The effectiveness of physical education classes on students’ physical fitness components is still controversial topic in Turkey. So, this study aims to compare the physical fitness characteristics of those who has attended a total of 2 hours of physical education classes once a week, and those who has participated in 2 hours of physical education plus three times 1 hours strength and conditioning training in a week for three months.  In this quasi-experimental study, the outcome of interest was measured only once, after exposing a non-random group of participants to a conditioning program, and compared to a control group. Data were collected from 24 male adolescents including 13 participants from experimental and 11 participants from control groups. For comparison of two groups and intra groups, independent t and paired t tests were used to determine the 12-week change in the physical fitness variables of the experimental and control groups. Also, Cohen’s d was computed to determine effect size of 12 weeks physical education courses and conditioning program. The results of this study show that there were significant differences between two groups in the variables of warm up hearth rate and aerobic endurance during the pre-test and in the variables of push-up, sit-up, aerobic endurance and anaerobic endurance during in the post-test in the favor of experimental group. While there was no significant change in push-up, shuttle and anaerobic endurance of the control group after 12 weeks, significant changes were observed in all variables of the experimental group after 12 weeks strength and conditioning program. In conclusion, considering the fact that traditional physical education courses are not effective enough in improving physical fitness, it can be proposed that it would be very effective for students to participate in additional physical and sports activities for at least 3 or 4 times in a week.

Physical education course, physical fitness, frequency of training and course.