Strength%20Increase%20after%20Whole%20Body%20Vibration%20Compared%20with%20Resistance%20training.

1
Strength Increase after Whole Body Vibration
Compared with Resistance training.

• Christophe Delecluse, Sabine Verschueren,
  Machteld Roelants
• Faculteit Lichamelijke Opvoeding en
  Kinesitherapie
• Katholieke Universiteit Leuven
• België

2
WBV-training positive influence on muscle
strength?

• Lack of scientific support
• Mechanism
• vibration stimulus
• stimulation sensory receptors in muscle
  (presumably muscle spindles)
• activation alpha motor neurons
• Tonic vibration reflex leading to muscle
  contraction
• stimulus for increase in strength?

3
Studies acute effects WBV

• Bosco et al. 1999 (Clin Physiol) volleyball
  players, increase in strength-speed,
  strength-power leg press
• Bosco et al. 2000 (Eur J Appl Physiol) team
  sports, 7 increase mechanical power
  knee-extensors (leg press), 3,8 increase jump
  height
• Torvinen et al. 2002 (Clin Physiol Func Im)
  3,2 increase isometric strength knee-extensors,
  2,5 increase jump height
• Torvinen et al. 2002 (Int J Sports Med) no
  effects on isometric strength knee-extensors,
  jump height

4
Long term WBV studies

• Bosco et al. 1998 (Biol of Sport) physically
  active subjects, 10 days WBV-training, 6,1
  increase in power, 12 increase jump height
• Runge et al. 2000 (J Musculoskel Neuron
  Interact) elderly subjects, 2 months
  WBV-training, 18 increase in chair rising time
• Torvinen et al. 2002 (Med Sci Sports and Exc)
  untrained subjects, 4 months WBV-training, 8,5
  increase jump height, 2,5 increase isometric
  strength knee-extensorsDe Ruiter et al. 2002
  (Geneeskunde en Sport) physically active
  subjects,no improvement in isometric and
  explosive strength knee-extensors
• No unambiguous results
• Differences in training schedules, group
  composition, physical condition
• No placebo group
• No comparison to regular resistance training

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Purpose of this study

• long term study
• Investigate effects on isometric strength
  knee-extensors of exercises performed on
  platforms with and without vibration (placebo)
• Compare effects to resistance training of
  moderate intensity (10-20RM)

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Method

• 67 young ladies (21,41,8 jaar)
• untrained
• 4 groups (random)
• WBV group, N18
• Placebo group (PL), N19
• Resistance group (RES), N18
• Control group (CO), N12
• 12 weeks, 3 x/week (36 sessions)

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WBV group PL group Static and dynamic
exercises for knee-extensors squat, deep
squat, one legged squat, lunge,...

• Vibration platform
• (Power Plate)
• progressive increase in intensity and volume
• 35-40Hz / 2,5-5,0mm
• 2,28 - 5,05g
• Total vibration time per session 3-20 min
• rest period 60-5 sec

• Placebo platform
• - equal platform not resulting in
  increased muscle contraction
• - amplitude negligible
• - acceleration only 0,4g

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EMG activity in the m. rectus femoris(high squat)
VIBRATION 35 Hz
9
EMG activity in the m. gastrocnemius
10
Resistance-training group

• University fitness centre
• 20 min warm up bicycle, step, treadmill
• Resistance training schedule with moderate
  intensity for knee-extensors (Kraemer 2002, ACSM)
• leg press, leg extension (Technogym) 2 sets

20 RM 15 RM 12 RM 10RM
W1 W3 W6 W9 W12
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Pre-post measuring

• Iso-kinetic dynamometer (REV9000, Technogym)
• maximum voluntary isometric strength
  knee-extensors (angle in knee 130)
• post-test min. 72 hours after last training
  session

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Results (1)
ISO
pre
230


post
210
190
Knee-extensor moment (N.m)
170
150
130
110
KR
WBV
PL
CO
N18
N18
N19
N12
Group
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Results (2)

• Isometric strength
• significant interaction effect (group x time)
• F (3)15,94 Plt0.001 (ANOVA for repeated
  measurements)
• significant increase (Plt0.001) pre-post
  (contrast analysis)
• in WBV group 16,6 10,8
• in RES group 14,4 5,3
• no significant difference (Pgt0.05) pre-post
• in PL group 3,8 11,4
• in CO group -7,3 15,9

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Causes of strength gain

• Hypothesis strength gain after 12 weeks WBV
  mainly due to neural adaptations resistance
  training (Enoka 1997, J Biomech)
• extensive sensory stimulation possible more
  efficient use of sensory information in
  production of strength
• input of proprioceptors (Ia, IIa, Ib) is used in
  building up isometric strength (Gandevia 2001,
  Physiol Rev)

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Conclusions (1)

• The muscle contractions during WBV efficient
  stimulus for strength gain in knee extensors in
  untrained subjects
• Torvinen et al. 2002
• only 3,7 increase in strength in knee-extensors
  after 2 months WBV-training ? placebo effect this
  study
• 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)
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Conclusions (2)

• 12 weeks WBV training with untrained ladies
• Strength gain in knee-extensors comparable to
  resistance training of moderate intensity
  (10-20RM)
• effect not attributable to stance or exercises on
  platform but to increased muscle activity (EMG)
  during WBV
• NO placebo-effect

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• Strength gain following 12 weeks of whole body
  vibration training
• C. Delecluse, M. Roelants, S. Verschueren
• Published in Medicine and Science in Sports and
  Exercise Vol.35, No.6, pp. 1033-1041, 2003