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The effects of a whole-body vibration program on muscle performance and flexibility in female athletes.

Fagnani F, Giombini A, Di Cesare A, Pigozzi F, Di Salvo V.

Sports Medicine Laboratory, Department of Health Sciences, University of Rome "IUSM", Rome, Italy.

OBJECTIVE: This randomized controlled study was designed to investigate the short-term effects of an 8-wk whole-body vibration protocol on muscle performance and flexibility in female competitive athletes. DESIGN: Twenty-six young volunteer female athletes (ages 21-27 yrs) were randomized to either the vibration group or control group. The vibration intervention consisted of an 8-wk whole-body vibration 3 times a week employed by standing on a vertical vibration platform. As outcome measures, three performance tests (counter-movement jump, extension strength of lower extremities with an isokinetic horizontal leg press, and a sit-and-reach test for flexibility) were performed initially and after 8 wks. RESULTS: A total of 24 athletes completed the study properly. In the vibration group (n = 13) whole-body vibration induced significant improvement of bilateral knee extensor strength (P < 0.001), counter-movements jump (P < 0.001), and flexibility (P < 0.001) after 8 wks of training. No significant changes were found for all the outcome measures for the control group (n = 11). CONCLUSIONS: Whole-body vibration is a suitable training method to improve knee extension maximal strength, counter-movement jump, and flexibility in a young female athlete if it is properly designed. Not only do the optimal frequency, amplitude, and g-forces need to be identified but also the level of muscle activation that would benefit more from vibration stimulation. The improvement of flexibility is important not only for performance but also for the prevention of muscle-tendon injury.

Fagnani F., Giombini A., Di Cesare A., Pigozzi F. & Di Salvo V. (2006). The effects of a whole-body vibration program on muscle performance and flexibility in female athletes. American Journal of Physical Medicine and Rehabilitation. 85(12). 956-962.

The effects of whole-body vibration on upper- and lower-body EMG during static and dynamic contractions.

Hazell TJ, Jakobi JM, Kenno KA.

University of Windsor, Department of Kinesiology, Faculty of Human Kinetics, 401 Sunset Avenue, Windsor, ON N9B 3P4. [email protected]

Whole-body vibration (WBV) training uses a vertically oscillating platform and reports suggest that this perturbation elicits reflexive muscle contractions that augment muscle activity and contribute to increased strength. No WBV study has measured both upper- and lower-body muscle activation. The purpose of this study was to determine the optimal WBV stimulus (frequency x amplitude) to increase electromyography (EMG) in upper- and lower-body muscles for three distinctive unloaded actions: isometric semi-squat, dynamic leg squats, and static and dynamic bilateral bicep curls. Surface EMG was measured for the vastus lateralis (VL), biceps femoris (BF), biceps brachii (BB), and triceps brachii (TB) in 10 recreationally active male university students (24.4+/-2.0 years; mean+/-SD) when WBV was administered at 2 and 4 mm and at 25, 30, 35, 40, and 45 Hz. EMG changes are reported as the difference between WBV and no WBV EMG root mean square expressed as a percentage of maximum voluntary exertion (%MVE). In static semi-squat, WBV increased muscle activity 2.9%-6.7% in the VL and 0.8%-1.2% in the BF. During dynamic squatting, WBV increased muscle activity in the VL by 3.7%-8.7% and in the BF by 0.4%-2.0%. In a static biceps curl, WBV had no effect on BB EMG, but did increase TB activity 0.3%-0.7%. During dynamic biceps curls, WBV increased BB EMG activity by 0.6%-0.8% and TB activity by 0.2%-1.0%. The higher WBV amplitude (4 mm) and frequencies (35, 40, 45 Hz) resulted in the greatest increases in EMG activity.

Hazell T.J., Jakobi J.M. & Kenno K.A. (2007). The effects of whole-body vibration on upper- and lower-body emg during static and dynamic contractions. Applied Physiology, Nutrition, and Metabolism. 32(6). 1156-1163.

A comparison of the physiologic effects of acute whole-body vibration exercise in young and older people.

Cochrane DJ, Sartor F, Winwood K, Stannard SR, Narici MV, Rittweger J.

Sport Management & Coaching, Department of Management, Massey University, Palmerston North, NZ. [email protected]

OBJECTIVE: To examine the acute physiologic effects of acute whole-body vibration (WBV) exercise in young and older people. DESIGN: Every participant performed 9 conditions in a static squat position, consisting of no vibration and WBV at 30Hz and 3 loads corresponding to (1) no load (0% body mass), (2) load of 20% body mass, and (3) load of 40% body mass. A Jendrassik voluntary contraction was also performed with no vibration and WBV at 30Hz with no load and 20% body mass. SETTING: Laboratory facilities at a university in the United Kingdom. PARTICIPANTS: Healthy young people (n=12; 6 men, 6 women; mean age, 21.5y) and 12 healthy older people (6 men, 6 women; mean age, 69.2y) from the local community. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The Physical Activity Questionnaire, anthropometric measures, counter-movement jump, and isometric maximal voluntary contraction with the Jendrassik maneuver were assessed in both groups. Oxygen uptake (Vo2), blood pressure, heart rate, and rating of perceived exertion (RPE) were recorded during WBV and load conditions as the outcome of the study. RESULTS: Both vibration and load were associated with an increase (P<.001) in Vo2 for older and young groups. WBV elicited the equivalent of a .35 metabolic equivalent (MET) increase in Vo2, with additional loads of 20% and 40% body mass increasing Vo2 by 0.8 and 1.2 METs, respectively. Additionally, there was an interaction effect of vibration and group in which the WBV-related Vo2 increase was less in the old compared with the young. Both vibration and load caused an increase in heart rate, blood pressure, and RPE (all P<.001); however, there were no significant group differences between young and older groups. The Jendrassik maneuver elicited an increase in Vo2 by 27.6% for the old and 33% for the young group (P<.001); however, there was no significant difference between groups. CONCLUSIONS: Vo2 significantly increased in both the older and young people with vibration and additional load and when the Jendrassik maneuver was superimposed with vibration and load. However, the elicited increase in Vo2 (1.2mL x kg(-1).min(-1)) from WBV may be an insufficient stimulus to improve cardiovascular fitness.

Cochrane D.J., Sartor F., Winwood K., Stannard S.R., Narici M.V. & Rittweger J. (2008). A comparison of the physiologic effects of acute whole-body vibration exercise in young and older people. Archives of Physical Medicine and Rehabilitation. 89(5). 815-821.

Influence of vibration on delayed onset of muscle soreness following eccentric exercise.

Bakhitiary AH, Safavi-Farokhi Z, Aminian-Far A.

Physiotherapy Department, Rehabilitation Faculty, Semnan University of Medical Sciences, Km 5 Road to Damghan, Semnan, Iran. [email protected]

Delayed onset muscle soreness (DOMS), which may occur after eccentric exercise, may cause some reduction in ability in sport activities. For this reason, several studies have been designed on preventing and controlling DOMS. As vibration training (VT) may improve muscle performance, we designed this study to investigate the effect of VT on controlling and preventing DOMS after eccentric exercise. METHODS: Fifty healthy non-athletic volunteers were assigned randomly into two experimental, VT (n = 25) and non-VT (n = 25) groups. A vibrator was used to apply 50 Hz vibration on the left and right quadriceps, hamstring and calf muscles for 1 min in the VT group, while no vibration was applied in the non-VT group. Then, both groups walked downhill on a 10 degrees declined treadmill at a speed of 4 km/hour. The measurements included the isometric maximum voluntary contraction force (IMVC) of left and right quadriceps muscles, pressure pain threshold (PPT) 5, 10 and 15 cm above the patella and mid-line of the calf muscles of both lower limbs before and the day after treadmill walking. After 24 hours, the serum levels of creatine-kinase (CK), and DOMS level by visual analogue scale were measured. RESULTS: The results showed decreased IMVC force (P = 0.006), reduced PPT (P = 0.0001) and significantly increased mean of DOMS and CK levels in the non-VT group, compared to the VT group (P = 0.001). CONCLUSION: A comparison by experimental groups indicates that VT before eccentric exercise may prevent and control DOMS. Further studies should be undertaken to ascertain the stability and effectiveness of VT in athletics.

Bakhitiary A.H., Safavi-Farokhi Z. & Aminian-Far A. (2007). Influence of vibration on delayed onset of muscle soreness following eccentric exercise. British Journal of Sports Medicine. 41(3). 145-148.

Acute whole body vibration training increases vertical jump and flexibility performance in elite female field hockey players.

Cochrane DJ, Stannard SR.

