Available online at www.sciencedirect.com Journal of Science and Medicine in Sport 13 (2010) 438–443 Original paper The acute effects of different whole-body vibration amplitudes and frequencies on flexibility and vertical jumping performance Vassilis Gerodimos a,∗ , Andreas Zafeiridis b , Konstantina Karatrantou a , Theodora Vasilopoulou a , Konstantina Chanou a , Eleni Pispirikou a a Department of Physical Education and Sport Sciences, University of Thessaly, Trikala, Greece b Department of Physical Education and Sport Sciences, Aristotle University of Thessaloniki at Serres, Greece Received 13 February 2009; received in revised form 27 August 2009; accepted 4 September 2009 Abstract Frequency and amplitude determine the training load of whole-body vibration (WBV) exercise and thereby possible neuromuscular adap- tations. We investigated the effects of amplitude and frequency of a single bout of WBV on flexibility and squat jump performance (SJ) and the time-course of these effects. In the amplitude study, twenty-five females performed three vibration protocols (VPs) for 6min at frequency of 25 Hz and amplitudes of 4 mm, 6 mm, and 8 mm and one control protocol (CP). In the frequency study, eighteen females performed three VPs at 6 mm amplitude and frequencies of 15 Hz, 20 Hz, and 30 Hz and one CP. Flexibility and SJ were measured before, immediately-post and 15min recovery. All protocols were performed on a side-to-side alternating vibration plate. In the amplitude study, flexibility was improved (p < 0.01) immediately-post in VP4, VP6, VP8 (31.8 ± 8.2, 31.9 ± 7.6, 31.5 ± 7.9, respectively) and at 15 min recovery (31.6 ± 8.1, 31.5 ± 7.9, 31.0 ± 8.2, respectively) vs. pre-vibration (30.2 ± 8.6, 30.3 ± 8.1, 30.2 ± 8.3, respectively), but remained unchanged in CP (30.6 ± 8.3 immediately-post, 30.7 ± 8.2 at 15 min vs. 30.4 ± 8.2 pre-vibration). In the frequency study, flexibility was improved (p < 0.01) immediately-post in VP15, VP20, VP30 (31.5 ± 5.2, 31.3 ± 5, 31.7 ± 5.3, respectively) and at 15 min recovery (31.3 ± 5.4, 31.3 ± 5.0, 31.3 ± 5.3, respectively) vs. pre-vibration (30.6 ± 5.4, 30.2 ± 5.7, 30.3 ± 5.9, respectively), but not in CP (30.7 ± 5.1 immediately- post, 30.6 ± 5 at 15 min vs. pre-vibration 30.5 ± 5.7). There were no significant effects of amplitude or frequency on SJ. In conclusion, a single WBV bout using a side-to-side alternating vibration plate may increase flexibility which persists for at least 15 min, without altering jumping performance. These effects were observed irrespective of frequency and amplitude. © 2009 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. Keywords: Squat jump; Sit and reach; Neuromuscular performance; Power; Dose–response 1. Introduction Whole-body vibration (WBV) is a new type of exercise that has been emerged in sports training and rehabilita- tion during the last decade. 1 Long-term WBV may increase muscular strength, power, and jumping performance. The enhancement in muscular performance is mostly observed in untrained and elderly individuals, while in young trained subjects the findings are equivocal. 2 The few studies that examined the effects of WBV training on flexibility demon- strated positive effects. 3–5 However, the acute effects of WBV on neuromuscular performance are less consistent. An ∗ Corresponding author. E-mail address: bgerom@pe.uth.gr (V. Gerodimos). acute bout of WBV (single or multiple reps) have shown to increase, 6–11 decrease, 10–12 or not change 13–15 vertical jump- ing ability, while flexibility appears to be improved 7,11,16 or unchanged. 11 Differences in loading parameters of WBV may account for these equivocal findings. The WBV loading parameters include frequency, ampli- tude, and duration. 1 The interaction of frequency and amplitude determine the WBV acceleration, and their dif- ferent combinations determine the training load. 17,18 Recent studies report significant effects of frequency and/or ampli- tude on jumping performance. 10,11,17,19 Information on the effects of frequency and amplitude on flexibility after an acute bout of WBV (single or multiple reps) are limited. The only study that manipulated loading parameters during WBV reported that flexibility improved after a low-frequency 1440-2440/$ – see front matter © 2009 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jsams.2009.09.001