Effect of an intense period of competition on race performance and self-reported illness in elite cross-country skiers

Scand J Med Sci Sports. 2015 Dec;25(6):846-53. doi: 10.1111/sms.12452. Epub 2015 Mar 27.


The aim of this study was to determine whether participating in a cross-country skiing stage race (Tour de Ski; TDS) affects subsequent illness incidence, training, and race performance. Self-reported training and illness data from 44 male and female elite cross-country skiers were included. In total, 127 years of data were collected (2-3 seasons per athlete). Illness incidence, training load, and performance in international competitions were calculated for athletes who did and did not participate in TDS. Forty-eight percent of athletes reported becoming ill during or in the days immediately after taking part in TDS vs 16% of athletes who did not participate. In both groups, illness incidence was somewhat lower for female athletes. For male athletes, race performance was significantly worse for 6 weeks following TDS vs 6 weeks before TDS. Furthermore, while female athletes who participated in TDS performed relatively better than controls in Olympics/World Championships, male athletes who participated in TDS typically performed worse in subsequent major championships. Participating in TDS appears to result in ∼ 3-fold increase in risk of illness in this period. Male athletes appear more prone to illness and also see a drop in race performance following TDS, possibly linked to differences in training load before and after the event.

Keywords: Endurance athletes; overreaching; training load; upper respiratory illness.

MeSH terms

  • Adult
  • Athletic Performance / physiology*
  • Athletic Performance / statistics & numerical data
  • Female
  • Gastrointestinal Diseases / epidemiology*
  • Gastrointestinal Diseases / microbiology
  • Heart Rate
  • Humans
  • Incidence
  • Lactic Acid / blood
  • Male
  • Physical Conditioning, Human / physiology*
  • Physical Conditioning, Human / statistics & numerical data
  • Respiratory Tract Infections / epidemiology*
  • Self Report
  • Sex Factors
  • Skiing / physiology*
  • Skiing / statistics & numerical data
  • Young Adult


  • Lactic Acid