The results of the present study have shown that the YYIET elicited maximal physiological responses in the young soccer players. However, the distance covered during the YYIET cannot be considered as a reflection of the individual’s maximal aerobic power. The present study has shown the YYIET to be a good field test to elicit peak physiological stress on regional level soccer players and provided the use of a portable gas analyser (K4b2, COSMED, Rome, Italy) is available, it could be considered as a valuable alternative to a treadmill running test. The lack of a significant relationship
between the distance covered during the YYIET and both YYIET and attained on the treadmill shows that running back and forward at increasing speeds is affected by variables other than just maximal aerobic power. Further research is required to investigate the possible factors influencing YYIET performance.