Whole-body vibration increases upper and lower body muscle activity in older adults: potential use of vibration accessories

Effect of whole-body vibration on neuromuscular activation and explosive power of lower limb: A systematic review and meta-analysis

OBJECTIVE

The review aimed to investigate the effects of whole-body vibration (WBV) on neuromuscular activation and explosive power.

METHODS

Keywords related to whole-body vibration, neuromuscular activation and explosive power were used to search four databases (PubMed, Web of Science, Google Scholar and EBSCO-MEDLINE) for relevant studies published between January 2000 and August 2021. The methodology of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses was used. The eligibility criteria for the meta-analysis were based on PICOST principles. Methodological assessment used the Cochrane scale. Heterogeneity and publication bias were assessed by I2 index and funnel plots, respectively. The WBV training cycle is a random effect model. Publication bias was also assessed based on funnel plots. This study was registered in PROSPERO (CRD42021279439).

RESULTS

A total of 156 participants data in 18 studies met the criteria and were included in the meta-analysis for quantitative synthesis. Results of the meta-analysis showed significant improvements in lower limb neuromuscular activation immediately after WBV compared with the baseline (SMD = 0.51; 95% CI: 0.26, 0.76; p<0.001), and no significant heterogeneity was observed (I2 = 38%, p = 0.07). In addition, the highest increase in lower limb explosive power was observed (SMD = 0.32; 95% CI: 0.11, 0.52; p = 0.002), and no significant heterogeneity (I2 = 0%, p = 0.80) was noted.

CONCLUSIONS

WBV training could improve neuromuscular activation and explosive power of the lower limb. However, due to different vibration conditions, further research should be conducted to determine standardized protocols targeting performance improvement in athletes and healthy personnel experienced in training.

Use of surface electromyography to evaluate effects of whole-body vibration exercises on neuromuscular activation and muscle strength in the elderly: a systematic review

PURPOSE

Reduction of muscle strength and lean mass, increase in the risk of falls, higher mortality, and morbidity are observed in geriatric syndromes. Physical activity is an effective intervention in reducing signs and symptoms of geriatric syndromes. Whole-body vibration exercise (WBVE) is an intervention with low cost and has been effective.

MATERIALS AND METHODS

The aim of this systematic review aimed to determine the effects of WBVE on neuromuscular activation and muscle strength in the elderly. Searches in PubMed, Embase, Science direct, and Scopus databases were conducted. Six studies, that analyzed the use of surface electromyography evaluating effects of WBVE on neuromuscular activation and muscle strength in the elderly, published in English, were included.

RESULTS

Six studies were included. One hundred forty-six individuals participated in the studies and 24 were males (16.43%), with an average age of 74.20 ± 7.66 years. Five publications were defined as "fair" methodological in the PEDro scale, the risk of bias was high and the risk of bias for non-randomized studies was moderate/high. In general, increased strength muscle was reported in the studies.

CONCLUSION

This systematic review suggests that WBVE might promote desirable neuromuscular responses in healthy elderly. However, it is necessary to perform further studies to reinforce the reported findings.IMPLICATIONS FOR REHABILITATIONThe reduction in lean mass and consequent reduction in muscle strength are present in healthy elderly people and the whole-body vibration exercise can reduce or alleviate these symptoms caused by the geriatric syndrome.Whole-body vibration exercise is a training modality that increases neuromuscular activation and muscle strength.Surface electromyography is a useful tool for the evaluation of the neuromuscular activation of the muscle fibers.

Superimposed vibration on suspended push-ups

Background

Superimposition of vibration has been proposed in sports training using several devices and methods to enhance muscle activation and strength adaptations. Due to the popularity of suspension training, vibration systems have recently been developed to increase the effects of this training method. The present cross-sectional study aims to examine the effects of superimposing vibration on one of the most popular exercises in strength and conditioning programs: push-ups.

Methods

Twenty-eight physically active men and women executed push-ups in three suspended conditions (non-vibration, vibration at 25 Hz, and vibration at 40 Hz). OMNI-Res scale was registered, and surface electromyographic signals were measured for the activity of the right and left external oblique, anterior deltoid, triceps brachii, sternal, and clavicular heads of the pectoralis major.

