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Biomedical Application of Vibration Energy: Biomedical Application of Vibration Energy: effects on the human bodyeffects on the human body

P. Abundo 1, C. Trombetta 2, C. Foti 3 and N. Rosato 1

1 Medical Engineering Service, Fondazione Policlinico Tor Vergata, Rome2 PhD student in Advanced Technology in Rehabilitation Medicine, Tor Vergata University, Rome

3 Tor Vergata University, Physical and Rehabilitation Medicine, Public Health Department,

Rome  February 9th 2010February 9th 2010

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Analysis of vibration Analysis of vibration peculiar parameterspeculiar parameters

Vibration Vibration human body human body

effectseffects

IndexIndex

Vibration producing Vibration producing methodsmethods

Negative Negative effectseffects

Safety of workers Safety of workers subject to subject to vibrationsvibrations

Positive Positive effectseffects

Therapeutic application in Therapeutic application in rehabilitation medicinerehabilitation medicine

Hormonal effectHormonal effect

Neuro-muscular system Neuro-muscular system effecteffect

Bone tissue effectBone tissue effect

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

Biomedical vibration Biomedical vibration applicationsapplications

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Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

Analysis of vibration peculiar parameters

Period = T [s]

Frequency =1/T [Hz]

Movement Amplitude [m]

Velocity [m/s]

Acceleration [m/s2]

4 Analysis of vibration peculiar parameters

tVonAccelerati

Human body feels more

the variation of a stimulus than its persistence

Vibration intensity

T

dttaT

an Squareon Root MeAccelerati0

2 )(1

Resonance frequency

Vibration is amplified and the maximum vibration amplitude

is theoretically infinite

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

5 Vibration producing methods

Centripetal force generated by a bodyrotating around a non barycentric axis

Rotating mass (m)

Uniform circular motion

Circumference radius equal to eccentricity (e)

Costant angular velocity in amplitude (Ω)

emtF 2)(

Mass

Non barycentric rotation axis

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

6 Vibration producing methods

Piezoelectric effect – Jacques and Pierre Curie (1880)

Crystals specific property

Mechanical stress (contraction or

expansion)

Alternating current

Crystal material thickness

Alternating current Frequency

Crystal wave vibration frequency

Optimize vibrating head dimensions and weight

Policrystal ceramic (Barium titanate -

BaTiO3)

Topaz Quartz

~MHz

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

7 Vibration producing methods

Magnetic-dynamic transducer

Membrane

Electric coils

Permanent magnet

Alternating current

IL

NHB

N= Coils number

L= Coils lenght

I= Coils current

m= Magnetic Permeability

Alternating current through

coils

Varying intensity magnet

Permanent magnetic field

Coils vibrations

Membrane

vibrations

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

8 Biomedical vibration applications

Biomedical vibration applications

Piezoelectric surgical scaler

(dental)

Piezoelectric Ultrasound

probes

Piezoelectric or electro-magnetic Lithotripter

(urological)

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

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Ultrasound rehabilitation therapy (piezoelectric)

Rehabilitation Vibration Therapeutic Exercise (oscillating

masses)

Biomedical vibration applications

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

10 Vibrations human body effects

Vibrations Frequency Bands

• 0 - 2 Hz → low frequency oscillations,

generated by means of transportation (buses,

airplains, ships);

• 2 - 40 Hz → middle frequency oscillations,

generated by machine tools and industrial plant;

• > 40 - 50 Hz → high frequency oscillations

generated by a lot of vibrating tools used in

industrial field Acceleration

Time Exposure

Contact Area

Contact Force

Ergonomical and environmental factors

Tissues Resonance Frequency

Body Effects

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

11 Vibrations human body negative effects

Negative effects: vibration wave energy transferred from the oscillation source to the exposed body causes different effects on

human tissues and organs crossed

Human Body

Tolerable vibration energy

level

Long terms damages

Human body deterioration

Human body doesn’t vibrate like a single mass with only one natural frequency, every

body part has a its own resonance frequency

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

12 Vibrations human body negative effects

Vibration Direction

Whole Body Vibrations

Low-middle frequency vibrations

Lower efficiency degree

Decrease of fatigue

threshold

Vibration Touch point

Hand Arm Vibrations High frequency vibrations

Local negative effects

Local VibrationsMiddle - High

frequency vibrations Local negative effects (not only on HA

system)

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

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Hand Arm System

Safety of workers subject to vibrations

In order to limit the negative effects of vibration on workers

D.Lgs 81/08

Equivalent Acceleration Exposure Limit Value = 5 5 m/sm/s22

8)8(

TeAA sum

Te = daily exposure time to vibrations (hour)8 = reference time (hours)ax, ay,az = r.m.s. acceleration values (in m/s2) along  x, y, z axis (ISO 5349-1: 2001)

Whole Body

Equivalent Acceleration Exposure Limit Value = 1 m/s1 m/s22

8)8(

TeAA Max

Te= daily exposure time to vibrations (hour)8 = reference time (hours)AMax = Maximum value among ax, ay, az ax, ay,az = r.m.s  acceleration values (in m/s2) along axis x, y, z (ISO 2631-1: 1997)

)a a (a 2z

2y

2x sumA

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

14 Vibrations human body positive effects

Reduced Exposure Time

Specific Oscillation Frequency

Positive Effects

Metabolic Adaptations

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

Skeletal and neuro-muscular system

+

Mechanical

Hormonal effects

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

15 Therapeutic applications of vibration energy in rehabilitation medicine

Whole Body Vibrations

Propagating to the whole human body

Vibrating Platforms

Hand Arm/Local Vibrations

involving Hand-Arm System or specific body

partVibrating Tools

…By using….

