Development and evaluation of the psychometric properties of a new measure of athlete insomnia: Insomnia in Response to Sports-related Stress Test questionnaire.

To develop and validate the Insomnia in Response to Sports-related Stress Test (IRSST) questionnaire, a new specific instrument with the goal of sensitively measuring vulnerability to sport-specific stressful situations among elite athletes. Five hundred and thirty-one competitive elite athletes (mean age = 17.6 ± 4.4 years) completed the Ford Insomnia Response to Stress Test (FIRST) questionnaire and the IRSST, a six-item questionnaire developed to assess the level of sleep disturbance in response to the commonly experienced sport-specific stressful situations. A development and validation process including substantive, structural, and external stages was used in the present study. One eigenvalue of the exploratory factor analyses was greater than 1.0 (i.e., 2.91, 48.52% of explained variance) whereas the scree test provided evidence for a one-factor solution, with all the six items achieving a loading of 0.40 or higher on the factor. Cronbach alpha was 0.77 and provided evidence for the reliability of the IRSST score. The correlation between IRSST and FIRST scores was 0.47 (p < 0.001, moderate effect size). These results provide strong evidence for construct validity, indicating that the IRSST is a promising scale for assessing the likelihood of sleep disruption due to sports-related stressful situations. The results of reliability and correlational analyses provided further evidence of the promising psychometric properties of the IRSST. We believe that the IRSST could provide to the sport and sleep science communities a sleep screening tool for use in this unique population.

Increased training load promotes sleep propensity and slow-wave sleep in endurance runners: Can a high-heat-capacity mattress topper modulate this effect?

The present study aimed to: (1) investigate sleep architecture in response to an overload training and taper periods among endurance runners; and (2) assess the sleep benefits of a high-heat-capacity mattress topper. Twenty-one trained male endurance runners performed a 2-week usual training regimen (baseline) followed by 2-week overload and taper periods. From overload to the end of the taper period, they were assigned into two groups based on the mattress topper used: high-heat-capacity mattress topper (n = 11) or low-heat-capacity mattress topper (n = 10). Training load was assessed daily using the session rating of perceived exertion. Following each period, sleep was monitored by polysomnography, and nocturnal core body temperature was recorded throughout the night. Irrespective of the group, awakening episodes > 5 min decreased following overload compared with baseline (-0.48, p = 0.05). Independently of mattress topper, each 100 A.U. increase in 7-day training load prior to polysomnographic recording was associated with higher slow-wave sleep proportion (ß = +0.13%; p = 0.05), lower sleep-onset latency (ß = -0.49 min; p = 0.05), and a reduction in the probability of transition from N1 sleep stage to wakefulness (ß = -0.12%; p = 0.05). Sleeping on a high-heat-capacity mattress topper did not affect any sleep variable compared with a low-heat-capacity mattress topper. Increased training loads promote slow-wave sleep and sleep propensity, highlighting the adaptative nature of sleep to diurnal activity and the role of sleep in physiological recovery. Further studies are required on the potential benefits of high-heat-capacity mattress toppers on sleep architecture among athletes.

Higher training loads affect sleep in endurance runners: Can a high-heat-capacity mattress topper mitigate negative effects?

This study investigates the impact of a training program on sleep among endurance runners and the benefits of chronically using a high-heat-capacity mattress topper (HMT). Twenty-one trained male athletes performed a 2-week usual training regimen, sleeping on a Low-heat-capacity Mattress Topper (LMT), followed by 2-week overload and taper periods. From overload, participants were assigned into two groups based on the mattress topper used: HMT (n = 11) or LMT (n = 10). Irrespective of the group, overload increased general stress and stress-reaction symptoms evaluated by questionnaires, with no decline in performance on a graded-exercise treadmill test, the majority of participant being "non-overreached" (n = 14). From a daily perspective, each additional 100 A.U. in training load, assessed using the session rating of perceived exertion, was associated with an impairment in subsequent sleep efficiency (ß = -0.2%; p < 0.01), wake after sleep onset (ß = +0.4 min; p < 0.05) and sleep onset latency (ß = +0.5 min; p < 0.05), which was unaffected by HMT use. Practitioners should be aware of sleep needs, especially during excessive training loads, whereas implementing individualised sleep strategies. Further studies should be conducted on potential benefits of HMT among athletes in various sleep conditions.

