Biorhythm is one of the latest topics in the field of identifying mind’s ergonomics. Of all the performances with which biorhythm deals is the physical performance. The purpose of present research is to study the effect of physical cycle of biorhythm on the designated factors of physical fitness among teenage volleyball players in the city of Qom. In the present field research, 30 people were selected out of volleyball players aged 12 to 15 at random in the city of Qom. Biorhythm cycles were obtained with the biorhythm software. Vertical jump and medicine ball throwing were used as tests associating with muscular power pull-up and sit-up were used as tests associating with muscular endurance in two states of charged (the second position) and discharged (the first position) of biorhythm physical cycle. The statistical correlated t test with the significance level of p≤0.05 was used to analyze data. The findings indicated that the tests pertaining to power including Vertical jump and medicine ball throwing were well-correlated with the physical cycle of biorhythm (p=0.042 p=0.019). However, the muscular endurance tests (revised sit-up and pull-up) did not show any significant difference between the two states and were not correlated with the physical cycle of biorhythm (p=0.75 p=0.73). The predictions by physical cycle of biorhythm on the muscular power of athletes are correct, but it was not possible with the muscular endurance of athletes. Of course, more researches should be conducted to increase the certainty of correctness predicted by the physical cycle of biorhythm. The prediction of this theory can be used to increase the performances of athletes in sports competitions if the biorhythm cycles prove right.