Two training-load paradoxes: can we work harder and smarter, can physical preparation and medical be teammates?

The authors have observed that in professional sporting organizations the staff responsible for physical preparation and medical care typically practice in relative isolation and display tension as regards their attitudes toward training-load prescription (much more and much less training, respectively). Recent evidence shows that relatively high chronic training loads, when they are appropriately reached, are associated with reduced injury risk and better performance. Understanding this link between performance and training loads removes this tension but requires a better understanding of the relationship between the acute:chronic workload ratio (ACWR) and its association with performance and injury. However, there remain many questions in the area of ACWR, and we are likely at an early stage of our understanding of these parameters and their interrelationships. This opinion paper explores these themes and makes recommendations for improving performance through better synergies in support-staff approaches. Furthermore, aspects of the ACWR that remain to be clarified-the role of shared decision making, risk:benefit estimation, and clearer accountability-are discussed

Internal and external match loads of university-level soccer players: a comparison between methods

The aim of this study was to use individualized intensity zones to compare the external (velocity and player load, PL) and internal loads (heart rate, HR) of a cohort of university-level soccer players. Thirteen soccer players completed a 40-m maximum speed test and the Yo-Yo intermittent recovery test 1 (Yo-Yo IR1) to determine individualized velocity and HR thresholds. Heart rate values and global positioning system (GPS) data of each player were recorded during 5 league matches. A large (r = 0.46; p </= 0.01) correlation was found between time spent in the low-intensity (LI) velocity zone (LIVZ) and the LI HR zone. Similarly, there were moderate (r = 0.25; p </= 0.01) to large (r = 0.57; p </= 0.01) correlations between the relative and absolute time spent in the moderate-intensity (MI) velocity zone (MIVZ) and the MI HR zone. No significant correlations (p </= 0.01) existed between the high-intensity (HI) velocity zones (HIVZ) and the HI HR zone. On the other hand, PL showed significant correlations with all velocity and HR (absolute and relative) variables, with the exception of a nonsignificant correlation between the HI HR variables and PL. To conclude, PL showed good correlations with both velocity and HR zones and therefore may have the potential to serve as a good indicator of both external and internal soccer match loads

The training-injury prevention paradox: should athletes be training smarter and harder?

Background There is dogma that higher training load causes higher injury rates. However, there is also evidence that training has a protective effect against injury. For example, team sport athletes who performed more than 18 weeks of training before sustaining their initial injuries were at reduced risk of sustaining a subsequent injury, while high chronic workloads have been shown to decrease the risk of injury. Second, across a wide range of sports, well-developed physical qualities are associated with a reduced risk of injury. Clearly, for athletes to develop the physical capacities required to provide a protective effect against injury, they must be prepared to train hard. Finally, there is also evidence that under-training may increase injury risk. Collectively, these results emphasise that reductions in workloads may not always be the best approach to protect against injury. Main thesis This paper describes the 'Training-Injury Prevention Paradox' model; a phenomenon whereby athletes accustomed to high training loads have fewer injuries than athletes training at lower workloads. The Model is based on evidence that non-contact injuries are not caused by training per se, but more likely by an inappropriate training programme. Excessive and rapid increases in training loads are likely responsible for a large proportion of non-contact, soft-tissue injuries. If training load is an important determinant of injury, it must be accurately measured up to twice daily and over periods of weeks and months (a season). This paper outlines ways of monitoring training load ('internal' and 'external' loads) and suggests capturing both recent ('acute') training loads and more medium-term ('chronic') training loads to best capture the player's training burden. I describe the critical variable-acute: chronic workload ratio-as a best practice predictor of training-related injuries. This provides the foundation for interventions to reduce players risk, and thus, time-loss injuries. Summary The appropriately graded prescription of high training loads should improve players' fitness, which in turn may protect against injury, ultimately leading to (1) greater physical outputs and resilience in competition, and (2) a greater proportion of the squad available for selection each week

Influence of tactical formation on average and peak demands of elite soccer match-play

Global Positioning Systems (GPS) have provided practitioners with information on the activity profiles of team-sport players. There is no available literature identifying the average or peak physical demands of elite soccer in the USA. This investigation aims to quantify the activity profiles and most demanding passages of elite soccer competition within different positions, periods, and tactical formations. Activity profiles were captured from 449 whole-period, and 661 peak-period data from 24 field players across a 31-game Major League Soccer season. Total distance covered (metres), average speed (m·min-1), and number of acceleration and deceleration (m·s-2) efforts were used to comprise whole-period profiles. Peak values for speed (m·min-1) were obtained by using a moving-average approach for durations lasting 1, 2, 3, 5, and 10 minutes. Across all positions the 4-2-3-1, 3-4-3, and 4-3-3 formations showed a decrease in average speed between the first and second halves. The 4-3-1-2 yielded greatest whole-period accelerations and decelerations for full backs, and overall distance covered and average speed for strikers. Most peak intensities were observed in the first half of match-play, with attacking midfielders and strikers demonstrating their greatest activity during the first half of a 4-3-1-2 formation. Altering tactical formations results in different physical outputs for all positional groups. Depending on the formation implemented, positional groups resulted in differences, with physical outputs, between halves during match-play