Results

A linear mixed model indicated a significant fixed effect for vibration at 25 Hz and 40 Hz on muscle activity. Suspended push-ups with superimposed vibration (25 Hz and 40 Hz) showed a significant higher activity on left (25 Hz: p = 0.036, d = 0.34; 40 Hz: p = 0.003, d = 0.48) and right external oblique (25 Hz: p = 0.004, d = 0.36; 40 Hz: p = 0.000, d = 0.59), anterior deltoid (25 Hz: p = 0.032, d = 0.44; 40 Hz: p = 0.003, d = 0.64), and global activity (25 Hz: p = 0.000, d = 0.55; 40 Hz: p = 0.000, d = 0.83) compared to non-vibration condition. Moreover, OMNI-Res significant differences were found at 25 Hz (6.04 ± 0.32, p = 0.000 d = 4.03 CI = 3.27, 4.79) and 40 Hz (6.21 ± 0.36 p = 0.00 d = 4.29 CI = 3.49, 5.08) compared to the non-vibration condition (4.75 ± 0.32).

Conclusion

Superimposing vibration is a feasible strategy to enhance the muscle activity of suspended push-ups.

Validation of Vibration Exercises on Enhancing Muscle Strength and Upper Limb Functionality among Pre-Frail Community-Dwelling Older Adults

Pre-frail older adults require appropriate exercise to enhance muscle strength as well as upper limb functionality. We developed a handheld vibrator and evaluated its effectiveness in enhancing muscle strength compared to conventional exercises among pre-frail community-dwelling older adults. Thirty-one pre-frail older adults (aged 75.5 ± 5.1 years) were recruited and randomly allocated to a vibration group (VG) and control group (CG). The VG underwent 20 minutes of vibration (frequency: 30 Hz, amplitude: 5 mm, horizontal vibration) using a handheld vibrator as well as 40 minutes of conventional exercise. The CG received 60 minutes of conventional exercise only. The primary outcome was muscle strength assessment (kg), and the secondary outcome included activities of daily living and instrumental activities of daily living scores. The comparisons between the outcome measures revealed no significant differences at the baseline level. Muscle strength of the dominant (ß = 2.49, p = 0.002) and non-dominant (ß = 1.89, p = 0.02) wrist flexion, brachioradialis (ß = 3.8, p = 0.01), and biceps brachii (ß = 3.02, p = 0.02) in the dominant upper limbs was significantly increased among the VG. The vibration intervention can enhance muscle strength in the upper limbs among pre-frail older adults.

Preliminary feasibility and acute physiological effects of a single session of upper limb vibration training for persons with spinal cord injury

CONTEXT

Strong upper limb musculature is essential for persons with spinal cord injury (SCI) to operate a manual wheelchair and live independently. Targeted upper limb vibration may be a viable exercise modality to build muscle efficiently while eliminating some of the barriers associated with exercise for persons with SCI.

OBJECTIVE

The purpose of this study was to assess preliminary feasibility of completing a single exercise session of upper limb vibration and compare the acute physiological effects to a single session of standard dumbbell resistance exercise.

METHODS

Individuals with SCI performed seven upper limb exercises (1) isometrically using a vibrating dumbbell at 30 Hz for 60 s (n = 22) and (2) using a standard isotonic resistance protocol (n = 15).

RESULTS

Nineteen (86.4%) of 22 participants were able to perform all vibration exercises at 30 Hz but hold time success rates varied from 33% (side flies and front raises) to 95% (internal rotation). No significant differences were found between vibration exercise and standard resistance protocol for blood lactate, power output, and heart rate (P > 0.05). Perceptions of the training were positive, with most participants (>70%) expressing interest to train with vibration in the future.

CONCLUSIONS

Vibration training was not feasible for all participants, suggesting an individualized approach to starting weight and progression may be necessary. Similar acute physiological changes were seen between vibration exercise and standard resistance protocol, suggesting they could have similar benefits. Additional research is needed to determine if vibration exercise is feasible and beneficial to incorporate into a long-term training program.

Whole body vibration in the static modified push-up position in untrained healthy women stimulates neuromuscular system potentiating increased handgrip myogenic response

OBJECTIVE

To investigate the acute effect of whole-body vibration (WBV) on handgrip strength (HS) and electromyographic activity of the flexor digitorum superficialis muscle of healthy women in the static push-up position.

