The Role of Sleep in Injuries and Performance Among Elite Female Ice Hockey Players

The Role of Sleep in Injuries and Performance Among Elite Female Ice Hockey Players | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article The Role of Sleep in Injuries and Performance Among Elite Female Ice Hockey Players Amanda Lahti, Emelie Stenman, Anton Grundberg, Kristina Sundquist This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8917450/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 12 You are reading this latest preprint version Abstract Background: Sleep may play a vital role in recovery, performance, and injury prevention among elite athletes. Aim: To examine sleep patterns, recovery, and their associations with injuries and team performance among Swedish elite female ice hockey players. Methods: All 224 players registered in The Swedish Women’s Hockey League (SDHL) were invited to this research project during the 2023/2024 season, and 158 (71%) completed a questionnaire on sleep and recovery. All injuries that lead to absence from training or games were prospectively recorded by team medical staff. Data were analyzed descriptively and with chi-square (χ²) tests. Results: Thirty-two players (20.8%) reported insufficient sleep, and 19 (12.3%) rated their sleep quality as poor. Ten (6.5%) had used sleep medication during the past month, 13 (8.4%) slept less than seven hours per night, and 43 (27.9%) lacked sufficient rest and relaxation. No significant associations were found between sleep variables and injury incidence. However, players from top and bottom-ranked teams reported significantly lower sleep medication use than those from mid-ranked teams (p = 0.003). Top-ranked teams also had the highest proportion achieving at least seven hours of sleep per night (100%, p < 0.001). Inadequate sleep was primarily attributed to early or late training sessions, post-game stress, and dual work commitments. Conclusion: Sleep variables were not associated with injury incidence but were associated with team performance. Optimizing training schedules and reducing dual-career demands may enhance sleep and support performance in elite female ice hockey players. Trial registration: ClinicalTrials.gov (ID: NCT06351618). Key findings One fifth of female elite ice hockey players do not think they get enough sleep, one tenth describes poor sleep quality and almost one third that they, besides sleep, do not get enough time to relax and recover. Sleep quality and duration were not significantly associated with injury incidence but with performance. Top and bottom-ranked teams had significantly higher proportion of players achieving a minimum of 7 hours of sleep per night, and less frequently used sleep medication than mid-ranked teams who had the poorest sleep outcomes. Early or late training sessions, post-game stress, and dual employment were the main barriers to adequate sleep, suggesting that optimizing schedules and reducing external pressures may improve both recovery and performance. Background It is well established that sleep has a direct impact on sports performance, including its influence on accuracy (1) cardiorespiratory function (2, 3) and psychomotor skills (4). Recently, there has been increasing recognition that poor sleep may be linked to a higher risk of sports-related injuries (5). Sports injuries can have an immediate negative impact on the physical and mental health of athletes (6). Long-term consequences include compromised team success, reduced activity levels, future impairments in quality of life, and increased risk of early-onset osteoarthritis. The International Olympic Committee (IOC) defines adequate sleep as at least seven hours per night for adults, proper circadian alignment, good perceived sleep quality, and the absence of sleep disorders like insomnia or sleep apnea (3). A systematic review and meta-analysis reported that adolescent athletes with chronic sleep deprivation were 1.6 times more likely to experience sports-related musculoskeletal injuries (4). However, another study did not find poor sleep to be an independent risk factor (5). Ice hockey players may be particularly prone to sleep disturbances compared to other disciplines due to demanding match schedules, frequent travel, unfamiliar sleeping environments, and late evening games with high physiological and cognitive arousal due to the high intensity of the sport. As an indoor sport, ice hockey also limits players’ exposure to natural daylight, which is essential for melatonin regulation and the maintenance of a healthy circadian rhythm. Swedish ice hockey players may face added challenges as daylight can be limited to one to three hours in most northern regions during parts of the competitive season from September to April. Female players may be extra vulnerable to sleeping disorders as they often face lower income and combine work or studies alongside their sport, and therefore more frequently also face early morning trainings (7). Despite the need for more knowledge on this important topic, few studies have examined sleep and recovery in ice hockey players, and existing reports are limited to small samples of men (8, 9, 10). The Swedish Women’s Hockey League (SDHL) represents a unique setting for this research, as it was the first elite women’s league to introduce body checking in 2022, thereby increasing the physical demands and game intensity. Since then, other leagues, including the North American Professional Women’s Hockey League (PWHL), have also implemented body checking. However, the SDHL was the first to adopt this rule change and therefore has the longest experience of full body contact in elite women’s ice hockey, providing a particularly relevant context for examining sleep, recovery, and injury risk under more physically demanding conditions. This study aims to examine: 1) the sleeping habits of Swedish female ice hockey players, including sleep quality, duration, use of sleeping pills, recovery beyond sleep, and the players' perceptions of factors contributing to insufficient sleep and recovery; and 2) the relationship between sleeping habits, recovery and injuries as well as with performance, where performance will be assessed by team standings in the league table. Method This study utilize baseline data from the Women’s Ice Hockey Injury Study , a research project with the overall aim to examine injuries in The Swedish Women’s Hockey League (SDHL), which is the only women’s league worldwide that permits body checking. The league consists of ten teams with approximately 20–25 players each. An email invitation was distributed to all 224 players registered in the SDHL for the 2023/2024 season, with contact details obtained through team managers. Eligible participants were aged 16 years or older. In total, 158 players (71%) consented to participate, including 21 (13%) under 18 years of age (range 16–37 years). The cohort represented all ten teams and playing positions. A previous dropout analysis found no differences in age or height between participants and non-participants (11). The study was designed in collaboration with representatives from the SDHL and the Swedish Ice Hockey Federation, who assisted with recruitment but had no access to or involvement in data analysis. Players received research information and a survey link via email, detailing the study, procedures, risks, benefits, and ethical considerations. Directly after confirming participation in the study, the participant was guided to an electronic online survey provided in both Swedish and English. The survey consisted of a variety of health-related questions including demographics, socioeconomics, player experience, medical history, previous injuries and questions regarding sleep and recovery. Sleep and recovery were assessed through the following self-reported survey items: Do you think you get enough sleep? 1) Yes, definitely 2) Yes, most of the time 3) No, somewhat insufficient 4) No, definitely insufficient If you are not getting enough sleep, what do you think is the reason? (open-ended) The free text answers were categorized into four themes based on characteristics of the responses (Table 3): Training times, stress after games, and combination with work Stress and mental load Lack of time /busy daily life Work and financial strain Academic or performance-related stress Personal or lifestyle factors How would you describe the average quality of your sleep? 1) Very good 2) Quite good 3) Quite poor 4) Very poor During the last month, how often have you used sleeping medication? 1) Three times per week or more 2) One to two times per week 3) Less than once per week 4) Never How many hours do you usually sleep during a normal night? (numeric response) Sleep variables were collected once at baseline (September–October 2023) and reflect habitual sleep patterns during the competitive season rather than day-to-day variations. No objective measures (e.g., actigraphy or wearable devices) were used. The selected sleep items reflect core domains recommended in consensus statements on sleep assessment in athletes, including sleep duration, perceived sleep quality and use of sleep medication (12). The items cover key domains commonly included in athlete sleep screening tools (12). The questionnaire used in your study was developed for this study or has previously been published elsewhere. The sleep questions used in the present study is presented in detail in Appendix 1. Recovery beyond sleep was assessed using a self-reported question regarding perceived adequacy of relaxation time: Besides sleep, do you think you get enough time to rest and relax? 