Kontribusi Kontribusi Power Otot Lengan Terhadap Kemampuan Service Bawah Siswa Kelas VIII SMP Muhammadiyah 2 Pekanbaru.

The problem in this research is the students' skill in serving under the volleyball is still not optimal, the service ball is often stuck in the net, the student's arm muscle strength is still weak so that when serving, the ball does not bounce well into the opponent's field. The purpose of this study was to determine the contribution of arm muscle power to the ability to service under eighth grade students of SMP Muhammadiyah 2 Pekanbaru. The type of this research is correlation. The population and sample in this study were students of class VIII SMP Muhammadiyah 2 Pekanbaru, amounting to 21 people. The research instruments used were underhand medicine ball throw tests and service tests under volleyball. The data analysis technique used is the correlation value test. Based on the results of the research that has been done, a conclusion can be drawn as follows: There is a contribution of arm muscle power to the ability of service under the eighth grade students of SMP Muhammadiyah 2 Pekanbaru City by 38.69% with a calculated value = 0.622> rtable = 0.433