Effects of physical activity participation on cognitive impairment in older adults population with disabilities.

Background: Existing research on the association between cognitive function and physical activity in the older adults population with disabilities is limited. Additionally, there is a need to explore avenues for enhancing the longevity and quality of life among these individuals. Objective: This study aimed to investigate the independent and joint associations between cognitive function and levels of physical activity in the older adults population with disabilities. Methods: A total of 315 older adults adults (men = 182, women = 133), identified with disabilities based on medical evaluation, were recruited from the first survey of the Korean Longitudinal Study of Aging (KLoSA). Participants underwent assessments for cognitive function, physical activity (PA), activities of daily living (ADLs), instrumental activities of daily living (IADLs), and grip strength. Results: ADLs (p < 0.001) and IADLs (p < 0.001) scores were significantly higher in the male normal cognitive group compared to both the male and female cognitive impairment groups. In an unadjusted model, disabled older adults individuals who did not meet the recommended PA guidelines showed an increased odds ratio for cognitive dysfunction (OR = 2.29, 95% CI = 1.32-3.97). Those participating in PA at least 1 day per week also demonstrated an elevated odds ratio (OR = 1.22, 95% CI = 1.08-1.38) for cognitive dysfunction compared to those who engaged in regular PA. A negative correlation was observed between K-MMSE scores and grip strength (r = 0.448, p < 0.001). Conclusion: This study provides robust evidence that disabled older adults individuals who do not meet the recommended guidelines for PA or who do not participate in PA at least once a week have an increased likelihood of cognitive impairment compared to those who are regularly active.

Exercise therapy for sarcopenia and diabetes.

Aging is characterized by the gradual deterioration of function at the molecular, cellular, tissue, and organism levels in humans. The typical diseases caused by changes in body composition, as well as functional decline in the human body's organs due to aging include sarcopenia and metabolic disorders. The accumulation of dysfunctional aging ß cells with age can cause decreased glucose tolerance and diabetes. Muscle decline has a multifactorial origin, involving lifestyle habits, disease triggers, and age-dependent biological changes. The reduced function of ß cells in elderly people lowers insulin sensitivity, which affects protein synthesis and interferes with muscle synthesis. The functional decrease and aggravation of disease in elderly people with less regular exercise or physical activity causes imbalances in food intake and a continuous, vicious cycle. In contrast, resistance exercise increases the function of ß cells and protein synthesis in elderly people. In this review, we discuss regular physical activities or exercises to prevent and improve health, which is sarcopenia as decreased muscle mass and metabolic disorders as diabetes in the elderly.

Eflapegrastim versus Pegfilgrastim for Chemotherapy-Induced Neutropenia in Korean and Asian Patients with Early Breast Cancer: Results from the Two Phase III ADVANCE and RECOVER Studies.

PURPOSE: We investigated the consistent efficacy and safety of eflapegrastim, a novel long-acting granulocyte-colony stimulating factor (G-CSF), in Koreans and Asians compared with the pooled population of two global phase 3 trials. Materials and Methods: Two phase 3 trials (ADVANCE and RECOVER) evaluated the efficacy and safety of fixed-dose eflapegrastim (13.2 mg/0.6 mL [3.6 mg G-CSF equivalent]) compared to pegfilgrastim (6 mg based on G-CSF) in breast cancer patients who received neoadjuvant or adjuvant docetaxel/cyclophosphamide. The primary objective was to demonstrate non-inferiority of eflapegrastim compared to pegfilgrastim in mean duration of severe neutropenia (DSN) in cycle 1, in Korean and Asian subpopulations. RESULTS: Among a total of 643 patients randomized to eflapegrastim (n=314) or pegfilgrastim (n=329), 54 Asians (29 to eflapegrastim and 25 to pegfilgrastim) including 28 Koreans (14 to both eflapegrastim and pegfilgrastim) were enrolled. The primary endpoint, DSN in cycle 1 in the eflapegrastim arm was non-inferior to the pegfilgrastim arm in Koreans and Asians. The DSN difference between the eflapegrastim and pegfilgrastim arms was consistent across populations: -0.120 days (95% confidence interval [CI], -0.227 to -0.016), -0.288 (95% CI, -0.714 to 0.143), and -0.267 (95% CI, -0.697 to 0.110) for pooled population, Koreans and Asians, respectively. There were few treatment-related adverse events that caused discontinuation of eflapegrastim (1.9%) or pegfilgrastim (1.5%) in total and no notable trends or differences across patient populations. CONCLUSION: This study may suggest that eflapegrastim showed non-inferior efficacy and similar safety compared to pegfilgrastim in Koreans and Asians, consistently with those of pooled population.

