Sleep Quality, Depression, and Injury Risks in Elite Fencing Athletes
Article information
Abstract
PURPOSE
This study aimed to examine the relationships among sleep quality, depression, and injury risk in elite fencing athletes.
METHODS
This cross-sectional study included 42 elite fencing athletes (aged 19–25 years) who participated in the Korea Junior National Team training camp. The athletes completed validated questionnaires, including the Pittsburgh Sleep Quality Index (PSQI) and Center for Epidemiologic Studies Depression Scale (CES-D). History of injury was assessed using self-reported data.
RESULTS
The CES-D scores were significantly higher in poor sleepers than that in good sleepers (p<0.05). The PSQI scores were significantly higher in the injured group than that in the non-injured group, even after adjusting for age, sex, sports experience, and body mass index (p<0.05). Depression had a significant moderating effect on the relationship between injury status and PSQI scores.
CONCLUSIONS
Poor sleep quality in elite fencing athletes was associated with a higher risk of depression and injury. Depression significantly moderated the relationship between injury and sleep quality. These findings suggest that poor sleep quality may increase depression and injury risk in elite fencing athletes.
INTRODUCTION
Sleep is an essential physiological need that accounts for one-third of the human life cycle. Sleep is considered a biological process that plays a pivotal role in physical recovery and homeostasis, rather than merely a physiological rest. Sleep has been shown to promote the secretion of growth hormones and suppress cortisol secretion, thereby creating an endocrine environment conducive to physical recovery [1]. These hor-monal changes demonstrate that sleep directly contributes to various physiological recovery processes, such as tissue regeneration, muscle recovery, and immune function regulation. Furthermore, inadequate sleep quality has been reported to be associated with negative psychological factors including anxiety and depression [2].
Sleep quality is a critical factor in the recovery of athletes and the prevention of injuries. Recent studies have indicated that athletes exhibit poorer sleep quality compared with nonathletes. Specifically, athletes have reported sleeping difficulties following competitions [3]. Similarly, approximately 40% of college athletes are reported to sleep seven hours or less during the week, with 51% experiencing fatigue during the day [4]. In athletes, impaired sleep quality has been reported to be associated with increased cortisol, impaired muscle glycogen recovery, cognitive changes, and increased mental fatigue [5]. Furthermore, stress induced by accumulated training has been demonstrated to impair muscle function, thereby reducing stability and increasing injury risk, which can subsequently affect performance [6]. Consequently, the physical recovery process that occurs during sleep is recognized as a critical component of training efficacy and the maintenance of athletic ability [7-9].
Sleep disorders are a prevalent feature of various diseases, including depression, bipolar disorder, post-traumatic stress disorder, and other anxiety disorders [10]. Previous studies have indicated that a significant proportion of college athletes are affected by depression, with 15.6–21.0% (one in five) experiencing symptoms [11,12]. A previous study of 958 athletes revealed that 28.8% exhibited anxiety symptoms and 21.7% depression symptoms. Furthermore, athletes with anxiety symptoms have demonstrated a 2.3-fold increased likelihood of sustaining injuries [13]. In particular, elite athletes, who undergo rigorous training regimens, fre-quent competition, and psychological stress, are expected to be more vulnerable to insufficient sleep, depression, and injury.
Fencing is a sport that demands rapid decision-making, exacting movements, and strategic thinking to anticipate the opponent's actions. The efficacy of these skills is contingent upon optimal cognitive and physical function [14]. Indeed, sleep is closely related to various cognitive abilities, including attention, concentration, reaction speed, memory, and executive function, which are essential elements in fencing. Sleep deprivation has been demonstrated to impair concentration and reaction speed, thereby negatively affecting the accuracy of fencing movements. Furthermore, the risk of injury during competition may be increased by cognitive decline and carelessness caused by sleep deprivation [15,16]. Furthermore, the high level of psychological pressure and concentration required during competitions has been shown to result in mental health issues among fencers, with a high risk of developing symptoms of depression. However, there is a paucity of studies that have been conducted to empirically analyze the association of sleep quality with depression and injury risks in elite fencers.
Therefore, the aim of this study was to ascertain the correlation of sleep quality with depression and injury risks in elite fencers, to demonstrate the importance of sleep management in maintaining the performance of fencers and preventing injuries.
