"Owing to considerable physical, endocrinological and metabolic adaptations, the analysis of biochemical data in elite and top-class athletes requires caution. With the aim to identify metabolic and biochemical adaptations to particular lifestyle conditions such as regular and strenuous physical exercise researchers measured the concentration of liver enzymes, bilirubin and serum  albumin in Jordanian top athletes. A healthy liver is essential to optimum performance 
  by athletes. Good liver function is required to burn fat, build muscle and provide energy. Sixty Jordanian first class athletes (34 males and 26 females, mean age 19.8±2 years with training experience of atleast 5 years and with a minimal training load of 18 training hours per week participated in competitive 
  different sports chosen in the study. Group of healthy male and female (control group), matched for age and gender was also included (n = 60). No subject revealed evidences of cardiovascular disease, diabetes (fasting glucose &lt;7 mmol L<SUP>-1</SUP>) or hypertension (blood pressure &lt;130/80 mm Hg) when tested by specialized physicians. The levels of AST, ALT and ALP for evaluation the liver functions in athletes in different groups were measured 15-18 h rest and 12 h fasting using commercial analytical kits. The results showed a significant differences (p&lt;0.5) were observed between experimental and control group for AST (34.18&plusmn;13.23 and 26.19&plusmn;7.42 U L<SUP>-1</SUP>, respectively) for ALT (28.47&plusmn;8.43 and 17.38&plusmn;10.83 U L<SUP>-1</SUP>, respectively) and for ALP (127.85&plusmn;67.54 and 83.49&plusmn;19.45 U L<SUP>-1</SUP>, respectively). The concentration of serum albumin was decreased in athletes but the difference did not reach statistical significance (controls: 4.82&plusmn; 0.37 g L<SUP>-1</SUP>; athletes: 4.72&plusmn;0.27 g L<SUP>-1</SUP>). No effect of endurance exercise on serum bilirubin in healthy  athletes. Researchers concluded that the most abnormalities observed on routine  biochemical screening in elite Jordanian athletes are of no clinical significance.