The Impact of Multisession Sleep-Hygiene Strategies on Sleep Parameters in Elite Swimmers.

PURPOSE: Short sleep duration and poor sleep quality are common in swimmers. Sleep-hygiene strategies demonstrated beneficial effects on several sleep parameters. The present study assessed the impact of a multisession sleep-hygiene training course on sleep in elite swimmers. METHODS: Twenty-eight elite swimmers (17 [2] y) participated. The sleep-hygiene strategy consisted of 3 interventions. Sleep was measured by actigraphy for 7 days before the beginning of the intervention (baseline), after the first collective intervention (postintervention), after the second collective intervention (postintervention 2), and, finally, after the individual intervention (postintervention 3). The Epworth Sleepiness Scale (ESS) was completed concurrently. Swimmers were classified into 2 groups: nonsomnolent (baseline ESS score ≤ 10, n = 13) and somnolent (baseline ESS score ≥ 11, n = 15). RESULTS: All swimmers had a total sleep time of <8 hours per night. Sixty percent of swimmers were moderately morning type. Later bedtime, less time in bed, and total sleep time were observed in the somnolent group compared with the nonsomnolent group at baseline. An interaction between training course and group factors was observed for bedtime, with a significant advance in bedtime between baseline, postintervention 2, and postintervention 3 for the somnolent group. CONCLUSIONS: The present study confirms the importance of implementing sleep-hygiene strategies, particularly in athletes with an ESS score ≥11. A conjunction of individual and collective measures (eg, earlier bedtime, napping, and delaying morning training session) could favor the total sleep time achieved.

Lockdown Duration and Training Intensity Affect Sleep Behavior in an International Sample of 1,454 Elite Athletes.

Objective: To investigate the effect of 1) lockdown duration and 2) training intensity on sleep quality and insomnia symptoms in elite athletes. Methods: 1,454 elite athletes (24.1 ± 6.7 years; 42% female; 41% individual sports) from 40 countries answered a retrospective, cross-sectional, web-based questionnaire relating to their behavioral habits pre- and during- COVID-19 lockdown, including: 1) Pittsburgh sleep quality index (PSQI); 2) Insomnia severity index (ISI); bespoke questions about 3) napping; and 4) training behaviors. The association between dependent (PSQI and ISI) and independent variables (sleep, napping and training behaviors) was determined with multiple regression and is reported as semi-partial correlation coefficient squared (in percentage). Results: 15% of the sample spent < 1 month, 27% spent 1-2 months and 58% spent > 2 months in lockdown. 29% self-reported maintaining the same training intensity during-lockdown whilst 71% reduced training intensity. PSQI (4.1 ± 2.4 to 5.8 ± 3.1; mean difference (MD): 1.7; 95% confidence interval of the difference (95% CI): 1.6-1.9) and ISI (5.1 ± 4.7 to 7.7 ± 6.4; MD: 2.6; 95% CI: 2.3-2.9) scores were higher during-compared to pre-lockdown, associated (all p < 0.001) with longer sleep onset latency (PSQI: 28%; ISI: 23%), later bedtime (PSQI: 13%; ISI: 14%) and later preferred time of day to train (PSQI: 9%; ISI: 5%) during-lockdown. Those who reduced training intensity during-lockdown showed higher PSQI (p < 0.001; MD: 1.25; 95% CI: 0.87-1.63) and ISI (p < 0.001; MD: 2.5; 95% CI: 1.72-3.27) scores compared to those who maintained training intensity. Although PSQI score was not affected by the lockdown duration, ISI score was higher in athletes who spent > 2 months confined compared to those who spent < 1 month (p < 0.001; MD: 1.28; 95% CI: 0.26-2.3). Conclusion: Reducing training intensity during the COVID-19-induced lockdown was associated with lower sleep quality and higher insomnia severity in elite athletes. Lockdown duration had further disrupting effects on elite athletes' sleep behavior. These findings could be of relevance in future lockdown or lockdown-like situations (e.g., prolonged illness, injury, and quarantine after international travel).

