Introduction: Despite the fact that importance of core muscles has determined in kinetic chains, the importance of each muscle, compared to the others was investigated rarely. The purpose of this study is to compare the effect of each core muscles fatigue on run jump 8 and three jumps single- leg tests.
Methodology: This Quasi-experimental research with repeated measurement (pretest, post-test) design was done on 30 physical education female students with average age of 23.46±2.54 years, average height of 1.63±0.05 cm and average weight of 55.61±7.67 kg. Participants did lower extremity function tests at the first session in normal conditions (without fatigue), and at next sessions (second, third and fourth) after performing a fatigue protocol of selected core muscles and the results were compared. In order to analyze the data paired samples T-test and repeated measures and SPSS version 19 were used.
Results: core muscles fatigue (flexor's fatigue, trunk extensor fatigue and hip abductor fatigue), with small effect size of the results in significant reduction in lower extremity function tests scores was in the (P<0.05). Overall, test scores after three jumps single-leg hip abductor muscle fatigue with the large effect size (0.82) trunk extensor and flexor muscles to fatigue, decreased.
Discussion: Function of core muscles affects lower extremity function tests, because the core muscle fatigue, cause to a reduction in the reaching distance in anterior direction and increases the number of errors in all the components of Y balance test. Exercises that can provide an improvement in core muscles endurance and their ability to cope with fatigue, are recommended and can be used by coaches and rehabilitation to be considered as a way to prevent injuries.