Massey University, Sport and Exercise, Palmerston North, New Zealand. [email protected]

OBJECTIVE: To quantify the acute effect of whole body vibration (WBV) training on arm countermovement vertical jump (ACMVJ), grip strength, and flexibility performance. METHODS: Eighteen female elite field hockey players each completed three interventions of WBV, control, and cycling in a balanced random manner. WBV was performed on a Galileo machine (26 Hz) with six different exercises being performed. For the control, the same six exercises were performed at 0 Hz, whilst cycling was performed at 50 W. Each intervention was 5 min in duration with ACMVJ, grip strength, and flexibility measurements being conducted pre and post intervention. RESULTS: There was a positive interaction effect (intervention x pre-post) of enhanced ACMVJ (p<0.001) and flexibility (p<0.05) parameters following WBV; however no changes were observed after the control and cycling interventions. There was no interaction effect for grip strength following the three interventions. CONCLUSIONS: Acute WBV causes neural potentiation of the stretch reflex loop as shown by the improved ACMVJ and flexibility performance. Additionally, muscle groups less proportionally exposed to vibration do not exhibit physiological changes that potentiate muscular performance.

Cochrane D.J. & Stannard S.R. (2005). Acute whole body vibration training increases vertical jump and flexibility performance in elite female field hockey players. British Journal of Sports Medicine. 39(11). 860-865.

Adaptive responses of human skeletal muscle to vibration exposure.

Bosco C, Colli R, Introini E, Cardinale M, Tsarpe,a O, Madella A, Tihanyi J, Viru A.

University of Rome-Tor Vergata, Italy.

The aim of this study was to investigate the effects of whole-body vibrations (WBV) on the mechanical behaviour of human skeletal muscle. For this purpose, six female volleyball players at national level were recruited voluntarily. They were tested with maximal dynamic leg press exercise on a slide machine with extra loads of 70, 90, 110 and 130 kg. After the testing, one leg was randomly assigned to the control treatment (C) and the other to the experimental treatment (E) consisting of vibrations. The subjects were then retested at the end of the treatment using the leg press. Results showed remarkable and statistically significant enhancement of the experimental treatment in average velocity (AV), average force (AF) and average power (AP) (P < 0.05-0.005). Consequently, the velocity-force and power-force relationship shifted to the right after the treatment. In conclusion, it was affirmed that the enhancement could be caused by neural factors, as athletes were well accustomed to the leg press exercise and the learning effect was minimized.

Bosco C., Colli R., Introini E., Cardinale M., Tsarpela O., Madella A., Tihanyi J. & Viru A. (1999). Adaptive responses of human skeletal muscle to vibration exposure. Clinical Physiology. 19(2). 183-187.

Acute changes in neuromuscular excitability after exhaustive whole body vibration exercise as compared to exhaustion by squatting exercise.

Rittweger J, Mutschelknauss M, Felsenberg D.

Institut für Physiologie, Freie Universität Berlin, Arnimallee, Berlin, Germany. [email protected]

The effects of hard squatting exercise with (VbX+) and without (VbX-) vibration on neuromuscular function were tested in 19 healthy young volunteers. Before and after the exercise, three different tests were performed: maximum serial jumping for 30 s, electromyography during isometric knee extension at 70% of the maximum voluntary torque, and the quantitative analysis of the patellar tendon reflex. Between VbX+ and VbX- values, there was no difference found under baseline conditions. Time to exhaustion was significantly shorter in VbX+ than in VbX- (349 +/- 338 s versus 515 +/- 338 s), but blood lactate (5.49 +/- 2.73 mmol l-1 versus 5.00 +/- 2.26 mmol l-1) and subjectively perceived exertion (rate of perceived exertion values 18.1 +/- 1.2 versus 18.6 +/- 1.6) at the termination of exercise indicate comparable levels of fatigue. After the exercise, comparable effects were observed on jump height, ground contact time, and isometric torque. The vastus lateralis mean frequency during isometric torque, however, was higher after VbX+ than after VbX-. Likewise, the tendon reflex amplitude was significantly greater after VbX+ than after VbX- (4.34 +/- 3.63 Nm versus 1.68 +/- 1.32 Nm). It is followed that in exercise unto comparable degrees of exhaustion and muscular fatigue, superimposed 26 Hz vibration appears to elicit an alteration in neuromuscular recruitment patterns, which apparently enhance neuromuscular excitability. Possibly, this effect may be exploited for the design of future training regimes.

Rittweger J., Mutschelknauss M. & Felsenberg D. (2003). Acute changes in neuromuscular excitability after exhaustive whole body vibration exercise as compared to exhaustion by squatting exercise. Clinical Physiology and Functional Imaging. 23(2). 81-86.

Whole body vibration exercise: training and benefits.

Dolny DG, Reyes GF.

Department HPERD, University of Idaho, College of Education, Human Performance Laboratory, Moscow, ID 83844, USA. [email protected]

In recent years, it has been suggested that exercise using whole body vibration (WBV) platforms may increase muscle activity and subsequently enhance muscle performance in both acute and chronic conditions. WBV platforms produce frequencies ranging from 15-60 Hz and vertical displacements from ~1-11 mm, resulting in accelerations of ~2.2-5.1 g. Acute exposure to WBV has produced mixed results in terms of improving jump, sprint, and measures of muscle performance. With WBV training, younger fit subjects may not experience gains unless some type of external load is added to WBV exercise. However, sedentary and elderly individuals have demonstrated significant gains in most measures of muscle performance, similar with comparable traditional resistance exercise training programs. WBV training also has demonstrated gains in flexibility in younger athletic populations and gains or maintenance in bone mineral density in postmenopausal women. These promising results await further research to establish preferred WBV training parameters.

DolnyD.G. & Reyes G.F. (2008). Whole body vibration exercise: training and benefits. Current Sports Medicine Reports. 7(3), 152-157.

Hormonal responses to whole-body vibration in men.

Bosco C, Iacovelli M, Tsarpela O, Cardinale M, Bonifazi M, Tihanyi J, Viru M, De Lorenzo A, Viru A.

Societa Stampa Sportiva, Rome, Italy. [email protected]

The aim of this study was to evaluate the acute responses of blood hormone concentrations and neuromuscular performance following whole-body vibration (WBV) treatment. Fourteen male subjects [mean (SD) age 25 (4.6) years] were exposed to vertical sinusoidal WBV, 10 times for 60 s, with 60 s rest between the vibration sets (a rest period lasting 6 min was allowed after 5 vibration sets). Neuromuscular performance tests consisting of counter-movement jumps and maximal dynamic leg presses on a slide machine, performed with an extra load of 160% of the subjects body mass, and with both legs were administered before and immediately after the WBV treatment. The average velocity, acceleration, average force, and power were calculated and the root mean square electromyogram (EMGrms) were recorded from the vastus lateralis and rectus femoris muscles simultaneously during the leg-press measurement. Blood samples were also collected, and plasma concentrations of testosterone (T), growth hormone (GH) and cortisol (C) were measured. The results showed a significant increase in the plasma concentration of T and GH, whereas C levels decreased. An increase in the mechanical power output of the leg extensor muscles was observed together with a reduction in EMGrms activity. Neuromuscular efficiency improved, as indicated by the decrease in the ratio between EMGrms and power. Jumping performance, which was measured using the counter-movement jump test, was also enhanced. Thus, it can be argued that the biological mechanism produced by vibration is similar to the effect produced by explosive power training (jumping and bouncing). The enhancement of explosive power could have been induced by an increase in the synchronisation activity of the motor units, and/or improved co-ordination of the synergistic muscles and increased inhibition of the antagonists. These results suggest that WBV treatment leads to acute responses of hormonal profile and neuromuscular performance. It is therefore likely that the effect of WBV treatment elicited a biological adaptation that is connected to a neural potentiation effect, similar to those reported to occur following resistance and explosive power training. In conclusion, it is suggested that WBV influences proprioceptive feedback mechanisms and specific neural components, leading to an improvement of neuromuscular performance. Moreover, since the hormonal responses, characterised by an increase in T and GH concentration and a decrease in C concentration, and the increase in neuromuscular effectiveness were simultaneous but independent, it is speculated that the two phenomena might have common underlying mechanisms.

Bosco C., Iacovelli M., Tsarpela O., Cardinale M., Bonifazi M., Tihanyi J., Viru M., De Lorenzo A. & Viru A. (2000). Hormonal responses to whole-body vibration in men. European Journal of Applied Physiology. 81(6). 449-454.

The rate of muscle temperature increase during acute whole-body vibration exercise.

Cochrane DJ, Stannard SR, Sargeant AJ, Rittweger J.