Ramadan Observance Exacerbated the Negative Effects of COVID-19 Lockdown on Sleep and Training Behaviors: A International Survey on 1,681 Muslim Athletes.

Objective: Disrupted sleep and training behaviors in athletes have been reported during the COVID-19 pandemic. We aimed at investigating the combined effects of Ramadan observance and COVID-19 related lockdown in Muslim athletes. Methods: From an international sample of athletes (n = 3,911), 1,681 Muslim athletes (from 44 countries; 25.1 ± 8.7 years, 38% females, 41% elite, 51% team sport athletes) answered a retrospective, cross-sectional questionnaire relating to their behavioral habits pre- and during- COVID-19 lockdown, including: (i) Pittsburgh sleep quality index (PSQI); (ii) insomnia severity index (ISI); (iii) bespoke questions about training, napping, and eating behaviors, and (iv) questions related to training and sleep behaviors during-lockdown and Ramadan compared to lockdown outside of Ramadan. The survey was disseminated predominately through social media, opening 8 July and closing 30 September 2020. Results: The lockdown reduced sleep quality and increased insomnia severity (both p < 0.001). Compared to non-Muslim (n = 2,230), Muslim athletes reported higher PSQI and ISI scores during-lockdown (both p < 0.001), but not pre-lockdown (p > 0.05). Muslim athletes reported longer (p < 0.001; d = 0.29) and later (p < 0.001; d = 0.14) daytime naps, and an increase in late-night meals (p < 0.001; d = 0.49) during- compared to pre-lockdown, associated with lower sleep quality (all p < 0.001). Both sleep quality (χ2 = 222.6; p < 0.001) and training volume (χ2 = 342.4; p < 0.001) were lower during-lockdown and Ramadan compared to lockdown outside of Ramadan in the Muslims athletes. Conclusion: Muslim athletes reported lower sleep quality and higher insomnia severity during- compared to pre-lockdown, and this was exacerbated by Ramadan observance. Therefore, further attention to Muslim athletes is warranted when a circadian disrupter (e.g., lockdown) occurs during Ramadan.

On the Road to Camarón: The Sleep of an Ultra-Endurance Athlete Cycling 10,000 km in 24 Days.

The impact of sleep on performance is fundamental for ultra-endurance athletes, but studies on this issue are rare. The current investigation examined the sleep and performance of a cyclist engaged in a simulated 10,000 km tour. The sleep behavior of the athlete (age, 57; height, 1.85 m; mass, 81 kg) before, during (i.e., 23 nights), and after the tour was monitored using a reduced-montage dry-electroencephalographic (EEG) device. The daily performance (i.e., number of kms) was recorded throughout the race. The cyclist set a new world record, completing 10,358 km in 24 days with a mean daily distance of ≈432 km in approximately 16 h, i.e., an average speed of ≈27 km/h. Sleep duration throughout the tour (5:13 ± 0:30) was reduced compared to the baseline sleep duration (7:00 ± 1:00), with a very large difference (ES = 2.3). The proportion of N3 during the tour (46 ± 7%) was compared to the measured N3 proportion during the baseline (27 ± 5%) and was found to be systematically outside the intra-individual variability (mean ± 1 SD), with a very large difference (ES = 3.1). This ultra-endurance event had a major influence on sleep-duration reduction and a notable modification in sleep architecture. The increase in slow-wave sleep during the race may be linked to the role of slow-wave sleep in physiological recovery.

COVID-19 Lockdowns: A Worldwide Survey of Circadian Rhythms and Sleep Quality in 3911 Athletes from 49 Countries, with Data-Driven Recommendations.

