Where the Trees Stood in Water

oai:currents.journals.yorku.ca:article/37295Where the Trees Stood in Water is a series of Cyanotype prints tracing the historic and contemporary transformations of Toronto’s Entertainment District. Each print is accompanied by an archival document which forms a narrative connecting geography to stories of colonization, industrialization and the transient bodies of those affected by the remaking of Toronto’s landscape. Juxtaposing text and image, Where the Trees… pushes against the archival documentation of Toronto’s past and challenges the stories told about colonialism, labour and migration. With playful reproductions, Bambitchell invites hidden, obscured, lost, and silenced narratives of colonial history to surface and tell new stories about the geography of Toronto’s core

Humans Optimize Ground Contact Time and Leg Stiffness to Minimize the Metabolic Cost of Running

Trained endurance runners appear to fine-tune running mechanics to minimize metabolic cost. Referred to as self-optimization, the support for this concept has primarily been collated from only a few gait (e.g., stride frequency, length) and physiological (e.g., oxygen consumption, heart rate) characteristics. To extend our understanding, the aim of this study was to examine the effect of manipulating ground contact time on the metabolic cost of running in trained endurance runners. Additionally, the relationships between metabolic cost, and leg stiffness and perceived effort were examined. Ten participants completed 5 × 6-min treadmill running conditions. Self-selected ground contact time and step frequency were determined during habitual running, which was followed by ground contact times being increased or decreased in four subsequent conditions whilst maintaining step frequency (2.67 ± 0.15 Hz). The same self-selected running velocity was used across all conditions for each participant (12.7 ± 1.6 km · h−1). Oxygen consumption was used to compute the metabolic cost of running and ratings of perceived exertion (RPE) were recorded for each run. Ground contact time and step frequency were used to estimate leg stiffness. Identifiable minimums and a curvilinear relationship between ground contact time and metabolic cost was found for all runners (r2 = 0.84). A similar relationship was observed between leg stiffness and metabolic cost (r2 = 0.83). Most (90%) runners self-selected a ground contact time and leg stiffness that produced metabolic costs within 5% of their mathematical optimal. The majority (n = 6) of self-selected ground contact times were shorter than mathematical optimals, whilst the majority (n = 7) of self-selected leg stiffness' were higher than mathematical optimals. Metabolic cost and RPE were moderately associated (rs = 0.358 p = 0.011), but controlling for condition (habitual/manipulated) weakened this relationship (rs = 0.302, p = 0.035). Both ground contact time and leg stiffness appear to be self-optimized characteristics, as trained runners were operating at or close to their mathematical optimal. The majority of runners favored a self-selected gait that may rely on elastic energy storage and release due to shorter ground contact times and higher leg stiffness's than optimal. Using RPE as a surrogate measure of metabolic cost during manipulated running gait is not recommended

Recurrent and subsequent injuries in professional and elite sport: a systematic review

This is the final version. Available on open access from Springer via the DOI in this record Availability of Data and Materials: Not applicable.Background: Injury surveillance in professional sport categorises injuries as either “new” or “recurrent”. In an attempt to make categorisation more specific, subsequent injury categorisation models have been developed, but it is not known how often these models are used. The aim was to assess how recurrent and subsequent injuries are reported within professional and elite sport. Methods: Online databases were searched using a search strategy. Studies needed to prospectively report injury rates within professional or elite sports that have published consensus statements for injury surveillance. Results: A total of 1322 titles and abstract were identified and screened. One hundred and ninety-nine studies were screened at full text resulting in 81 eligible studies. Thirty studies did not report recurrent injuries and were excluded from data extraction. Within the studies that reported recurrent injuries, 21 reported the number and percentage; 13 reported only the proportion within all injuries; three reported only the number; five reported the number, percentage and incidence; and two only reported the incidence. Seven studies used subsequent injury terminology, with three reporting subsequent injury following concussion, one using an amended subsequent injury model and three using specific subsequent injury categorisation models. The majority of subsequent injuries (ranging from 51 to 80%) were categorised as different and unrelated to the index injury. The proportion of recurrent injuries (exact same body area and nature related to index injury) ranged from 5 to 21%. Conclusions: Reporting recurrent or subsequent injuries remains inconsistent, and few studies have utilised subsequent injury models. There is limited understanding of subsequent injury risk, which may affect the development of injury prevention strategies. Trial Registration: CRD42019119264Knowledge Economy Skills Scholarships (KESS 2)Welsh Government’s European Social Fund (ESF) convergence programme for West Wales and the Valley

An interdisciplinary examination of stress and injury occurrence in athletes

This paper adopts a novel, interdisciplinary approach to explore the relationship between psychosocial factors, physiological stress-related markers and occurrence of injury in athletes using a repeated measures design across a 2-year data collection period. At three data collection time-points, athletes completed measures of major life events, the reinforcement sensitivity theory personality questionnaire, muscle stiffness, heart rate variability and postural stability, and reported any injuries they had sustained since the last data collection. Two Bayesian networks were used to examine the relationships between variables and model the changes between data collection points in the study. Findings revealed muscle stiffness to have the strongest relationship with injury occurrence, with high levels of stiffness increasing the probability of sustaining an injury. Negative life events did not increase the probability of injury occurrence at any single time-point; however, when examining changes between time points, increases in negative life events did increase the probability of injury. In addition, the combination of increases in negative life events and muscle stiffness resulted in the greatest probability of sustaining an injury. Findings demonstrated the importance of both an interdisciplinary approach and a repeated measures design to furthering our understanding of the relationship between stress-related markers and injury occurrence