Sport Management and Coaching, Department of Management, Massey University, Private Bag 11 222, Palmerston North, New Zealand, [email protected]

This study compared the rate of muscle temperature (T (m)) increase during acute whole-body vibration (WBV), to that of stationary cycling and passive warm-up. Additionally we wanted to determine if the purported increase in counter-movement jump and peak power cycling from acute WBV could be explained by changes in muscle temperature. Eight active participants volunteered for the study, which involved a rest period of 30 min to collect baseline measures of muscle, core, skin temperature, heart rate (HR), and thermal leg sensation (TLS), which was followed by three vertical jumps and 5 s maximal cycle performance test. A second rest period of 40 min was enforced followed by the intervention and performance tests. The change in T (m) elicited during cycling was matched in the hot bath and WBV interventions. Therefore cycling was performed first, proceeded by, in a random order of hot bath and acute WBV. The rate of T (m) was significantly greater (P < 0.001) during acute WBV (0.30 degrees C min(-1)) compared to cycle (0.15 degrees C min(-1)) and hot bath (0.09 degrees C min(-1)) however there was no difference between the cycle and hot bath, and the metabolic rate was the same in cycling and WBV (19 mL kg(-1) min(-1)). All three interventions showed a significant (P < 0.001) increase in countermovement jump peak power and height. For the 5 s maximal cycle test (MIC) there were no significant differences in peak power between the three interventions. In conclusion, acute WBV elevates T (m) more quickly than traditional forms of cycling and passive warm-up. Given that all three warm-up methods yielded the same increase in peak power output, we propose that the main effect is caused by the increase in T (m).

Cochrane D.J., Stannard S.R., Sargeant A.J. & Rittweger J. (2008). The rate of muscle temperature increase during acute whole-body vibration exercise. European Journal of Applied Physiology. [Epub ahead of print]

Effects of vibration and resistance training on neuromuscular and hormonal measures.

Kvorning T, Bagger M, Caserotti P, Madsen K.

Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark. [email protected]

The aim was to study whether whole body vibration (WBV) combined with conventional resistance training (CRT) induces a higher increase in neuromuscular and hormonal measures compared with CRT or WBV, respectively. Twenty-eight young men were randomized in three groups; squat only (S), combination of WBV and squat (S+V) and WBV only (V). S+V performed six sets with eight repetitions with corresponding eight repetition maximum (RM) loads on the vibrating platform, whereas S and V performed the same protocol without WBV and resistance, respectively. Maximal isometric voluntary contraction (MVC) with electromyography (EMG) measurements during leg press, counter movement jump (CMJ) measures (mechanical performance) including jump height, mean power (Pmean), peak power (Ppeak) and velocity at Ppeak (Vppeak) and acute hormonal responses to training sessions were measured before and after a 9-week training period. ANOVA showed no significant changes between the three groups after training in any neuromuscular variable measured [except Pmean, S higher than V (P<0.05)]. However, applying t tests within each group revealed that MVC increased in S and S+V after training (P<0.05). Jump height, Pmean and Ppeak increased only in S, concomitantly with increased Vppeak in all groups (P<0.05). Testosterone increased during training sessions in S and S+V (P<0.05). Growth hormone (GH) increased in all groups but S+V showed higher responses than S and V (P<0.05). Cortisol increased only in S+V (P<0.05). We conclude that combined WBV and CRT did not additionally increase MVC and mechanical performance compared with CRT alone. Furthermore, WBV alone did not increase MVC and mechanical performance in spite of increased GH.

Kvorning T., Bagger M., Caserotti P. & Madsen K. (2006). Effects of vibration and resistance training on neuromuscular and hormonal measures. European Journal of Applied Physiology. 96(5). 615-625.

Effects of whole body vibration training on muscle strength and sprint performance in sprint-trained athletes.

Delecluse C, Roelants M, Diels R, Koninckx E, Verschueren S.

Exercise Physiology and Biomechanics Laboratory, Faculty of Physical Education and Physiotherapy, Department of Kinesiology, Katholieke Universiteit Leuven, Leuven, Belgium. [email protected]

Despite the expanding use of Whole Body Vibration training among athletes, it is not known whether adding Whole Body Vibration training to the conventional training of sprint-trained athletes will improve speed-strength performance. Twenty experienced sprint-trained athletes (13 male symbol, 7 female symbol, 17-30 years old) were randomly assigned to a Whole Body Vibration group (n=10: 6 male symbol and 4 female symbol) or a Control group (n=10: 7 male symbol, 3 female symbol). During a 5-week experimental period all subjects continued their conventional training program, but the subjects of the Whole Body Vibration group additionally performed three times weekly a Whole Body Vibration training prior to their conventional training program. The Whole Body Vibration program consisted of unloaded static and dynamic leg exercises on a vibration platform (35-40 Hz, 1.7-2.5 mm, Power Plate). Pre and post isometric and dynamic (100 degrees/s) knee-extensor and -flexor strength and knee-extension velocity at fixed resistances were measured by means of a motor-driven dynamometer (Rev 9000, Technogym). Vertical jump performance was measured by means of a contact mat. Force-time characteristics of the start action were assessed using a load cell mounted on each starting block. Sprint running velocity was recorded by means of a laser system. Isometric and dynamic knee-extensor and knee-flexor strength were unaffected (p>0.05) in the Whole Body Vibration group and the Control group. As well, knee-extension velocity remained unchanged (p>0.05). The duration of the start action, the resulting start velocity, start acceleration, and sprint running velocity did not change (>0.05) in either group. In conclusion, this specific Whole Body Vibration protocol of 5 weeks had no surplus value upon the conventional training program to improve speed-strength performance in sprint-trained athletes.

Delecluse C., Roelants M., Diels R., Koninckx E. & Verschueren S. (2005). Effects of whole body vibration training on muscle strength and sprint performance in sprint-trained athletes. International Journal of Sports Medicine. 26(8). 662-668.

Effects of 24 weeks of whole body vibration training on body composition and muscle strength in untrained females.

Roelants M, Delecluse C, Goris M, Verschueren S.

Exercise Physiology and Biomechanics Laboratory, Faculty of Physical Education and Physiotherapy, Department of Kinesiology, Katholieke Universiteit Leuven, Tervuursevest 101, 3001 Leuven, Belgium.

The aim of this study was to investigate and to compare the effect of 24 weeks "whole body vibration" training and fitness training on body composition and on muscle strength. Forty-eight untrained females (21.3 +/- 2.0 yr) participated in the study. The whole body vibration group (N = 18) performed unloaded static and dynamic exercises on a vibration platform (35 - 40 Hz, 2.5 - 5.0 mm; Power Plate). The fitness group (N = 18) followed a standard cardiovascular (15 - 40 min) and resistance training program including dynamic leg press and leg extension exercises (20 - 8 RM). Both groups trained 3 times weekly. The control group (N = 12) did not participate in any training. Body composition was determined by means of underwater weighing. Additionally 12 skinfolds were assessed. Isometric (0 degrees /s) and isokinetic (50 degrees /s, 100 degrees /s, 150 degrees /s) knee-extensor strength was measured by means of a motor-driven dynamometer (Technogym). Over 24 weeks there were no significant changes (p > 0.05) in weight, in percentage body fat, nor in skinfold thickness in any of the groups. Fat free mass increased significantly in the whole body vibration group (+ 2.2 %) only. A significant strength gain was recorded in the whole body vibration group (24.4 +/- 5.1 %; 5.9 +/- 2.1 %; 8.3 +/- 4.4 %; 7.6 +/- 1.5 %) and in the fitness group (16.5 +/- 1.7 %; 12.0 +/- 2.7 %; 10.4 +/- 2.3 %; 10.2 +/- 1.9 %), at 0 degrees /s, 50 degrees /s, 100 degrees /s and 150 degrees /s respectively. In conclusion, 24 weeks whole body vibration training did not reduce weight, total body fat or subcutaneous fat in previously untrained females. However, whole body vibration training induces a gain in knee-extensor strength combined with a small increase in fat free mass. The gain in strength is comparable to the strength increase following a standard fitness training program consisting of cardiovascular and resistance training.

Roelants M., Delecluse C., Goris M. & Verschueren S. (2004). Effects of 24 weeks of whole body vibration training on body composition and muscle strength in untrained females. International Journal of Sports Medicine. 25(1).

Effect of 4-min vertical whole body vibration on muscle performance and body balance: a randomized cross-over study.

Torvinen S, Sievanen H, Jarvinen TA, Pasanen M, Kontulainen S, Kannus P.

Bone Research Group, UKK Institute, Tampere, Finland. [email protected]

The purpose of this randomized cross-over study was to investigate the effects of a 4-min long, 2-mm vertically-vibrating vibration-exercise on muscle performance and body balance in healthy subjects. Sixteen volunteers (eight men and women aged 18-35 years) underwent both the 4-min vibration- and sham-interventions in a randomized order on different days. Performance- and balance-tests (stability platform, grip strength, extension strength of lower extremities, tandem-walk, vertical jump and shuttle-run) were done 10 minutes before (baseline) and 2 and 60 minutes after the intervention. In addition, the effect of vibration on the surface electromyography (EMG) of soleus, vastus lateralis, gluteus medius, and paravertebralis muscles was investigated during the vibration. The 4-min vibration-loading did not induce any statistically significant change in the performance- or balance-tests at the 2- or 60-min tests. Interestingly, however, the mean power frequency of the EMG in the vastus lateralis and gluteus medius muscles decreased during the vibration-intervention, indicating muscle fatigue, particularly in the hip region. It was concluded that a 4-min long, 2-mm vertically-vibrating vibration-stimulus did not induce changes in the performance and balance tests. Future studies should focus on evaluating the effects of different kinds of vibration-regimens, as well as the long-term effects of vibration-training, on body balance and muscle performance, and, as a broader objective, on bone.