OBJECTIVE: In a convenience sample of athletes, we conducted a survey of COVID-19-mediated lockdown (termed 'lockdown' from this point forward) effects on: (i) circadian rhythms; (ii) sleep; (iii) eating; and (iv) training behaviors. METHODS: In total, 3911 athletes [mean age: 25.1 (range 18-61) years, 1764 female (45%), 2427 team-sport (63%) and 1442 elite (37%) athletes] from 49 countries completed a multilingual cross-sectional survey including the Pittsburgh Sleep Quality Index and Insomnia Severity Index questionnaires, alongside bespoke questions about napping, training, and nutrition behaviors. RESULTS: Pittsburgh Sleep Quality Index (4.3 ± 2.4 to 5.8 ± 3.1) and Insomnia Severity Index (4.8 ± 4.7 to 7.2 ± 6.4) scores increased from pre- to during lockdown (p < 0.001). Pittsburgh Sleep Quality Index was predominantly influenced by sleep-onset latency (p < 0.001; + 29.8%), sleep efficiency (p < 0.001; - 21.1%), and total sleep time (p < 0.001; - 20.1%), whilst Insomnia Severity Index was affected by sleep-onset latency (p < 0.001; + 21.4%), bedtime (p < 0.001; + 9.4%), and eating after midnight (p < 0.001; + 9.1%). During lockdown, athletes reported fewer training sessions per week (- 29.1%; d = 0.99). Athletes went to bed (+ 75 min; 5.4%; d = 1.14) and woke up (+ 150 min; 34.5%; d = 1.71) later during lockdown with an increased total sleep time (+ 48 min; 10.6%; d = 0.83). Lockdown-mediated circadian disruption had more deleterious effects on the sleep quality of individual-sport athletes compared with team-sport athletes (p < 0.001; d = 0.41), elite compared with non-elite athletes (p = 0.028; d = 0.44) and older compared with younger (p = 0.008; d = 0.46) athletes. CONCLUSIONS: These lockdown-induced behavioral changes reduced sleep quality and increased insomnia in athletes. Data-driven and evidence-based recommendations to counter these include, but are not limited to: (i) early outdoor training; (ii) regular meal scheduling (whilst avoiding meals prior to bedtime and caffeine in the evening) with appropriate composition; (iii) regular bedtimes and wake-up times; and (iv) avoidance of long and/or late naps.

Are elite track and field athletes on track? The impact of COVID-19 outbreak on sleep behavior and training characteristics.

The Covid-19 outbreak forced many governments to enter a nationwide lockdown. The aim of this study was to evaluate, by means of a survey, changes in sleep parameters and physical activity characteristics of elite track and field athletes in three periods: before the lockdown (T0), during the lockdown (09th March - 03rd May 2020, T1) and the first month after the lockdown (T2). This study was conducted from May 2020 to June 2020 and data were collected using an offline survey with 89 elite track and field athletes (mean age: 24.7 ± 5.4; n = 43 males; n = 46 females). The survey consisted of demographic data and questions on physical activity and sleep behavior at T0, T1 and T2. Athletes reported lower sleep quality scores at T1 compared to T0 and T2 (p < 0.0001) and registered delayed bedtime, wake-up time and longer sleep latency during the lockdown compared to pre-lockdown and post-lockdown whereas no changes in total sleep time were reported. No inter-group differences were detected in sleep characteristics between short- and long-term disciplines and between genders. The weekly training volume decreased from 16.1 ± 5.7 hours at T0 to 10.7 ± 5.7 hours at T1 (p < 0.0001) whereas no significant differences were detected in training volume during the lockdown in relation to the square footage of the house (p = 0.309). Alcohol (p = 0.136) and caffeine intake (p = 0.990) and use of electronic devices (p = 0.317) were similar pre-, during, and post-lockdown. The unprecedented circumstances of the Covid-19 pandemic had negative impacts on the Italian track and field athletes' sleep and training volumes.

Sleep-Wake Behavior in Elite Athletes: A Mixed-Method Approach.