METHODS

Twenty-eight women received four experimental tests in a randomized order: A) Control - rest in seating position with feet on the floor and hands in the supine position on the lower limbs. There was no vibration stimulus; B) Placebo - push-up position with their hands on the vibratory platform that remained disconnected, but with a sonorous stimulus mimicking the vibration; C) Low vibration and D) High vibration - push-up position with their hands on the vibratory platform using one of the vibratory stimulus intensity: low vibration: 25 Hz/2 mm/49.30 m s^-2; or high vibration: 45 Hz/2 mm/159.73 m s^-2. Participants remained 5 min in each situation. HS and electromyography (EMG) were performed at baseline and after all four experimental tests. The index of neural efficiency (i.e. the ratio between EMG and HS) was also calculated to determine the efficiency of muscle contraction. Statistical analysis was performed by ANOVA two-way design mixed test with Tukey's post hoc test, being considered significant p < 0.05.

RESULTS

High vibration increased HS compared with all the other experimental tests (p = 0.0006, F = 6.03). There was a reduction of EMG activity of the flexor digitorum superficialis muscle only after high vibration (p = 0.0135, F = 6.22), which was accompanied by lower values of the index of neural efficiency after intervention (between-group difference, p = 0.0002, F = 0.674).

CONCLUSION

WBV in the push-up position has an acute positive effect on HS accompanied by a lower index of neural efficiency, providing a better efficiency of muscle contraction.

Acute effect of flexible bar exercise on scapulothoracic muscles activation, on isometric shoulder abduction force and proprioception of the shoulder of individuals with and without subacromial pain syndrome

BACKGROUND

There is currently no evidence about the effects of neuromuscular facilitation after the use of a flexible bar on scapulothoracic muscle activity in individuals with subacromial pain syndrome. The study aimed to assess the acute effect of flexible bar exercise and subjective fatigue on scapulothoracic muscle activity, shoulder proprioception, and shoulder abduction force of subjects with and without symptoms of subacromial pain syndrome.

METHOD

Fifty subjects with subacromial pain syndrome and 50 asymptomatic subjects were recruited. A short-term flexible bar exercise was performed to assess the vibratory stimulus effects on scapulothoracic muscle activity, shoulder proprioception, and shoulder abduction force, and the same exercise was performed on a long-term basis to assess the effects of subjective fatigue. The activities of the serratus anterior and three portions of the trapezius muscle were investigated using surface electromyography during arm elevation. The active joint position sense error was assessed to determine shoulder proprioception using a laser pointer. A hand-held dynamometer was used to assess isometric shoulder abduction force.

FINDINGS

No significant intra-group differences were found in scapulothoracic muscle activity, as well as in active joint position sense error and isometric shoulder abduction force in either group (p >0.05).

INTERPRETATION

The acute effects of flexible bar exercise and subjective fatigue were unable to influence scapulothoracic muscle activation, shoulder joint position sense, and isometric shoulder abduction force in subacromial pain syndrome.

Modulation of Cortical Activity by High-Frequency Whole-Body Vibration Exercise: An fNIRS Study

CONTEXT

Whole-body vibration (WBV) has shown many positive effects on the human body in rehabilitation and clinical settings in which vibration has been used to elicit muscle contractions in spastic and paretic muscles.

OBJECTIVE

The purpose of this study was to investigate whether WBV exercise (WBVe) differently modulates the cortical activity associated with motor and prefrontal function based on its frequency.

METHODS

A total of 18 healthy male adults (mean age: 25.3 [2.4] y) participated in this study and performed WBVe (Galileo Advanced plus; Novotec Medical, Pforzheim, Germany) under 3 different vibration frequency conditions (4-mm amplitude with 10-, 20-, and 27-Hz frequencies) and a control condition (0-mm amplitude with 0-Hz frequency). Each condition consisted of 2 alternating tasks (squatting and standing) every 30 seconds for 5 repetitions. All subjects performed the 4 conditions in a randomized order.

MAIN OUTCOME MEASURE

Cortical activation during WBVe was measured by relative changes in oxygenated hemoglobin concentration over the primary motor cortex, premotor cortex, supplementary motor area, and prefrontal and somatosensory cortices using functional near-infrared spectroscopy.

RESULTS

Oxygenated hemoglobin concentration was higher during the 27-Hz vibration condition than the control and 10-Hz vibration conditions. Specifically, these changes were pronounced in the bilateral primary motor cortex (P < .05) and right prefrontal cortex (P < .05). In contrast, no significant changes in oxygenated hemoglobin concentration were observed in any of the cortical areas during the 10-Hz vibration condition compared with the control condition.