1) Yes, definitely 2) Yes, most of the time 3) No, somewhat inadequate 4) No, definitely inadequate 5) No, far from adequate Throughout the 2023/2024 season, a designated medical professional team (physician or physiotherapist) at each club reported injuries resulting in time-loss from training or competition to a central electronic register using a standardized injury card. Only time-loss injuries, defined as those causing absence from training or games (13), were included in the analysis. Dental injuries and illness were not included as cause of absence. Although reporting was mandatory for all SDHL teams, only data from players who had consented to participate were analyzed. Participation was voluntary, with the option to withdraw at any time. The study was approved by the Swedish Ethical Review Authority (Dnr: 2023-06114-01), adhered to the Declaration of Helsinki, and was registered at ClinicalTrials.gov (ID: NCT06351618). Statistical analysis Statistical analyses were performed using R version 4.4.2 (R Core Team, 2024). Descriptive statistics used to summarize player characteristics and sleep-related variables are presented as means and standard deviations (SD) or medians and inter-quartile ranges (IQR) for continuous variables, while categorical variables are presented as frequencies and percentages (%). The sleep-related variables are dichotomized, and the final league standings are grouped into top (1–3), mid (4–6), and bottom-ranked teams (7–10) to avoid identifying individual participants. Group comparisons of categorical variables were performed using chi-square (χ²) tests or Fisher’s exact tests, and of continuous variables using Welch’s t-tests or Mann-Whitney U-tests comparing injuries and ANOVA or Kruskal-Wallis tests comparing team standings. Associations were considered statistically significant at a p-value < 0.05. Results A total of 158 SDHL players participated in the study, representing all ten teams in the league. Sixty-three players (41%) sustained a time-loss injury during the 2023/2024 season. The median age in all players was 23.2 years (IQR 6.2). No significant differences were observed between injured and non-injured players regarding age, height, weight, BMI (Table 1), or for any of the sleep and recovery variables. When grouped by team performance based on final league standings during the season 2023/2024, all players in the top 3 teams reported sleeping at least seven hours per night, compared with 81% in mid-ranked and 92% in bottom-ranked teams (p < 0.001) (Table 2). Sleep medication use once per week or more was reported by 1.9% of players in top 3 teams, 17.0% in mid-ranked, and 2.0% in bottom-ranked teams (p = 0.003). 83% of players in the top 3 teams reported sufficient rest compared to 68% and 63% among players in the mid- and bottom-ranked teams respectively; however, this difference was not statistically significant (p = 0.05). While players from mid-ranked teams (positions 4–6) reported the poorest sleep characteristics overall, players in the bottom-ranked teams (7–10) did not differ substantially from the top teams in terms of sleep duration or quality, despite their lower league performance. Free text responses about reasons for not getting enough sleep among players reporting insufficient sleep (n=32) are presented in Table 3. The most common reasons were training times, stress after games, and combining ice hockey with work (n=11). Representative quotations are provided to illustrate each theme. Table 1. Characteristics stratified by injury of elite ice hockey players in SDHL, season 2023/2024. Characteristic Total, n=154 Injured, n=63 Not injuried, n=91 p-value Age, median (IQR) 23.2 (6.2) 23.8 (6.2) 22.9 (6.3) 0.31 Body weight (kg), mean (SD) 68.4 (6.8) 69.6 (6.1) 67.6 (7.1) 0.07 Body height (cm), mean (SD) 169.1 (5.5) 170.0 (5.1) 168.5 (5.8) 0.08 BMI (kg/m2), mean (SD) 23.9 (1.9) 24.0 (1.5) 23.8 (2.1) 0.41 Do you think you get enough sleep? n (%) 0.61 Yes 120 (77.9) 51 (81.0) 69 (75.8) No 32 (20.8) 12 (19.0) 20 (22.0) Missing 2 (1.3) 0 (0.0) 2 (2.2) How would you describe the average quality of your sleep? n (%) 0.66 Good 133 (86.4) 56 (88.9) 77 (84.6) Poor 19 (12.3) 7 (11.1) 12 (13.2) Missing 2 (1.3) 0 (0.0) 2 (2.2) During the last month, how often have you used sleeping medication? n (%) 0.52 Once per week or more 10 (6.5) 3 (4.8) 7 (7.7) Less than once per week 142 (92.2) 60 (95.2) 82 (90.1) Missing 2 (1.3) 0 (0.0) 2 (2.2) How many hours do you usually sleep during a normal night? n (%) 0.82 ≥ 7 hours 139 (90.3) 58 (92.1) 81 (89.0) < 7 hours 13 (8.4) 5 (7.9) 8 (8.8) Missing 2 (1.3) 0 (0.0) 2 (2.2) Besides sleep, do you think you get enough time to rest and relax? n (%) 0.43 Yes 109 (70.8) 43 (68.3) 66 (72.5) No 43 (27.9) 20 (31.7) 23 (25.3) Missing 2 (1.3) 0 (0.0) 2 (2.2) Table 2. Sleep and recovery characteristics of SDHL players stratified by team performance according to final league standings during the 2023/2024 season Characteristic Team standing 1 – 3 Team standing 4 – 6 Team standing 7 – 10 p-value Age, median (IQR) 23.1 (7.0) 23.4 (5.9) 22.9 (5.9) 0.74 Body weight (kg), mean (SD) 68.3 (5.8) 67.0 (6.7) 69.8 (7.6) 0.11 Body height (cm), mean (SD) 169.0 (4.6) 169.3 (5.8) 169.1 (6.3) 0.96 BMI (kg/m2), mean (SD) 23.9 (1.7) 23.4 (2.2) 24.4 (1.7) 0.034 Do you think you get enough sleep? n (%) 0.08 Yes 46 (85.2) 32 (68.1) 42 (82.4) No 8 (14.8) 15 (31.9) 9 (17.6) How would you describe the average quality of your sleep? n (%) 0.09 Good 50 (92.6) 37 (78.7) 46 (90.2) Poor 4 (7.4) 10 (21.3) 5 (9.8) During the last month, how often have you used sleeping medication?, n (%) 0.003 Once per week or more 1 (1.9) 8 (17.0) 1 (2.0) Less than once per week 53 (98.1) 39 (83.0) 50 (98.0) How many hours do you usually sleep during a normal night? n (%) <0.001 ≥ 7 hours 54 (100.0) 38 (80.9) 47 (92.2) < 7 hours 0 (0.0) 9 (19.1) 4 (7.8) Besides sleep, do you think you get enough time to rest and relax? n (%) 0.05 Yes 45 (83.3) 32 (68.1) 32 (62.7) No 9 (16.7) 15 (31.9) 19 (37.3) Statistically significant values are bolded (p<0.05). Table 3 . Reported reasons from 32 female elite ice hockey players for insufficient sleep among SDHL players (qualitative analysis) Theme / Cause n Citations Training times, stress after games, and combination with work 11 “Late trainings and trainings have made it difficult to fall asleep at night.” “Can’t sleep at night after training/game and get up early for work.” “No time to unwind after training and have to get up early to work and earn money.” Stress and mental load 9 “A lot of stress.” Lack of time / busy daily life 4 “A lot going on in everyday life.” Work and financial strain 1 “Working two jobs and coming home late because I can’t afford a car.” Academic or performance-related stress 3 “Late nights due to difficulty sleeping, stress about performance in school, hockey, etc.” Personal or lifestyle factors 4 “I’m going late to bed.” Discussion In this study, sleep patterns among elite female ice hockey players were associated with team performance but not with injury incidence. About one fifth of the players reported insufficient sleep, one tenth poor sleep quality, and nearly one third insufficient time for relaxation and recovery beyond sleep. Players from top- and bottom-ranked teams reported lower use of sleep medication and a higher proportion achieving at least seven hours of sleep per night compared to mid-ranked teams. Early or late training sessions, post-game stress, and dual work or study commitments emerged as key barriers to sufficient sleep, underscoring the importance of structural and psychosocial factors in supporting recovery and performance. Previous studies have demonstrated that both chronic sleep restriction and acute sleep deprivation (e.g., ≤ 5 hours the night before competition) may increase injury risk through impaired neuromuscular control and reaction time ( 14 ). As our study assessed habitual sleep patterns rather than night-to-night variation, we cannot exclude a potential acute effect of short-term sleep loss preceding injury events. Athletes are known to use pharmacological aids to manage sleep problems related to competition, travel, and psychological arousal ( 15 ), and this may also apply to elite female ice hockey players. However, according to data from the Swedish National Board of Health and Welfare ( 16 ), approximately 5.9% among females aged 20–24 years in the general population use prescribed sleep medication in 2024, which is comparable to the 6.5% observed in the present study. One plausible explanation is that the players’ overall health, structured lifestyles, and high physical fitness may, despite their early schedules, travel, and competitive demands, contribute