Concussion increases within-player injury risk in male professional rugby union

Objectives: To assess within-player change in injury risk and between-player subsequent injury risk associated with concussive and common non-concussive injuries in professional rugby union. Methods: This prospective cohort study in Welsh professional male rugby union analysed within-player and between-player injury risk for five common injuries: concussion, thigh haematoma, hamstring muscle strain, lateral ankle sprain and acromioclavicular joint sprain. Survival models quantified within-player injury risk by comparing precommon (before) injury risk to postcommon (after) injury risk, whereas between-player subsequent injury risk was quantified by comparing players who had sustained one of the common injuries against those who had not sustained the common injury. HRs and 95% CIs were calculated. Specific body area and tissue type were also determined for new injuries. Results: Concussion increased the within-player overall injury risk (HR 1.26 (95% CI 1.11 to 1.42)), elevating head/neck (HR 1.47 (95% CI 1.18 to 1.83)), pelvic region (HR 2.32 (95% CI 1.18 to 4.54)) and neurological (HR 1.38 (95% CI 1.08 to 1.76)) injury risk. Lateral ankle sprains decreased within-player injury risk (HR 0.77 (95% CI 0.62 to 0.97)), reducing head/neck (HR 0.60 (95% CI 0.39 to 0.91)), upper leg and knee (HR 0.56 (95% CI 0.39 to 0.81)), joint and ligament (HR 0.72 (95% CI 0.52 to 0.99)) and neurological (HR 0.55 (95% CI 0.34 to 0.91)) injury risk. Concussion (HR 1.24 (95% CI 1.10 to 1.40)), thigh haematomas (HR 1.18 (95% CI 1.04 to 1.34)) and hamstring muscle strains (HR 1.14 (95% CI 1.01 to 1.29)) increased between-player subsequent injury risk. Conclusion: Elevated within-player injury risk was only evident following concussive injuries, while lateral ankle sprains reduced the risk. Both concussion and ankle injuries altered head/neck and neurological injury risk, but in opposing directions. Understanding why management of ankle sprains might be effective, while current concussion management is not at reducing such risks may help inform concussion return to play protocols

Injury in starting and replacement players from five professional men’s rugby unions

Objectives: The aim of this study was to compare the incidence, severity, and burden of injury in starting and replacement players from professional men’s teams of five rugby unions. Methods: Match injuries of greater than 24 h time-loss (including data on the severity, match quarter, event, body region) and player minutes of match exposure data were collated for all starting and replacement players in the men’s English Premiership, Welsh Pro14 (both 2016/17–2018/19 seasons), and Australian, New Zealand, and South African Super Rugby (all 2016–2018 seasons) teams. Injury incidences and mean injury burden (incidence × days missed) were calculated, and rate ratios (RRs) (95% confidence intervals [CIs]) were used to compare injury incidence and burden between starting (reference group) and replacement players. Results: Overall injury incidence was not different between starters and replacements for all injuries (RR = 0.98, 95% CI 0.88–1.10), nor for concussions (RR = 0.85; 95% CI 0.66–1.11). Mean injury burden was higher for replacement players (RR = 1.31, 95% CI 1.17–1.46). Replacement injury incidence was lower than the starters in the third (RR = 0.68, 95% CI 0.51–0.92) and fourth (RR = 0.78, 95% CI 0.67–0.92) match quarters. Injury incidence was not different between starters and replacements for any match event or body region, but compared with starters, replacements’ injury burden was higher in lower limbs (RR = 1.24, 95% CI 1.05–1.46) and in the tackled player (RR = 1.30, 95% CI 1.01–1.66). Conclusion: This study demonstrated a lower injury incidence in replacement players compared with starters in the second half of matches, with a higher injury burden for replacement players due to higher mean injury severity

Injury in starting and replacement players from five professional men’s rugby unions

