Fig 1. Development of symptom status.

Symptom status of all 60 athletes at t₀ (first examination date) and t₁ (3.3 ± 0.5 months post first examination). 35 of 44 athletes, who had persistent symptoms at t₀ still stated persistent symptoms at t₁ (progression group PS-PS). Nine athletes became symptom-free over three months (progression group PS-SF). 14 of the 16 athletes remained symptom-free over the observation period (SF-SF). Two athletes developed symptoms over time. Data were collected with medical history and the International Consensus CFS questionnaire [24].