PURPOSE: Using a mixed-method approach, this investigation aimed to examine athletes' sleeping patterns along with the socio-physiological acute and chronic stressors affecting their sleep. METHODS: Fifteen elite athletes (M age = 21.7 years; SD = 2.2) were monitored daily during a typical in-season training period (20 ± 1 days) and completed individual semi-structured interviews. Their sleep was analyzed using actigraphy and sleep diaries. A content analysis method was used to assess qualitative interviews. RESULTS: Three factors influencing sleep emerged from the qualitative interview analyses, i.e., sleep environment, training and study requirements. Half the athletes (8/15) complained about their sleeping environment with noise and/or bedroom temperature and/or mattress quality and/or light exposure presented as an issue. "Complainers" notably exhibited impaired (p < 0.05) sleep efficiency and wake after sleep onset compared with "non-complainers." Daily training load showed correlations (p < 0.05) with wake after sleep onset and sleep onset latency. "Student athletes" exhibited later bedtime and earlier wake-up time compared with "non-student athletes," leading to a reduced total sleep time (6:50 ± 1:13 vs. 7:06 ± 0:53; p < 0.05; d = 0.20). CONCLUSION: An individualized assessment of sleep using actigraphy and interviews, with consideration to various socio-physiological factors, is recommended. Individualized sleep interventions with consideration to physiological (e.g., training load), behavioral (e.g., screen use) and environmental factors (e.g., room temperature, noise, mattress), can then be provided to each athlete.

Managing Travel Fatigue and Jet Lag in Athletes: A Review and Consensus Statement.

Athletes are increasingly required to travel domestically and internationally, often resulting in travel fatigue and jet lag. Despite considerable agreement that travel fatigue and jet lag can be a real and impactful issue for athletes regarding performance and risk of illness and injury, evidence on optimal assessment and management is lacking. Therefore 26 researchers and/or clinicians with knowledge in travel fatigue, jet lag and sleep in the sports setting, formed an expert panel to formalise a review and consensus document. This manuscript includes definitions of terminology commonly used in the field of circadian physiology, outlines basic information on the human circadian system and how it is affected by time-givers, discusses the causes and consequences of travel fatigue and jet lag, and provides consensus on recommendations for managing travel fatigue and jet lag in athletes. The lack of evidence restricts the strength of recommendations that are possible but the consensus group identified the fundamental principles and interventions to consider for both the assessment and management of travel fatigue and jet lag. These are summarised in travel toolboxes including strategies for pre-flight, during flight and post-flight. The consensus group also outlined specific steps to advance theory and practice in these areas.

Effect of the Depth of Cold Water Immersion on Sleep Architecture and Recovery Among Well-Trained Male Endurance Runners.

Introduction: The aim of the present study was to investigate the effect of the depth of cold water immersion (CWI) (whole-body with head immersed and partial-body CWI) after high-intensity, intermittent running exercise on sleep architecture and recovery kinetics among well-trained runners. Methods: In a randomized, counterbalanced order, 12 well-trained male endurance runners ( V . O2max = 66.0 ± 3.9 ml·min-1·kg-1) performed a simulated trail (≈18:00) on a motorized treadmill followed by CWI (13.3 ± 0.2°C) for 10 min: whole-body immersion including the head (WHOLE; n = 12), partial-body immersion up to the iliac crest (PARTIAL; n = 12), and, finally, an out-of-water control condition (CONT; n = 10). Markers of fatigue and muscle damage-maximal voluntary isometric contraction (MVIC), countermovement jump (CMJ), plasma creatine kinase [CK], and subjective ratings-were recorded until 48 h after the simulated trail. After each condition, nocturnal core body temperature (T core) was measured, whereas sleep and heart rate variability were assessed using polysomnography. Results: There was a lower T core induced by WHOLE than CONT from the end of immersion to 80 min after the start of immersion (p < 0.05). Slow-wave sleep (SWS) proportion was higher (p < 0.05) during the first 180 min of the night in WHOLE compared with PARTIAL. WHOLE and PARTIAL induced a significant (p < 0.05) decrease in arousal for the duration of the night compared with CONT, while only WHOLE decreased limb movements compared with CONT (p < 0.01) for the duration of the night. Heart rate variability analysis showed a significant reduction (p < 0.05) in RMSSD, low frequency (LF), and high frequency (HF) in WHOLE compared with both PARTIAL and CONT during the first sequence of SWS. No differences between conditions were observed for any markers of fatigue and muscle damage (p > 0.05) throughout the 48-h recovery period. Conclusion: WHOLE reduced arousal and limb movement and enhanced SWS proportion during the first part of the night, which may be particularly useful in the athlete's recovery process after exercise. Future studies are, however, required to assess whether such positive sleep outcomes may result in overall recovery optimization.