to good sleep quality, which may help to maintain sleep medication usage comparable to those of the general population. However, our data do not clarify why sleep medication use differed between team standings. One possibility is that players in mid-ranked teams experience greater dissatisfaction, being neither at the top nor bottom, which may increase anxiety and disturbed sleep ( 17 ). Another explanation is that while adequate sleep and recovery support performance among top-ranked teams, other factors such as physical fitness, talent, and organizational resources may play a stronger role among lower-ranked teams. In other words, one cannot simply “rest into” top performance. Moreover, top-ranked teams may benefit from more professionalized conditions, less external stress, fewer secondary commitments, and better resources, which could further support better recovery and sleep than mid and bottom-ranked teams. Mid-ranked teams may experience greater competitive uncertainty, fluctuating playoff prospects, and performance-related stress, potentially contributing to sleep disturbances. In contrast, top teams may benefit from greater organizational stability and resources, while bottom teams may face reduced competitive pressure late in the season. In the present study, no significant associations were observed between sleep variables and injury incidence. Recently, there has been increasing recognition that poor sleep may be linked to a higher risk of sports-related injuries ( 14 ), although some studies have failed to demonstrate such associations ( 5 , 18 ). Sports injuries may have multifactorial causes, and sleep likely interacts with factors such as training load ( 8 ), hormonal cycles ( 19 ), psychological stress and illness ( 6 ), as well as immune function ( 20 ), rather than serving as an independent risk factor. Although the current study did not identify an association between sleep and injury, such an effect cannot be completely ruled out and should be further investigated in future research. The qualitative findings indicate that sleep insufficiency among SDHL players is closely linked to structural and psychosocial factors such as training schedules, post-game stress, and dual career demands. These demands often force female players to train at unfavorable hours, unlike male professionals who benefit from financial support. Achieving more equitable conditions and reducing reliance on secondary employment may be crucial for optimizing sleep, recovery and performance in female players and thereby to the continued development of women’s ice hockey. Strengths of this study include the large and representative cohort, the inclusion of all SDHL teams, and the use of a standardized injury reporting system. Another strength is the comprehensive assessment of multiple sleep-related variables, providing a rare and detailed overview of sleep patterns among female ice hockey players. These data contribute valuable insight into an understudied population and may also be generalizable to other female team sport athletes facing similar structural and psychosocial challenges. Limitations include the absence of potential confounding factors such as mental health and prior injuries, which complicate causal interpretation. Additionally, self-reported sleep data may introduce bias, and the time-loss injury definition could underestimate overuse injuries, illnesses, or conditions not resulting in absence from play. In addition, the low prevalence of short sleep (< 7h) limits statistical power to detect associations with injury. This may partly explain the null findings. Taken together with the relatively limited number of injury events, multivariable regression analyses adjusting for potential confounders were not performed, as such models would have risked statistical instability and overfitting. According to the commonly applied rule of at least 10 outcome events per predictor variable in logistic regression models, the available sample size limited the number of variables that could be reliably included. Future studies with larger cohorts and more injury events are warranted to enable adjusted analyses. Another limitation is that sleep variables were assessed through self-report at a single time point, reflecting habitual sleep patterns rather than day-to-day variation. Objective monitoring of sleep across the entire season (e.g., actigraphy or wearable technology) would have strengthened the design and enabled examination of temporal relationships between acute sleep disturbances and subsequent injury events. The present approach limits our ability to establish whether poor sleep preceded injury, and therefore causal inferences regarding time-sequenced associations should be interpreted with caution. Future longitudinal studies incorporating continuous objective sleep monitoring are warranted to better clarify potential cause–effect relationships. Conclusions In conclusion, sleep quality and duration were not associated with injury incidence but with team performance in female elite ice hockey players. Players from top-ranked teams demonstrated more favorable sleep behaviors and less reliance on sleep medication compared with mid-ranked teams. Addressing barriers such as irregular training schedules, post-game stress, and dual-career demands may be essential to improve sleep, recovery, and performance among elite female ice hockey players, especially in the mid-ranked teams. Declarations Declaration of funding This research received no external funding. Ethics approval and consent to participate This study was conducted in accordance with the Declaration of Helsinki and was approved by the Swedish Ethical Review Authority (Dnr: 2023-06114-01). Informed consent was obtained from all participants. Trial registration ClinicalTrials.gov identifier: NCT06351618. Registered on: 2024-04-02. Consent for publication Not Applicable Data availability The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request. Author Contribution AL is the corresponding author and contributed to writing the manuscript. ES contributed intellectually and served as a supervisor. AG performed the statistical analysis. KS is the senior author, supervised the project, and contributed to drafting and revising the manuscript. References Mah CD, Mah KE, Kezirian EJ, Dement WC. The effects of sleep extension on the athletic performance of collegiate basketball players. Sleep. 2011;34(7):943-50. Mougin F, Simon-Rigaud ML, Davenne D, Renaud A, Garnier A, Kantelip JP, et al. Effects of sleep disturbances on subsequent physical performance. Eur J Appl Physiol Occup Physiol. 1991;63(2):77-82. 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Supplementary Files Appendix1.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 08 Apr, 2026 Reviews received at journal 25 Mar, 2026 Reviewers agreed at journal 25 Mar, 2026 Reviewers agreed at journal 22 Mar, 2026 Reviews received at journal 19 Mar, 2026 Reviewers agreed at journal 19 Mar, 2026 Reviewers agreed at journal 17 Mar, 2026 Reviewers invited by journal 17 Mar, 2026 Editor assigned by journal 16 Mar, 2026 Editor invited by journal 24 Feb, 2026 Submission checks completed at journal 23 Feb, 2026 First submitted to journal 23 Feb, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8917450","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":609086014,"identity":"caafd3d7-741a-4e3c-b01b-b02b80a0e2d1","order_by":0,"name":"Amanda Lahti","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+ElEQVRIiWNgGAWjYBACNhDBw8AgwyDBwHDgAwMDYwM7AS38UC08DBLMDAdngLQwE9Ai2YCkhZmHGC0G1w4/e/CmhoGHf3b/wcO2OTayDcw8Bow/KvBouZ1mbjjnGAOPxJ3DDIdzt6UZg7Qw85zBpyXBTJqHDeiwG8kgLYcTwVoY23Brsb+d/k2a5x8DjzxIi+W2/2AtjD//4bMlx0yat42BxwCkhXHbAbAWBt4GvFrKJOf2SfAY3kg2ONi7Ldm4jZmt4DDPMXxa0rdJvPlmIyd3I/Hxh5/b7GT72Zs3PvxRg1sLFEggmKD0cICghlEwCkbBKBgFeAEAPWRMvsK0nSoAAAAASUVORK5CYII=","orcid":"","institution":"Lund University","correspondingAuthor":true,"prefix":"","firstName":"Amanda","middleName":"","lastName":"Lahti","suffix":""},{"id":609086015,"identity":"48bc7453-fd1d-4cd5-91be-58e8ea3a03b2","order_by":1,"name":"Emelie Stenman","email":"","orcid":"","institution":"Lund University","correspondingAuthor":false,"prefix":"","firstName":"Emelie","middleName":"","lastName":"Stenman","suffix":""},{"id":609086016,"identity":"f58460fd-3904-46a5-9890-267abc0143b0","order_by":2,"name":"Anton Grundberg","email":"","orcid":"","institution":"Lund University","correspondingAuthor":false,"prefix":"","firstName":"Anton","middleName":"","lastName":"Grundberg","suffix":""},{"id":609086017,"identity":"34cdbc0a-63a2-4a4e-ae3a-673e2c419d80","order_by":3,"name":"Kristina Sundquist","email":"","orcid":"","institution":"Lund University","correspondingAuthor":false,"prefix":"","firstName":"Kristina","middleName":"","lastName":"Sundquist","suffix":""}],"badges":[],"createdAt":"2026-02-19 12:09:02","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8917450/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8917450/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105563194,"identity":"3e446887-61e7-49a8-9740-c4efa3b8e89f","added_by":"auto","created_at":"2026-03-27 12:46:18","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":633224,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8917450/v1/7ef5846d-3fdf-4880-bf58-5d5e7136843b.pdf"},{"id":105078826,"identity":"1aa1b801-89ad-49ac-8c7d-4ffc927e830e","added_by":"auto","created_at":"2026-03-20 17:06:39","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":256007,"visible":true,"origin":"","legend":"","description":"","filename":"Appendix1.docx","url":"https://assets-eu.researchsquare.com/files/rs-8917450/v1/f6a63c5c8a392f3c1436c626.