1 Biomedical Application of Vibration Energy: effects 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, Rome 2 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 2010 February 9th 2010

2 Analysis of vibration peculiar parameters Vibration human body effects Index Vibration producing methods Vibration producing methods Negative effects Safety of workers subject to vibrations Positive effects Therapeutic application in rehabilitation medicine Hormonal effect Neuro-muscular system effect Bone tissue effect Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo Biomedical vibration applications

3 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/s 2 ]

4 Analysis of vibration peculiar parameters Human body feels more the variation of a stimulus than its persistence Vibration intensity 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 body rotating around a non barycentric axis Rotating mass (m) Uniform circular motion Circumference radius equal to eccentricity (e) Costant angular velocity in amplitude (Ω) 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 - BaTiO 3 ) 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 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 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

9 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 Hz → low frequency oscillations, generated by means of transportation (buses, airplains, ships); Hz → middle frequency oscillations, generated by machine tools and industrial plant; > 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 Vibrations Middle - High frequency vibrations Local negative effects (not only on HA system) Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

13 Hand Arm System Safety of workers subject to vibrations In order to limit the negative effects of vibration on workers D.Lgs 81/08 5 m/s 2 Equivalent Acceleration Exposure Limit Value = 5 m/s 2 T e = daily exposure time to vibrations (hour) 8 = reference time (hours) a x, a y,a z = r.m.s. acceleration values (in m/s 2 ) along x, y, z axis (ISO : 2001) Whole Body 1 m/s 2 Equivalent Acceleration Exposure Limit Value = 1 m/s 2 T e = daily exposure time to vibrations (hour) 8 = reference time (hours) A Max = Maximum value among a x, a y, a z a x, a y,a z = r.m.s acceleration values (in m/s 2 ) along axis x, y, z (ISO : 1997) 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): , 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 part Vibrating 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 concentration after whole body vibration exercise (10 times for 60 s, with 60 s rest time - B before, A after) Vibration frequency 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: , 2000; Kvorning T., Bagger M., Caserotti P. - Effects of vibration and resistance training on neuromuscular and hormonal measures. Eur J Appl Physiol Mar;96(5): 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 /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: , 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), , 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 factor Bone tissue adaptive response Bone Deformation Signal proportional to the applied load Increase of bone forming osteocyte osteoblast Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

21 Positive stimulus for the whole body Vibration Energy Qualified clinicians Using appropriate devices/procedures Using specific frequency Patient application By IF Conclusions THEN Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo

22 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

23 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

24 Biomedical Application of Vibration Energy: effects 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, Rome 2 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 2010 February 9th 2010 Thanks for the attention