GB2227173A

GB2227173A - Stimulation of muscles

Info

Publication number: GB2227173A
Application number: GB8900645A
Authority: GB
Inventors: Hugh Wilmott Grenfell
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-01-12
Filing date: 1989-01-12
Publication date: 1990-07-25
Also published as: GB8900645D0; WO1990007955A1

Abstract

A method of stimulation of a muscle or group of muscles of a living animal (in particular a human animal) which comprises causing small involuntary contractions of the muscle(s) between large voluntary exercise contractions thereof, the small involuntary contractions being insufficient to cause movement of the joints acted on by the relevant muscles.

Description

Stimulation of Muscles The present invention is concerned with stimulation of muscles.

Sudden violent contraction of a muscle, as in running, jumping, lifting and throwing is immediately followed by virtually complete relaxation of that muscle.

During contraction of a muscle, the chemical energy necessary for the functioning of the muscle is derived, in simple terms, from a cycle of chemical reactions in which glycogen, which is a carbohydrate derived from food, is converted into lactic acid, which is a waste product. Ihe muscle contains its own store of glycogen ready for immediate use. If the muscle continues to contract in repetetive exercise, more and more glycogen is used up until there are insufficient chemical reactants for the muscle to usefully contract; the muscle is then fatigued. At the same time, lactic acid builds up in the muscle causing pain.If the muscle exercise is continued then damage can occur, resulting in stiffness and continued pain for a period after the exercise When a muscle contracts, blood is expelled while when it relaxes blood enters the muscle; the more the muscle contracts the more blood is expelled. This fresh blood enters through the arteries carrying nutrients to replace those used during contraction, and the old blood is pushed out through the veins carrying waste products for conversion in other parts of the body and eventual expulsion as carbon dioxide and water in the breath or in urine.

The muscles therefore act as pumps for blood; a muscle that is not used to exercise is an inefficient pump.

It may contract reasonably well but immediately after the contraction it relaxes completely, becomes flabby and lacks tone. Lactic acid gradually builds up in the muscle and the muscle becomes painful and stiff after only moderate exercise. Such a muscle is easily damaged.

In contrast, a muscle that has undergone regular exercise is far more efficient as a pump. It does not become flabby after a contraction and always maintains a certain amount of tone. Lactic acid is removed from such a muscle reasonably well and so the level of exercise before the muscle becomes painful is much higher and, since lactic acid is pumped away after exercise, the muscle has less tendency to become painful and stiff.

Such a muscle is able to store far more nutrients than an unexercised muscle and is therefore able to do much more work before the onset of fatigue.

As a muscle is exercised the muscle fibres become larger and stronger and the whole muscle increases its bulk.

The rate at which the muscle increases its bulk depends on the rate at which it converts amino-acids in the food to useful muscle proteins. lhis is in turn determined by the rate at which useful chemical reactions occur which is, of course, the rate of exercise and the rate of supply of nutrients in the blood.

The limits to the rate of exercise are the rate at which nutrients can get to the muscle and the rate at which waste products can be pumped away, that is the blood flow through the muscle and its concentration of nutrients.

Anabolic steroids, used illegally by some athletes, have the effect of restricting the loss of nitrogen from the body so that nutrients available for conversion to muscle protein are in greater abundance. This can be a great danger to health however since the balance of reactions within the body is upset and no-one knows what long term effect this might have. If the blood flow through the muscle were to be increased, however, then then this would act against conversion of nitrogenous compounds to muscle protein.

It is an object of the present invention to provide a method of enhancing blood flow through muscles.

According to the present invention, there is provided a method of stimulation of a muscle or group of muscles of a living animal (in particular a human animal) which comprises causing small involuntary contractions of said muscle(s) between large voluntary exercise contractions thereof, said small involuntary contractions being insufficient to cause movement of the joints acted on by the relevant muscles.

Ihe involuntary contractions are preferably caused by means of external stimulation, for example, using an electrical stimulator such as those described in, for example, European patent specification 219204 or U.K patent specification 2175806 or 2136297. Such electrical stimulation is preferably applied according to the invention in a continuous manner in the course of a prolonged period of exercise, lasting typically about 30 minutes or more.

The frequency of the electrical stimulation is generally in the range 2 to 20 Hertz, preferably 10 to 15 Hertz.

The electrical stimulation is typically employed by using a pair of conductive electrodes (of, for example, graphiteimpregnated silicone rubber) applied to the skin of the user.

The muscle or group of muscles stimulated in the method according to the invention are preferably arm or leg muscles, and in particular those muscles used in athletic activity, such as the quadriceps, biceps or the like. Ihe small involuntary contractions of such muscles employ a relatively minor proportion of the muscle energy to pump blood faster, and so enhance the rate of supply of nutrients.

In an example, blood flow measurement using Ultrasonic Doppler Blood Flow equipment in the femoral artery gave a blood flow of 576 mls/min when the muscles were completely relaxed. This flow rate increased to 1053 mls/min when small involuntary contractions were stimulated in the quadriceps muscle between the voluntary contractions by means of a continuous application of an electrical current via a pair of electrodes applied to the skin of the user; the electrical stimulation was applied at a voltage of 20S and a current of 20 milliamps, but this varies considerably from person to person and muscle to muscle.

The accompanying drawing shows the observed changes in the rate of the blood flow through the artery of the user. It will be noted that the diastolic peak flow rate had increased considerably whereas the systolic peak flow remained the same. The average systolic flow had, however, also increased.

Claims

CLAIMS:

1. A method of stimulation of a muscle or group of muscles of a living animal, which comprises causing small involuntary contractions of said muscle or group of muscles between large voluntary exercise contractions thereof, said small involuntary contractions being insufficient to cause movement of joints acted on by said muscle or group of muscles.

2. A method according to claim 1, wherein said involuntary contractions are caused by means of external stimulation applied via the skin of said animal.

3. A method according to claim 2, wherein said external stimulation is provided by an electrical stimulator including a pair of conductive electrodes applied to said skin arranged to stimulate a predetermined muscle or group of muscles.

4. A method according to claim 3, wherein said electrical stimulation is applied continuously in the course of a prolonged period of exercise of said muscle or group of muscles.

5. A method according to claim 3, wherein said electrical stimulation has a frequency in the range 2 to 20 Hertz.

6. A method according to any of claims 1 to 5, wherein said animal is human.

7. A method according to claim 6, wherein said muscle or group of muscles comprise leg or arm muscles used in athletic activity.