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"The Role of Sleep in Injuries and Performance Among Elite Female Ice Hockey Players","fulltext":[{"header":"Key findings","content":"\u003cul\u003e\n \u003cli\u003eOne fifth of female elite ice hockey players do not think they get enough sleep, one tenth describes poor sleep quality and almost one third that they, besides sleep, do not get enough time to relax and recover.\u003c/li\u003e\n \u003cli\u003eSleep quality and duration were not significantly associated with injury incidence but with performance.\u003c/li\u003e\n \u003cli\u003eTop and bottom-ranked teams had significantly higher proportion of players achieving a minimum of 7 hours of sleep per night, and less frequently used sleep medication than mid-ranked teams who had the poorest sleep outcomes.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eEarly or late training sessions, post-game stress, and dual employment were the main barriers to adequate sleep, suggesting that optimizing schedules and reducing external pressures may improve both recovery and performance.\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"Background","content":"\u003cp\u003eIt is well established that sleep has a direct impact on sports performance, including its influence on accuracy (1) cardiorespiratory function (2, 3) and psychomotor skills (4). Recently, there has been increasing recognition that poor sleep may be linked to a higher risk of sports-related injuries (5). Sports injuries can have an immediate negative impact on the physical and mental health of athletes (6). Long-term consequences include compromised team success, reduced activity levels, future impairments in quality of life, and increased risk of early-onset osteoarthritis.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe International Olympic Committee (IOC) defines adequate sleep as at least seven hours per night for adults, proper circadian alignment, good perceived sleep quality, and the absence of sleep disorders like insomnia or sleep apnea (3). A systematic review and meta-analysis reported that adolescent athletes with chronic sleep deprivation were 1.6 times more likely to experience sports-related musculoskeletal injuries (4). However, another study did not find poor sleep to be an independent risk factor (5).\u003c/p\u003e\n\u003cp\u003eIce hockey players may be particularly prone to sleep disturbances compared to other disciplines due to demanding match schedules, frequent travel, unfamiliar sleeping environments, and late evening games with high physiological and cognitive arousal due to the high intensity of the sport. As an indoor sport, ice hockey also limits players\u0026rsquo; exposure to natural daylight, which is essential for melatonin regulation and the maintenance of a healthy circadian rhythm.\u003c/p\u003e\n\u003cp\u003eSwedish ice hockey players may face added challenges as daylight can be limited to one to three hours in most northern regions during parts of the competitive season from September to April. Female players may be extra vulnerable to sleeping disorders as they often face lower income and combine work or studies alongside their sport, and therefore more frequently also face early morning trainings (7).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDespite the need for more knowledge on this important topic, few studies have examined sleep and recovery in ice hockey players, and existing reports are limited to small samples of men (8, 9, 10). The Swedish Women\u0026rsquo;s Hockey League (SDHL) represents a unique setting for this research, as it was the first elite women\u0026rsquo;s league to introduce body checking in 2022, thereby increasing the physical demands and game intensity. Since then, other leagues, including the North American Professional Women\u0026rsquo;s Hockey League (PWHL), have also implemented body checking. However, the SDHL was the first to adopt this rule change and therefore has the longest experience of full body contact in elite women\u0026rsquo;s ice hockey, providing a particularly relevant context for examining sleep, recovery, and injury risk under more physically demanding conditions.\u003c/p\u003e\n\u003cp\u003eThis study aims to examine: 1) the sleeping habits of Swedish female ice hockey players, including sleep quality, duration, use of sleeping pills, recovery beyond sleep, and the players\u0026apos; perceptions of factors contributing to insufficient sleep and recovery; and 2) the relationship between sleeping habits, recovery and injuries as well as with performance, where performance will be assessed by team standings in the league table.\u003c/p\u003e"},{"header":"Method","content":"\u003cp\u003eThis study utilize baseline data from the \u003cem\u003eWomen\u0026rsquo;s Ice Hockey Injury Study\u003c/em\u003e, a research project with the overall aim to examine injuries in The Swedish Women\u0026rsquo;s Hockey League (SDHL), which is the only women\u0026rsquo;s league worldwide that permits body checking. The league consists of ten teams with approximately 20\u0026ndash;25 players each.\u003c/p\u003e\n\u003cp\u003eAn email invitation was distributed to all 224 players registered in the SDHL for the 2023/2024 season, with contact details obtained through team managers. Eligible participants were aged 16 years or older. In total, 158 players (71%) consented to participate, including 21 (13%) under 18 years of age (range 16\u0026ndash;37 years). The cohort represented all ten teams and playing positions. A previous dropout analysis found no differences in age or height between participants and non-participants (11). The study was designed in collaboration with representatives from the SDHL and the Swedish Ice Hockey Federation, who assisted with recruitment but had no access to or involvement in data analysis.\u003c/p\u003e\n\u003cp\u003ePlayers received research information and a survey link via email, detailing the study, procedures, risks, benefits, and ethical considerations. Directly after confirming participation in the study, the participant was guided to an electronic online survey provided in both Swedish and English. The survey consisted of a variety of health-related questions including demographics, socioeconomics, player experience, medical history, previous injuries and questions regarding sleep and recovery. Sleep and recovery were assessed through the following self-reported survey items:\u003c/p\u003e\n\u003col start=\"1\" type=\"1\"\u003e\n \u003cli\u003e\u003cem\u003eDo you think you get enough sleep?\u003c/em\u003e\u003cbr\u003e\u0026nbsp;\u0026emsp;1) Yes, definitely\u003cbr\u003e\u0026nbsp;\u0026emsp;2) Yes, most of the time\u003cbr\u003e\u0026nbsp;\u0026emsp;3) No, somewhat insufficient\u003cbr\u003e\u0026nbsp;\u0026emsp;4) No, definitely insufficient\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eIf you are not getting enough sleep, what do you think is the reason?\u003c/em\u003e (open-ended)\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003eThe free text answers were categorized into four themes based on characteristics of the responses (Table 3):\u0026nbsp;\u003c/p\u003e\n\u003col\u003e\n \u003cli\u003eTraining times, stress after games, and combination with work\u003c/li\u003e\n \u003cli\u003eStress and mental load\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eLack of time /busy daily life\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eWork and financial strain\u003c/li\u003e\n \u003cli\u003eAcademic or performance-related stress\u003c/li\u003e\n \u003cli\u003ePersonal or lifestyle factors\u0026nbsp;\u003c/li\u003e\n\u003c/ol\u003e\n\u003col start=\"3\" type=\"1\"\u003e\n \u003cli\u003e\u003cem\u003eHow would you describe the average quality of your sleep?\u003c/em\u003e\u003cbr\u003e\u0026nbsp;\u0026emsp;1) Very good\u003cbr\u003e\u0026nbsp;\u0026emsp;2) Quite good\u003cbr\u003e\u0026nbsp;\u0026emsp;3) Quite poor\u003cbr\u003e\u0026nbsp;\u0026emsp;4) Very poor\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eDuring the last month, how often have you used sleeping medication?\u003c/em\u003e\u003cbr\u003e\u0026nbsp;\u0026emsp;1) Three times per week or more\u003cbr\u003e\u0026nbsp;\u0026emsp;2) One to two times per week\u003cbr\u003e\u0026nbsp;\u0026emsp;3) Less than once per week\u003cbr\u003e\u0026nbsp;\u0026emsp;4) Never\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eHow many hours do you usually sleep during a normal night?