Strength Increase after Strength Increase after Whole Body Vibration Whole Body Vibration

Compared with Resistance Compared with Resistance training.training.

Christophe Delecluse, Sabine Verschueren, Machteld Christophe Delecluse, Sabine Verschueren, Machteld RoelantsRoelants

Faculteit Lichamelijke Opvoeding en KinesitherapieFaculteit Lichamelijke Opvoeding en Kinesitherapie

Katholieke Universiteit LeuvenKatholieke Universiteit Leuven

BelgiëBelgië

WBV-training: positive WBV-training: positive influence on muscle influence on muscle

strength?strength?

Lack of scientific supportLack of scientific support Mechanism:Mechanism:

vibration stimulusvibration stimulus

stimulation sensory receptors in muscle (presumably stimulation sensory receptors in muscle (presumably muscle spindles)muscle spindles)

activation alpha motor neuronsactivation alpha motor neurons

Tonic vibration reflex leading to muscle Tonic vibration reflex leading to muscle contraction: contraction:

stimulus for increase in strength?stimulus for increase in strength?

Studies acute effects WBVStudies acute effects WBV

Bosco et al. 1999 Bosco et al. 1999 (Clin Physiol):(Clin Physiol): volleyball players, increase in volleyball players, increase in strength-speed, strength-power leg pressstrength-speed, strength-power leg press

Bosco et al. 2000 Bosco et al. 2000 (Eur J Appl Physiol): (Eur J Appl Physiol): team sports, 7% increase team sports, 7% increase mechanical power knee-extensors (leg press), 3,8% increase jump mechanical power knee-extensors (leg press), 3,8% increase jump heightheight

Torvinen et al. 2002 Torvinen et al. 2002 (Clin Physiol & Func Im): (Clin Physiol & Func Im): 3,2% increase 3,2% increase isometric strength knee-extensors, 2,5% increase jump heightisometric strength knee-extensors, 2,5% increase jump height

Torvinen et al. 2002 Torvinen et al. 2002 (Int J Sports Med):(Int J Sports Med): nono effects on isometric effects on isometric strength knee-extensors, jump heightstrength knee-extensors, jump height

Bosco et al. 1998 Bosco et al. 1998 (Biol of Sport):(Biol of Sport): physically active subjects, 10 days physically active subjects, 10 days WBV-training, 6,1% increase in power, 12% increase jump heightWBV-training, 6,1% increase in power, 12% increase jump height

Runge et al. 2000 Runge et al. 2000 (J Musculoskel Neuron Interact)(J Musculoskel Neuron Interact): elderly subjects, 2 : elderly subjects, 2 months WBV-training, 18% increase in ‘chair rising time’months WBV-training, 18% increase in ‘chair rising time’

Torvinen et al. 2002 Torvinen et al. 2002 (Med Sci Sports and Exc): (Med Sci Sports and Exc): untrained subjects, 4 untrained subjects, 4 months WBV-training, 8,5% increase jump height, 2,5% increase months WBV-training, 8,5% increase jump height, 2,5% increase isometric strength knee-extensorsisometric strength knee-extensorsDe Ruiter et al. 2002 De Ruiter et al. 2002 (Geneeskunde en Sport)(Geneeskunde en Sport): physically active : physically active subjects,no improvement in isometric and explosive strength knee-subjects,no improvement in isometric and explosive strength knee-extensorsextensors

No unambiguous results:No unambiguous results:–Differences in training schedules, group Differences in training schedules, group

composition, composition, physical condition physical condition–No placebo groupNo placebo group–No comparison to regular resistance trainingNo comparison to regular resistance training

Long term WBV studiesLong term WBV studies

Purpose of this studyPurpose of this study

long term study:long term study:

– Investigate effects on isometric Investigate effects on isometric strength knee-extensors of exercises strength knee-extensors of exercises performed on platforms with and performed on platforms with and without vibration (placebo)without vibration (placebo)

– Compare effects to resistance training Compare effects to resistance training of moderate intensity (10-20RM)of moderate intensity (10-20RM)

MethodMethod

67 young ladies (21,4±1,8 jaar)67 young ladies (21,4±1,8 jaar) untraineduntrained 4 groups (random)4 groups (random)

WBV group, N=18WBV group, N=18Placebo group (PL), N=19Placebo group (PL), N=19Resistance group (RES), Resistance group (RES),

N=18N=18Control group (CO), N=12Control group (CO), N=12

12 weeks, 3 x/week (36 sessions)12 weeks, 3 x/week (36 sessions)

WBV group PL group WBV group PL group Static and dynamic exercises for knee-extensors: Static and dynamic exercises for knee-extensors:

squat, deep squat, one legged squat, squat, deep squat, one legged squat, lunge,...lunge,...

