT (HPmetVT2), to examine difference in match-play demands. Results: VT2IFT mean values represent 146%, 138%, 167%, and 144% increases in the HIR dose across adjustables, edge forwards, middle forwards, and outside backs, respectively. Distance covered above VT2IFT was almost certainly greater (ES range = 0.79–1.03) than absolute thresholds across all positions. Trivial to small differences were observed between VT1IFT and MIRTh, while small to moderate differences were reported between HPmetVT2 and HPmetTh. Conclusions: These results reveal that the speed at which players begin to run at higher intensities depends on individual capacities and attributes. As such, using absolute HIR speed thresholds underestimates the physical HIR load. Moreover, absolute MIR and high metabolic thresholds may over- or underestimate the work undertaken above these thresholds depending on the respective fitness of the individual. Therefore, using relative thresholds enables better prescription and monitoring of external training loads based on measured individual physical capacities