Impacts of Subtype on Clinical Feature and Outcome of Male Breast Cancer: Multicenter Study in Korea (KCSG BR16-09).

PURPOSE: The treatment of male breast cancer (MBC) has been extrapolated from female breast cancer (FBC) because of its rarity despite their different clinicopathologic characteristics. We aimed to investigate the distribution of intrinsic subtypes based on immunohistochemistry, their clinical impact, and treatment pattern in clinical practice through a multicenter study in Korea. MATERIALS AND METHODS: We retrospectively analyzed clinical data of 248 MBC patients from 18 institutions across the country from January 1995 to July 2016. RESULTS: The median age of MBC patients was 63 years (range, 25 to 102 years). Among 148 intrinsic subtype classified patients, 61 (41.2%), 44 (29.7%), 29 (19.5%), and 14 (9.5%) were luminal A, luminal B, human epidermal growth factor receptor 2, and triple-negative breast cancer, respectively. Luminal A subtype showed trends for superior survival compared to other subtypes. Most hormone receptor-positive patients (166 patients, 82.6%) received adjuvant endocrine treatment. Five-year completion of adjuvant endocrine treatment was associated with superior disease-free survival (DFS) in patients classified with an intrinsic subtype (hazard ratio [HR], 0.15; 95% confidence interval [CI], 0.04 to 0.49; p=0.002) and in all patients (HR, 0.16; 95% CI, 0.05 to 0.54; p=0.003). CONCLUSION: Distribution of subtypes of MBC was similar to FBC and luminal type A was most common. Overall survival tended to be improved for luminal A subtype, although there was no statistical significance. Completion of adjuvant endocrine treatment was associated with prolonged DFS in intrinsic subtype classified patients. MBC patients tended to receive less treatment. MBC patients should receive standard treatment according to guidelines as FBC patients.

Effects of Black Maca supplement on isokinetics muscular performance of elite women's handball players: placebo-controlled, crossover study.

Background: The aim of this study was to investigate the changes in isokinetic muscular performance among female adolescent elite handball athletes with the supplementation of Black Maca (BM). Methods: Eight elite handball athletes were recruited for the present study. The intake capsules contained 2,500 mg of 100% concentrated BM extract and a placebo each, for 4 weeks. Isokinetic muscular performance and physical fitness were measured three times at 4-week intervals after the intake of BM and placebo, including baseline. Results: The one-way Analysis of Variance (ANOVA) analysis showed a significant improvement in 20 m-shuttle run (P < 0.001), 30°/s flexor (P < 0.01), and 120°/s flexor (P < 0.01) in isokinetic muscle function of the trunk, and 180°/s right extensor (P < 0.05), 180°/s left extensor (P < 0.05), and 180°/s left flexor (P < 0.01) in isokinetic muscle function of the knee, after BM supplementation. Post-hoc analysis indicated that the BM group had significantly higher results compared to the baseline and placebo groups in terms of 20 m-shuttle run, 30°/s flexor and 120°/s flexor of the trunk, 180°/s right extensor, 180°/s left extensor, and 180°/s left flexor of the knee. Conclusion: BM supplementation can have a positive effect on improving the performance of elite handball players who engage in high-intensity movements by enhancing their isokinetic muscle function and endurance.