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

16 Hormonal effects

Testosterone and growth-hormone concentration

Cortisol concentration

Significant statistical improvement of testosterone and GH serum concentrationafter whole body vibration exercise (10 times for 60 s, with 60 s rest time - B before,

A after)

Vibration frequency 20-50 Hz

Bosco C., Iacovelli M., Tsarpela O., Cardinale M., Bonifazi M., Tihanyi J., Viru M., De Lorenzo A., Viru A. - Hormonal responses to whole-body vibration in man. Eur J Appl Physiol. 81: 449-454, 2000; Kvorning T., Bagger M., Caserotti P. - Effects of vibration and resistance training on neuromuscular and hormonal measures. Eur J Appl Physiol. 2006 Mar;96(5): 615-25

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

17 Neuro-muscular system effect

Tonic Vibration Reflex

Locally applied vibrations to the muscle and to

tendon structure (10-40 Hz)

Whole Body Vibrations (1-50

Hz)

Muscle spindle receptors activation

Strengthening of the stimulation input, through the spindle

motor-neural connections (stretch reflex)

Hagbarth e Eklund, 1966; Johnston e coll, 1970; Arcangel e coll., 1971; Armstrong e coll., 1987; Matyas e coll., 1986; Samuelson e coll., 1989; Bosco e coll., 2000; Y. Nishihira, T. Iwasaki, A. Hatta, T. Wasaka, T. Kaneda, K. Kuroiwa, S. Akiyama, T. Kida, K. Ryol - Effect of whole Body Vibration Stimulus and Voluntary Contraction on Motoneuron Pool, Advances in Exercise and Sports Physiology, Vol. 8, No. 4 - 03/03/2004

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

18 Neuro-muscular system effect

Human explosive power improvement

Better motor unit synchronization

Improvement of synergistic muscles coordination

Increase of contractile ability in muscular area subject to vibration exercise induces an evident “right-shift” of force-velocity curve and of force-power one

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

19 Bone Tissue effect

Vibration Therapeutic

Exercise

Muscular function improvement

Effective stress on insertion bone

Bone mass development

Positively interfere on bone metabolism, also in

osteoporotic degeneration case

therapy of choice concerning the geriatric

medicine and the osteoporosis prevention

Rubin e coll., Nature, 441: 603-604, 2001; Miyamoto K., Mori S., Tsuij S., Tanaka S., Mashiba T., Komatsubara S., Akijama T., Kawanishi J., Norimatsu H. - Whole Body Vibration Exercise in the Elderly People; P506F IBMS Osaka 2003

Rubin C., Turner A.S., Bain S., Mallinckrodt

C., McLeod K. - Low mechanical

signals strengthen long bones. Nature, 412(6847), 603-604,

2001.Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

20 Bone Tissue effect

Upper and lower limb bone fractures

treatment

More quickly bone reparation

Mechanical factorBone tissue adaptive

response

Bone DeformationSignal

proportional to the applied load

Increase of bone forming

osteocyte

osteoblast

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

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Positive stimulus for the whole body

Vibration Energy

Qualified clinicians Using appropriate

devices/procedures Using specific frequency

Patient application

ByIFIF

Conclusions

THENTHEN

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

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Conclusions

Application fields

In rehabilitation plans in which, an optimization of methods

aimed at extensibility of muscle-tendon complex

improvement, is required;

In geriatric patologies, to improve myo-osteo-articular

functionality and in osteoporotic patients;

In sport field as alternative/complementary training method

oriented to an explosive-force improvement;

In workplans oriented to painful pathologies such as in chronic

low back- pain therapy

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

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Conclusions

…Last, but not least…

if applied in non specific way, WBV treatments could have non positive effects

The optimum is obtained localizing vibrations to a specific

body part

Importance of application

mechanisms

When a systemic response is

required

Whole body vibrations

When a local response is

required

Local vibrations

Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

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Biomedical Application of Vibration Energy: Biomedical Application of Vibration Energy: effects on the human bodyeffects on the human body

P. Abundo 1, C. Trombetta 2, C. Foti 3 and N. Rosato 1

1 Medical Engineering Service, Fondazione Policlinico Tor Vergata, Rome2 PhD student in Advanced Technology in Rehabilitation Medicine, Tor Vergata University, Rome

3 Tor Vergata University, Physical and Rehabilitation Medicine, Public Health Department,

Rome  February 9th 2010February 9th 2010

Thanks for the

attention