CONCLUSION

This study provides evidence that the motor network and prefrontal cortical areas of healthy adult males can be activated by 27-Hz WBVe. However, WBVe at lower frequencies did not induce significant changes in cortical activation.

Effect of whole-body vibration exercise in the pelvic floor muscles of healthy and unhealthy individuals: a narrative review

The aim of this narrative review was to determine effects of whole body vibration exercises (WBVE) on the pelvic floor muscle (PFM) of healthy and unhealthy individuals. Searches were performed in the databases PubMed, Scopus, Science Direct and PEDRo. The level of evidence and methodological quality of the selected papers were determined. It was included six studies with a total of 189 participants (95.76% women) with ages ranging from 18 to 68 years. It was reported that WBVE: (I) improves the PFMs strength and quality of life (QOL) in individuals with urinary incontinence; (II) does not cause (PFM) fatigue in nulliparous continent women; (III) leads to higher (PFM) activation in subjects with weakened (PFM) and achieves higher pelvic floor (PF) activation than maximum voluntary contraction alone; (IV) in an individual with postprostatectomy stress urinary incontinence (SUI), over a period of 6 weeks after starting treatment, the patient regained continence (usage of 1 safety pad) and (V) has a significant effect on the electromyographic response and additionality and the rating of perceived exertion (RPE) significantly increased with increased frequency of the mechanical vibration. Relevant findings are presented and demonstrated that the WBVE might be highly relevant to the management of clinical disorders of the (PFM). Nevertheless, this intervention must be more understood and known to be used in the management of individuals with impairment of the (PFM) and there is the necessity of more research in this area.

Sex-Related Differences in the Accuracy of Estimating Target Force Using Percentages of Maximal Voluntary Isometric Contractions vs. Ratings of Perceived Exertion During Isometric Muscle Actions

Keller, JL, Housh, TJ, Smith, CM, Hill, EC, Schmidt, RJ, and Johnson, GO. Sex-related differences in the accuracy of estimating target force using percentages of maximal voluntary isometric contractions vs. ratings of perceived exertion during isometric muscle actions. J Strength Cond Res 32(11): 3294-3300, 2018-The purpose of this study was to examine sex-related differences in the accuracy of estimating actual target force and to compare the accuracy of estimating actual target force using percentages of maximal voluntary isometric contraction (MVIC) or ratings of perceived exertion (RPE) values during isometric leg flexion and leg extension muscle actions. Twenty adults, 10 women and 10 men, (mean ± SD age: 22.9 ± 2.9 years) completed pretest MVICs to calculate actual target force values at 10, 30, 50, 70, and 90% of MVIC. Additional trials were then randomized for estimating actual target force using percentages of MVIC or RPE values during isometric leg flexion or leg extension. For isometric leg flexion, the women and men overestimated (p ≤ 0.05) the actual target force at 10% for the percentage of MVIC and RPE trials and underestimated the actual target force at 90% for the RPE trial. For isometric leg extension, the women overestimated the actual target force at 10% for the percentage of MVIC trial and RPE trial. The men overestimated actual target force at 10 and 30% for the percentage of MVIC trial and overestimated actual target force at 10% during the RPE trial for isometric leg extension. Also, the men underestimated actual target force at 90% for both the percentage of MVIC trial and RPE trial. Men require more familiarization than women to accurately estimate isometric leg extension force values. Caution should be used when estimating force production as a percentage of MVIC or RPE value for training prescriptions.

Effect of whole-body vibration on neuromuscular performance: A literature review

BACKGROUND

Whole-body vibration (WBV) is a neuromuscular training method that has recently received popularity in health and fitness centers, as an additional or substitute method to conventional training and therapy, in order to improve muscle strength and power.

OBJECTIVE

The purpose of this review is to critically observe the effect of WBV training on neuromuscular performance in view of its ability to enhance the muscles strength, power, and flexibility; and also to investigate the influence of the different vibration characteristics (viz., method of application of vibration, frequency, and amplitude) and exercise protocols on the effect of this training.

METHOD

For this review 24 studies or articles were examined, and based on exclusion and inclusion criteria, 5 studies were finally selected; and an attempt was made to uncover the factors influencing the improvement in neuromuscular performance as a result of WBV intervention. During the review, it was considered to include and discuss as many characteristics as possible, such as, knee extension, knee flexion, counter movement jump (CMJ), squat exercise, and jumping height (JH).

