Effects of whole body vibration training on muscle strength and sprint performance in sprint-trained athletes

Despite the expanding use of Whole Body Vibration training among athletes, it is not known whether adding Whole Body Vibratil on training to the conventional training of sprint-trained athletes will improve speed-strength performance. Twenty experienced sprint-trained athletes (13 male, 7 female, 17-30 years old) were randomly assigned to a Whole Body Vibration group (n = 10: 6 male and 4 female) or a Control group (n = 10: 7 male, 3 female). During a 5-week experimental period all subjects continued their conventional training program, but the subjects of the Whole Body Vibration group additionally performed three times weekly a Whole Body Vibration training prior to their conventional training program. The Whole Body Vibration program consisted of unloaded static and dynamic leg exercises on a vibration platform (35 - 40 Hz, 1.7 - 2.5 mm, Power PlateO). Pre and post isometric and dynamic (100 degrees/s) knee-extensor and -flexor strength and knee-extension velocity at fixed resistances were measured by means of a motor-driven dynamometer (Rev 9000, Techno-gym (R)). Vertical jump performance was measured by means of a contact mat. Force-time characteristics of the start action were assessed using a load cell mounted on each starting block. Sprint running velocity was recorded by means of a laser system. Isometric and dynamic knee-extensor and knee-flexor strength were unaffected (p > 0.05) in the Whole Body Vibration group and the Control group. As well, knee-extension velocity remained unchanged (p > 0.05). The duration of the start action, the resulting start velocity, start acceleration, and sprint running velocity did not change (> 0.05) in either group. In conclusion, this specific Whole Body Vibration protocol of 5 weeks had no surplus value upon the conventional training program to improve speed-strength performance in sprint-trained athletes.