COVID-19 Prevention Guidance and the Incidence of Febrile Neutropenia in Patients with Breast Cancer Receiving TAC Chemotherapy with Prophylactic Pegfilgrastim.

Chemotherapy-induced febrile neutropenia (FN) is a medical emergency that causes severe adverse effects and death. Respiratory infections are one of the main causes of fever in patients with FN. We studied whether infection prevention and control (IPC) guidance for coronavirus 2019 disease reduced the incidence of FN. We reviewed female patients with breast cancer treated with adjuvant docetaxel, doxorubicin, and cyclophosphamide with prophylactic pegfilgrastim between 2019 and 2021. IPC guidance was implemented in April 2020. There was no difference in the incidence of chemotherapy-induced neutropenia between patients with and without IPC. In patients with IPC, the incidence of FN (9.5%) was lower than that of patients without IPC (27.9%). The hospitalization duration (0.7 ± 1.5 days) and total hospital cost (279.6 ± 42.6 USD) of the IPC group were significantly lower than that of the non-IPC group (2.0 ± 3.8 days and 364.7 ± 271.6 USD, respectively). IPC guidance should be implemented to prevent FN in high-risk patients with breast cancer.

Usefulness of Hounsfield Units and the Serum Neutrophil-to-Lymphocyte Ratio as Prognostic Factors in Patients with Breast Cancer.

Breast cancer is a leading cause of death worldwide. Tumor vascularity and immune disturbances are hallmarks of cancer. This study aimed to investigate the reciprocal effect of tumor vascularity, assessed by the tumor-to-aorta ratio (TAR) of Hounsfield units (HU) on computed tomography (CT), and host immunity, represented by the serum neutrophil-to-lymphocyte ratio (NLR) from peripheral, complete blood cell counts and its impact on patient survival. Female patients with breast cancer who received primary treatment between 2003 and 2018 at Wonju Severance Hospital, Korea, were included. The final cohort included 740 patients with a mean age of 54.3 ± 11.3 (22−89) years. The TAR was 0.347 ± 0.108 (range, 0.062−1.114) and the NLR was 2.29 ± 1.53 (0.61−10.47). The cut-off value for the TAR and NLR were 0.27 and 1.61, respectively. The patients with a TAR > 0.27 showed a poor recurrence free-interval (RFI) only when their NLR was larger than 1.61, and vice versa. The patients showed worse RFI when they had both high TAR and NLR. Our results suggest a dynamic reciprocal communication between tumor vascularity and systemic immunity.

Effects of Leisure-Time Physical Activity on Cognitive Reserve Biomarkers and Leisure Motivation in the Pre-Diabetes Elderly.

The purpose of this study was to investigate the change in cognitive reserve biomarkers of the pre-diabetic individual according to the types of leisure-time physical activity (aerobic or resistance physical activity). The research subjects (n = 184) who participated in the survey were pre-diabetic and diabetic patients who were visiting university hospitals and welfare centers. The intervention subjects (n = 36) who were elderly females with pre-diabetes volunteered to participate in the study by performing regular physical exercise (aerobic or resistance exercise). The study participants were 65 years of age or older with pre-diabetes defined by a glycated hemoglobin (HbA1c) level of (5.7−6.4)%. All research subjects performed motivation and stress questionnaire survey. All intervention subjects participated in leisure-time physical activity (LTPA) for 12 weeks. Body composition, HbA1c, and cognitive reserve biomarkers were measured at baseline, and at 6 and 12 weeks. LTPA motivation confirmed that the LTPA participants had a high level of motivation. Stress confirmed that the stress level of LTPA participants was low. Two-way within-factor ANOVA revealed significant group × time interaction for weight (p < 0.05), BMI (p < 0.01), % fat (p < 0.001), SBP (p < 0.05), HbA1c (p < 0.001), BDNF (p < 0.001), and Beta-Amyloid 1−42 (p < 0.001). In both physical activity groups, HbA1c (p < 0.001), NGF (p < 0.05), BDNF (p < 0.05), and Cathepsin B (p < 0.05) improved significantly at 12 weeks, compared to baseline and 6 weeks. In the resistance physical activity group, Beta-Amyloid 1−42 (p < 0.01) and Homocysteine (p < 0.05) significantly decreased at 12 weeks, compared to baseline and at 6 weeks. The LTPA showed high levels of integrated and identified regulation among leisure motive types, and the level of stress was found to be low. The LTPA is effective in reducing the HbA1c levels of the pre-diabetes elderly. In addition, the pre-diabetes elderly were found to have increased NGF, BDNF, and cathepsin B, and decreased Beta-Amyloid 1−42 and homocysteine. Regular leisure-time physical activity has a positive effect on cognitive reserve biomarkers through improving glycemic control by reducing weight and % fat in the pre-diabetes elderly.