RESULT

Whole-body vibration, along with additional exercise training, has a potential to induce substantial improvement in neuromuscular performance.

CONCLUSION

Whole-body vibration can bring about improvement in muscles strength, power, and flexibility. The main factors associated with the improvement in muscles performance are range of amplitude and frequency, type of vibration and its method of application, training intensity, exercise protocol, and the characteristics of the participants.

Different fatigue-resistant leg muscles and EMG response during whole-body vibration

The purpose of this study was to determine the effects of static whole-body vibration (WBV) on the Electromyograhic (EMG) responses of leg muscles, which are fatigue-resistant in different manner. The study population was divided into two groups according to the values obtained by the Fatigue Index [Group I: Less Fatigue Resistant (LFR), n=11; Group II: More Fatigue Resistant (MFR), n=11]. The repeated electromyographic (EMG) activities of four leg muscles were analyzed the following determinants: (1) frequency (30 Hz, 35 Hz and 40 Hz); (2) stance position (static squat position); (3) amplitude (2 mm and 4 mm) and (4) knee flexion angle (120°), (5) vertical vibration platform. Vibration data were analyzed using Minitab 16 (Minitab Ltd, State College, PA, USA). The significance level was set at p<.05. The study results showed that static WBV stimuli given at different frequencies and amplitudes resulted in a significant increase (p<.05) in compared, the LFR group showed significantly (1) higher rates of quadriceps femoris and hamstring muscle fatigue (p<.05), (2) higher levels of knee extensor and flexor torque (p<.05) and (3) higher percentage increases in EMG activation at higher frequencies (max at 40 Hz) and amplitudes (4 mm) (p<.05). The present study can be used for the optimal prescription of vibration exercise and can serve to guide the development of training programs.

Short-Term Effects of Whole-Body Vibration Combined with Task-Related Training on Upper Extremity Function, Spasticity, and Grip Strength in Subjects with Poststroke Hemiplegia: A Pilot Randomized Controlled Trial

OBJECTIVE

The aim of this study was to determine the effect of whole-body vibration training combined with task-related training on arm function, spasticity, and grip strength in subjects with poststroke hemiplegia.

DESIGN

Forty-five subjects with poststroke were randomly allocated to 3 groups, each with 15 subjects as follows: control group, whole-body vibration group, and whole-body vibration plus task-related training group. Outcome was evaluated by clinical evaluation and measurements of the grip strength before and 4 weeks after intervention.

RESULTS

Our results show that there was a significantly greater increase in the Fugl-Meyer scale, maximal grip strength of the affected hand, and grip strength normalized to the less affected hand in subjects undergoing the whole-body vibration training compared with the control group after the test. Furthermore, there was a significantly greater increase in the Wolf motor function test and a decrease in the modified Ashworth spasticity total scores in subjects who underwent whole-body vibration plus task-related training compared with those in the other 2 groups after the test.

CONCLUSIONS

The findings indicate that the use of whole-body vibration training combined with task-related training has more benefits on the improvement of arm function, spasticity, and maximal grip strength than conventional upper limb training alone or with whole-body vibration in people with poststroke hemiplegia.

EMG activity of upper limb on spinal cord injury individuals during whole-body vibration

Whole-body vibration (WBV) has shown positive results increasing electromyographic (EMG) activity and strength in a healthy population when applied to upper and lower limbs. The aim of this study was to verify if WBV increases the EMG signal of the upper limb muscles in patients with spinal cord injury (SCI). For this study, 15 patients with SCI were selected and one single session of WBV was applied to the upper limb. Five sessions of 30 s at 30 Hz were applied and EMG of anterior deltoid and forearm muscles was measured. The results show that EMG activity had a significant increase during WBV session compared with baseline muscle activity. These results support WBV as an efficient tool to increase the upper body EMG in individuals with SCI.

Do whole body vibration exercises affect lower limbs neuromuscular activity in populations with a medical condition? A systematic review

BACKGROUND

The use of surface electromyography (sEMG) to evaluate muscle activation when executing whole body vibration exercises (WBVE) in studies provide neuromuscular findings, in healthy and diseased populations.

OBJECTIVES

Perform a systematic review of the effects of WBVE by sEMG of lower limbs in non-healthy populations.