Torvinen S., Sievanen H., Jarvinen T.A., Pasanen M., Kontulainen S. & Kannus P. (2002). Effect of 4-min vertical whole body vibration on muscle performance and body balance: a randomized cross-over study. International Journal of Sports Medicine. 23(5). 374-379.

Effects of vibration exercise on muscle performance and mobility in an older population.

Rees S, Murphy A, Watsford M.

School of Leisure, Sport and Tourism, University of Technology, Sydney, Australia.

This study was designed to investigate the effects of vibration on muscle performance and mobility in a healthy, untrained, older population. Forty-three participants (23 men, 20 women, 66-85 y old) performed tests of sit-to-stand (STS), 5- and 10-m fast walk, timed up-and-go test, stair mobility, and strength. Participants were randomly assigned to a vibration group, an exercise-withoutvibration group, or a control group. Training consisted of 3 sessions/wk for 2 mo. After training, the vibration and exercise groups showed improved STS (12.4%, 10.2%), 5-m fast walk (3.0%, 3.7%), and knee-extension strength (8.1%, 7.2%) compared with the control (p < 0.05). Even though vibration training improved lower limb strength, it did not appear to have a facilitatory effect on functional-performance tasks compared with the exercise-without-vibration group. Comparable mobility and performance changes between the experimental groups suggest that improvements are linked with greater knee-extension strength and largely attributed to the unloaded squats performed by both exercise groups.

Rees S., Murphy A. & Watsford M. (2007). Effects of vibration exercise on muscle performance and mobility in an older population. Journal of Aging and Physical Activity. 15(4). 367-381.

Improving strength and postural control in young skiers: whole-body vibration versus equivalent resistance training.

Mahieu NN, Wityrouw E, Van de Voorde D, Michilsens D, Arbyn V, Van den Broecke W.

*Ghent University, Ghent, Belgium.

Context: Several groups have undertaken studies to evaluate the physiologic effects of whole-body vibration (WBV). However, the value of WBV in a training program remains unknown. Objective: To investigate whether a WBV program results in a better strength and postural control performance than an equivalent exercise program performed without vibration. Design: Randomized, controlled trial. Setting: Laboratory. Patients or Other Participants: Thirty-three Belgian competitive skiers (ages = 9-15 years). Intervention(s): Subjects were assigned to either the WBV group or the equivalent resistance (ER) group for 6 weeks of training at 3 times per week. Main Outcome Measure(s): Isokinetic plantar and dorsiflexion peak torque, isokinetic knee flexion and extension peak torque, explosive strength (high box test), and postural control were assessed before and after the training period. Results: Both training programs significantly improved isokinetic ankle and knee muscle strength and explosive strength. Moreover, the increases in explosive strength and in plantar-flexor strength at low speed were significantly higher in the WBV group than in the ER group after 6 weeks. However, neither WBV training nor ER training seemed to have an effect on postural control. Conclusions: A strength training program that includes WBV appears to have additive effects in young skiers compared with an equivalent program that does not include WBV. Therefore, our findings support the hypothesis that WBV training may be a beneficial supplementary training technique in strength programs for young athletes.

Mahieu N.N., Wityrouw E., Van de Voorde D., Michilsens D., Arbyn V. & Van den Broecke W. (2006). Improving strength and postural control in young skiers: whole-body vibration versus equivalent resistance training. Journal of Athletic Training. 41(3). 286-293.

Vibration training: benefits and risks.

Mester J, Kleinoder H, Yue Z.

Institute of Training Science and Sport Informatics, German Sport University, Cologne, Germany.

The main results of our recent several studies, i.e. the measurements of vibration training results for single case and group studies as well as the cardiovascular parameter measurements during vibrations and the corresponding hydrodynamic analysis, are summarized. Our studies and previous work all confirm that vibration training is an effective training method in order to improve maximal strength and flexibility as well as various other factors if the training is properly designed. Some recommendations regarding the proper ranges of frequencies, amplitudes and exposure duration of vibration training are made based on the existing vibration training practice and mechanism analysis, although much work remains to be carried out in order to set up clear rules for various groups of people so that maximal training results could be expected and in the meantime potential dangerous effects could be avoided. Cardiovascular parameter measurements confirm that total peripheral resistance (TPR) to the blood flow is increased during body vibration. Hydrodynamic analysis offers the mechanism for the increase of TPR through the deformation of vessels. As a reaction of compensation, more capillaries are probably opened in order to keep a necessary level of cardiac output needed for the body, resulting in more efficient gas and material metabolism between the blood and muscle fibres. This might be one of the reasons for the various potential beneficial effects of vibration training.

Mester J., Kleinoder H. & Yue Z. (2006). Vibration training: benefits and risks. Journal of Biomechanics. 39(6). 1056-1065.

Effect of 8-month controlled study.

Torvinen S, Kannnus P, Sievanen H, Jarvinen TA,  vertical whole body vibration on bone, muscle performance, and body balance: a randomized Pasanen TA, Kontulainen S, Nenonen A, Jarvinen TL, Paakkala T, Jarvinen M, Vuori I.

Bone Research Group, UKK Institute, Tampere, Finland.

Recent animal studies have given evidence that vibration loading may be an efficient and safe way to improve mass and mechanical competence of bone, thus providing great potential for preventing and treating osteoporosis. Randomized controlled trials on the safety and efficacy of the vibration on human skeleton are, however, lacking. This randomized controlled intervention trial was designed to assess the effects of an 8-month whole body vibration intervention on bone, muscular performance, and body balance in young and healthy adults. Fifty-six volunteers (21 men and 35 women; age, 19-38 years) were randomly assigned to the vibration group or control group. The vibration intervention consisted of an 8-month whole body vibration (4 min/day, 3-5 times per week). During the 4-minute vibration program, the platform oscillated in an ascending order from 25 to 45 Hz, corresponding to estimated maximum vertical accelerations from 2 g to 8 g. Mass, structure, and estimated strength of bone at the distal tibia and tibial shaft were assessed by peripheral quantitative computed tomography (pQCT) at baseline and at 8 months. Bone mineral content was measured at the lumbar spine, femoral neck, trochanter, calcaneus, and distal radius using DXA at baseline and after the 8-month intervention. Serum markers of bone turnover were determined at baseline and 3, 6, and 8 months. Five performance tests (vertical jump, isometric extension strength of the lower extremities, grip strength, shuttle run, and postural sway) were performed at baseline and after the 8-month intervention. The 8-month vibration intervention succeeded well and was safe to perform but had no effect on mass, structure, or estimated strength of bone at any skeletal site. Serum markers of bone turnover did not change during the vibration intervention. However, at 8 months, a 7.8% net benefit in the vertical jump height was observed in the vibration group (95% CI, 2.8-13.1%; p = 0.003). On the other performance and balance tests, the vibration intervention had no effect. In conclusion, the studied whole body vibration program had no effect on bones of young, healthy adults, but instead, increased vertical jump height. Future human studies are needed before clinical recommendations for vibration exercise.

Torvinen S., Kannus P., Sievanen H., Jarvinen T.A., Pasanen T.A., Kontulainen S., Nenonen A., Jarvinen T.L. Paakkala T., Jarvinen M. & Vuori I. (2003). Effect of 8-month vertical whole body vibration on bone, muscle performance, and body balance: a randomized controlled study. Journal of Bone and Mineral Research. 18(5). 876-884.

The acute effect of vibration exercise on concentric muscular characteristics.

Cochrane DJ, Stannard SR, Walmsely A, Firth EC.

Department of Management, Massey University, New Zealand.

This study was designed to compare the acute effect of vibration exercise with a concentric-only activity (arm cranking) on concentric-only muscle action using an upper body isoinertial exercise. Twelve healthy, physically active men, 30.0y+/-6.1 (mean+/-S.D.); height 1.81m+/-0.06; and weight 83.4kg+/-9.7, performed four maximal prone bench pull (PBP) efforts before and after a 5-min period of three different interventions: (1) acute vibration exercise (VBX); (2) arm cranking (AC); and (3) control (no exercise) (NVBX). Electromyography (EMG) activity was assessed from the middle trapezius muscle during PBP. Acute VBX was induced with an electric-powered dumbbell (DB) (frequency 26Hz, amplitude 3mm), with 30-s exposures at five different shoulder positions. NVXB was performed with the participants holding the DB with the machine turned off, and AC was performed at 25W. There was a significant (interventionxpre-post) interaction such that acute VBX and AC enhanced peak power by 4.8% (p<0.001) and 3.0% (p<0.001), respectively, compared to NVBX (-2.7%). However, there was no effect of any treatments on EMG activity compared to the control. In conclusion, acute VBX provides an acute ergogenic effect which potentiates concentric-only muscle performance, though not to a significantly greater extent than concentric (arm cranking) exercise.

