Table 1.

PECOS (participants, exposure, comparator, outcomes, study design) approach

PECOS element	Details
Participants	Elite and sub-elite athletes, non-athletes and healthy subjects
Exposure	AMPD1 C34T polymorphism genotyping
Comparators	Athletes (endurance and power sports athletes) versus controls (non-athletes)
Outcomes	Genotypic and allelic frequencies of AMPD1 C34T polymorphism
Study design	Cross sections, case-controls, cohorts and all interventional studies