B82172 Course in English 1st Faculty of Medicine Charles University
APPLIANCES FOR REGENERATION AND AESTHETIC MEDICINE 7 Doc. MUDr. Leoš Středa, Ph.D. .
7. PASSIVE GYMNASTICS, ELECTROSTIMULATION
INTRODUCING Passive electro-gymnastics is method of strenghtening (hardening) and toning up muscles throughout the body. Electric stimulation of muscles – myostimulator. The instrument is applied mainly to the parts of the body where flaccid muscles or a thicker fatty layer exists; usually the abdomen, hips, thighs or arms. It is also applied to the parts where undesirable symptoms of cellulite occur.
PASSIVE ELECTROGYMNASTICS PRINCIPLES Computer controlled electric impulses are adjusted to the human body. They are similar to nerve´s electric impulses (neuron action potential). Myostimulator impulses are independent of physiological mechanisms. It allows in muscle such contraction, which is unpossible during active physical exercise (training).
NEURON ACTION POTENTIAL ď‚˘
Computer controlled electric impulses are adjusted to the human body. They are similar to nerveÂ´s electric impulses (neuron action potential).
MUSCLE CONTRACTION (1) Striates (příčně pruhovaný) muscles fiber generates tension through the action of actin and myosin Muscle contraction is controlled by the central nervous system. The brain sends signals, in the form of action potentials to the motor neuron that inervates several muscle fibers
MUSCLE CONTRACTION (2) While nerve impulse profiles are almost always the same, skeletal muscles are able to produce varying levels of contractile force ď‚˘ During regular exercise the refractory period enforces long breaks between action potentials ď‚˘
REFRACTORY PERIOD IN NAP Neuron action potential last approx 2 ms. Absolute refractory period lasts 1ms (all sodium channels are not yet reset and therefore, no second action potential can be fired). Relative refractory period lasts 10-15 ms (some sodium channels are reset completely, and only a stronger than normal stimulus is required to fire a second action potential. Refractory periods are 6-8 times longer than neuron action potential
BIOPHYSICAL VIEW ON THE CONTRACTION Huxley-Hunsen´s
the weaker actin filaments are inserted between thicker myosin filaments. The required energy is obtained by ATP cleavage (štěpení ATP).
theory of muscle contraction:
MUSCLE ELECTROSTIMULATION FOR BODY BUILDING Myostimulator transmits repetitive electric impulses to muscles. These impulses are controlled externally (microprocessor, not by human physiology limits). The rate of stimulationss is much higher than in physical training, because refractory period is omitted. ď‚˘ Summation of electrical and mechanical responses causes to prolonged contractile activity ď‚˘
EFFECT OF MYOSTIMULATORS) More prolonged contractile activity requires synthesis of ATP by adding to aerobic metabolism also anaerobic metabolism. Aerobic metabolism: 1 mole of glucose produces 38 moles of ATP . Anaerobic metabolism (less efficient): 1 mole of glucose produces only 2 moles of ATP.
Prolonged contractile activity of muscle requires higher energy input, i.e. consumption of energy is higher than in normal physical exercising.
BODY BUILDING A very powerful contraction is the result of more nearly complete tetanus in a larger fraction of the motor units of a muscle. ď‚˘ Myostimulators are constructed to achieved such contraction in skeletal muscles. ď‚˘
NEURON ACTION POTENTIAL MYOSTIMULATOR IMPULSES
Subject for medicine students. Lecture by Ass. Prof. Dr. Leoš Středa, M.D., Ph.D. 1st Faculty of Medicine, Charles University Prague, Czech...