Cochrane D.J., Stannard S.R., Walmsely A. & Firth E.C. (2007). The acute effect of vibration exercise on concentric muscular characteristics. Journal of Science and Medicine in Sport. [Epub ahead of print].

Biological reaction to vibration--implications for sport.

Mester J, Spitzenfeil P, Schwarzer J, Seifriz F.

Institute for Theory and Practice of Training and Movement, German Sport University, Cologne.

In many situations of everyday life, vibration load occurs. Here whole body vibration in vehicles, such as boats, cars, helicopters and others as well as hand-transmitted vibration (motor saws etc.) can be named. As vibration is assumed liable to cause various threats to human health, a great number of studies in work science focussed on dose-effect relations and concepts for prevention. Although in many sports remarkable vibration load also occurs, there is very little research on the potential dangers and benefits of vibration stimuli, e.g. on whole body vibration and the implications for muscular activity and neuromuscular control in sport. In personal studies the damping behaviour and training effects under whole body vibration were investigated. Various research areas have been studied in order to approach the relevant topics: neuromuscular and posture control, energy metabolism in terms of oxygen uptake under whole body vibration and local concentration of phosphates by means of 31P-MRS. Furthermore the effects of a strength training under whole body vibration were analysed. The results underline that vibration is a neglected research topic in sport science from the preventive point of view as well as from the one focussing on the improvement of sport performance.

Mester J., Spitzenfeil P., Schwarzer J. & Seifriz F. (1999). Biological reaction to vibration--implications for sport. Journal of Science and Medicine in Sport. 2(3). 211-226.

Differential effects of whole body vibration durations on knee extensor strength.

Stewart JA, Cochrane DJ, Morton RH.

New Zealand Institute of Sport, Wellington, New Zealand.

The effectiveness and optimality of whole body vibration (WBV) duration on muscular strength is yet to be determined. Hence the aim of this study was to investigate the effects of three different durations of continuous WBV exposure on isometric right knee extensor strength measured pre and post exposure. The study involved 12 trained male subjects (age 23.7+/-4.2 years, height 1.82+/-0.06m, weight 81.8+/-15.5kg). Pre and post knee extensor strength was measured using the Biodextrade mark System 3. Peak and mean torques were recorded over three maximal 2s contractions with 10s intervals. All subjects completed three interventions of WBV lasting 2, 4, or 6min, in a balanced randomized order. Whole body vibration was performed on the Galileotrade mark machine set at 26Hz with peak-to-peak amplitude of 4mm. We found significant interaction (durationxpre-post) effects for both peak and mean torque. Two minutes of WBV provided a significantly different (p<0.05) effect (peak torque +3.8%, mean torque +3.6%) compared to 4min (-2.7% and -0.8%, respectively), and compared to 6min (-6.0% and -5.2%, respectively), while 4min produced significantly different results compared to 6min for peak torque measurements only. Two minutes of WBV produced an improvement in isometric right knee extension strength compared to 4 and 6min, both of which produced strength decreases. Nevertheless, the mechanisms and optimal dose-response character of vibration exposure remain unclear.

Stewart J.A., Cochrane D.J. & Morton R.H. (2007). Differential effects of whole body vibration durations on knee extensor strength. Journal of Science and Medicine in Sport. [Epub ahaed of print]

Effect of whole body vibration training on lower limb performance in selected high-level ballet students.

Annini G, Padua E, Castagna C, Salvo VD, Minichella S, Tsarpela O, Manzi V, D'Pttavio S.

School of Sport and Exercise Sciences, Faculty of Medicine and Surgery, Tor Vergata University, Rome, Italy. [email protected]

The aim of this study was to examine the effects of 8 weeks of whole body vibration (WBV) training on vertical jump ability (CMJ) and knee-extensor performance at selected external loads (50, 70, and 100 kg; leg-press exercise) in elite ballerinas. Twenty-two (age, 21.25 +/- 1.5 years) full-time ballerinas were assigned randomly to the experimental (E, n = 11) and control (C, n = 11) groups. The experimental group was submitted to WBV training 3 times per week before ballet practice. During the training period, the E and C groups undertook the same amount of ballet practice. Posttraining CMJ performance significantly increased in E group (6.3 +/- 3.8%, p < 0.001). Furthermore, E group showed significant (p < 0.05-0.001) posttraining average leg-press power and velocity improvements at all the external loads considered. Consequently, the force-velocity and power-velocity relationship shifted to the right after WBV training in the E group. The results of the present study show that WBV training is an effective short-term training methodology for inducing improvements in knee-extensor explosiveness in elite ballerinas.

Annini G., Padua E., Castagna C., Salvo V.D., Minichella S., Tsarpela O., Manzi V. & Dettavio S. (2007). Effect of whole body vibration training on lower limb performance in selected high-level ballet students. Journal of Strength and Conditioning Research. 21(4). 1072-1076.

The acute effect of whole-body vibration on the hoffmann reflex.

Armstrong WJ, Nestle HN, Grinnell DC, Cole LD, Van Gilder EL, Warren GS, Capizzi EA.

Department of Kinesiology, Hope College, Holland, Michigan, USA. [email protected]

The extent to which motoneuron pool excitability, as measured by the Hoffmann reflex (H-reflex), is affected by an acute bout of whole-body vibration (WBV) was recorded in 19 college-aged subjects (8 male and 11 female; mean age 19 +/- 1 years) after tibial nerve stimulation. H/M recruitment curves were mapped for the soleus muscle by increasing stimulus intensity in 0.2- to 1.0-volt increments with 10-second rest intervals between stimuli, until the maximal M-wave and H-reflex were obtained. After determination of Hmax and Mmax, the intensity necessary to generate an H-reflex approximately 30% of Mmax (mean 31.5% +/- 4.1%) was determined and used for all subsequent measurements. Fatigue was then induced by 1 minute of WBV at 40 Hz and low amplitude (2-4 mm). Successive measurements of the H-reflex were recorded at the test intensity every 30 seconds for 30 minutes post fatigue. All subjects displayed a significant suppression of the H-reflex during the first minute post-WBV; however, four distinct recovery patterns were observed among the participants (alpha = 0.50). There were no significant differences between genders across time (P = 0.401). The differences observed in this study cannot be explained by level or type training. One plausible interpretation of these data is that the multiple patterns of recovery may display variation of muscle fiber content among subjects. Future investigation should consider factors such as training specificity and muscle fiber type that might contribute to the differing H-reflex response, and the effect of WBV on specific performance measures should be interpreted with the understanding that there may be considerable variability among individuals. Recovery times and sample size should be adjusted accordingly.

Armstrong W.J., Nestle H.N., Grinnell D.C., Cole L.D., Van Gilder E.L., Warren G.S. & Capizzi E.A. (2008). The acute effect of whole-body vibration on the hoffmann reflex. Journal of Strength and Conditioning Research. 22(2). 471-476.

Acute Effect of Whole-Body Vibration on Sprint and Jumping Performance in Elite Skeleton Athletes.

Bullock N, Martin DT, Ross A, Rosemond CD, Jordan MJ, Marino FE.

1Department of Physiology, Australian Institute of Sport, Belconnen, Australia; 2School of Human Movement Studies, Charles Sturt University, Bathurst, Australia; 3New Zealand Academy of Sport, South Island, Dunedin, New Zealand; 4Department of Biomechanics, Australian Institute of Sport, Belconnen, Australia; 5Canadian Sport Centre-Calgary, University of Calgary, Calgary, Alberta, Canada.

Bullock, N, Martin, DT, Ross, A, Rosemond, CD, Jordan, MJ, and Marino, FE. Acute effect of whole-body vibration on sprint and jumping performance in elite skeleton athletes. J Strength Cond Res 22: 1371-1374, 2008.-The winter sliding sport known as skeleton requires athletes to produce a maximal sprint followed by high speed sliding down a bobsled track. Athletes are required to complete the course twice in 1 hour and total time for the 2 runs determines overall ranking. The purpose of this investigation was to examine the effect of whole-body vibration (WBV) on lower body power to explore the utility of WBV as an ergogenic aid for skeleton competition. Elite skeleton athletes (1 male and 6 females) completed an unloaded squat jump (SQJ) immediately followed by 2 countermovement jumps (CMJs) and a maximal 30-m sprint before and after WBV or no vibration (CON) using a crossover design. The second 30-m sprint was slower following both CON (1.4% decrement; p = 0.05) and WBV (0.7% decrement; p = 0.03). Mean vertical velocity was maintained following WBV in the SQJ but decreased following CON (p = 0.03). There was a trend for athletes to commence the SQJ from a higher starting stance post-WBV compared to CON (p = 0.08). WBV decreased total vertical distance traveled compared to CON in the SQJ (p = 0.006). WBV had little effect on peak velocity, jump height, dip, and peak acceleration or any CMJ parameters. When sprint athletes' warm up and perform maximal jumps and a 30-m sprint with 15-20 minutes of recovery before repeating the sequence, the second series of performances tend to be compromised. However, when WBV is used before the second series of efforts, some aspects of maximal jumping and sprinting appear to be influenced in a beneficial manner. Further research is required to explore whether WBV can improve the second sprint for athletes in actual competition and/or what sort of WBV protocol is optimal for these populations.