\u003c/em\u003e (numeric response)\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003eSleep variables were collected once at baseline (September\u0026ndash;October 2023) and reflect habitual sleep patterns during the competitive season rather than day-to-day variations. No objective measures (e.g., actigraphy or wearable devices) were used. The selected sleep items reflect core domains recommended in consensus statements on sleep assessment in athletes, including sleep duration, perceived sleep quality and use of sleep medication (12). The items cover key domains commonly included in athlete sleep screening tools (12). The questionnaire used in your study was developed for this study or has previously been published elsewhere.\u0026nbsp;The sleep questions used in the present study is presented in detail in Appendix 1. Recovery beyond sleep was assessed using a self-reported question regarding perceived adequacy of relaxation time:\u003c/p\u003e\n\u003col start=\"6\" type=\"1\"\u003e\n \u003cli\u003e\u003cem\u003eBesides sleep, do you think you get enough time to rest and relax?\u003c/em\u003e\u003cbr\u003e\u0026nbsp;\u0026emsp;1) Yes, definitely\u003cbr\u003e\u0026nbsp;\u0026emsp;2) Yes, most of the time\u003cbr\u003e\u0026nbsp;\u0026emsp;3) No, somewhat inadequate\u003cbr\u003e\u0026nbsp;\u0026emsp;4) No, definitely inadequate\u003cbr\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;5) No, far from adequate \u0026nbsp;\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003eThroughout the 2023/2024 season, a designated medical professional team (physician or physiotherapist) at each club reported injuries resulting in time-loss from training or competition to a central electronic register using a standardized injury card. Only time-loss injuries, defined as those causing absence from training or games (13), were included in the analysis. Dental injuries and illness were not included as cause of absence. Although reporting was mandatory for all SDHL teams, only data from players who had consented to participate were analyzed.\u003c/p\u003e\n\u003cp\u003eParticipation was voluntary, with the option to withdraw at any time. The study was approved by the Swedish Ethical Review Authority (Dnr: 2023-06114-01), adhered to the Declaration of Helsinki, and was registered at ClinicalTrials.gov (ID: NCT06351618).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eStatistical analysis\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eStatistical analyses were performed using R version 4.4.2 (R Core Team, 2024). Descriptive statistics used to summarize player characteristics and sleep-related variables are presented as means and standard deviations (SD) or medians and inter-quartile ranges (IQR) for continuous variables, while categorical variables are presented as frequencies and percentages (%). The sleep-related variables are dichotomized, and the final league standings are grouped into top (1\u0026ndash;3), mid (4\u0026ndash;6), and bottom-ranked teams (7\u0026ndash;10) to avoid identifying individual participants. Group comparisons of categorical variables were performed using chi-square (\u0026chi;\u0026sup2;) tests or Fisher\u0026rsquo;s exact tests, and of continuous variables using Welch\u0026rsquo;s t-tests or Mann-Whitney U-tests comparing injuries and ANOVA or Kruskal-Wallis tests comparing team standings. Associations were considered statistically significant at a p-value \u0026lt; 0.05.\u0026nbsp;\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 158 SDHL players participated in the study, representing all ten teams in the league. Sixty-three players (41%) sustained a time-loss injury during the 2023/2024 season. The median age in all players was 23.2 years (IQR 6.2). No significant differences were observed between injured and non-injured players regarding age, height, weight, BMI (Table 1), or for any of the sleep and recovery variables.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWhen grouped by team performance based on final league standings during the season 2023/2024, all players in the top 3 teams reported sleeping at least seven hours per night, compared with 81% in mid-ranked and 92% in bottom-ranked teams (p \u0026lt; 0.001) (Table 2). Sleep medication use once per week or more was reported by 1.9% of players in top 3 teams, 17.0% in mid-ranked, and 2.0% in bottom-ranked teams (p = 0.003). 83% of players in the top 3 teams reported sufficient rest compared to 68% and 63% among players in the mid- and bottom-ranked teams respectively; however, this difference was not statistically significant (p = 0.05). While players from mid-ranked teams (positions 4\u0026ndash;6) reported the poorest sleep characteristics overall, players in the bottom-ranked teams (7\u0026ndash;10) did not differ substantially from the top teams in terms of sleep duration or quality, despite their lower league performance.\u003c/p\u003e\n\u003cp\u003eFree text responses about reasons for not getting enough sleep among players reporting insufficient sleep (n=32) are presented in Table 3. The most common reasons were training times, stress after games, and combining ice hockey with work (n=11). Representative quotations are provided to illustrate each theme.\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 100px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 1.\u003c/strong\u003e Characteristics stratified by injury of elite ice hockey players in SDHL, season 2023/2024.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCharacteristic\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTotal, n=154\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eInjured, n=63\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNot injuried, n=91\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eAge, median (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e23.2 (6.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e23.8 (6.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e22.9 (6.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e0.31\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eBody weight (kg), mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e68.4 (6.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e69.6 (6.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e67.6 (7.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e0.07\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eBody height (cm), mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e169.1 (5.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e170.0 (5.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e168.5 (5.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e0.08\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eBMI (kg/m2), mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e23.9 (1.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e24.0 (1.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e23.8 (2.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e0.41\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eDo you think you get enough sleep? n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e0.61\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Yes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e120 (77.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e51 (81.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e69 (75.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; No\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e32 (20.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e12 (19.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e20 (22.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Missing\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e2 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e2 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eHow would you describe the average quality of your sleep? n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e0.66\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Good\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e133 (86.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e56 (88.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e77 (84.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Poor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e19 (12.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e7 (11.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e12 (13.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Missing\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e2 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e2 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eDuring the last month, how often have you used sleeping medication? n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e0.52\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Once per week or more\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e10 (6.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e3 (4.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e7 (7.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Less than once per week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e142 (92.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e60 (95.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e82 (90.