METHODS
1. Participants
This study was conducted in a sample of 47 fencers selected as the next generation of Korean national representatives in 2023. Prior to study initiation, all participants were provided with a comprehensive ex-planation of the purpose and procedures of the study. They were also re-quested to sign a consent form for voluntary participation. After excluding five participants with missing data, the final analysis was conducted with the data collected from 42 participants. All research procedures were approved by the Institutional Review Board (IRB) of the Korea Institute of Sport Science (Approval No. KISS-23020-2307-02).
2. Procedure
This study was conducted as a cross-sectional analysis targeting fencers selected for the 2023 Korean Next Generation National Team Proj-ect. Participants completed a self-reported questionnaire under the su-pervision of the investigator in an undisturbed, stable environment, providing demographic and athlete-related information (age, athletic experience, history of injury, etc.) as well as sleep habits, sleep quality, circadi-an rhythm type, and depressive symptoms, followed by physical measurements (Table 1).
Characteristics of study participants according to sleep quality
3. Data collection
1) Sleep quality
Sleep quality was evaluated using the Korean version of the Pittsburgh Sleep Quality Index (PSQI) [17]. This scale is used to measure overall sleep quality by separately assessing seven components: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep distribution, sleep medication, and daytime dysfunction. Total PSQI scores ranges from 0 to 21, with higher scores indicating low sleep quality. Participants were classified as follows: good sleepers (score <5.5) and poor sleepers (score ≥5.5) [18].
2) Depression
The severity of depression was gauged employing the Center for Epidemiological Studies-Depression Scale (CES-D), a self-report scale [19]. This scale consisted of 20 items, measuring the frequency of depressive symptoms experienced over the past week. The scores ranged from 0 to 60, with a higher score indicating a higher level of depression. A total score ≤20 points was regarded as normal, whereas >21 points was classified as indicative of depressive symptoms [20].
4. Investigation of injuries
Injury status was investigated using a self-report questionnaire. The injury questionnaire underwent modifications and supplementations based on the Injury Report Form of the International Olympic Com-mittee (IOC) to suit domestic sports sites, and was reviewed by experts. The questionnaire was designed to collect information such as injury experience during the athletic career, injury location, diagnosis, timing of occurrence (training/competition), status (new/recurring/worsening), cause, extent of training restrictions post-injury, treatment, and current pain. Injuries were defined as any musculoskeletal injury diagnosed by healthcare professionals [21].
5. Data processing
Continuous variables were expressed as mean±standard error, and categorical variables were expressed as frequencies and percentages (%). Normality was assessed using the Shapiro–Wilk test. When normality was satisfied, independent t-tests were employed for statistical analysis. Conversely, when normality was not met, the Mann–Whitney U test (nonparametric test) was utilized for data evaluation. Furthermore, factors that could influence depression and sleep quality (age, sex, body mass index [BMI, kg/m2], and length of athletic career [months]) were designated as covariates, and analysis of covariance (ANCOVA) was conducted to evaluate the relationship between sleep quality and depression, injury status, and sleep quality. A hierarchical regression analysis was performed to investigate the effect of depressive symptoms on the relationship between injury and sleep quality, based on the methodology devel-oped by Baron and Kenny [22]. In this procedure, the first step involves establishing a rudimentary model is established through the incorporation of independent and moderator variables; the subsequent step involves incorporating dependent variables; and the final step involves interaction terms between independent and moderator variables being added to ascertain the significance of the moderating effect. The moderating effect is determined by the significance of the interaction term [22]. All statistical analyses were performed using IBM SPSS Statistics version 29.0 (IBM Inc., Chicago, IL, USA), and the statistical significance level was set at p <.05.
Effect size was calculated using Cohen's d value, a standardized measure for continuous variables, and classified according as small (d≤0.2), medium (0.2≤ d≤0.8), or large (d >0.8) [23].