Vibration platformVibration platform (Power Plate®)(Power Plate®) progressive increase in progressive increase in

intensity and volumeintensity and volume

– 35-40Hz / 2,5-5,0mm35-40Hz / 2,5-5,0mm– 2,28 - 5,05g2,28 - 5,05g– Total vibration time Total vibration time

per session: 3-20 per session: 3-20 minmin

– rest period: 60-5 secrest period: 60-5 sec

Placebo platformPlacebo platform

- equal platform not - equal platform not resulting in increased resulting in increased muscle contractionmuscle contraction

- amplitude negligible- amplitude negligible

- acceleration only 0,4g- acceleration only 0,4g

0.4

0.3

0.2

0.1

0.0

EM

G a

ctivity (

V)

20151050

0.4

0.3

0.2

0.1

0.0EM

G a

ctivity (

V)

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0.4

0.3

0.2

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EM

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ctivity (

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Time (s)

rms=0.0461 rms=0.0528

rms=0.0603 rms=0.0641

rms=0.0591 rms=0.0798

WBV 35Hz

Placebo

Controlm. rectus femoris

EMG activity in the m. rectus EMG activity in the m. rectus femorisfemoris

(high squat)(high squat)

VIBRATION 35 Hz

EMG activity in the m. EMG activity in the m. gastrocnemiusgastrocnemius

0.12

0.08

0.04

0.00EM

G a

ctivity (

V)

20151050

0.12

0.08

0.04

0.00EM

G a

ctivity (

V)

20151050

0.12

0.08

0.04

0.00EM

G a

ctivity (

V)

20151050Time (s)

Vibration 35Hz

rms=0.00400 rms=0.02151

rms=0.00562rms=0.00447

rms=0.00570 rms=0.00571

WBV 35 Hz

Placebo

Controlm. gastrocnemius

Resistance-training groupResistance-training group

University fitness centreUniversity fitness centre 20 min warm up: bicycle, step, treadmill20 min warm up: bicycle, step, treadmill Resistance training schedule with moderate Resistance training schedule with moderate

intensity for knee-extensors (Kraemer 2002, intensity for knee-extensors (Kraemer 2002, ACSM)ACSM)

leg press, leg extension (Technogym®): 2 setsleg press, leg extension (Technogym®): 2 sets

W1 W3 W6 W9 W12

20 RM 15 RM 12 RM 10RM

Pre-post measuringPre-post measuring

Iso-kinetic dynamometer Iso-kinetic dynamometer

(REV9000, Technogym®)(REV9000, Technogym®)

maximum voluntary isometric maximum voluntary isometric

strength knee-extensors strength knee-extensors

(angle in knee: 130°)(angle in knee: 130°)

post-test: min. 72 hours after post-test: min. 72 hours after

last training sessionlast training session

Results (1)Results (1)

ISO †

110

130

150

170

190

210

230

KRN=18

WBVN=18

PLN=19

CON=12

Group

Kn

ee-e

xten

sor

mom

ent

(N.m

)

pre

post* *

Results (2)Results (2)

Isometric strengthIsometric strength– significant interaction effect (group x time)significant interaction effect (group x time)

F (3)=15,94; P<0.001 (ANOVA for repeated F (3)=15,94; P<0.001 (ANOVA for repeated measurements)measurements)

– significant increase (P<0.001) pre-post (contrast significant increase (P<0.001) pre-post (contrast analysis):analysis):

in WBV group: 16,6 ± 10,8% in WBV group: 16,6 ± 10,8% in RES group: 14,4% ± 5,3%in RES group: 14,4% ± 5,3%

– no significant difference (P>0.05) pre-post:no significant difference (P>0.05) pre-post: in PL group: 3,8 ± 11,4 %in PL group: 3,8 ± 11,4 % in CO group: -7,3 ± 15,9%in CO group: -7,3 ± 15,9%

Causes of strength gainCauses of strength gain

Hypothesis: strength gain after 12 weeks Hypothesis: strength gain after 12 weeks WBV mainly due to neural adaptations ~ WBV mainly due to neural adaptations ~ resistance training resistance training (Enoka 1997, (Enoka 1997, J BiomechJ Biomech))

– extensive sensory stimulation: possible more extensive sensory stimulation: possible more efficient use of sensory information in efficient use of sensory information in production of strengthproduction of strength

input of proprioceptors (Ia, IIa, Ib) is used input of proprioceptors (Ia, IIa, Ib) is used in building up isometric strength in building up isometric strength (Gandevia (Gandevia 2001, 2001, Physiol RevPhysiol Rev))

Conclusions (1)Conclusions (1)

The muscle contractions during WBV efficient The muscle contractions during WBV efficient stimulus for strength gain in knee extensors in stimulus for strength gain in knee extensors in untrained subjectsuntrained subjects

Torvinen et al. 2002: Torvinen et al. 2002: – only 3,7% increase in strength in knee-only 3,7% increase in strength in knee-

extensors after 2 months WBV-training extensors after 2 months WBV-training placebo effect this studyplacebo effect this study

– this study: 16,6%this study: 16,6%

Difference in training schedule: time, volume, intensity,…

‘full motor unit activation’ leads to fatigue in motor units = stimulus to strength gain

(Sales 1987, Exerc Sport Sci Rev)

Conclusions (2)Conclusions (2)

12 weeks WBV training with untrained 12 weeks WBV training with untrained ladies:ladies:– Strength gain in knee-extensors comparable to Strength gain in knee-extensors comparable to

resistance training of moderate intensity (10-resistance training of moderate intensity (10-20RM)20RM)

– effect not attributable to stance or exercises on effect not attributable to stance or exercises on platform but to increased muscle activity (EMG) platform but to increased muscle activity (EMG) during WBVduring WBV

NO placebo-effectNO placebo-effect

Strength gain following 12 weeks of Strength gain following 12 weeks of whole body vibration trainingwhole body vibration training– C. Delecluse, M. Roelants, S. C. Delecluse, M. Roelants, S.

VerschuerenVerschueren Published in Published in Medicine and Science in Sports Medicine and Science in Sports

and Exercise and Exercise Vol.35, No.6, pp. 1033-1041, Vol.35, No.6, pp. 1033-1041, 20032003