i like this song.. reminds me when I was a kid..huhu

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VO2 max has been defined as:

“the highest rate of oxygen consumption attainable during maximal or exhaustive exercise” (3).

As exercise intensity increases so does oxygen consumption. However, a point is reached where exercise intensity can continue to increase without the associated rise in oxygen consumption. To understand this in more practical terms, take a look at the diagram below:

The point at which oxygen consumption plateaus defines the VO2 max or an individual’s maximal aerobic capacity. It is generally considered the best indicator of cardiorespiratory endurance and aerobic fitness. However, as we’ll discuss in a moment, it is more useful as an indicator of a person’s aerobic potential or upper limit than as a predictor of success in endurance events.

Aerobic power, aerobic capacity and maximal oxygen uptake are all terms used interchangeably with VO2 max.

VO2 max is usually expressed relative to bodyweight because oxygen and energy needs differ relative to size. It can also be expressed relative to body surface area and this may be a more accurate when comparing children and oxygen uptake between sexes.

VO2 Max In Athletes and Non Athletes

VO2 max varies greatly between individuals and even between elite athletes that compete in the same sport. The table below lists normative data for VO2 max in various population groups:

Genetics plays a major role in a person’s VO2 max  and heredity can account for up to 25-50% of the variance seen between individuals. The highest ever recorded VO2 max is 94 ml/kg/min in men and 77 ml/kg/min in women. Both were cross-country skiers.

Untrained girls and women typically have a maximal oxygen uptake 20-25% lower than untrained men. However, when comparing elite athletes, the gap tends to close to about 10% . Taking it step further, if VO2 max is adjusted to account for fat free mass in elite male and female athletes, the differences disappear in some studies. Cureton and Collins  suggest that sex-specific essential fat stores account for the majority of metabolic differences in running between men and women.

article from http://www.sport-fitness-advisor.com/

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Depletion of the body’s carbohydrate stores and dehydration are two factors that will limit prolonged exercise.

Dehydration

Sweating is the way in which the body maintains its core temperature at 37 degrees centigrade. This results in the loss of body fluid and electrolytes (minerals such as chloride, calcium, magnesium, sodium and potassium) and if unchecked will lead to dehydration and eventually circulatory collapse and heat stroke. The effect of fluid loss on the body is as follows:

% body weight lost as sweat	Physiological Effect
2%	Impaired performance
4%	Capacity for muscular work declines
5%	Heat exhaustion
7%	Hallucinations
10%	Circulatory collapse and heat stroke

Reference: “The Maintenance of Fluid Balance during Exercise”, International Journal of Sports Medicine, vol. 15(3), pp. 122-125, 1994

Electrolytes

Electrolytes serve three general functions in the body:

• many are essential minerals
• they control osmosis of water between body compartments
• they help maintain the acid-base balance required for normal cellular activities

The sweat that evaporates from the skin contains a variety of electrolytes. The electrolyte composition of sweat is variable but comprises of the following components:

• Sodium
• Potassium
• Calcium
• Magnesium
• Chloride
• Bicarbonate
• Phosphate
• Sulphate

A litre of sweat typically contains 0.02g Calcium, 0.05g Magnesium, 1.15g Sodium, 0.23g Potassium and 1.48g Chloride. This composition will vary from person to person.

Glucose

Carbohydrate is stored as glucose in the liver and muscles and is the most efficient source of energy as it requires less oxygen to be burnt than either protein or fat. The normal body stores of carbohydrate in a typical athlete are:

• 70kg male athlete - Liver glycogen 90g and muscle glycogen 400g
• 60kg female athlete - Liver glycogen 70g and muscle glycogen 300g.

During hard exercise, carbohydrate can be depleted at a rate of 3-4 grams per minute. If this is sustained for 2 hours or more, a very large fraction of the total body carbohydrate stores will be exhausted and if not checked will result in reduced performance. Recovery of the muscle and liver glycogen stores after exercise will normally require 24-48 hours for complete recovery.

During exercise, there is in an increased uptake of blood glucose by the muscles and to prevent blood glucose levels falling the liver produces glucose from the liver stores and lactate.

Consuming carbohydrate before, during and after exercise will help prevent blood glucose levels falling too low and help maintain the body’s glycogen stores. Many athletes cannot consume food before or during exercise and therefore a formulated drink that will provide carbohydrate is required.

Rehydration

Fluid absorption

Two main factors affect the speed at which fluid from a drink gets into the body:

• the speed at which it is emptied from the stomach
• the rate at which it is absorbed through the walls of the small intestine

The higher the carbohydrate levels in a drink the slower the rate of stomach emptying. Isotonic drinks with a carbohydrate level of between 6 and 8% are emptied from the stomach at a rate similar to water. Electrolytes, especially sodium and potassium, in a drink will reduce urine output, enable the fluid to empty quickly from the stomach, promote absorption from the intestine and encourage fluid retention.

Reference: “The Effect of Different Forms of Fluid Provision on Exercise Performance”, International Journal of Sports Medicine, vol. 14, p. 298, 1993)

What’s wrong with water?

Drinking plain water causes bloating, suppresses thirst and thus further drinking. A poor choice where high fluid intake is required. Water contains no carbohydrate or electrolytes.