METHODS

The search using the defined keywords was performed in PubMed, PEDRo and EMBASE databases by three independent researchers. Applying the PRISMA statement several studies were selected according to eligibility criteria and organized for the review. Full papers were included if they described effects of WBVE for the treatment of illnesses, evaluated by sEMG of lower limbs independently on the year of the publication; in comparison or associated with other treatment and evaluation techniques.

RESULTS

Seven publications were selected; two in spinal cord injury patients, one in Friedreich's ataxia patients, three in stroke patients and one study in breast cancer survivors. Reported effects of WBV in were muscle activation by sEMG and also on strength, blood flow and exercise resistance; even in paretic limbs.

CONCLUSION

By the use of sEMG it was verified that WBVE elicits muscle activation in diseased population. These results may lead to the definition of exercise protocols to maintain or increase muscular activation. However, due to the heterogeneity of methods among studies, there is currently no consensus on the sEMG signal processing. These strategies might also induce effects on muscle strength, balance and flexibility in these and other illnesses.

Effect of Direct Whole-Body Vibration on Upper-Body Muscular Power in Recreational, Resistance-Trained Men

Jones, MT, Martin, JR, Jagim, AR, and Oliver, JM. Effect of direct whole-body vibration on upper-body muscular power in recreational, resistance-trained men. J Strength Cond Res 31(5): 1371-1377, 2017-To determine the acute effect of whole-body vibration (WBV) on upper-body power, 15 men (mean ± SD; age 21.5 ± 2.3 years; height 173.1 ± 6.5 cm; and weight 77.2 ± 13.8 kg) with ≥1-year resistance training experience and a bench press (BP): body mass ratio ≥1.25 participated in a repeated-measures crossover design. Session 1 included body composition ([Bod Pod] 15.76 ± 6.7% body fat), 3 repetition maximum BP, and familiarization with: seated medicine ball throw (SMBT), plyometric push-up (PPU) on a force plate, and vertical WBV platform. Sessions 2-5 were randomly ordered across condition and test, separated by 24 hours, and consisted of a warm-up followed by 4 × 30-second push-up holds (2 × elbows at 90° and 2 × arms extended) performed on the vibration platform with WBV (frequency: 30 Hz, amplitude: 2-4 mm, 1:1 work: relief ratio) or no WBV. Seated medicine ball throw and PPU were tested immediately, 1, 5, and 10 minutes post. Standardized magnitude-based inferences were used to define outcomes. A likely positive effect of WBV was observed for SMBT at 10 minutes post. A likely negative effect of WBV resulted at 1 minute in time-to-peak force. A possibly positive effect was observed 10 minutes post. A possibly negative effect was observed 10 minutes post for peak power, and a likely negative effect of WBV was observed on time-to-peak power immediate post. Incorporating a 10-minute rest period is recommended when implementing power exercises after upper-body static-hold exercises during WBV exposure.

Effects of Different Magnitudes of Whole-Body Vibration on Dynamic Squatting Performance

The purpose of this study was to examine the effects (a) of different whole-body vibration (WBV) accelerations when applied simultaneously during a set of squats on performance and perceived exertion and (b) of different linear increases and decreases of vibrations during the squats. It is a randomized, crossover experimental design. Undergraduate students (3 female; 16 male) participated. Each participant completed 5 laboratory sessions in this study (4 familiarization and 1 test session). The test session then had each participant complete one 20-second set of dynamics quarter-squats for 5 separate conditions followed by 5 minutes of rest. Squatting was performed at maximum speed from full extension knee with plantar-flexion ankle to a knee angle of 70° (0° = anatomic position) with dorsiflexion ankle. All sets were performed on the WBV platform in random order, where the 5 different conditions were (a) no WBV-sham, (b) 30 Hz (30 Hz low amplitude), (c) 50 Hz (50 Hz high amplitude), (d) 30-50 Hz (increasing frequency from 30 to 50 Hz; 1 Hz per second with high amplitude), and (e) 50-30 Hz (decreasing frequency from 50 to 30 Hz; 1 Hz per second). There was a significant decrease in the mean velocity of squatting performed during the 30- to 50-Hz condition compared with all other conditions (p ≤ 0.05). There were a significantly lower amount of repetitions performed during the 30- to 50-Hz exposure compared with the no-WBV and 30-Hz conditions. There was a significantly lower Rating of Perceived Exertion (RPE) during the 30-Hz condition compared with the no-WBV, 50-Hz, 30-50-Hz, and 50-30-Hz conditions.