Bullock N., Martin D.T., Ross A., Rosemond C.D., Jordan M.J. & Marino F.E. (2008). Acute effect of whole-body vibration on sprint and jumping performance in elite skeleton athletes. Journal of Strength and Conditioning Research. [Epub ahead of print]

Influence of vibration training on energy expenditure in active men.

Fernandez JM, Nuñez VM, Poblador MS, Garatachea N, Bresciani G, González-Gallego J, van den Tillaar R.

Section for Human Movement Science, Faculty of Social and Technology Management, Norwegian University of Science and Technology, Trondheim. roland.tillaar@svt.ntnu.no

Muscle strain is one of the most common injuries, resulting in a decreased range of motion (ROM) in this group of muscles. Systematic stretching over a period of time is needed to increase the ROM. The purpose of this study was to determine if whole-body vibration (WBV) training would have a positive effect on flexibility training (contract-release method) and thereby on the ROM of the hamstring musculature. In this study, 19 undergraduate students in physical education (12 women and 7 men, age 21.5 +/- 2.0 years) served as subjects and were randomly assigned to either a WBV group or a control group. Both groups stretched systematically 3 times per week for 4 weeks according to the contract-release method, which consists of a 5-second isometric contraction with each leg 3 times followed by 30 seconds of static stretching. Before each stretching exercise, the WBV group completed a WBV program consisting of standing in a squat position on the vibration platform with the knees bent 90 degrees on the Nemes Bosco system vibration platform (30 seconds at 28 Hz, 10-mm amplitude, 6 times per training session). The results show that both groups had a significant increase in hamstring flexibility. However, the WBV group showed a significantly larger increase (30%) in ROM than did the control group (14%). These results indicate that WBV training may have an extra positive effect on flexibility of the hamstrings when combined with the contract-release stretching method.

Whole-body-vibration training increases knee-extension strength and speed of movement in older women.

Roelants M, Delecluse C, Verschueren SM.

Exercise Physiology and Biomechanics Laboratory, Faculty of Physical Education and Physiotherapy, Department of Kinesiology, Katholieke Universiteit Leuven, Leuven, Belgium.

OBJECTIVES: To investigate the effects of 24 weeks of whole-body-vibration (WBV) training on knee-extension strength and speed of movement and on counter-movement jump performance in older women. DESIGN: A randomized, controlled trial. SETTING: Exercise Physiology and Biomechanics Laboratory, Leuven, Belgium. PARTICIPANTS: Eighty-nine postmenopausal women, off hormone replacement therapy, aged 58 to 74, were randomly assigned to a WBV group (n=30), a resistance-training group (RES, n=30), or a control group (n=29). INTERVENTION: The WBV group and the RES group trained three times a week for 24 weeks. The WBV group performed unloaded static and dynamic knee-extensor exercises on a vibration platform, which provokes reflexive muscle activity. The RES group trained knee-extensors by performing dynamic leg-press and leg-extension exercises increasing from low (20 repetitions maximum (RM)) to high (8RM) resistance. The control group did not participate in any training. MEASUREMENTS: Pre-, mid- (12 weeks), and post- (24 weeks) isometric strength and dynamic strength of knee extensors were measured using a motor-driven dynamometer. Speed of movement of knee extension was assessed using an external resistance equivalent to 1%, 20%, 40%, and 60% of isometric maximum. Counter-movement jump performance was determined using a contact mat. RESULTS: Isometric and dynamic knee extensor strength increased significantly (P<.001) in the WBV group (mean+/-standard error 15.0+/-2.1% and 16.1+/-3.1%, respectively) and the RES group (18.4+/-2.8% and 13.9+/-2.7%, respectively) after 24 weeks of training, with the training effects not significantly different between the groups (P=.558). Speed of movement of knee extension significantly increased at low resistance (1% or 20% of isometric maximum) in the WBV group only (7.4+/-1.8% and 6.3+/-2.0%, respectively) after 24 weeks of training, with no significant differences in training effect between the WBV and the RES groups (P=.391; P=.142). Counter-movement jump height enhanced significantly (P<.001) in the WBV group (19.4+/-2.8%) and the RES group (12.9+/-2.9%) after 24 weeks of training. Most of the gain in knee-extension strength and speed of movement and in counter-movement jump performance had been realized after 12 weeks of training. CONCLUSION: WBV is a suitable training method and is as efficient as conventional RES training to improve knee-extension strength and speed of movement and counter-movement jump performance in older women. As previously shown in young women, it is suggested that the strength gain in older women is mainly due to the vibration stimulus and not only to the unloaded exercises performed on the WBV platform.

Roelants M., Delecluse C. & Verschueren S.M. (2004). Whole-body-vibration training increases knee-extension strength and speed of movement in older women. Journal of the American Geriatrics Society. 52(6). 901-908.

Variation in neuromuscular responses during acute whole-body vibration exercise.

Abercromby AF, Amonette WE, Layne CS, McFarlin BK, Hinman MR, Paloski WH.

Wyle Laboratories, Inc., Houston, TX 77058, USA. andrew.abercromby-1@nasa.gov

PURPOSE: Leg muscle strength and power are increased after whole-body vibration (WBV) exercise. These effects may result from increased neuromuscular activation during WBV; however, previous studies of neuromuscular responses during WBV have not accounted for motion artifact. METHODS: Sixteen healthy adults performed a series of static and dynamic unloaded squats with and without two different directions of WBV (rotational vibration, RV; and vertical vibration, VV; 30 Hz; 4 mmp-p). Activation of unilateral vastus lateralis, biceps femoris, gastrocnemius, and tibialis anterior was recorded using EMG. During RV and VV, increases in EMG relative to baseline were compared over a range of knee angles, contraction types (concentric, eccentric, isometric), and squatting types (static, dynamic). RESULTS: After removing large, vibration-induced artifacts from EMG data using digital band-stop filters, neuromuscular activation of all four muscles increased significantly (P<or=0.05) during RV and VV. Average responses of the extensors were significantly greater during RV than VV, whereas responses of the tibialis anterior were significantly greater during VV than RV. For all four muscles, responses during static squatting were greater than or equal to responses during dynamic squatting, whereas responses during eccentric contractions were equal to or smaller than responses during concentric and isometric contractions. Neuromuscular responses of vastus lateralis, gastrocnemius, and tibialis anterior were affected by knee angle, with greatest responses at small knee angles. CONCLUSIONS: Motion artifacts should be removed from EMG data collected during WBV. We propose that neuromuscular responses during WBV may be modulated by leg muscle cocontraction as a postural control strategy and/or muscle tuning by the CNS intended to minimize soft-tissue vibration.

Abercromby A.F., Amonette W.E., Layne C.S., McFarlin B.K., Hinman M.R. & Paloski W.H. (2007). Variation in neuromuscular responses during acute whole-body vibration exercise. Medicine and Science in Sports and Exercise. 39(9). 1642-1650.

Vibration exposure and biodynamic responses during whole-body vibration training.

Abercromby AF, Amonette WE, Layne CS, McFarlin BK, Kinman MR, Paloski WH.

Wyle Laboratories, Inc., Houston, TX 77058, USA. andrew.abercromby-1@nasa.gov

PURPOSE: Excessive, chronic whole-body vibration (WBV) has a number of negative side effects on the human body, including disorders of the skeletal, digestive, reproductive, visual, and vestibular systems. Whole-body vibration training (WBVT) is intentional exposure to WBV to increase leg muscle strength, bone mineral density, health-related quality of life, and decrease back pain. The purpose of this study was to quantitatively evaluate vibration exposure and biodynamic responses during typical WBVT regimens. METHODS: Healthy men and women (N = 16) were recruited to perform slow, unloaded squats during WBVT (30 Hz; 4 mm(p-p)), during which knee flexion angle (KA), mechanical impedance, head acceleration (Ha(rms)), and estimated vibration dose value (eVDV) were measured. WBVT was repeated using two forms of vibration: 1) vertical forces to both feet simultaneously (VV), and 2) upward forces to only one foot at a time (RV). RESULTS: Mechanical impedance varied inversely with KA during RV (effect size, eta(p)(2): 0.668, P < 0.01) and VV (eta(p)(2): 0.533, P < 0.05). Ha(rms) varied with KA (eta(p)(2): 0.686, P < 0.01) and is greater during VV than during RV at all KA (P < 0.01). The effect of KA on Ha(rms) is different for RV and VV (eta(p)(2): 0.567, P < 0.05). The eVDV associated with typical RV and VV training regimens (30 Hz, 4 mm(p-p), 10 min.d(-1)) exceeds the recommended daily vibration exposure as defined by ISO 2631-1 (P < 0.01). CONCLUSIONS: ISO standards indicate that 10 min.d(-1) WBVT is potentially harmful to the human body; the risk of adverse health effects may be lower during RV than VV and at half-squats rather than full-squats or upright stance. More research is needed to explore the long-term health hazards of WBVT.

