This study aimed to investigate whether whole-body vibration (WBV) combined with extra-load training can enhance the strength and speed of trained athletes compared to isolated WBV training or loaded training only. Twenty-one elite male track and field athletes were assigned at random to a loaded vibration (LV) training group (n = 7), an unloaded vibration (ULV) training group (n = 7), and a loaded training (LT) group (n = 7). During 4 weeks of training, the LV group received the vibration stimulus (30 Hz and 4 mm) accompanied by a load comprising 75% of the maximum voluntary contraction (MVC), the ULV group received the same vibration stimulus without any load, and the LT group received only a load of 75% MVC without any vibration stimulus. The knee extensor isometric strength, and the concentric and eccentric strength were measured using an isokinetic dynamometer at 300°/s at a 30-m sprint speed prior to and following the training period. A two-way mixed analysis of variance (time × group) was used to analyze the differences. Significant time × group interactions were observed for all the dependent variables (P < .05). Regarding the post hoc analysis results, the LV group exhibited significant improvements for all the dependent variables after training (P < .05), whereas the ULV group showed significantly lower sprint speeds (P < .05). The LV group demonstrated significantly superior eccentric strength compared with that of the ULV and LT groups after training (P < .05), and also produced significantly superior sprint speeds compared with that of the ULV group after training (P < .05).
The study found that vibration combined with extra-load training for 4 weeks significantly increased the muscle strength and speed of the elite male track and field athletes.