Variation in myokine and adipokine levels according to menstrual cycle following regular resistance exercise.

BACKGROUND: The purpose of this study was to analyze the differences between myokine and adipokine factors under stable conditions according to the menstrual cycle (luteal and follicular phases) and to investigate the effect of regular resistance exercise on the changes in myokine and adipokine factors according to menstrual cycle in obese female college students. METHODS: The study participants were female college students with a body fat percentage of 30% or more (N.=20), divided into two groups: luteal phase (N.=12) and follicular phase (N.=8). They performed regular resistance exercise three times a week, 60 minutes daily, for 16 weeks. Parameters measured include body composition via impedance, visceral fat area using computed tomography and myokine and adipokine factors in blood. RESULTS: Levels of BDNF (P<0.05), NGF (P<0.01), and adiponectin (P<0.01) were significantly increased in the luteal phase group after 16 weeks relative to the baseline values. Leptin (P<0.01) was significantly decreased in the luteal phase group after 16 weeks. Weight, Body Mass Index, %fat, and visceral fat area were significantly decreased in both groups after 16 weeks. Muscle mass was significantly increased in both groups after 16 weeks. CONCLUSIONS: Regular resistance exercise affected the reduction in visceral fat area and had a positive effect on body composition which might be altered favorably by myokines and adipokines. Thus, the timing of blood collection is very important in obese female college students.

Differences in body composition and physical fitness of Korean national bobsleigh and skeleton athletes.

BACKGROUND: The aim of this study was to classify Olympic medalists and non-medalists among national bobsled and skeleton athletes and determine the physical fitness differences between the two groups. METHODS: Five bobsleigh and skeleton athletes who won gold and silver medals in the 2018 Pyeongchang Winter Olympics and 11 national bobsled and skeleton team athletes were recruited. The participants were assessed for physiological parameters such as body composition, anthropometry, physical fitness, isokinetic strength, and maximum strength. RESULTS: Physical fitness factors back strength (t=2.571, P<0.05), squat ability (t=3.061, P<0.01), and left and right leg curls (t=4.578, P<0.001; t=4.719, P<0.001, respectively) were significantly different between the groups. The original value of the primary discriminant analysis was 1.868 and the canonical correlation was 0.807. The average value of the discriminant function of the medalists was 1.896, while the of the non-medalists was -0.862, indicating that the two groups were completely different. CONCLUSIONS: Medalists have higher squat abilities, abdominal strength, and leg curl strength than non-medalists, particular regarding hamstring strength. Currently, in most sports events, athletes undergo physical training to improve performance; however, training programs that reflect the characteristics of the sport and the physical characteristics of excellent athletes are still insufficient.

Comparison of the Data of a Next-Generation Sequencing Panel from K-MASTER Project with That of Orthogonal Methods for Detecting Targetable Genetic Alterations.

