title: An 8-year longitudinal study of overreaching in 114 elite female Chinese wrestlers.
abstract: BACKGROUND
  Successful training involves structured overload but must avoid the combination of excessive overload and inadequate recovery.
  
  
  OBJECTIVE
  The aim of this study was to determine the incidence of functional overreaching (FOR), nonfunctional overreaching (NFOR), and overtraining syndrome in elite female wrestlers during their normal training and competition schedules and to explore the utility of blood markers for the early detection of overreaching. Classification of FOR, NFOR, and overtraining syndrome was based on the European Congress of Sports Medicine position statement.
  
  
  METHODS
  Case series.
  
  
  METHODS
  China Institute of Sport Science.
  
  
  METHODS
  Over an 8-year period, 114 wrestlers from the women's Asian wrestling team were monitored to help identify if and when they experienced FOR, NFOR, or overtraining syndrome.
  
  
  METHODS
  Creatine kinase, hemoglobin, testosterone, and cortisol were measured throughout the period to identify whether wrestlers were outside the reference intervals (constructed from normal recovery data) during periods of overreaching and not overreaching.
  
  
  RESULTS
  Among the 114 athletes, there were 13 (3.6%) instances of FOR, 23 (6.4%) instances of NFOR, and 2 (0.6%) instances of overtraining syndrome. The diagnostic sensitivity for FOR was 38%, 15%, 45%, and 18% for creatine kinase, hemoglobin, testosterone, and cortisol, respectively. The diagnostic sensitivity for NFOR was 29%, 33%, 26%, and 35% for creatine kinase, hemoglobin, testosterone, and cortisol, respectively. Specificity was 79%, 88%, 90%, and 82% for creatine kinase, hemoglobin, testosterone, and cortisol, respectively. Post hoc analysis showed no mean differences in creatine kinase (F = 0.5, P = .47), hemoglobin (F = 3.8, P = .052), testosterone (F = 0.2, P = .62), or cortisol (F = 0.04, P = .85) between monitoring periods when wrestlers were and were not diagnosed with FOR and NFOR.
  
  
  CONCLUSIONS
  Coaches and sports scientists should not use single blood variables as markers of overreaching in elite female wrestlers.
authors.affiliation: China Institute of Sport Science, Beijing, China;
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
authors.forename: Zihong
authors.initials: Z
authors.lastname: He
authors.forename: Jiexiu
authors.initials: J
authors.lastname: Zhao
authors.forename: Dalang
authors.initials: D
authors.lastname: Tao
authors.forename: Kuiyuan
authors.initials: K
authors.lastname: Xu
authors.forename: Adrian
authors.initials: A
authors.lastname: Midgley
authors.forename: Lars
authors.initials: L
authors.lastname: McNaughton
mesh_terms: D000328:Adult; D056352:Athletes; D015415:Biomarkers / Q000097:blood; D002681:China; D003402:Creatine Kinase / Q000097:blood*; D012090:Cumulative Trauma Disorders / Q000097:blood / Q000145:classification / Q000175:diagnosis / Q000209:etiology; D042241:Early Diagnosis; D005260:Female; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008137:Longitudinal Studies; D015203:Reproducibility of Results; D013178:Sports Medicine / Q000379:methods; D013739:Testosterone / Q000097:blood*; D014952:Wrestling / Q000502:physiology*
chemical_list: D015415:Biomarkers; D006454:Hemoglobins; D013739:Testosterone; D003402:Creatine Kinase; D006854:Hydrocortisone
keywords: blood markers; fatigue; overtraining; underperformance