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Missing\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e2 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e2 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eHow many hours do you usually sleep during a normal night? n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e0.82\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026ge; 7 hours\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e139 (90.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e58 (92.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e81 (89.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026lt; 7 hours\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e13 (8.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e5 (7.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e8 (8.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Missing\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e2 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e2 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eBesides sleep, do you think you get enough time to rest and relax? n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e0.43\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Yes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e109 (70.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e43 (68.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e66 (72.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; No\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e43 (27.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e20 (31.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e23 (25.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Missing\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e2 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e0 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 17px;\"\u003e\n \u003cp\u003e2 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 11px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 2.\u003c/strong\u003e Sleep and recovery characteristics of SDHL players stratified by team performance according to final league standings during the 2023/2024 season\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eCharacteristic\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTeam standing 1 \u0026ndash; 3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTeam standing 4 \u0026ndash; 6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTeam standing 7 \u0026ndash; 10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAge, median (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23.1 (7.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23.4 (5.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e22.9 (5.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.74\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBody weight (kg), mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e68.3 (5.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e67.0 (6.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e69.8 (7.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBody height (cm), mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e169.0 (4.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e169.3 (5.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e169.1 (6.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.96\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBMI (kg/m2), mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23.9 (1.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23.4 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e24.4 (1.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.034\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eDo you think you get enough sleep? n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.08\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Yes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e46 (85.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e32 (68.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e42 (82.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; No\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8 (14.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e15 (31.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9 (17.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eHow would you describe the average quality of your sleep? n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.09\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Good\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e50 (92.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e37 (78.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e46 (90.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Poor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4 (7.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10 (21.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5 (9.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eDuring the last month, how often have you used sleeping medication?, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.003\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Once per week or more\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1 (1.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8 (17.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1 (2.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Less than once per week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e53 (98.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e39 (83.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e50 (98.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eHow many hours do you usually sleep during a normal night? n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026ge; 7 hours\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e54 (100.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e38 (80.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e47 (92.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026lt; 7 hours\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9 (19.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4 (7.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBesides sleep, do you think you get enough time to rest and relax? n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Yes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e45 (83.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e32 (68.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e32 (62.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; No\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9 (16.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e15 (31.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e19 (37.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eStatistically significant values are \u003cstrong\u003ebolded\u0026nbsp;\u003c/strong\u003e(p\u0026lt;0.05).\u003c/p\u003e\n\u003ctable border=\"1\" cellpadding=\"0\" class=\"fr-table-selection-hover\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 3\u003c/strong\u003e. Reported reasons from 32 female elite ice hockey players for insufficient sleep among SDHL players (qualitative analysis)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eTheme / Cause\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003en\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eCitations\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eTraining times, stress after games, and combination with work\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cem\u003e\u0026ldquo;Late trainings and trainings have made it difficult to fall asleep at night.\u0026rdquo;\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003e\u0026ldquo;Can\u0026rsquo;t sleep at night after training/game and get up early for work.\u0026rdquo;\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003e\u0026ldquo;No time to unwind after training and have to get up early to work and earn money.\u0026rdquo;\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eStress and mental load\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cem\u003e\u0026ldquo;A lot of stress.\u0026rdquo;\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eLack of time / busy daily life\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cem\u003e\u0026ldquo;A lot going on in everyday life.\u0026rdquo;\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eWork and financial strain\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cem\u003e\u0026ldquo;Working two jobs and coming home late because I can\u0026rsquo;t afford a car.\u0026rdquo;\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eAcademic or performance-related stress\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cem\u003e\u0026ldquo;Late nights due to difficulty sleeping, stress about performance in school, hockey, etc.\u0026rdquo;\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003ePersonal or lifestyle factors\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cem\u003e\u0026ldquo;I\u0026rsquo;m going late to bed.