PURPOSE: K-MASTER project is a Korean national precision medicine platform that screened actionable mutations by analyzing next-generation sequencing (NGS) of solid tumor patients. We compared gene analyses between NGS panel from the K-MASTER project and orthogonal methods. MATERIALS AND METHODS: Colorectal, breast, non-small cell lung, and gastric cancer patients were included. We compared NGS results from K-MASTER projects with those of non-NGS orthogonal methods (KRAS, NRAS, and BRAF mutations in colorectal cancer [CRC]; epidermal growth factor receptor [EGFR], anaplastic lymphoma kinase [ALK] fusion, and reactive oxygen species 1 [ROS1] fusion in non-small cell lung cancer [NSCLC], and Erb-B2 receptor tyrosine kinase 2 (ERBB2) positivity in breast and gastric cancers). RESULTS: In the CRC cohort (n=225), the sensitivity and specificity of NGS were 87.4% and 79.3% (KRAS); 88.9% and 98.9% (NRAS); and 77.8% and 100.0% (BRAF), respectively. In the NSCLC cohort (n=109), the sensitivity and specificity of NGS for EGFR were 86.2% and 97.5%, respectively. The concordance rate for ALK fusion was 100%, but ROS1 fusion was positive in only one of three cases that were positive in orthogonal tests. In the breast cancer cohort (n=260), ERBB2 amplification was detected in 45 by NGS. Compared with orthogonal methods that integrated immunohistochemistry and in situ hybridization, sensitivity and specificity were 53.7% and 99.4%, respectively. In the gastric cancer cohort (n=64), ERBB2 amplification was detected in six by NGS. Compared with orthogonal methods, sensitivity and specificity were 62.5% and 98.2%, respectively. CONCLUSION: The results of the K-MASTER NGS panel and orthogonal methods showed a different degree of agreement for each genetic alteration, but generally showed a high agreement rate.

Phase II study of DHP107 (oral paclitaxel) in the first-line treatment of HER2-negative recurrent or metastatic breast cancer (OPTIMAL study).

BACKGROUND: Standard intravenous (IV) paclitaxel is associated with hypersensitivity/toxicity. Alternative IV formulations have improved tolerability but still require frequent hospital visits and IV infusion. DHP107 is a novel oral formulation of paclitaxel that is approved in South Korea for the treatment of gastric cancer. METHODS: This multicenter, phase II study using a Simon's two-stage design investigated the efficacy and safety of DHP107 200 mg/m2 administered orally twice daily on days 1, 8, and 15 every 4 weeks for the first-line treatment of recurrent or metastatic HER2-negative breast cancer. RESULTS: Thirty-six patients were enrolled and 31 were assessable for efficacy. Patient median age was 57 years (range = 34-81) and 11 (31%) had triple-negative disease. A median of seven cycles (range = 1-28) of DHP107 was administered. Objective response rate was 55% (17 patients), all partial responses, according to the investigator's decision and independent central review (ICR), and 44% (4/9 patients) in those with triple-negative disease. Disease control rate (partial response and stable disease) was 74% (23 patients) according to the investigator's decision and ICR. In the intention-to-treat (ITT) population of all enrolled participants, the objective response rate was 50% (18/36 patients). Median progression-free survival was 8.9 months [95% confidence interval [CI]: 5.2-12.3) and median time to treatment failure was 8.0 months (95% CI: 4.2-10.0). DHP107 had an acceptable toxicity profile. All patients experienced treatment-emergent adverse events; the most common adverse events were decreased neutrophil count (81% all grades and 78% grade ⩾ 3) followed by peripheral sensory neuropathy (61% all grades and 8% grade 3). However, there was no febrile neutropenia or sepsis. CONCLUSION: DHP107 showed promising efficacy and acceptable tolerability in this phase II study and is currently being investigated in the OPTIMAL phase III study (NCT03315364). TRIAL REGISTRATION: This trial was registered with ClinicalTrials.gov identifier: NCT03315364.

