ABSTRACT
The purpose of this study was to examine the acute effects of different vibration loads (frequency and amplitude) of whole-body vibration (WBV) on flexibility and explosive strength of lower limbs in springboard divers. Eighteen male and female divers, aged 19 ± 2 years, volunteered to perform 3 different WBV protocols in the present study. To assess the vibration effect, flexibility and explosive strength of lower limbs were measured before (Pre), immediately after (Post 1) and 15 min after the end of vibration exposure (Post 15). Three protocols with different frequencies and amplitudes were used in the present study: a) low vibration frequency and amplitude (30 Hz/2 mm); b) high vibration frequency and amplitude (50 Hz/4 mm); c) a control protocol (no vibration). WBV protocols were performed on a Power Plate platform, whereas the no vibration divers performed the same protocol but with the vibration platform turned off. A two-way ANOVA 3 x 3 (protocol × time) with repeated measures on both factors was used. The level of significance was set at p < 0.05. Univariate analyses with simple contrasts across time were selected as post hoc tests. Intraclass coefficients (ICC) were used to assess the reliability across time. The results indicated that flexibility and explosive strength of lower limbs were significantly higher in both WBV protocols compared to the no vibration group (NVG). The greatest improvement in flexibility and explosive strength, which occurred immediately after vibration treatment, was maintained 15 min later in both WBV protocols, whereas NVG revealed a significant decrease 15 min later, in all examined strength parameters. In conclusion, a bout of WBV significantly increased flexibility and explosive strength in competitive divers compared with the NVG. Therefore, it is recommended to incorporate WBV as a method to increase flexibility and vertical jump height in sports where these parameters play an important role in the success outcome of these sports.
ABSTRACT
The purpose of this study was to examine the acute effect of a single bout of whole body vibration (WBV) on flexibility and explosive strength of lower limbs in young artistic gymnasts. Thirty-two young competitive gymnasts volunteered to participate in this study, and were allocated to either the vibration group or traditional body weight training according to the vibration protocol. The vibration intervention consisted of a single bout of eccentric and concentric squatting movements on a vibration platform that was turned on (vibration group: VG n = 15), whereas the traditional body weight (no vibration) group performed the same training protocol with the WBV device turned off (NVG: n= 17). Flexibility (sit and reach test) and explosive strength tests [squat jump (SJ), counter movement jump (CMJ), and single leg squat (right leg (RL) and left leg (LL))] were performed initially (pre-test), immediately after the intervention (post-test 1), and 15 minutes after the end of the intervention programme (post-test 15). Four 2x3 ANOVAs were used to examine the interaction between group (VG vs NVG) and time (pre, post 1, and post 15) with respect to examined variables. The results revealed that a significant interaction between group and time was found with respect to SJ (p < 0.05). However, no significant interaction between group and time was found with respect to flexibility, CMJ, RL and LL after the end of the intervention programme (p > 0.05). Further, the percentage improvement of the VG was significantly greater in all examined variables compared to the NVG. This study concluded that WBV training improves flexibility and explosive strength of lower limbs in young trained artistic gymnasts and maintains the initial level of performance for at least 15 minutes after the WBV intervention programme.
