Purpose:
The study compared power during concentric-only and countermovement (CM) bench press with different ranges of motion (ROM) on a stable and unstable surface.

Methods:
A group of 22 fit men performed three repetitions of 1) full ROM concentric-only bench press, 2) full ROM CM bench press, 3) half ROM concentric-only bench press, and 4) half ROM CM bench press, on a bench (stable) and Swiss ball (unstable) at 60% 1RM. The FiTRO Dyne Premium system was used to monitor force and velocity and calculate power. Mean values of power during the acceleration and the entire concentric phases were analyzed.

Results:
No significant differences were found in mean power during concentric-only bench press on the bench and Swiss ball performed at half ROM and full ROM. Likewise, mean power during the concentric phase of half-range CM bench press on the bench and Swiss ball did not differ significantly. However, power values during full-range CM bench press were significantly higher on the bench than on Swiss ball. These differences were even more pronounced for mean power during the acceleration phase of full-range CM bench press on the bench compared with the Swiss ball. Contrary to this, these values did not differ significantly when the barbell was lifted during half ROM bench press on the bench and Swiss ball.

Conclusions:
Power was significantly lower during full-range CM bench press on the Swiss ball than on the bench, however, values did not differ significantly during stable and unstable half-range CM bench press.