The Relationships Between Training Load, Type of Sport, and Sleep Among High-Level Adolescent Athletes.

PURPOSE: To evaluate the effects of sporting activities, training loads, and athletes' characteristics on sleep among high-level adolescent athletes, in a controlled training and academic environment. METHODS: A total of 128 high-level adolescent athletes (age = 15.2 [2.0] y), across 9 different sports, completed common sleep questionnaires and were monitored daily (7.3 [2.7] d) during a typical in-season training period. Sleep was analyzed using actigraphy and sleep diaries, whereas training load was evaluated using the session rating of perceived exertion, and muscle soreness and general fatigue were reported with the aid of visual analog scales. Separate linear mixed-effects models were fitted, including the athlete as a random effect and the following variables as fixed effects: the sport practiced (categorical predictor), daily training load, age, and sex. Different models were used to compare sleep variables among sports and to assess the influence of training load, age, and sex. RESULTS: The mean total sleep time was 7.1 (0.7) hours. Swimmers presented increased sleep fragmentation, training loads, perceived muscle soreness, and general fatigue compared with athletes who engaged in other sports. Independent of any sport-specific effects, a higher daily training load induced an earlier bedtime and reduced total sleep time and perceived sleep quality, with higher sleep fragmentation. Moreover, female athletes experienced increased total sleep time and worse sleep quality in response to stress compared with those in males. CONCLUSION: In a controlled training and academic environment, high-level adolescent athletes did not achieve the recommended sleep duration. Impaired sleep quality and quantity could be partially explained by increased training loads.

Exercise-Based Injury Prevention in High-Level and Professional Athletes: Narrative Review and Proposed Standard Operating Procedure for Future Lockdown-Like Contexts After COVID-19.

In regular times, implementing exercise-based injury prevention programs into the training routine of high-level and professional athletes represents a key and challenging aspect to decrease injury risk. Barriers to implementing such prevention programs have previously been identified such as lack of resources, logistic issues or motivation. The COVID-19 pandemic associated with restrictions on daily life dramatically impacted sports participation from training to competition. It is therefore reasonable to assume that such lockdown-like context has exacerbated the challenge to implement exercise-based injury prevention programs, potentially leading to a greater musculoskeletal injury risk. In this narrative review, recommendations are proposed for building an expertise- and evidence-based Standard Operating Procedure for injury prevention in lockdown-like contexts for high-level and professional athletes. The following recommendations can be provided: (1) assess the global and sport-specific risks in the light of the ongoing cause of isolation; (2) adapt remote training materials and programs; (3) ensure regular quality communication within the staff, between athletes and the staff as well as between athletes; (4) follow the athlete's mental well-being; and (5) plan for a safe return-to-sports as well as for an ongoing monitoring of the load-recovery balance. These key domains should further be addressed to comply with local policies, which are subject to change over time in each individual country. The use of these recommendations may improve the readiness of athletes, coaches, physicians and all sports stakeholders for future lockdown-like contexts.

Personality traits, stress appraisals and sleep in young elite athletes: A profile approach.

