Acute enhancement of lower-extremity dynamic strength and flexibility with whole-body vibration
ABSTRACT The purpose of this investigation was to examine the acute effects of whole-body vibration (WBV) on muscular strength, flexibility, and heart rate (HR). Twenty adults (10 men, 10 women) untrained to WBV participated in the study. All subjects completed assessment of lower-extremity isokinetic torque, flexibility, and HR immediately before and after 6 minutes of WBV and 6 minutes of leg cycling ergometry (CYL), in randomized order. During WBV, subjects stood upright on a vibration platform for a total of 6 minutes. Vibration frequency was gradually increased during the first minute to a frequency of 26 Hz, which was maintained for the remaining 5 minutes. During CYL, power output was gradually increased to 50 W during the first minute and maintained at that power output for the remaining 5 minutes. Lower-extremity flexibility was determined using the sit-and-reach box test. Peak and average isokinetic torque of knee extension and flexion were measured by means of a motor-driven dynamometer with velocity fixed at 120 degrees .s. Change scores for the outcome measures were compared between treatments using Student's paired t-tests. Analysis revealed significantly greater HR acceleration with CYL (24.7 bpm) than after WBV (15.8 bpm). The increase of sit-and-reach scores after WBV (4.7 cm) was statistically greater (p < 0.05) than after CYL (0.8 cm). After WBV, increases in peak and average isokinetic torque of knee extension, 7.7% and 9.6%, were statistically greater than after CYL (p < 0.05). Average torque of knee flexion also increased more with WBV (+7.8%) than with CYL (-1.5%) (p < 0.05). The findings of this study indicate that short-term WBV standing elicits acute enhancements of lower-extremity muscular torque and flexibility, suggesting the application of this technology as a preparatory activity before more intense exercise.
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- "WBV has been promoted as an ergogenic aid mode and, given its time efficiency for eliciting mild cardiovascular and metabolic changes (Cochrane et al., 2008; Rittweger, Schiessl and Felsenberg, 2001), it may be a suitable warm-up option to elicit temperature-related processes (Cochrane, 2011). Many researchers have reported temporary improvements in jumping ability after a single session of WBV (Bazett-Jones, Finch and Dugan, 2008; Cochrane and Stannard, 2005; Torvinen et al., 2002; Cormie et al., 2006; Jacobs and Burns, 2009; Sands et al., 2008), muscle force and power (Bosco et al., 2000; Stewart, Cochrane and Morton, 2009) which might be due to neural adaptations (Cochrane and Stannard, 2005). Since, as the increased motoneuron excitability is regarded as an integral part to enhance sprint performance (Ross, Leveritt and Riek, 2001) it could hypothesized that WBV may be a favorable method to enhance sprint performance (Cochrane, 2011). "
ABSTRACT: Whole-body vibration is a neuromuscular training method and has been suggested as an acute ergogenic aid mode before practice, training and competition activities of athletes. The aim of this study was to investigate the acute effects of a whole-body vibration session on sprint running kinematics and neuromuscular performance in well trained track & field sprinters. 30 sprint athletes participated in this study (age 21.6 ± 4.1 years, height 1.76 ± 5.0 m, body mass 71.2 ± 6.4 kg). Both experimental (with vibration) and control (without vibration) groups performed a single session of whole-body vibration consisted of two dynamic exercises (half squat / lunge) using a body vibration platform (90 s, 50 Ηz, 2 mm). Performance tests (60m sprint, counter movement jump, muscle power and sit & reach test) were performed before and after 6 min the whole-body vibration session. Counter movement jump was reduced after whole-body vibration by 3.9%, whereas all the other analyzed parameters remained unchanged. The results of this study do not support the use of whole-body vibration as an acute ergogenic aid during standardized warm-up in well trained track and field sprinters.
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- "The amplitude of the device was controlled by adjusting the foot position from 1 to 3, with the higher the position, the greater the amplitude and the frequency of the vibration was set at 30 Hz and 2 mm amplitude. According to other studies (Bosco et al., 2000; Cochrane & Stannard, 2005; Fagnani, Giombini, Di Cesare, Pigozzi, & Di Salvo, 2006; Jacobs & Burns, 2009; Mahiu et al., 2006; Torvinen et al., 2002a,b "
ABSTRACT: The purpose of this study was to examine whether whole-body vibration (WBV) training results in short-term performance improvements in flexibility, strength and balance tests in comparison to an equivalent exercise program performed without vibration. Eleven elite rhythmic gymnasts completed a WBV trial, and a control, resistance training trial without vibration (NWBV). The vibration trial consisted of eccentric and concentric squatting exercises on a vibration platform that was turned on, whereas the NWBV involved the same training protocol with the platform turned off. Balance was assessed using the Rhythmic Weight Shift (RWS) based on the EquiTest Dynamic Posturography system; flexibility was measured using the sit & reach test, and lower limb explosive strength was evaluated using standard exercises (squat jump, counter movement jump, single leg squat). All measurements were performed before (pre) immediately after the training program (post 1), and 15 minutes after the end of the program (post 15). Data were analyzed using repeated measures ANOVA was used with condition (WBV-NWBV) as the primary factor and time (pre, post 1, post 15) as the nested within subjects factor, followed by post-hoc pairwise comparison with Bonferroni corrections. Results confirmed the hypothesis of the superiority of WBV training, especially in the post 15 measurement, in all flexibility and strength measures, as well as in a number of balance tests.Human movement science 09/2013; 33. DOI:10.1016/j.humov.2013.07.023 · 2.03 Impact Factor
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- "The rationale for the parameter selection was based on several studies that have shown that WBV training with a knee flexion angle of 5°–60° causes beneficial effects on jump height, lower extremity muscle torque and flexibility (Jacobs and Burns 2009; Stewart et al. 2009; Torvinen et al. 2002). "
ABSTRACT: This study aimed to assess the influence of different whole body vibration (WBV) determinants on the electromyographic (EMG) activity during WBV in order to identify those training conditions that cause highest neuromuscular responses and therefore provide optimal training conditions. In a randomized cross-over study, the EMG activity of six leg muscles was analyzed in 18 subjects with respect to the following determinants: (1) vibration type (side-alternating vibration (SV) vs. synchronous vibration (SyV), (2) frequency (5-10-15-20-25-30 Hz), (3) knee flexion angle (10°-30°-60°), (4) stance condition (forefoot vs. normal stance) and (5) load variation (no extra load vs. additional load equal to one-third of the body weight). The results are: (1) neuromuscular activity during SV was enhanced compared to SyV (P < 0.05); (2) a progressive increase in frequency caused a progressive increase in EMG activity (P < 0.05); (3) the EMG activity was highest for the knee extensors when the knee joint was 60° flexed (P < 0.05); (4) for the plantar flexors in the forefoot stance condition (P < 0.05); and (5) additional load caused an increase in neuromuscular activation (P < 0.05). In conclusion, large variations of the EMG activation could be observed across conditions. However, with an appropriate adjustment of specific WBV determinants, high EMG activations and therefore high activation intensities could be achieved in the selected muscles. The combination of high vibration frequencies with additional load on an SV platform led to highest EMG activities. Regarding the body position, a knee flexion of 60° and forefoot stance appear to be beneficial for the knee extensors and the plantar flexors, respectively.Arbeitsphysiologie 04/2012; 113(1). DOI:10.1007/s00421-012-2402-0 · 2.30 Impact Factor