OBJECTIVES : The aim of this study was to compare the incidence, severity, and burden of injury in starting and replacement players from professional men’s teams of five rugby unions. METHODS : Match injuries of greater than 24 h time-loss (including data on the severity, match quarter, event, body region) and player minutes of match exposure data were collated for all starting and replacement players in the men’s English Premiership, Welsh Pro14 (both 2016/17–2018/19 seasons), and Australian, New Zealand, and South African Super Rugby (all 2016–2018 seasons) teams. Injury incidences and mean injury burden (incidence × days missed) were calculated, and rate ratios (RRs) (95% confidence intervals [CIs]) were used to compare injury incidence and burden between starting (reference group) and replacement players. RESULTS : Overall injury incidence was not different between starters and replacements for all injuries (RR = 0.98, 95% CI 0.88–1.10), nor for concussions (RR = 0.85; 95% CI 0.66–1.11). Mean injury burden was higher for replacement players (RR = 1.31, 95% CI 1.17–1.46). Replacement injury incidence was lower than the starters in the third (RR = 0.68, 95% CI 0.51–0.92) and fourth (RR = 0.78, 95% CI 0.67–0.92) match quarters. Injury incidence was not different between starters and replacements for any match event or body region, but compared with starters, replacements’ injury burden was higher in lower limbs (RR = 1.24, 95% CI 1.05–1.46) and in the tackled player (RR = 1.30, 95% CI 1.01–1.66). CONCLUSION : This study demonstrated a lower injury incidence in replacement players compared with starters in the second half of matches, with a higher injury burden for replacement players due to higher mean injury severity.World Rugby.https://link.springer.com/journal/40279hj2024Sports MedicineSDG-03:Good heatlh and well-bein

Injury epidemiology in male professional Rugby Union: player-specific injury analysis and its application to starter and replacement players

This thesis investigated the epidemiology of injuries in professional Rugby Union and the methods in which they are analysed and reported. Furthermore, the thesis explored the development and application of a player-specific method of analysing injuries. Chapter 3 investigated match injuries within the Welsh regional professional Rugby Union teams, demonstrating a higher incidence than previously reported in professional Rugby Union (99.1 injuries/1000 match hours). In addition, the highest proportion of injuries in matches were sustained during the tackle event (50-63%). Whilst this study followed the recommendations of the consensus statement, Chapter 4 aimed to identify whether research in elite or professional sports with published consensus statements also follow their respective recommendations. Chapter 4 demonstrated that there remain inconsistencies with regards to reporting injuries, identifying that the pooling of injury data across individuals remains a common issue within research. As this method is recommended by the consensus statement on data collection and analysis procedures within Rugby Union, Chapter 5 explored a player-specific approach to analysing and reporting injuries. The consensus statement method of calculating team-level exposure, using the standard number of players in a team and standard match length, was compared against the use of global positioning systems (GPS) to identify if the consensus statement provides an adequate method of analysing injury incidence. Interestingly, there were differences between the injury incidence calculated using standard match length and the injury incidence using GPS-derived exposure hours (59.5 vs 95.7 injuries/1000 match hours, respectively). While the team-level injury incidence was influenced by the number of players providing consent, the study demonstrated that team-level injury incidence does not reflect the variation in injury rates at a player-specific level, with 94% of players falling outside of the 95% confidence intervals for the team-level injury incidence. In addition, an alternative to injury incidence statistic was explored through analysing the probability of injury. This identified that when players at the same incidence are exposed to higher match hours, they have a higher probability of incurring multiple injuries. The player-specific methods of analysis from this Chapter were applied in Chapter 6, where the injury rates and mechanisms of starter and replacement players were analysed. Chapter 6 identified that starters had a higher injury incidence than replacement players (80.8 vs 57.2 injuries/1000 match hours, respectively). When accounting for the number of replacements used in a match, the injury rate per player exposure did not change for each number of replacements used. However, the number of replacement players had a significant effect on the number of match injuries, where injuries increased by 12% per replacement used (p = 0.037). This increase may, in part, be due to a small number of matches using less than seven replacements (20%). Therefore, further analysis accounting for the replacement time-in-game was also implemented, showing a non-significant 1% increase in injury for every 10 minutes of replacement player time-in-game (p = 0.099). Chapter 6 also identified that the tackle event was the mechanism responsible for the highest proportion of injuries for both starter and replacement players. The propensity for injury was similar for tackles involving two starters or two replacements, with a higher injury propensity only shown when an injured starter was tackling a replacement ball carrier. Starter and replacement players exhibited different characteristics during an injury inciting tackle, specifically when the injured player was making a tackle. Replacement players maintained a lower body position, predominantly using a shoulder tackle and contacting the upper leg of the ball carrier. In contrast, starters demonstrated a higher body position, contacting the ball carriers head whilst in an upright position. This thesis demonstrated that whilst consensus statements are important for the consistent definition and data collection associated with injury surveillance, there remains inaccuracies and inconsistencies with the way data is analysed and reported. The lack of research reporting the subsequent injuries fails to consider the potential for multiple injury occurrence at a player specific level. Furthermore, the continued pooling of data across individuals within a team (team-level injury incidence) fails to account for the variation in injury rates at a player-specific level. This is emphasised further when player-specific analysis is applied to starter and replacement players. The application of a player-specific analysis demonstrated that current regulations associated with the use of replacement players within matches is appropriate. Importantly, however, the analysis of tackle characteristics at a player-specific level demonstrated differences in injury inciting tackle characteristics between players. Where possible, methods such as GPS-derived exposure and probability analysis should be incorporated within injury surveillance to provide a more comprehensive player-specific analysis of injury that can aid in injury management and improve player welfare. In addition, injury risk mitigation strategies associated with the tackle should incorporate a player-specific approach, specifically considering the type of player (i.e. starter or replacement player) used within matches</div