The aim of this study was to identify young elite athletes' personality profiles using a person-centred approach and to investigate whether the profiles significantly differ in stress and sleep. 260 athletes from a variety of sports completed a questionnaire package to assess neuroticism and conscientiousness traits, stress appraisals (i.e. intensity and directional interpretation of stress, challenge and threat appraisals), and various indicators of sleep (i.e. sleep quality, social jet lag, Ford insomnia response to stress test (FIRST)). A latent profile analysis (LPA) approach was used to identify personality profiles based on the scores of neuroticism and conscientiousness. A multivariate analysis of variance was performed to examine if the athletes belonging to different personality profiles differ on stress appraisals and indicators of sleep. Three profiles emerged: Maladaptive profile (high levels of conscientiousness and neuroticism); Highly adaptive profile (moderate level of conscientiousness and low level of neuroticism); Adaptive profile (high level of conscientiousness and moderate level of neuroticism). Results showed that athletes from the adaptive profile reported significantly lower scores of stress intensity and threat appraisal than those from other profiles. Athletes from the maladaptive profile reported significantly higher levels of FIRST than those from other profiles as well as worse sleep quality and lower levels of challenge appraisal than the athletes from the highly adaptive profile. These results suggest that investigating personality profile may be useful in identifying athletes at higher risk of stress sensitivity and worsening sleep that are likely to benefit from preventive actions (e.g. cognitive behavioural therapy interventions).

Sleep and the athlete: narrative review and 2021 expert consensus recommendations.

Elite athletes are particularly susceptible to sleep inadequacies, characterised by habitual short sleep (<7 hours/night) and poor sleep quality (eg, sleep fragmentation). Athletic performance is reduced by a night or more without sleep, but the influence on performance of partial sleep restriction over 1-3 nights, a more real-world scenario, remains unclear. Studies investigating sleep in athletes often suffer from inadequate experimental control, a lack of females and questions concerning the validity of the chosen sleep assessment tools. Research only scratches the surface on how sleep influences athlete health. Studies in the wider population show that habitually sleeping <7 hours/night increases susceptibility to respiratory infection. Fortunately, much is known about the salient risk factors for sleep inadequacy in athletes, enabling targeted interventions. For example, athlete sleep is influenced by sport-specific factors (relating to training, travel and competition) and non-sport factors (eg, female gender, stress and anxiety). This expert consensus culminates with a sleep toolbox for practitioners (eg, covering sleep education and screening) to mitigate these risk factors and optimise athlete sleep. A one-size-fits-all approach to athlete sleep recommendations (eg, 7-9 hours/night) is unlikely ideal for health and performance. We recommend an individualised approach that should consider the athlete's perceived sleep needs. Research is needed into the benefits of napping and sleep extension (eg, banking sleep).

Effect of an Innovative Mattress and Cryotherapy on Sleep after an Elite Rugby Match.

INTRODUCTION: This study aimed to explore the relationship between elite rugby union match and postmatch sleep architecture and to investigate the effects of a high-heat capacity mattress (MAT) and a whole-body cryotherapy (WBC) session on postmatch sleep architecture. METHODS: Nineteen elite male U23 rugby union players performed in three official matches, followed by three experimental conditions, in a randomized order: MAT, WBC, and no intervention (CONT). Match load was evaluated using GPS trackers and video analyses. Sleep architecture was assessed by polysomnography (PSG). Core body temperature (CBT) and mattress surface temperature were monitored during sleep. Linear mixed-effects models were conducted to assess the effects of each experimental condition on sleep, with match load variables as covariates. RESULTS: A lower wake after sleep onset (ß = -10.5 min, P < 0.01) and higher rapid eye movement sleep proportion (ß = +2.8%, P < 0.05) were reported for MAT compared with CONT. Moreover, lower mean CBT (ß = -0.135°C, P < 0.001) and mean mattress surface temperature (ß = -2.736°C, P < 0.001) during sleep were observed for MAT compared CONT. WBC did not affect nocturnal CBT nor interfere with sleep architecture. For every 100-m increase in high-speed running distance, a higher slow wave sleep (ß = +1.1%, P = 0.05) and lower light sleep proportion (ß = -1.2%, P < 0.05) proportion were observed. Conversely, for every 10 supplementary collisions, lower slow wave sleep (ß = -1.9, P = 0.09) and higher light sleep (ß = +2.9%, P < 0.001) proportion were observed. CONCLUSION: MAT use had a positive effect on sleep architecture after an elite rugby union match, potentially through a more efficient nocturnal heat transfer.

The effect of night-time exercise on sleep architecture among well-trained male endurance runners.

