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In this profile we deal with the sciences, which explain the 'workings' of Ju Jitsu, including anatomy, physiology, biomechanics, advice, injury prevention, treatment and rehabilitation, etc.

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Category: Physiology

Lactic Acid - Myth Busted....


By Jujitsu, 2016-02-07

This article intends to dispel the many myths perpetuated by so called experts in respect of Lactic Acid. Many, Coaches, Physiotherapists, Trainers etc., have claimed that lactic acid is responsible for all ills, making you sore, injuring your muscles, causing cramp, leading to oxygen debt etc., etc. The list goes on and on. Nothing could be further from the truth. Lactic acid is not a bad substance at all in fact it may actually be rather nice in a way, as far as metabolites are concerned. Read more....

In order to prevent being long winded it is suffice to say that lactic acid is the breakdown product of glucose and glycogen produced during glycolysis. The prefix ‘glyco’ refers to the sugar – glucose (which when strung together and stored in the muscle makes glycogen). ‘Lysis’ means the splitting or breakdown. Therefore glycolysis means the splitting or breakdown of glucose. Essentially, lactic acid is a glucose molecule split in half. Glycolysis can proceed so quickly that the formation of pyruvate far exceeds the capacity of the mitochondria to accept pyruvate into the Krebs cycle. The Krebs cycle ultimately results in the aerobic formation of ATP the primary form of cell energy. The excess pyruvate is converted into lactic acid.
You should also know that the terms lactic acid and lactate are often used interchangeably, even though they really aren’t the same compound. The lactic acid formed through glycolysis quickly releases a hydrogen ion and forms lactate.

Does lactic acid make you sore?
The belief in this is actually a myth perpetuated by the ignorant. It has been know for over 16 years that lactic acid has noting to do with delayed onset of muscle soreness. The soreness is attributed to the unaccustomed overwork of the muscle. Mechanically, the myofibrils of the muscle tear during eccentric contractions of the muscle, that when the muscle contracts as it actually lengthens. It is surprising but muscles actually do that. In fact if your body performed only concentric contractions it would never get sore.

Although concentric contractions don’t produce the damage that eccentric contractions do, concentric contractions produce more lactic acid. Now if lactic acid were so bad, wouldn’t it make more sense that concentric contractions should cause the soreness?
Approximately 75% of the lactic acid made during exercise is used as fuel and the remaining 25% is converted to glucose in the kidney and liver.

Does massage help remove lactic acid?
Many exercise Therapists claim that one way massage helps your muscles recover by enhancing the removal of lactic acid followed by a hot salty bath. There is absolutely no evidence to support this theory. Massage may make you feel good but there is no evidence to indicate that there is any change to the amounts of lactic acid in the blood before and after a massage following strenuous activity. Test have been carried out and found that mild exercise after a strenuous session is more beneficial. This doesn’t suggest that massage for sportspeople is useless, just that it has nothing to do with the evacuation of lactic acid.
Lactic acid – what is it good for?

Firstly, the accumulation of lactic acid during exercise can interfere with muscle contraction, nerve conduction and energy production which can lead to acute fatigue. This is one reason why you tire during a training session. However lactic acid is not just a by-product of energy metabolism; it’s an important energy source.

The glucose paradox hypothesis suggests that when you ingest dietary carbohydrate, instead of it entering the liver and being converted into glycogen, it may actually bypass the liver and enter the circulatory system for conversion directly in the skeletal muscle system. Alternatively, lactate can enter the body’s systems be converted into glycogen in the liver where other tissue such as the heart, liver and kidneys can use it as fuel on demand. The heart cannot function well without large amounts of lactic acid and after about 1 hour of finishing exercise there is no lactic acid left in the skeletal muscle. During the recovery, the heart demands the lactic acid for its use as a fuel.

So why this backward path for liver glycogen formation? Lactate is removed quicker from the blood than glucose which expedites the disposal of dietary carbohydrate without a tremendous insulin surge and stimulation of fat storage. Lactic acid can also be used as an important fuel or as a source for glucose and glycogen synthesis. When exercising intensely, lactic acid produced in your fast twitch fibres can actually go to a slow twitch fibre, which can then use it as fuel. Approximately 75% of the lactic acid made during exercise is used as fuel and the remaining 25% is converted to glucose in the kidney and liver. The removal of accumulated lactic acid helps avert excessively high levels and conversion of lactate into glucose, helps maintain sufficient levels of blood glucose which is very important during prolonged exercise. Additionally, during prolonged intensive exercise when the muscle demand for glucose is depleted in e.g. the legs, lactic acid can be obtained from inactive muscles, in this case the arms, chest, etc., from their glycogen stores. This lactic acid then travels to the liver to be converted into glucose to be shuttled back to the muscle via the bloodstream. In the muscle it serves as a substrate for glycogen synthesis, so even your inactive muscles play an important role in muscle recovery.

