This study was performed to determine the impact of sex and sport-discipline on physical fitness and bone markers in young sub-elite track and field athletes. One hundred and forty-four track and field sub-elite athletes (78 males aged 17.8±1.6 years; 66 females aged 17.2±1.9 years) volunteered to participate in this study and were categorized according to their disciplines in endurance (EG: n=67) or power athletes (PG: n=77). A significant main effect of sex was observed for C-telopeptide type I collagen (CTx) (F=11.37; p<0.001; propeptide of procollagen type I (PINP) (F=7.96; p<0.05; 2=0.07, moderate). The average CTx, OC and P1NP levels were significantly higher in males compared with females (0