RESULTS
1. Physical characteristics of the participants
Among the 42 elite fencers included in this study, mean age, BMI, and exercise history were 22.1±1.8 years, 22.7±2.0 kg/m2, and 116.3±19.5 months, respectively. Based on a PSQI cut-off score of 5.5, participants were classified as good sleepers (n=14, 33.3%), and poor sleepers (n=28, 66.7%). No significant differences were observed between good sleepers and poor sleepers in terms of physical characteristics (Table 1). A comprehensive investigation into their sleep characteristics revealed that poor sleepers exhibited significantly higher sleep latency than good sleepers (good sleepers; 13.2±7.0 minutes vs. poor sleepers; 39.4±34.8 minutes; p<.01). In addition, total sleep time (7.7±1.4 vs. 6.4±1.2 hours; p <.01) and sleep efficiency (97.6±3.3 vs. 90.5±11.7%; p <.01) significantly lower in poor sleepers than in good sleepers (Table 2).
Comparison of sleep components according to sleep quality
2. Comparison of depression status by sleep quality classification
After controlling for covariates (age, sex, BMI, and length of athletic career), poor sleepers showed significantly higher depression levels than good sleepers (13.5±6.94 vs. 18.25±9.13 points; p <.05) (Fig. 1).
CES-D (Center for Epidemiological Studies-Depression Scale) scores according to sleep quality. ANCOVA was conducted after adjusting for age, sex, BMI, and length of athletic career. PSQI, Pittsburgh Sleep Quality In-dex; CES-D, Center for Epidemiological Studies-Depression Scale. * p<.05.
3. Comparison of sleep quality components by injury status
After controlling for covariates (age, sex, BMI, and length of athletic career), PSQI scores were higher in the injured than in the non-injured group (6.0±2.4 vs. 8.2±3.9 points; p <.05) (Fig. 2). Moreover, the sleep quality component sleep latency was higher in the injured group (p =.08, d >0.8) (Table 3).
PSQI (Pittsburgh Sleep Quality Index) scores according to injury status. ANCOVA was conducted after adjusting for age, sex, BMI, and length of athletic career. PSQI, Pittsburgh Sleep Quality Index. * p<.05.
Comparison of PSQI components by Injury status
4. Moderating effect of depression on the relationship between injury and sleep quality
In analyzing the moderating effect of depression on the relationship between injury status and sleep quality, injury status showed a significant effect on sleep quality in the first step (p <.05). In the second step of the analysis, depression showed a significant effect on sleep quality (p <.05), and R2 increased from 0.11 to 0.22, indicating an increase in ex-planatory power. This moderating effect of depression level signifies that the impact of injury on sleep quality markedly increases with depression levels (Fig. 3, Table 4).
Moderating effect of depression on the sleep relationship between injury and sleep quality solid arrows indicate direct associations, and dashed arrows indicate moderate associations.
Moderating effect of depression on the relationship between injury and sleep quality
DISCUSSION
The primary objective of this study was to verify the relationship between sleep quality, depression, and injury in 42 elite fencers. The findings revealed that inadequate sleep quality in elite fencers exerted a detrimental influence on depressive symptoms and injury incidence. Even after controlling for age, sex, BMI, and athletic career, poor sleep quality was associated with elevated levels of depression and injury risk. In addition, depression showed a significant moderating effect on the relationship between injury and sleep quality. These findings suggest that higher levels of depression are associated with an increased risk of injury-related sleep quality impairment.
Among the fencers who participated in this study, 66.7% were classified as having low sleep quality (PSQI≥5.5), consistent with the results of previous studies conducted among elite athletes. A previous study of sleep quality in 479 elite athletes revealed that 52% had poor sleep quality, characterized by long sleep latency, total sleep time, and low sleep efficiency [24]. These findings indicate not declines in both subjective sleep satisfaction and objective sleep structure. Bender et al. [25] reported that athletes exhibited longer sleep latency and lower overall sleep quality compared with nonathletes. In addition, Cameron et al. [26] reported that athletes exhibited a greater total sleep duration compared with nonathletes but a lower regularity in sleep and poorer quality in their sleep environment. These findings underscore the significance of not only the quantitative aspect of sleep, defined by its duration, but also the qualitative elements of sleep regularity and the influence of the environment. Fencing is a sport that demands agility, reaction speed, and concentration. These characteristics are closely related to sleep quality. Neverthe-less, it is noteworthy that the fencers who participated in the present study exhibited a general tendency to experience insufficient sleep. Sleep deprivation has been demonstrated to exert a detrimental effect on the psychological and physiological recovery of athletes, as well as on their athletic performance, suggesting the need for a systematic intervention to manage sleep in elite fencers.