Relationship between metabolic syndrome and moderate-to-vigorous physical activity among adults 18 years old and over.

The prevalence of metabolic syndrome (MetS) risk factors among the Korean population requires effective health surveillance and examination of the effects of preventative behaviors. Thus, the objective of this study is to evaluate the relationships between the clustering of MetS and MVPA in a large sample of 36,987 Koreans ranging from 20 to 80 years of age. This study recruited a total of 36,987 adults (23,813 males and 13,174 females). All participants were assessed for moderate-to-vigorous physical activity (MVPA) using the Korean version short form of the International Physical Activity Questionnaire (IPAQ). The International Diabetes Federation and the Adult Treatment Panel III criteria for blood pressure, hyperglycemia, low high-density lipoprotein cholesterol (HDL-C), and high triglycerides (TG) defined MetS. Waist circumference (WC) was determined by Asian-Pacific region populations. According to the 150-minute MVPA, there were differences in MetS risk factors in young adult males, and only three factors (WC, HDL-C, and TG) were different males in ≥ 70 years old. In females, there was a difference in MetS risk factors in the elderly, and only three factors (WC, blood pressure, and TG) were different females in ≤ 29 years old. The males who did not met the recommended MVPA had a 1.16 to 3.14 -times increase in the MetS risk factors. The females who did not met the recommended MVPA had a 1.18 to 2.57 -times increase in the MetS risk factors. Our study provides evidence that Korean adults who do not engage in recommended MVPA levels increase the odds ratio for each of the MetS risk factors when compared to those who meet the recommendations.

The effect of whole body vibration on the sprint ability of Korean national bobsled and skeleton athletes.

This study aims to find out whether whole body vibration has an effect on the sprint ability to shorten the time of bobsled-skeleton athletes. Seventeen bobsled-skeleton athletes (male = 11, female = 6) were recruited from Korea Winter Olympics National Team. Participants were randomly assigned to either a sprint immediately after whole body vibration or a sprint without whole body vibration protocol during two separate visits by a period of 3 months. To evaluate the effects of the sprint ability, measurements were performed 60-m sprint recorded test. In males, at the 45m (p<0.05) significant faster sprint section record after WBV more than Non-WBV. In females, at the 15m (p<0.05), 30m (p<0.01), 45m (p<0.05), and 60m (p<0.05) significant faster sprint section record after WBV more than Non-WBV. In males, at the 30m (p<0.05), 45m (p<0.05), and 50m (p<0.05) significant faster sprint cumulative record after WBV more than Non-WBV. In females, at the 15m (p<0.05), 30m (p<0.05), 45m (p<0.01), 50m (p<0.01), and 60m (p<0.01) significant faster sprint cumulative record after WBV more than Non-WBV. This study indicated that significant faster after WBV more than Non-WBV in males and females bobsled-skeleton athletes.

Effect of Resistance Exercise on the Lipolysis Pathway in Obese Pre- and Postmenopausal Women.

Physical exercise may stimulate lipolytic activity within adipose tissue. Furthermore, resistance exercise may contribute to the more efficient reduction in adipose tissue mass and prevent the accumulation thereof in obese women. The purpose of this study was to examine the effects of regular resistance exercise for 12 weeks on the lipolysis pathway in women with obesity. Twenty-three pre- and postmenopausal women with body fat percentages of 30% or more were divided into the premenopausal group (n = 9) and the postmenopausal group (n = 14). All subjects participated in resistance exercise training for 12 weeks. Anthropometric and physical fitness tests were performed on all participants. Protein analyses were performed on extracted subcutaneous fatty tissue, and changes in the relevant protein levels in the samples were analyzed by Western blotting. All serum samples were submitted for enzyme-linked immunosorbent assay measurements of adipocyte factors. After 12 weeks, the adipose triglyceride lipase, monoacylglycerol lipase, and perilipin1 protein levels were significantly lower in the postmenopausal group than in the premenopausal group. The hormone-sensitive lipase protein levels were significantly higher in the postmenopausal group than in the premenopausal group. In addition, leptin concentrations were significantly decreased after resistance exercise in the postmenopausal group. Adiponectin concentrations were significantly increased after resistance exercise in both groups. These findings indicate that regular resistance exercise is effective in reducing the weight and body fat of obese premenopausal women, and in the secretion of adiponectin. On the other hand, postmenopausal women were found to have redeced weight and body fat, and were found to be positive for the secretion of adipokine factors. In addition, positive changes in lipolysis pathway factors in adipose tissue promote lipid degradation and reduce fat mass. Thus, regular resistance exercise shows positive changes in the lipolysis pathway more effectively in weight and body fat reduction in postmenopausal women than in premenopausal women.