Abercromby A.F., Amonette W.E., Layne C.S., McFarlin B.K., Hinman M.R. & Paloski W.H. (2007). Vibration exposure and biodynamic responses during whole-body vibration training. Medicine and Science in Sports and Exercise. 39(10). 1794-1800.

Strength increase after whole-body vibration compared with resistance training.

Delecluse C, Roelants M, Verschueren S.

Exercise Physiology and Biomechanics Laboratory, Faculty of Physical Education and Physiotherapy, Department of Kinesiology, Katholieke Universiteit Leuven, Belgium. christophe.delecluse@flok.kuleuven.ac.be

PURPOSE: The aim of this study was to investigate and to compare the effect of a 12-wk period of whole-body vibration training and resistance training on human knee-extensor strength. METHODS: Sixty-seven untrained females (21.4 +/- 1.8 yr) participated in the study. The whole-body vibration group (WBV, N = 18) and the placebo group (PL, N = 19) performed static and dynamic knee-extensor exercises on a vibration platform. The acceleration of the vibration platform was between 2.28 g and 5.09 g, whereas only 0.4 g for the PL condition. Vibration (35-40 Hz) resulted in increased EMG activity, but the EMG signal remained unchanged in the PL condition. The resistance-training group (RES, N = 18) trained knee extensors by dynamic leg-press and leg-extension exercises (10-20 RM). All training groups exercised 3x wk-1. The control group (CO, N = 12) did not participate in any training. Pre- and postisometric, dynamic, and ballistic knee-extensor strength were measured by means of a motor-driven dynamometer. Explosive strength was determined by means of a counter-movement jump. RESULTS: Isometric and dynamic knee-extensor strength increased significantly (P < 0.001) in both the WBV group (16.6 +/- 10.8%; 9.0 +/- 3.2%) and the RES group (14.4 +/- 5.3%; 7.0 +/- 6.2%), respectively, whereas the PL and CO group showed no significant (P > 0.05) increase. Counter-movement jump height enhanced significantly (P < 0.001) in the WBV group (7.6 +/- 4.3%) only. There was no effect of any of the interventions on maximal speed of movement, as measured by means of ballistic tests. CONCLUSIONS: WBV, and the reflexive muscle contraction it provokes, has the potential to induce strength gain in knee extensors of previously untrained females to the same extent as resistance training at moderate intensity. It was clearly shown that strength increases after WBV training are not attributable to a placebo effect.

Delecuse C., Roelants M. & Verschueren S. (2003). Strength increase after whole-body vibration compared with resistance training. Medicine and Science in Sports and Exercise. 35(6). 1033-1041.

Effect of four-month vertical whole body vibration on performance and balance.

Torvinen S, Kannus P, Sievanen H, Jarvinen TA, Pasanen M, Kontulainen S, Jarvinen M, Oja P, Vuori I.

Bone Research Group, UKK Institute, Kaupinpuistonkatu 1, FIN-33500 Tampere, Finland. losato@uta.fi

PURPOSE: This randomized controlled study was designed to investigate the effects of a 4-month whole body vibration-intervention on muscle performance and body balance in young, healthy, nonathletic adults. METHODS: Fifty-six volunteers (21 men and 35 women, aged 19-38 yr) were randomized to either the vibration group or control group. The vibration-intervention consisted of a 4-month whole body vibration training (4 min.d(-1), 3-5 times a week) employed by standing on a vertically vibrating platform. Five performance tests (vertical jump, isometric extension strength of the lower extremities, grip strength, shuttle run, and postural sway on a stability platform) were performed initially and at 2 and 4 months. RESULTS: Four-month vibration intervention induced an 8.5% (95% CI, 3.7-13.5%, P=0.001) net improvement in the jump height. Lower-limb extension strength increased after the 2-month vibration-intervention resulting in a 3.7% (95% CI, 0.3-7.2%, P=0.034) net benefit for the vibration. This benefit, however, diminished by the end of the 4-month intervention. In the grip strength, shuttle run, or balance tests, the vibration-intervention showed no effect. CONCLUSION: The 4-month whole body vibration-intervention enhanced jumping power in young adults, suggesting neuromuscular adaptation to the vibration stimulus. On the other hand, the vibration-intervention showed no effect on dynamic or static balance of the subjects. Future studies should focus on comparing the performance-enhancing effects of a whole body vibration to those of conventional resistance training and, as a broader objective, on investigating the possible effects of vibration on structure and strength of bones, and perhaps, incidence of falls of elderly people.

Torvinen S., Kannus P., Sievanen H., Jarvinen T.A., Pasanen M., Kontulainen S., Jarvinen M., Oja P. & Vuori I. (2002). Effect of four-month vertical whole body vibration on performance and balance. Medicine and Science in Sports and Exercise. 34(9). 1523-1528.

Knee extensor fatigability after bedrest for 8 weeks with and without countermeasure.

Mulder ER, Kuebler WM, Gerrits KH, Rittweger J, Felsenberg D, Stegeman DF, de Haan A.

Radboud University Nijmegen Medical Center, Department of Clinical Neurophysiology, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands. e.mulder@neuro.umcn.nl

We analyzed the effects of gravitational unloading on muscular fatigability and the effectiveness of resistive vibration exercise to counteract these changes. Changes in knee extensor fatigability as a consequence of 8 weeks of horizontal bedrest with or without daily resistive vibration exercise were evaluated in 17 healthy male volunteers. Bedrest increased fatigability (% decrease in maximal voluntary isometric torque per minute exercise) from -7.2 +/- 0.5 to -10.2 +/- 1.0%/min (P < 0.05), which was accompanied by a decline (of 52.0 +/- 3.7%, P < 0.05) in muscle blood flow. Daily resistive vibration exercise training during bedrest prevented increases in fatigability (from -10.8 +/- 1.8 to -8.4 +/- 1.6%/min, P < 0.05), and mitigated the reduction in blood flow (decline of 26.1 +/- 5.1%, P < 0.05). Daily resistive exercise may thus be suggested as an effective countermeasure during spaceflight and illness-related prolonged bedrest to combat the detrimental changes in muscle endurance that result from gravitational unloading.

Mulder E.R., Kuebler W.M., Gerrits K.H., Rittweger J., Felsenberg D., Stegeman D.F. & de Haan A. (2007). Knee extensor fatigability after bedrest for 8 weeks with and without countermeasure. Muscle & Nerve. 36(6). 798-806.

Effects of whole-body vibration exercise on lower-extremity muscle strength and power in an older population: a randomized clinical trial.

Rees SS, Murphy AJ, Watsford ML.

School of Leisure, Sport and Tourism, University of Technology, Sydney (Kuring-gai Campus), PO Box 222, Lindfield, NSW, 2070, Australia. sven.rees@uts.edu.au

BACKGROUND AND PURPOSE: Vibration training is a relatively new exercise intervention. This study investigated the effects of vibration exercise on strength (force-producing capacity) and power in older adults who are healthy. PARTICIPANTS AND METHODS: Thirty participants (mean age=73.7 years, SD=4.6) were randomly assigned to a vibration exercise training (VIB) group or an exercise without vibration training (EX) group. The interventions consisted of 3 sessions per week for 8 weeks. Outcome measures included isokinetic flexor and extensor strength and power of the hip, knee, and ankle. RESULTS: The VIB group significantly improved ankle plantar flexor strength and power compared with the EX group. However, there were no significant differences between the VIB and EX groups for knee flexor or extensor strength. DISCUSSION AND CONCLUSION: Vibration training contributed to an increase in plantar flexor strength and power. However, the strength gains for the knee and hip flexors and extensors for the VIB group and the EX group were comparable. Future vibration protocols should explore different body positions to target muscles higher up on the leg.

Rees S.S., Murphy A.J. & Watsford M.L. (2008). Effects of whole body vibration exercise on lower-extremity muscle strength and power in an older population: a randomized clinical trial. Physical Therapy. 88(4). 462-470.

Strength training effects of whole-body vibration?

Nordlund MM, Thorstensson A.

The Swedish School of Sport and Health Sciences (GIH), Stockholm, Sweden. maria.nordlund@gih.se

Whole-body vibration (WBV) has been suggested to have a beneficial effect on muscle strength. Manufacturers of vibration platforms promote WBV as an effective alternative or complement to resistance training. This study aimed to review systematically the current (August 2005) scientific support for effects of WBV on muscle strength and jump performance. MEDLINE and SPORT DISCUS were searched for the word vibration in combination with strength or training. Twelve articles were included in the final analysis. In four of the five studies that used an adequate design with a control group performing the same exercises as the WBV group, no difference in performance improvement was found between groups, suggesting no or only minor additional effects of WBV as such. Proposed neural mechanisms are discussed.