Bioinformatics to Guide Musculoskeletal Modeling: A Retrospective Study from Olympic Water Polo Athletes

GNYACSM Original Research Abstract Bioinformatics to Guide Musculoskeletal Modeling: A Retrospective Study from Olympic Water Polo Athletes DEL VECCHIO TONY, WHITNEY HAYLEY, GABBETT TIM Seshadri Lab; Bioengineering; Lehigh University; Bethlehem, PA Category: Masters Advisor / Mentor: Seshadri, Dhruv [email protected] ABSTRACT There is a pressing need for effective injury prevention methods to mitigate time-loss injuries. This study aims to develop a robust injury risk assessment model for water polo athletes by assessing the interplay between load-response metrics, and leveraging artificial intelligence to forecast wellness based on prior assessments. PURPOSE Water polo athletes present with upper extremity injuries in the hip, knee, and elbow due to the physical demands of the constant treading of water coupled with the overhead throwing motions required to compete. There lacks longitudinal data to ascertain workload injury relationships in water polo. This study addressed this shortcoming by studying load-response relationships on Olympic water polo athletes during training and performance over a two-year period. METHODS Load response variables, such as energy, sleep duration, and acute to chronic workload ratio (ACWR) were studied on thirteen female Australian Olympic water polo athletes from 2019-2021 spanning 17,000 data points. Tests such as Shapiro and ANOVA tests were used to correlate workload and wellbeing profiles to injury risk. The training load and wellbeing metrics were compared for the least and most injured athletes (p \u3c 0.05 deemed statistically significant). Principal component analysis (PCA) clustering was used to identify a linear combination of variables that captures their interrelationships, optimizing data representation through dimensionality reduction, creating optimized variables. RESULTS The most injured athlete tended to exhibit higher average ACWR values (1.15 + 0.4) compared to uninjured counterparts (1.13 + 0.4), (p = 0.874). Injured athletes had wellness metrics that were 10% higher compared to uninjured athletes. The most injured athlete reported slightly higher average energy, (1.14 ± 0.6), when compared with the least injured athlete, (1.14 ± 0.6). The PCA model accounted for 91% of variance in the data. CONCLUSION Self-reported wellbeing metrics alone may not suffice for comprehensive athlete wellness assessment. The integration of wearable technology with subjective assessments would provide both objective and subjective data to augment the predictive power of such models thereby enabling the development of athlete-specific training and rehabilitation protocols

Influence of playing standard and physical fitness on activity profiles and post-match fatigue during intensified junior rugby league competition

BACKGROUND: The aim of this study was to determine whether the fatigue responses to the same intensified rugby league competition differed depending on playing standard and physical fitness. METHODS: Players from a high-standard (n = 15) and a low-standard (n = 16) junior rugby league team had lower body neuromuscular fatigue, perceptual wellbeing, and blood creatine kinase (CK) assessed over an intensified competition. Global positioning system units measured match activity profiles and rating of perceived exertion-assessed internal loads. Players were divided into high- and low-fitness groups across the two standards based on Yo-Yo intermittent recovery test performance. RESULTS: Playing intensity increased with playing standard and fitness levels (high-standard = 92 +/- 6 m.min(-1) vs. 88 +/- 6 m.min(-1); low-standard = 88 +/- 2 m.min(-1) vs. 83 +/- 6 m.min(-1)). Despite greater internal and external loads, high-fitness players showed smaller reductions in lower body power (high-standard effect size [ES] = -0.74; low-standard ES = -0.41). High-standard players had smaller increases in blood CK (77% +/- 94% vs. 113% +/- 81%; ES = -0.41), primarily due to very small increases in the high-fitness group (50% +/- 45%). CONCLUSIONS: Increased fitness leads to greater internal and external workloads during intensified competition, smaller increases in blood CK, and less neuromuscular fatigue. Maximising player fitness should be a primary goal of coaches in order to increase match workloads and reduce post-match fatigue during intensified competition. KEY POINTS: Increased physical fitness results in greater relative and absolute match workloads.Increased physical fitness results in less fatigue and muscle damage during an intensified competition.Coaching staff should aim to maximise physical fitness in order to optimise match performance and reduce player fatigue

Can the workload–injury relationship be moderated by improved strength, speed and repeated-sprint qualities?