Increasing Mortality in Korean Patients With Breast Cancer: High Mortality Rate in Elderly Breast Cancer Population Due to Suboptimal Treatment and Other Diseases.

BACKGROUND: The incidence of breast cancer in Asia, including Korea, has rapidly increased. Each country has shown different clinical features. This study presents a comprehensive understanding of breast cancer in different age groups in Korea and determines potential measures for improving patient survival. METHODS: Patients diagnosed with invasive breast cancer stages I to III with available clinicopathologic and follow-up data were included in the study. Kaplan-Meier survival graphs were generated for each group and compared using log-rank test. The hazard ratio for each risk factor was calculated using the Cox regression model and the 95% confidence interval. RESULTS: The final cohort included 833 patients with a mean age of 51.3±11.3 years (range, 22-89 years), and 191 (22.9%) of them were aged >60 years. Patients aged ≥60 years had worse overall survival (OS) and distant disease-free survival than those aged <60 years. Although no difference was observed in the tumor biology, elderly patients showed significant differences in practice patterns: they tended to undergo mastectomy (40.2% vs 62.8%, P<0.001), did not receive the standard chemotherapy (88.4% vs 69.3%, P < 0.001), and had a higher risk of developing second primary cancer or diseases other than breast cancer (1.2% vs 6.8%, P < 0.001), which significantly correlated with poor survival in elderly patients. CONCLUSION: Less-than-the-standard treatment of care or development of a second primary disease resulted in poor prognosis in elderly patients in Korea. A multi-institutional and multinational study is warranted to elucidate the clinical features of breast cancer in Asian patients.

Sleep quality and athletic performance according to chronotype.

BACKGROUND: When studying the quality of sleep in relation to athletic performance, the athlete's chronotype and habitual time consider important factors. We aim to investigate the sleep quality and athletes' performance according to chronotype in elite athletes. METHODS: Three hundred forty elite athletes (males = 261, females = 79) were recruited for the present study. All participants were screening for chronotype by the Korean versions of the Morningness - Eveningness Questionnaire (MEQ-K). The Pittsburgh Sleep Quality Index (PSQI) and Wingate Anaerobic Test (WAnT) were measurement after screening. RESULTS: PSQI global score, PSQI sleep quality, PSQI sleep onset latency, PSQI sleep disturbance, and PSQI daytime dysfunction were significant differences among the groups. WAnT mean power (W), mean power (W/kg), peak power (W), and peak power (W/kg) were significant differences among the groups. A negative correlation coefficient was found between PSQI score and WAnT mean power (W) (r = - 0.256, p < 0.01), mean power (W/kg) (r = - 0.270, p < 0.01), peak power (W) (r = - 0.220, p < 0.01), and peak power (W/kg) (r = - 0.248, p < 0.01). CONCLUSIONS: This study indicates that related poor sleep quality and late-type chronotype may reduce the athletes' performance in elite athletes. In addition, the sleep quality is much higher in the early-type chronotype than in the late-type chronotype. Moreover, it also the athletic performance was better in the early-type chronotype than in the late-type chronotype.