An important metabolic regulator
Since lactic acid is half the size of glucose, it penetrates cellular membranes easier. Unlike glucose, which requires insulin to help transport it across the cell membrane, lactic acid needs no hormonal support. Muscles can release large amounts of lactic acid into general circulation, where it can serve as a potential fuel source and precursor for glycogenesis. So the next time anyone tries to bamboozle you with the side effects of lactic acid, you can smile back knowingly and dispel the myths.

 

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Dripping with Sweat


By Jujitsu, 2016-01-19

Why do people love to sweat? The reasons are many. Excessive sweat accumulation creates the illusion of hard work and the thought that some sweat is good, more must be better. Sweat is a natural, rather pure, and inevitable product of exercising but the effectiveness o a workout in terms of fat loss, calories burned and cardiovascular conditioning bears little relationship to how much sweat is created. What really counts is the amount and type of activity you participate in.

WHAT ACTUALLY HAPPENS WHEN YOU SWEAT
When you exercise, your body produces excess heat as the muscles turn fuel into energy Your skin plays a key role in keeping you cool Blood carries excess hear from deep inside your body to your skin, allowing heat to radiate from the skin's surface. This blood shun or transfer is exemplified by a red face or flushed skin on a hot day.
Meanwhile, the body perspires, dumping water on your skin. Evaporation of sweat cools the body. Through perspiration and breathing fluid and heat is lost. Because this fluid comes from blood plasma, profuse sweating reduces blood volume. As blood supply and volume decreases, the exercising skeletal muscles can perform efficiently.
This also adds strain to the heart and blood delivery system. The blood shunt from the core of the body and decreased blood volume will cause the heart to beat more times per minute to meet the exercise oxygen needs or the working skeletal muscles and heart muscle. A faster heating heart muscle needs more oxygen because it is working harder. In this high stressed situation oxygen delivery may not be able to meet the oxygen needs of the heart. The skeletal muscles that literally move you can recover from this 'oxygen debt' however the heart muscle does not have the capacity to sustain muscle contraction without act equate oxygen. The end result of overheating could be a heart attack.

STAYING COOL
Even a moderate amount of exercise can build your core temperature up to 37.5-38ºc.
To minimise sweating whilst exercising
• drink approximately 100 ml of water every 10-15 minutes
• wear loose or "breathable'' clothing.
• exercise in an environment that is well ventilated and slightly cool at the start.
 
The quest for attainment of "dripping wet’ status is counter-productive from a safety and calorie burned standpoint. Excessive heat exposure or dehydration results in physiological strain to the body. You may produce a lot of sweat as the body frantically tries to cool its core temperature, but you may end up exercising a shorter duration at a lower intensity and the experience may be less than fun.
Physiologists suggest that 13 degrees Celsius is the highest temperature at which you can expect to perform your best. Temperature is not the sole cause of heat problems. Heat plus humidity (partly influenced by poor ventilation) is even more dangerous. The fact remains that cool rind well ventilated environments present the best conditions for "hard cardiovascular workouts".
Classroom or "home gym" temperatures may be warmer than 13 degrees Celsius, especially in the summer months. Because of this, it is important not to further increase the temperature and humidity by turning up the thermostat closing off ventilation, or wearing excessive clothing in order to retain heat.
The key is to create an environment that is appropriate to the activity you are going to participate in. A stretching session is different than a high intensity cardiovascular or strength workout. In this case you might want a room that is 21 degrees Celsius as warm temperatures facilitate stretching anti will help to promote relaxation. In a public facility where it may not be possible to control room temperature, a cooler environment is preferable, allowing you to add/take off clothing to help regulate temperature.
Though many people can tolerate a hotter; "stuffier," higher risk environment, there are issues of liability, safety and enjoyment. Some exercisers may have undiagnosed asymptomatic heart disease or some other ailment. A situation like this puts this person at risk because of the excessive demand it places on the heart.

WHAT'S ANOTHER REASON PEOPLE SWEAT
The answer is to lose weight. Excessively hot environments and layered clothing do promote water loss, and temporary weight loss through sweating. Like wise, plastic and rubberised suits may dangerously compromise your cooling system. You sweat excessively under them, but they don't allow evaporation and cooling to occur. Striving to "sweat! off the pounds" results only in loss of water weight which you'll replace as soon as you begin to drink fluids.

DO WOMEN REALLY NEVER SWEAT OR AT BEST ONLY GLISTEN?
Women are generally less prolific sweaters than men. A woman's cooling system probably relies more on blood circulation to transfer heat though the skin. Then as skin and core temperatures rise, sweating kicks in. Men make greater use of evaporative cooling. While men and women handle excess heat differently, their heat tolerance is about the same. It is obvious that quantity of sweat and onset of sweating once again fails to be the "measure" for effective exercise. Too many people think. "the harder you work, the more you sweat." And, "those not sweating aren't working hard enough." The answer to these..... NO SORRY YOU’RE WRONG.
Sweating to lose weight or create a false sense about the hardness of your workout should be avoided. For years sweating has been touted as means to good health. Unfortunately, there is little, if any demonstrable relationship between sweating and improved health.