\u0026rdquo;\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, sleep patterns among elite female ice hockey players were associated with team performance but not with injury incidence. About one fifth of the players reported insufficient sleep, one tenth poor sleep quality, and nearly one third insufficient time for relaxation and recovery beyond sleep. Players from top- and bottom-ranked teams reported lower use of sleep medication and a higher proportion achieving at least seven hours of sleep per night compared to mid-ranked teams. Early or late training sessions, post-game stress, and dual work or study commitments emerged as key barriers to sufficient sleep, underscoring the importance of structural and psychosocial factors in supporting recovery and performance.\u003c/p\u003e \u003cp\u003ePrevious studies have demonstrated that both chronic sleep restriction and acute sleep deprivation (e.g., \u0026le;\u0026thinsp;5 hours the night before competition) may increase injury risk through impaired neuromuscular control and reaction time (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e). As our study assessed habitual sleep patterns rather than night-to-night variation, we cannot exclude a potential acute effect of short-term sleep loss preceding injury events.\u003c/p\u003e \u003cp\u003eAthletes are known to use pharmacological aids to manage sleep problems related to competition, travel, and psychological arousal (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e), and this may also apply to elite female ice hockey players. However, according to data from the Swedish National Board of Health and Welfare (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e), approximately 5.9% among females aged 20\u0026ndash;24 years in the general population use prescribed sleep medication in 2024, which is comparable to the 6.5% observed in the present study. One plausible explanation is that the players\u0026rsquo; overall health, structured lifestyles, and high physical fitness may, despite their early schedules, travel, and competitive demands, contribute to good sleep quality, which may help to maintain sleep medication usage comparable to those of the general population.\u003c/p\u003e \u003cp\u003eHowever, our data do not clarify why sleep medication use differed between team standings. One possibility is that players in mid-ranked teams experience greater dissatisfaction, being neither at the top nor bottom, which may increase anxiety and disturbed sleep (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e). Another explanation is that while adequate sleep and recovery support performance among top-ranked teams, other factors such as physical fitness, talent, and organizational resources may play a stronger role among lower-ranked teams. In other words, one cannot simply \u003cem\u003e\u0026ldquo;rest into\u0026rdquo;\u003c/em\u003e top performance. Moreover, top-ranked teams may benefit from more professionalized conditions, less external stress, fewer secondary commitments, and better resources, which could further support better recovery and sleep than mid and bottom-ranked teams.\u003c/p\u003e \u003cp\u003eMid-ranked teams may experience greater competitive uncertainty, fluctuating playoff prospects, and performance-related stress, potentially contributing to sleep disturbances. In contrast, top teams may benefit from greater organizational stability and resources, while bottom teams may face reduced competitive pressure late in the season.\u003c/p\u003e \u003cp\u003eIn the present study, no significant associations were observed between sleep variables and injury incidence. Recently, there has been increasing recognition that poor sleep may be linked to a higher risk of sports-related injuries (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e), although some studies have failed to demonstrate such associations (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). Sports injuries may have multifactorial causes, and sleep likely interacts with factors such as training load (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e), hormonal cycles (\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e), psychological stress and illness (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e), as well as immune function (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e), rather than serving as an independent risk factor. Although the current study did not identify an association between sleep and injury, such an effect cannot be completely ruled out and should be further investigated in future research.\u003c/p\u003e \u003cp\u003eThe qualitative findings indicate that sleep insufficiency among SDHL players is closely linked to structural and psychosocial factors such as training schedules, post-game stress, and dual career demands. These demands often force female players to train at unfavorable hours, unlike male professionals who benefit from financial support. Achieving more equitable conditions and reducing reliance on secondary employment may be crucial for optimizing sleep, recovery and performance in female players and thereby to the continued development of women\u0026rsquo;s ice hockey.\u003c/p\u003e \u003cp\u003eStrengths of this study include the large and representative cohort, the inclusion of all SDHL teams, and the use of a standardized injury reporting system. Another strength is the comprehensive assessment of multiple sleep-related variables, providing a rare and detailed overview of sleep patterns among female ice hockey players. These data contribute valuable insight into an understudied population and may also be generalizable to other female team sport athletes facing similar structural and psychosocial challenges.\u003c/p\u003e \u003cp\u003eLimitations include the absence of potential confounding factors such as mental health and prior injuries, which complicate causal interpretation. Additionally, self-reported sleep data may introduce bias, and the time-loss injury definition could underestimate overuse injuries, illnesses, or conditions not resulting in absence from play. In addition, the low prevalence of short sleep (\u0026lt;\u0026thinsp;7h) limits statistical power to detect associations with injury. This may partly explain the null findings. Taken together with the relatively limited number of injury events, multivariable regression analyses adjusting for potential confounders were not performed, as such models would have risked statistical instability and overfitting. According to the commonly applied rule of at least 10 outcome events per predictor variable in logistic regression models, the available sample size limited the number of variables that could be reliably included. Future studies with larger cohorts and more injury events are warranted to enable adjusted analyses.\u003c/p\u003e \u003cp\u003eAnother limitation is that sleep variables were assessed through self-report at a single time point, reflecting habitual sleep patterns rather than day-to-day variation. Objective monitoring of sleep across the entire season (e.g., actigraphy or wearable technology) would have strengthened the design and enabled examination of temporal relationships between acute sleep disturbances and subsequent injury events. The present approach limits our ability to establish whether poor sleep preceded injury, and therefore causal inferences regarding time-sequenced associations should be interpreted with caution. Future longitudinal studies incorporating continuous objective sleep monitoring are warranted to better clarify potential cause\u0026ndash;effect relationships.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn conclusion, sleep quality and duration were not associated with injury incidence but with team performance in female elite ice hockey players. Players from top-ranked teams demonstrated more favorable sleep behaviors and less reliance on sleep medication compared with mid-ranked teams. Addressing barriers such as irregular training schedules, post-game stress, and dual-career demands may be essential to improve sleep, recovery, and performance among elite female ice hockey players, especially in the mid-ranked teams.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eDeclaration of funding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research received no external funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was conducted in accordance with the Declaration of Helsinki and was approved by the Swedish Ethical Review Authority (Dnr: 2023-06114-01). Informed consent was obtained from all participants.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTrial registration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eClinicalTrials.gov identifier: NCT06351618. Registered on: 2024-04-02.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot Applicable\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAL is the corresponding author and contributed to writing the manuscript. ES contributed intellectually and served as a supervisor. AG performed the statistical analysis. KS is the senior author, supervised the project, and contributed to drafting and revising the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eMah CD, Mah KE, Kezirian EJ, Dement WC. The effects of sleep extension on the athletic performance of collegiate basketball players. Sleep. 