The aim of the present study was to investigate the effects of night-time (21:00 hours) high-intensity, intermittent exercise on sleep architecture among well-trained athletes in a laboratory setting. In a randomized, counterbalanced order, 11 well-trained male runners completed a simulated trail-running exercise (TRAIL) on a motorized treadmill and a resting condition (REST; no exercise during the day). After each condition, nocturnal autonomic nervous system activity and core body temperature (CBT) were measured and sleep was analysed using polysomnography and actigraphy. Markers of muscle damage (maximal voluntary contraction [MVC], plasma creatine kinase concentration [CK] and perceived muscle soreness) were recorded before and immediately (POST), 24 hr (H24) and 48 hr (H48) after exercise. TRAIL induced a high level of fatigue and mild exercise-induced muscle damage, as determined by a reduction in MVC (-9.4%, p < .01, d = -1.36) and increases in [CK] (+176.0%, p < .01, d = 1.49) and perceived muscle soreness (+4.5 UA, p < .01, d = 2.17) compared with REST at H24. A trend for increased non-rapid eye movement (+4.2%; p = .10; d = 0.86) and reduced rapid eye movement (-4.4%; p = .07; d = -0.87) during sleep was observed for TRAIL compared with the REST condition. Moreover, compared with REST, TRAIL significantly increased CBT and nocturnal HR during the first part of the night. In conclusion, sleep architecture was modified after night-time, high-intensity exercise among well-trained runners.

The influence of playing position in soccer on the recovery kinetics of cognitive and physical performance.

BACKGROUND: The physical activity and playing actions performed during a soccer match vary according to player position. The aim of the present study was to analyze the recovery kinetics of cognitive performance, physical performance and subjective ratings after a competitive soccer match. METHODS: Eight goalkeepers and eight outfield players played in the match with data collected before, 45 min, 24 h and 48 h after the match. Subjective ratings, Vienna Reaction Test (reaction time, motor time), Vienna Determination Test (number of stimuli, number of correct responses), squat jump, countermovement jump and 6-s sprint were analyzed. RESULTS: No significant interaction between position and time was found for Vienna Reaction Test and Vienna Determination Test performance. No significant interaction between position and time was found for squat jump and countermovement jump but squat jump and countermovement jump significantly decreased (P<0.01) at 24 h. Countermovement jump performance was still significantly affected at 48h (P<0.05). A significant interaction between position and time (P<0.05) was found for 6-s sprint. Sprint performance was significantly reduced for outfield players only immediately after the match (P<0.01). There was no interaction effect of position and time on subjective ratings. A significant correlation was found between number of jumps and ball kicks performed during the match by goalkeepers and the change score in squat jump (r =-0.90; P<0.01) and countermovement jump (r =-0.90; P<0.01) observed at 48 h. CONCLUSIONS: Outfield players require a longer time than goalkeepers to recover sprint performance whilst cognitive function tested in the present study is not affected by the match whatever the position.

Case Study: Sleep and Injury in Elite Soccer-A Mixed Method Approach.

Nédélec, M, Leduc, C, Dawson, B, Guilhem, G, and Dupont, G. Case study: sleep and injury in elite soccer. A mixed method approach. J Strength Cond Res 33(11): 3085-3091, 2019-This case study allowed an examination of the link between sleep and injury occurrence in an elite male soccer player competing in French League 1 and Union of European Football Associations matches. During 4 months, a mixed method approach was used, combining actigraphic sleep assessment with qualitative interviews on a daily basis. Three injuries were reported over the study period. Sleep onset latency (SOL), both in the single night (117 ± 43 minutes) and in the week (78 ± 50 minutes) before injury occurrence, was longer than preseason baseline values (18 ± 13 minutes; effect size (ES): 3.1 and 1.6, respectively). Similarly, sleep efficiency in the single night (73 ± 7%) and the week (75 ± 7%) before injury occurrence was lower than baseline (90 ± 3%; ES: 3.2 and 2.8, respectively). In this case study, SOL and efficiency were altered on the night and in the week before injury occurrence. Individualized assessment of sleep during congested playing schedules may be useful to aid in preventing injury occurrence.