Nordlund M.M. & Thorstensson A. (2007). Strength training effects of whole-body vibration? Scandinavian Journal of Medicine and Science in Sports. 17(1). 12-17.

Effects on leg muscular performance from whole-body vibration exercise: a systematic review.

Rehn B, Lidstrom J, Skoglund J, Lindstrom B.

Department of Community Medicine and Rehabilitation, Division of Physiotherapy, Umeå University, Umeå, Sweden. borje.rehn@physiother.umu.se

The purpose of this study was to investigate the effects on leg muscular performance from whole-body vibration exercise. Literature search was performed on the databases Pubmed, Cinahl, ISI web of science (Sci-expanded, SSCI) and Embase (Rehab & Physical Med). Rating of 19 relevant studies was performed (14 on long-term exercise and five on short-term exercise) using a score system for the methodological quality. Several randomized-controlled trial studies of high to moderate quality show similar improvements from long-term regimen on muscular performance in the legs after a period of whole-body vibration exercise. As there were few studies on short-term exercise and as they had no control groups, the same convincing improvements regarding muscular performance were not achieved. Preliminarily, there is strong to moderate evidence that long-term whole-body vibration exercise can have positive effects on the leg muscular performance among untrained people and elderly women. There is no clear evidence for effects on muscular performance after short-term vibration stimuli.

Rehn B., Lidstrom J., Skoglund J. & Lindstrom B. (2007). Effects on leg muscular performance from whole-body vibration exercise: a systematic review. Scandinavian Journal of Medicine and Science in Sports. 17(1). 2-11.

The use of vibration training to enhance muscle strength and power.

Luo J, McNamara B, Moran K.

School of Sport Science and Health, Dublin City University, Dublin, Ireland.

Vibration has been combined with conventional resistance training in an attempt to attain greater gains in neuromuscular performance than from conventional resistance training alone. Although there is a lack of strictly controlled studies on the vibration training effect, current findings in this area suggest that vibration may have a beneficiary acute and/or chronic training effect on strength and power enhancement. However, the effect of vibration on strength and power development appears dependent upon the vibration characteristics (method of application, amplitude and frequency) and exercise protocols (training type, intensity and volume) employed. Vibration amplitude and frequency determine the load that vibration imposes on the neuromuscular system. This vibration load should be in an optimal range to elicit strength and power enhancement. To activate the muscle most effectively, vibration frequency should be in the range of 30-50 Hz. It is less clear to what the optimal amplitude should be, but smaller amplitudes may be insufficient to elicit an enhancement. It should also be noted that the method of vibration application (i.e. vibration applied directly or indirectly to a targeted muscle) may have an influence on the magnitude of amplitude and frequency that are delivered to the muscle and, therefore, may have an influence on vibration training effect.The employment of a greater exercise intensity and volume within a vibration training programme may facilitate a larger enhancement in strength and power. In addition, benefits from vibration training may be greater in elite athletes than non-elite athletes.Further studies are required to examine these inter-dependencies, especially in relation to chronic adaptation to dynamic exercises, which are the most relevant response to practitioners, but where the least amount of research has been undertaken.

Luo J., McNamara B. & Moran K. (2005). The use of vibration training to enhance muscle strength and power. Sports Medicine. 35(1). 23-41.

Vibrations and their applications in sport. A review.

Issurin VB.

Institute for Physical Education and Sport, Elite Sport Department of Israel at the Wingate, Israel.

In sport, mechanical vibration is used as a massage tool and/or for training purposes. Two varieties of vibration training (VT) can be distinguished: strength exercises with superimposed vibratory stimulation (VS exercises) and motor tasks performed under whole body vibration (the WBV training). Vibratory massage has been used extensively since the beginning of the 20th century while VT is a relatively new technique. In the research literature, the main subjects addressed have been acute and cumulative effects of VS on flexibility and strength. Marked enhancement effects were obtained in medium-duration stretching and short-duration dynamic strength exercises while prolonged efforts did not show positive impact. The observed effects of vibration depend on various neural facilitatory and inhibitory mechanisms. In comparison to VS exercises, WBV tasks generate more global neuromuscular, metabolic and hormonal responses. WBV training resulted in significant changes in several motor variables, with stretch-shortening cycle tests (such as countermovement jumps, serial high jumps, etc.) being the most sensitive to WBV treatment. Based on available knowledge about proprioceptive spinal reflexes-that feedback from the primary endings of motor spindles produces a stimulatory effect via increased discharge of a-motoneurons, and activation of Golgi tendon organs (GTO) evokes inhibition of muscle action-a hypothesis has been proposed that VT enhances excitatory inflow from muscle spindles to the motorneuron pools and depresses inhibitory impact of GTO due to the accommodation to vibration stimuli. The intensity and duration of vibration used in VT dramatically exceed the standards for occupational vibration established by the International Organization for Standardization.

Issurin V.B. (2005). Vibrations and their applications in sport. a review. The Journal of Sports Medicine and Physical Fitness. 45(3). 324-336.

Impact of whole-body vibration training versus fitness training on muscle strength and muscle mass in older men: a 1-year randomized controlled trial.

Bogaerts A, Delecluse C, Claessens AL, Coudyzer W, Boonen S, Verschueren SM.

Division of Musculoskeletal Rehabilitation, Katholieke Universiteit Leuven, Tervuursevest 101, Leuven, Belgium.

BACKGROUND: This randomized controlled study investigated the effects of 1-year whole-body vibration (WBV) training on isometric and explosive muscle strength and muscle mass in community-dwelling men older than 60 years. METHODS: Muscle characteristics of the WBV group (n = 31, 67.3 +/- 0.7 years) were compared with those of a fitness (FIT) group (n = 30, 67.4 +/- 0.8 years) and a control (CON) group (n = 36, 68.6 +/- 0.9 years). Isometric strength of the knee extensors was measured using an isokinetic dynamometer, explosive muscle strength was assessed using a counter movement jump, and muscle mass of the upper leg was determined by computed tomography. RESULTS: Isometric muscle strength, explosive muscle strength, and muscle mass increased significantly in the WBV group (9.8%, 10.9%, and 3.4%, respectively) and in the FIT group (13.1%, 9.8%, and 3.8%, respectively) with the training effects not significantly different between the groups. No significant changes in any parameter were found in the CON group. CONCLUSION: WBV training is as efficient as a fitness program to increase isometric and explosive knee extension strength and muscle mass of the upper leg in community-dwelling older men. These findings suggest that WBV training has potential to prevent or reverse the age-related loss in skeletal muscle mass, referred to as sarcopenia.

Bogaerts A., Delecluse C., Claessens A.L., Coudyzer W., Boonen S. & Verschueren S.M. (2007). Impact of whole-body vibration training versus fitness training on muscle strength and muscle mass in older men: a 1-year randomized controlled trial. The Journals of Gerontology. 62(6). 630-650.

Br J Sports Med. 2008 May;42(5):373-8. Epub 2008 Jan 8.

A comparative study of whole body vibration training and conventional training on knee proprioception and postural stability after anterior cruciate ligament reconstruction.

Moezy A, Olyaei G, Hadian M, Razi M, Faghihzadeh S.

School of Rehabilitation, Medical Sciences/Tehran University, Tehran, Iran.

Abstract

OBJECTIVE: To compare the effect of a whole body vibration training (WBVT) programme with a conventional training (CT) programme on knee proprioception and postural stability after anterior cruciate ligament (ACL) reconstruction.

METHODS: Twenty athletes with unilateral ACL reconstruction were randomly assigned to the WBVT or CT group; all participants received 12 sessions of WBVT or conventional training. Absolute error in joint repositioning for two target angles (30 degrees and 60 degrees ) was measured with the Biodex dynamometer; bilateral dynamic postural stability (anteroposterior, mediolateral and overall stability indices) was measured with the Biodex Stability System pre-intervention and post-intervention.

RESULTS: The improvement in postural stability in the WBVT group was significantly greater than that in the CT group (p< or =0.05). The p values of the changing scores of open overall, open anteroposterior, open mediolateral, closed overall, closed anteroposterior and closed mediolateral stability indices were 0.002, 0.010, 0.0001, 0.001, 0.0001 and 0.046, respectively. In addition, there were significant differences in all averages of absolute angular error at 60 degrees and 30 degrees between the WBVT and CT groups in both knees (p = 0.001 in healthy knees and p = 0.001 and p = 0.0001 in reconstructed knees), apart from the healthy knees at the 30 degrees target position, which was not significant (p = 0.131).

CONCLUSIONS: Whole body vibration training improved proprioception and balance in athletes with reconstructed ACL.

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