A comparison of depression levels between good and poor sleepers revealed significantly higher levels in the latter, consistent with previous findings that link sleep disturbances to mental health outcomes in elite athletes [18]. Jiang et al. [27] reported that depressive symptoms tended to worsen as sleep quality scores increased. Moreover, studies have indicated that sleep components reduce in the presence of depression. Joo et al. [28] reported that lower sleep quality was associated with a higher likelihood of depressive symptoms, and Gao & Wang [29] reported a significant correlation between sleep quality and depressive symptoms in athletes. Elite athletes experience training intensity, competitive pressure, and performance demands that exceed those of the general population, often resulting reduced sleep quality. Such declines can negatively impact fatigue recovery and emotional stability, thereby exacerbating depressive symptoms. Sleep problems among elite athletes are of particular concern because of their multifaceted nature, which is influenced by factors such as training environments and competition schedules in addition to personal issues. Accordingly, there is a compelling need to enhance the sleep quality of elite fencers and to detect and address depressive symptoms at an early stage, as this can ultimately contribute to the enhancement of their performance.
The analysis of differences in sleep quality according to injury status revealed that the injured group had significantly lower sleep quality, suggesting a strong association between injury and sleep quality. In particular, injury was associated with the sleep latency component, with a very high effect size (≥0.8), suggesting that injury status may affect the qualitative characteristics of sleep. A study of the United States Special Forces soldiers showed diminished sleep quality among those with musculoskeletal injuries [30]. In addition, athletes who get less than 8 hours of sleep per day have been reported to be 1.7 times more likely to sustain injuries [31]. Altogether, these findings indicate a close correlation between sleep quality and injury incidence in athletes, suggesting that sleep should be regarded as an important factor in both recovery and injury prevention. Future studies are required to determine whether poor sleep quality truly increases injury risk and to investigate methods for preventing injuries through improved sleep.
This study has several limitations. First, the sample size of 42 is relatively small, limiting the generalizability of the results to all fencers or elite athletes of other age groups. Given the potential variability in sleep and psychological characteristics influenced by factors such as sex, age, training intensity, and competition level, future studies should include larger samples encompassing athletes with a wider range of characteristics and backgrounds. Second, sleep, the main variable in this study, was assessed using self-report questionnaires, which may have been influenced by subjective perceptions or reporting biases. Future studies could enhance the reliability of results by incorporating objective sleep measurement methods, such as wearable devices or polysomnography. Third, owing to the nature of fencing, external factors (e.g., contact with opponents, use of equipment, and competition space) may influence injury occurrence. However, this study was focused on internal factors. Future studies should therefore include a variety of injury-related factors. Despite these limitations, this study possesses academic significance by providing a comprehensive analysis of the relationships between sleep quality, depression, and injury in elite fencers. Consequently, it serves as a basis for future health management and intervention strategies for athletes.
CONCLUSION
This study was conducted to examine the relationships between sleep quality, depression, and injury in elite fencers, as well as the moderating effect of depression on the relationship between injury and sleep quality. The results showed an association between sleep quality decline and high levels of depression and increased injury risk. Moderation analysis revealed that higher levels of depression were associated with an increased risk of sleep quality decline due to injury. These findings suggest that sleep quality may influence emotional health and physical condition in elite fencers, highlighting the need for systematic sleep assessment and intervention to be incorporated into athlete management programs. Future studies should incorporate a more diverse array of variables and longitudinal designs to elucidate the causal relationships between sleep quality, depression, and injury.
Notes
CONFLICT OF INTEREST
The authors declare that they have not received any financial or other support from any organization in the preparation of this study, and that there are no relationships that could influence the content of this study.
AUTHOR CONTRIBUTIONS
Conceptualization: Y Choi, J Cho; Data curation: S Kim, Y Choi, SH Park, K Kim, HB Kwak, J Cho; Formal analysis: S Kim, Y Choi, J Cho; Methodology: RK Kim, T Kim, J Cho; Writing-original draft: S Kim, Y Choi; Writing-review & editing: S Kim, T Kim, Y Choi, J Cho.