Objectives: The aim of this study was to investigate potential moderators (i.e. lower body strength, repeated-sprint ability [RSA] and maximal velocity) of injury risk within a team-sport cohort. Design: Observational cohort study. Methods: Forty male amateur hurling players (age: 26.2 ± 4.4 year, height: 184.2 ± 7.1 cm, mass: 82.6 ± 4.7 kg) were recruited. During a two-year period, workload (session RPE × duration), injury and physical qualities were assessed. Specific physical qualities assessed were a three-repetition maximum Trapbar deadlift, 6 × 35-m repeated-sprint (RSA) and 5-, 10- and 20-m sprint time. All derived workload and physical quality measures were modelled against injury data using regression analysis. Odds ratios (OR) were reported against a reference group. Results: Moderate weekly loads between ≥1400 AU and ≤1900 AU were protective against injury during both the pre-season (OR: 0.44, 95% CI: 0.18–0.66) and in-season periods (OR: 0.59, 95% CI: 0.37–0.82) compared to a low load reference group (≤1200 AU). When strength was considered as a moderator of injury risk, stronger athletes were better able to tolerate the given workload at a reduced risk. Stronger athletes were also better able to tolerate larger week-to-week changes (&gt;550–1000 AU) in workload than weaker athletes (OR = 2.54–4.52). Athletes who were slower over 5-m (OR: 3.11, 95% CI: 2.33–3.87), 10-m (OR: 3.45, 95% CI: 2.11–4.13) and 20-m (OR: 3.12, 95% CI: 2.11–4.13) were at increased risk of injury compared to faster athletes. When repeated-sprint total time (RSAt) was considered as a moderator of injury risk at a given workload (≥1750 AU), athletes with better RSAt were at reduced risk compared to those with poor RSAt (OR: 5.55, 95%: 3.98–7.94). Conclusions: These findings demonstrate that well-developed lower-body strength, RSA and speed are associated with better tolerance to higher workloads and reduced risk of injury in team-sport athletes. © 2018 Sports Medicine Australi

Sports Science Roundtable: Does Sports Science Research Influence Practice?

As sports scientists, we claim to make a signifi cant contribution to the body of knowledge that infl uences athletic practice and performance. Is this the reality? At the inaugural congress of the Australian Association for Exercise and Sports Science, a panel of well-credentialed academic experts with experience in the applied environment debated the question, Does sports-science research influence practice? The fi rst task was to defi ne “sports-science research,” and it was generally agreed that it is concerned with providing evidence that improves sports performance. When practices are equally effective, sports scientists also have a role in identifying practices that are safer, more time effi cient, and more enjoyable. There were varying views on the need for sports-science research to be immediately relevant to coaches or athletes. Most agreed on the importance of communicating the results of sports-science research, not only to the academic community but also to coaches and athletes, and the need to encourage both short- and long-term research. The panelists then listed examples of sports-science research that they believe have infl uenced practice, as well as strategies to ensure that sports-science research better infl uences practice

The effect of ball carrying on the sprinting speed of international rugby union players

Speed is considered to be a highly valuable ability in rugby union. One unique aspect of rugby is that players need to be effective at sprinting while carrying a rugby ball. Previous research reported that amateur club players were slower while sprinting with the ball, than without. The purpose of the current research was to examine how sprinting while carrying a ball affected the sprinting speed of international rugby players. Twenty-six international players performed 6 x 40 m sprints under three conditions: Ball One Hand (B1H), Ball Two Hands (B2H) and No Ball (NB). Timing gates were placed at the 0 m, 10 m, 30 m and the 40m mark of the sprint. The 0-10m was used to examine initial acceleration; 30-40 m was used to examine maximal velocity and the 10-30 m section to analyze the acceleration up to maximal velocity. Comparisons were also made between backs and forwards. Backs were found to be faster than forwards at each of the splits for the NB, B1H and B2H conditions (0.04 - 0.08 s,

Effect of different repeated-high-intensity-effort bouts on subsequent running, skill performance, and neuromuscular function

Purpose: To assess the impact of different repeated-high-intensity-effort (RHIE) bouts on player activity profiles, skill involvements, and neuromuscular fatigue during small-sided games. Participants: 22 semiprofessional rugby league players (age 24.0 ± 1.8 y, body mass 95.6 ± 7.4 kg). Methods: During 4 testing sessions, they performed RHIE bouts that each differed in the combination of contact and running efforts, followed by a 5-min off-side small-sided game before performing a second bout of RHIE activity and another 5-min small-sided game. Global positioning system microtechnology and video recordings provided information on activity profiles and skill involvements. A countermovement jump and a plyometric push-up assessed changes in lower- And upper-body neuromuscular function after each session. Results: After running-dominant RHIE bouts, players maintained running intensities during both games. In the contact-dominant RHIE bouts, reductions in moderate-speed activity were observed from game 1 to game 2 (ES = -0.71 to -1.06). There was also moderately lower disposal efficiency across both games after contact-dominant RHIE activity compared with running-dominant activity (ES = 0.62-1.02). Greater reductions in lower-body fatigue occurred as RHIE bouts became more running dominant (ES = -0.01 to -1.36), whereas upper-body fatigue increased as RHIE bouts became more contact dominant (ES = -0.07 to -1.55). Conclusions: Physical contact causes reductions in running intensity and the quality of skill involvements during game-based activities. In addition, the neuromuscular fatigue experienced by players is specific to the activities performed