IS IT WRONG TO DRIP WITH SWEAT?
Of course not. If you work at an exercise intensity that you've progressively attained, drink lots of water before, during and after your session. Wear appropriate clothing that encourages the cooling processes of the body. Exercise in a cool and well ventilated environment if indoors, and you still end up dripping wet with sweat... "Nice workout!"

Posted in: Physiology | 0 comments

Haemostasis


By Jujitsu, 2016-01-19

The objective of this article is to look at haemostasis viz., the arrest of bleeding from broken blood vessels which involves 3 steps:

(1)   VASCULAR SPASM

• The first step in haemostasis is when a blood vessel is disrupted the smooth muscle surrounding the vessel constricts as a result of a response to injury and sympathetic induced vaso-constriction formation of a platelet plug. Platelets are small cells which aggregate and coagulate at the site of injury to arrest bleeding.
 
(2)  BLOOD COAGULATION OR CLOTTING

CLOT FORMATION
• Platelets do not normally adhere to vessels due to prostacylin
• When vessels are disrupted they expose collagen fibres (afibrous protein), platelets congregate at the site and begin to release the chemicals Adenosine Di-Phosphate (ADP) which cause platelet aggregation 
• Pplatelets also release chemicals called Thromboxin 2A to enhance the blood coagulation. Thromboxin catalyses fibrinogen to fibrin to form a clot only at the site of injury 
• Clot is fully developed in between 3 - 6 minutes.

(3)  CLOT RETRACTION

• Once a clot has formed, platelets contrct within the clot and shrinks the fibrin meshwork pulling the edges of the damages vessels together.
• During clot retraction, the fluid is squeezed from the clot. This fluid is essentially plasma minus the fibrinogen and other clotting precursors and is called serum.
• A clot is a transient dance to stop bleeding until the vessel can be repaired.
• Platelets secrete a chemical partially responsible for the invasion of fibroblasts which form a scar at the site or defect.  
• When the clot is no longer required, clot retraction occurs to prevent haemmorage. The clot is dissolved by plasmin, a fibrolinic enzyme.  
• Phagocytic white blood cells remove debris and products of clot dissolution.  
 
SUMMARY
 
In summary, a VASCULAR SPASM occurs followed by PLATELET AGGREGATION & PLATELET PLUG leading to CLOT FORMATION and finally CLOT RETRACTION.
 
 
FUNCTION OF THE BLOOD
 
The main function of the blood is to carry Oxygen (O2) to sites for Cellular respiration  and Carbon Dioxide (CO2)  to Lungs for expulsion and Wastes to the Kidneys for expulsion. Further to that it also has the function of maintaining the ph of the body maintaining the body temperature. The blood also carries electrolytes in plasma for membrane excitability and  osmotic function. The blood also has other duties viz defending the body against infection, invading disease causing cells and cancer cells.
 

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Rehydration


By Jujitsu, 2016-01-07

Rehydration

When training the body will lose fluids. This can have a deleterious effect on the body and its systems and cause collapse.

It will be important, particularly in warm environments, or high humidity, or altitude to rehydrate effectively.

The body is set up in a way that through the digestive system, water and salts can be re-absorbed by ingested fluids. These substances are vital to support life and facilitate the function of other organs. Water unfortunately has a high surface tension and in itself is not quickly absorbed. Yet the only active way to replace water lost through dehydration is by ingestion.

We have found through science that the most effective way to increase water absorption in the body is to change its properties and make it isotonic.  This involves adding some sugar syrup to about 1% per volume which will act to hold the water within the gastrointestinal tract long enough for sufficient quantities to be absorbed.

Making an isotonic fluid.

In training you will need about 2 litres of isotonic fluid for ingestion.

Take a suitably sized jug and add 2 litres of water. Tap water is as good as bottled water. Then add approximated 1% of the total volume of sugar syrup, something like Ribena or other propriety diluting juice. The effect will be that the water will have a hint of flavour and a hint of colour. Half a teaspoon of salt into the solution will help break the tensile strength of the water molecule thereby facilitating the easy transference of fluids in the G.I. tract.

By using too much syrup, the fluid will be held in the stomach where the sugar will be broken down. This may cause a feeling of tiredness, nausea and actual sickness during training as blood is redirected to the digestive system, to digest the fluids, instead of the muscles.

 

Should you need any further advice on this issue, please contact 

Scottish Ju Jitsu Association
Coaching Unit
93 Douglas Street
Dundee
DD1 5AZ

(01382) 201601

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