2011;34(7):943-50.\u003c/li\u003e\n\u003cli\u003eMougin F, Simon-Rigaud ML, Davenne D, Renaud A, Garnier A, Kantelip JP, et al. Effects of sleep disturbances on subsequent physical performance. Eur J Appl Physiol Occup Physiol. 1991;63(2):77-82.\u003c/li\u003e\n\u003cli\u003eMougin F, Bourdin H, Simon-Rigaud ML, Didier JM, Toubin G, Kantelip JP. Effects of a selective sleep deprivation on subsequent anaerobic performance. Int J Sports Med. 1996;17(2):115-9.\u003c/li\u003e\n\u003cli\u003eKnufinke M, Nieuwenhuys A, Maase K, Moen MH, Geurts SAE, Coenen AML, et al. Effects of Natural Between-Days Variation in Sleep on Elite Athletes\u0026apos; Psychomotor Vigilance and Sport-Specific Measures of Performance. J Sports Sci Med. 2018;17(4):515-24.\u003c/li\u003e\n\u003cli\u003eGao B, Dwivedi S, Milewski MD, Cruz AI, Jr. Lack of Sleep and Sports Injuries in Adolescents: A Systematic Review and Meta-analysis. J Pediatr Orthop. 2019;39(5):e324-e33.\u003c/li\u003e\n\u003cli\u003eHaugen E. Athlete Mental Health \u0026amp; Psychological Impact of Sport Injury. Operative Techniques in Sports Medicine. 2022;30(1):150898.\u003c/li\u003e\n\u003cli\u003eWalsh NP, Halson SL, Sargent C, Roach GD, N\u0026eacute;d\u0026eacute;lec M, Gupta L, et al. Sleep and the athlete: narrative review and 2021 expert consensus recommendations. Br J Sports Med. 2020.\u003c/li\u003e\n\u003cli\u003eNordstr\u0026oslash;m A, Bahr R, Bache-Mathiesen LK, Clarsen B, Talsnes O. Association of Training and Game Loads to Injury Risk in Junior Male Elite Ice Hockey Players: A Prospective Cohort Study. Orthop J Sports Med. 2022;10(10):23259671221129646.\u003c/li\u003e\n\u003cli\u003eMustapich C, Koehle M. The Effects of Training Load and Non‐Training Stress on Injury Risk in Collegiate Ice Hockey Players. Translational Sports Medicine. 2021;4.\u003c/li\u003e\n\u003cli\u003eMerrigan JJ, Stone JD, Kraemer WJ, Friend C, Lennon K, Vatne EA, et al. Analysis of Sleep, Nocturnal Physiology, and Physical Demands of NCAA Women\u0026apos;s Ice Hockey Across a Championship Season. J Strength Cond Res. 2024;38(4):694-703.\u003c/li\u003e\n\u003cli\u003eLahti A, Grundberg A, Stenman E, Sundquist K. Physical Characteristics of Swedish Female Professional Ice Hockey Players Allowed Body Checking. J Strength Cond Res. 2024.\u003c/li\u003e\n\u003cli\u003eSamuels C, James L, Lawson D, Meeuwisse W. The Athlete Sleep Screening Questionnaire: a new tool for assessing and managing sleep in elite athletes. British Journal of Sports Medicine. 2016;50(7):418-22.\u003c/li\u003e\n\u003cli\u003eBahr R, Clarsen B, Derman W, Dvorak J, Emery CA, Finch CF, et al. International Olympic Committee consensus statement: methods for recording and reporting of epidemiological data on injury and illness in sport 2020 (including STROBE Extension for Sport Injury and Illness Surveillance (STROBE-SIIS)). British Journal of Sports Medicine. 2020;54(7):372-89.\u003c/li\u003e\n\u003cli\u003eMilewski MD, Skaggs DL, Bishop GA, Pace JL, Ibrahim DA, Wren TA, et al. Chronic lack of sleep is associated with increased sports injuries in adolescent athletes. J Pediatr Orthop. 2014;34(2):129-33.\u003c/li\u003e\n\u003cli\u003eWalsh NP, Halson SL, Sargent C, Roach GD, N\u0026eacute;d\u0026eacute;lec M, Gupta L, et al. Sleep and the athlete: narrative review and 2021 expert consensus recommendations. British Journal of Sports Medicine. 2021;55(7):356-68.\u003c/li\u003e\n\u003cli\u003eStatistikdatabas f\u0026ouml;r l\u0026auml;kemedel [Internet]. 2024 [cited 2025-10-28].\u003c/li\u003e\n\u003cli\u003eReardon CL, Gorczynski P, Hainline B, Hitchcock M, Rice S. Anxiety Disorders in Athletes. Clin Sports Med. 2024;43(1):33-52.\u003c/li\u003e\n\u003cli\u003eDobrosielski DA, Sweeney L, Lisman PJ. The Association Between Poor Sleep and the Incidence of Sport and Physical Training-Related Injuries in Adult Athletic Populations: A Systematic Review. Sports Med. 2021;51(4):777-93.\u003c/li\u003e\n\u003cli\u003eBARLOW A, BLODGETT JM, WILLIAMS S, PEDLAR CR, BRUINVELS G. Injury Incidence, Severity, and Type Across the Menstrual Cycle in Female Footballers: A Prospective Three Season Cohort Study. Medicine \u0026amp; Science in Sports \u0026amp; Exercise. 2024;56(6):1151-8.\u003c/li\u003e\n\u003cli\u003eKozjek NR, Tonin G, Gleeson M. Nutrition for optimising immune function and recovery from injury in sports. Clinical Nutrition ESPEN. 2025;66:101-14.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-sports-science-medicine-and-rehabilitation","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ssmr","sideBox":"Learn more about [BMC Sports Science, Medicine and Rehabilitation](http://bmcsportsscimedrehabil.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ssmr/default.aspx","title":"BMC Sports Science, Medicine and Rehabilitation","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-8917450/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8917450/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003eSleep may play a vital role in recovery, performance, and injury prevention among elite athletes.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAim: \u003c/strong\u003eTo examine sleep patterns, recovery, and their associations with injuries and team performance among Swedish elite female ice hockey players.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eAll 224 players registered in The Swedish Women’s Hockey League (SDHL) were invited to this research project during the 2023/2024 season, and 158 (71%) completed a questionnaire on sleep and recovery. All injuries that lead to absence from training or games were prospectively recorded by team medical staff. Data were analyzed descriptively and with chi-square (χ²) tests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eThirty-two players (20.8%) reported insufficient sleep, and 19 (12.3%) rated their sleep quality as poor. Ten (6.5%) had used sleep medication during the past month, 13 (8.4%) slept less than seven hours per night, and 43 (27.9%) lacked sufficient rest and relaxation. No significant associations were found between sleep variables and injury incidence. However, players from top and bottom-ranked teams reported significantly lower sleep medication use than those from mid-ranked teams (p = 0.003). Top-ranked teams also had the highest proportion achieving at least seven hours of sleep per night (100%, p \u0026lt; 0.001). Inadequate sleep was primarily attributed to early or late training sessions, post-game stress, and dual work commitments.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eSleep variables were not associated with injury incidence but were associated with team performance. Optimizing training schedules and reducing dual-career demands may enhance sleep and support performance in elite female ice hockey players.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTrial registration:\u003c/strong\u003e ClinicalTrials.gov (ID: NCT06351618).\u003c/p\u003e","manuscriptTitle":"The Role of Sleep in Injuries and Performance Among Elite Female Ice Hockey Players","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-20 17:06:34","doi":"10.21203/rs.3.rs-8917450/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-04-08T08:13:23+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-25T23:55:32+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"323353776010659757709294372239638341217","date":"2026-03-25T09:17:22+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"225997046586297130265608498029066918270","date":"2026-03-22T23:49:15+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-19T11:06:50+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"187100144231007048189187938126060482063","date":"2026-03-19T10:01:19+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"120011077332581889009855694584092966625","date":"2026-03-17T21:11:32+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-17T18:55:13+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-16T13:18:45+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-02-24T06:41:24+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-23T13:21:01+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Sports Science, Medicine and Rehabilitation","date":"2026-02-23T13:15:58+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-sports-science-medicine-and-rehabilitation","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ssmr","sideBox":"Learn more about [BMC Sports Science, Medicine and Rehabilitation](http://bmcsportsscimedrehabil.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ssmr/default.aspx","title":"BMC Sports Science, Medicine and Rehabilitation","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a78b2154-d1a8-465b-bdaa-d7ecc7450fea","owner":[],"postedDate":"March 20th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-03-20T17:06:34+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-20 17:06:34","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8917450","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8917450","identity":"rs-8917450","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}