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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
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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
Index Analysis of vibration peculiar parameters Safety of workers subject to vibrations Vibration human body effects Vibration producing methods Negative effects Therapeutic application in rehabilitation medicine Hormonal effect Neuro-muscular system effect Bone tissue effect Biomedical vibration applications Positive effects 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] Biomedical Application of Vibration Energy: effects on the human bodyPaolo Abundo
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 bodyPaolo Abundo
Vibration producing methods Centripetal force generated by a body rotating around a non barycentric axis Non barycentric rotation axis Rotating mass (m) Uniform circular motion Circumference radius equal to eccentricity (e) Costant angular velocityin amplitude (Ω) Mass Biomedical Application of Vibration Energy: effects on the human bodyPaolo Abundo
Vibration producing methods Piezoelectric effect – Jacques and Pierre Curie (1880) ~MHz Crystal material thickness Alternating current Frequency Crystals specific property Mechanical stress (contraction or expansion) Alternating current Crystal wave vibration frequency Optimize vibrating head dimensions and weight Policrystal ceramic (Barium titanate - BaTiO3) Quartz Topaz Biomedical Application of Vibration Energy: effects on the human bodyPaolo Abundo
Vibration producing methods Magnetic-dynamic transducer Alternating current through coils Membrane Electric coils Permanent magnet Alternating current Varying intensity magnet N= Coils number L= Coils lenght I= Coils current m= Magnetic Permeability Permanent magnetic field Coils vibrations Membrane vibrations Biomedical Application of Vibration Energy: effects on the human bodyPaolo Abundo
Biomedical vibration applications Biomedical vibration applications Piezoelectric or electro-magnetic Lithotripter (urological) Piezoelectric surgical scaler (dental) Piezoelectric Ultrasound probes Biomedical Application of Vibration Energy: effects on the human bodyPaolo Abundo
Biomedical vibration applications Ultrasound rehabilitation therapy (piezoelectric) Rehabilitation Vibration Therapeutic Exercise (oscillating masses) Biomedical Application of Vibration Energy: effects on the human bodyPaolo Abundo
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 bodyPaolo Abundo
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 Human body doesn’t vibrate like a single mass with only one natural frequency, every body part has a its own resonance frequency Tolerable vibration energy level Long terms damages Human body deterioration Biomedical Application of Vibration Energy: effects on the human bodyPaolo Abundo
Vibrations human body negative effects Vibration Direction Vibration Touch point Lower efficiency degree Low-middle frequency vibrations Whole Body Vibrations Decrease of fatigue threshold High frequency vibrations Hand Arm Vibrations Local negative effects Middle - High frequency vibrations Local negative effects (not only on HA system) Local Vibrations Biomedical Application of Vibration Energy: effects on the human bodyPaolo Abundo
Safety of workers subject to vibrations In order to limit the negative effects of vibration on workers D.Lgs 81/08 Hand Arm System 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) Equivalent Acceleration Exposure Limit Value = 5 m/s2 Whole Body Te= daily exposure time to vibrations (hour) 8 = reference time (hours) AMax = Maximum value among ax, ay, azax, ay,az = r.m.s acceleration values (in m/s2) along axis x, y, z (ISO 2631-1: 1997) Equivalent Acceleration Exposure Limit Value = 1 m/s2 Biomedical Application of Vibration Energy: effects on the human bodyPaolo Abundo
Vibrations human body positive effects + Specific Oscillation Frequency Reduced Exposure Time Positive Effects Metabolic Adaptations Mechanical Skeletal and neuro-muscular system Hormonal effects 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. Biomedical Application of Vibration Energy: effects on the human bodyPaolo Abundo
Therapeutic applications of vibration energy in rehabilitation medicine …By using…. Whole Body Vibrations Propagating to the whole human body Vibrating Platforms Hand Arm/Local Vibrationsinvolving Hand-Arm System or specific body part Vibrating Tools Biomedical Application of Vibration Energy: effects on the human bodyPaolo Abundo
Hormonal effects Testosterone and growth-hormone concentration Cortisol concentration Vibration frequency 20-50 Hz 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) 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 bodyPaolo Abundo
Neuro-muscular system effect Strengthening of the stimulation input, through the spindle motor-neural connections (stretch reflex) Locally applied vibrations to the muscle and to tendon structure (10-40 Hz) Whole Body Vibrations (1-50 Hz) Muscle spindle receptors activation Tonic Vibration 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 bodyPaolo Abundo
Neuro-muscular system effect Better motor unit synchronization Human explosive power improvement 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 bodyPaolo Abundo
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 C., Turner A.S., Bain S., Mallinckrodt C., McLeod K. - Low mechanical signals strengthen long bones. Nature, 412(6847), 603-604, 2001. 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 Biomedical Application of Vibration Energy: effects on the human bodyPaolo Abundo
Bone Tissue effect Upper and lower limb bone fractures treatment More quickly bone reparation Bone tissue adaptive response Mechanical factor Signal proportional to the applied load Bone Deformation osteocyte Increase of bone forming osteoblast Biomedical Application of Vibration Energy: effects on the human bodyPaolo Abundo
Conclusions Vibration Energy By IF Patient application • Qualified clinicians • Using appropriate devices/procedures • Using specific frequency Positive stimulus for the whole body THEN Biomedical Application of Vibration Energy: effects on the human body Paolo Abundo
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
Conclusions if applied in non specific way, WBV treatments could have non positive effects …Last, but not least… Importance of application mechanisms The optimum is obtained localizing vibrations to a specific body part 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
Thanks for the attention 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