In this simple study, the authors applied five minutes of focal muscle vibration to the shoulder external rotators and evaluated the range of motion pre-and post-vibration. In just five minutes, shoulder internal rotation using the behind the back reach test increased by 4.1°, while shoulder internal rotation when the arm was abducted 90° increased by a surprising 11.4°. The authors also measured muscle strength, and unlike stretching protocols used to increase range of motion, focal muscle vibration produced significant increases in range of motion with no negative effects on muscle strength. The authors state that because focal muscle vibration increases range of motion without reducing force output, it would be an effective way to warm up before sport. The interesting thing about this study is that like many studies on focal muscle, the authors used a vibration frequency of about 60 cps. But unlike other studies, the vibrating devices had an amplitude of displacement of 5 mm, which is a lot. Most prior studies showing improved range of motion following focal muscle vibration incorporate displacements of about 0.5 mm, but the large displacement used in this study shows that the oscillation frequency is perhaps the most important, so if you would like to use a handheld massage device to increase range of motion, look for products that oscillate at about 3600 RPM. Importantly, prior research shows that using focal muscle vibration before sport can significantly reduce delayed onset muscle soreness following strenuous activity (Chang Y, et al. European Journal of Sport Science. 2024 Jan).