Effects of whole body vibration on strength and jumping performance in volleyball and beach volleyball players

The primary aim of this study was to examine the effects of 6-week strength training with whole body vibration (WBV) on leg strength and jumping performance in volleyball and beach volleyball players. Twenty-three sub-elite male volleyball (VB; n=12) and beach volleyball players (BVB; n=11) aged 21.2±3.0 years were divided into two groups and subjected to 6 weeks of strength training (three one-hour sessions per week): (I) 12 players (6 VB and 6 BVB players) underwent training with WBV (30-40 Hz, 1.7-2.5 mm, 3.0-5.7 g), and (II) 11 players (6 VB and 5 BVB players) underwent traditional strength training. Squat jump (SJ) and countermovement squat jump (CMJ) measurements by the Ergo Tester contact platform and maximum leg press test (1RM) were conducted. Three-factor (2 time x 2 WBV use x 2 discipline) analysis of variance for SJ, CMJ and 1RM revealed a significant time main effect (p<0.001), a WBV use effect (p<0.001) and a discipline effect (p<0.001). Significantly greater improvements in the SJ (p<0.001) and CMJ (p<0.001) and in 1RM (p<0.001) were found in the WBV training groups than in traditional training groups. Significant 3-way interaction effects (training, WBV use, discipline kind) were also found for SJ, CMJ and 1RM (p=0.001, p<0.001, p=0.001, respectively). It can be concluded that implementation of 6-week WBV training in routine practice in volleyball and beach volleyball players increases leg strength more and leads to greater improvement in jump performance than traditional strength training, but greater improvements can be expected in beach volleyball players than in volleyball players.

Whole-body vibration applied during upper body exercise improves performance

Whole-body vibration (WBV) training has exercisers perform static and dynamic resistance training exercises on a ground-based platform. Exposure to WBV exposure has demonstrated benefits and no effect on lower body strength, power, and performance. The aim of this study was to determine if WBV exposure (50 Hz, 2.51 mm) has any potentiating effects postexercise by measuring the kinematic variables of a set of upper body elbow-extensor exercise (70% one-repetition maximum [1RM]) to volitional exhaustion. Sixteen recreationally active students (12 male and 4 female) performed 3 different experimental conditions on separate days. Each condition had the subjects perform 1 set of elbow-extension exercise to fatigue with 1 of 3 WBV treatments: WBV simultaneously during the set (AE); 60 seconds after application of WBV for 30 seconds (RE); and no WBV (CTRL). Kinematic parameters of each repetition were monitored by linking a rotary encoder to the highest load plate. The mean velocity and acceleration throughout the set and perceived exertion were analyzed. A significant increase (p < 0.05) was observed in the mean velocity for the whole set in the AE condition vs. the CTRL condition. The mean acceleration was significantly higher (p < 0.05) in the AE condition in comparison with RE (increased by 45.3%) and CTRL (increased by 50.4%) conditions. The positive effect induced by WBV on upper-limb performance is only achieved when the stimulus is applied during the exercise. However, WBV applied 60 seconds before upper body exercise results in no benefit.

Vibration training for upper body: transmission of platform vibrations through cables

The aim of the present study was to evaluate the vibration transmission from a vibration platform through Vectran cables to the upper body and its relationship to induced muscular activation. Fifteen clinically healthy participants performed 3 different arm exercises-biceps curl, triceps curl, and lateral raise. Vibration transmission to the upper body was assessed over a wide range of accelerations (from 1.90 to 5.98 g) and frequencies (from 25 to 40 Hz). To assess the vibration transmission, 7 triaxial accelerometers were attached from the hand up to the head, and the root-mean-square of acceleration signal of each site-specific body point was calculated. Muscular activity of biceps brachii, triceps brachii, deltoid, and upper trapezius was recorded. The results showed a significant attenuation of the platform accelerations transmitted through the Vectran cables to the upper body. Handle vibration ranged between 27 and 44% of the acceleration delivered by the platform depending on platform vibration parameters (acceleration/frequency). Vibration increased the muscle activity of biceps brachii, triceps brachii, deltoid, and upper trapezius muscles significantly only during biceps curl exercises. No frequency or acceleration effect was found on the size of the muscle response. The results of the present study suggest that a cable-pulley resistance system on a vibration platform channels the vibration safely from the platform to the arms and induces additional muscle activation in some arm muscles when biceps curl exercises are performed.