Calculating personal fluid needs

During an endurance event, you should drink just enough to be sure you lose no more than 2% of pre-race weight. This can be achieved in the following way:

• Record your naked body weight immediately before and after a number of training sessions, along with details of distance/duration, clothing and weather conditions
• Add the amount of fluid taken during the session to the amount of weight lost - 1 kilogram (kg) is roughly equivalent to 1 litre of fluid (1lb approx. 0.5 litre)
• After a few weeks you should begin to see some patterns emerging and can calculate your sweat rate per hour
• Once you know what your sweat losses are likely to be in any given set of environmental conditions, you can plan your drinking strategy for any particular event

Sports Drinks

There are three types of sports drink all of which contain various levels of fluid, electrolytes and carbohydrate.

Type	Content
Isotonic	Fluid, electrolytes and 6 to 8% carbohydrate
Hypotonic	Fluids, electrolytes and a low level of carbohydrate
Hypertonic	High level of carbohydrate

The osmolality of a fluid is a measure of the number of particles in a solution. In a drink, these particles will comprise of carbohydrate, electrolytes, sweeteners and preservatives. In blood plasma the particles will comprise of sodium, proteins and glucose. Blood has an osmolality of 280 to 330mOsm/kg. Drinks with an osmolality of 270 to 330mOsm/kg are said to be in balance with the body’s fluid and are called Isotonic. Hypotonic fluids have fewer particles than blood and Hypertonic have more particles than blood.

Consuming fluids with a low osmolality, e.g. water, results in a fall in the blood plasma osmolality and reduces the drive to drink well before sufficient fluid has been consumed to replace losses.

Which is most suitable?

Isotonic - quickly replaces fluids lost by sweating and supplies a boost of carbohydrate. This drink is the choice for most athletes - middle and long distance running or team sports. Glucose is the body’s preferred source of energy therefore it may be appropriate to consume Isotonic drinks where the carbohydrate source is glucose in a concentration of 6% to 8% - e.g. High Five, SiS Go, Boots Isotonic, Lucozade Sport.

Hypotonic - quickly replaces fluids lost by sweating. Suitable for athletes who need fluid without the boost of carbohydrate e.g. jockeys and gymnasts.

Hypertonic - used to supplement daily carbohydrate intake normally after exercise to top up muscle glycogen stores. In ultra distance events, high levels of energy are required and Hypertonic drinks can be taken during exercise to meet the energy requirements. If used during exercise Hypertonic drinks need to be used in conjunction with Isotonic drinks to replace fluids.

Want to make your own?

Isotonic - 200ml of orange squash (concentrated orange), 1 litre of water and a pinch of salt (1g). Mix all the ingredients together and keep chilled

Hypotonic - 100ml of orange squash (concentrated orange), 1 litre of water and a pinch of salt (1g). Mix all the ingredients together and keep chilled.

Hypertonic - 400ml of orange squash (concentrated orange), 1 litre of water and a pinch of salt (1g). Mix all the ingredients together and keep chilled.

Dental Health

Sports drinks commonly contain citric acid. All acids have an erosive potential but the method of drinking will influence whether or not those acids affect the teeth. Sports drinks should be consumed as quickly as possible, preferably with a straw and not be held or swished around the mouth. Retaining drinks in the mouth will only increase the risk of erosion. Refrigerated drinks will have a reduced erosive potential, as the acid dissolution constant is temperature dependant.

Reference: Dr A Milosevic. Dental health and the serious athlete. Good Dietary Practice. Vol 9: Issue 2

Food for thought

In a trial conducted by scientists in the city of Aberdeen it was determined that a 2% carbohydrate-electrolyte drink provided a more effective combat to exercise fatigue in a hot climate when compared to a 15% carbohydrate-electrolyte mixture.

Reference: Galloway SDR & Maughan RJ, The effects of substrate and fluid provision on ermoregulatory and metabolic responses to prolonged exercise in a hot environment. Journal of Sports Sciences, Vol 18, No5, pp339-351

Seven Rules of Hydration

• The rate of passage of water from your stomach into your small intestine depends on how much fluid is actually in your stomach. If there is lots of water there, fluid flow from stomach to intestine is like a springtime flood; if there is little water, the movement resembles a lightly dripping tap. Therefore, to increase stomach-intestinal flow (and overall absorption of water) you need to deposit a fair amount of liquid in your stomach just before you begin your exercise. In fact, 10-12 ounces of fluid is a good start. This will feel uncomfortable at first, so practice funneling this amount of beverage into your “tank” several times before an actual competition.
• To sustain a rapid movement of fluid into your small intestine during your exertions, take three to four sips of beverage every 10 minutes if possible, or five to six swallows every 15 minutes.
• If you are going to be exercising for less than 60 minutes, do not worry about including carbohydrate in your drink; plain water is fine. For exercise that is more prolonged you will want the carbohydrate.
• Years of research have suggested that the correct concentration of carbohydrate in your drink is about 5 to 7%. Most commercial sports drinks fall within this range, and you can make your own 6% drink by mixing five tablespoons of table sugar with each litre of water that you use. A bit of sodium boosts absorption; one-third teaspoon of salt per litre of water is about right. Although 5 to 7% carbohydrate solutions seem to work best for most individuals, there is evidence that some endurance athletes can fare better with higher concentrations. In research carried out at Liverpool John Moores University, for example, cyclists who ingested a 15% maltodextrin solution improved their endurance by 30 per cent compared to individuals who used a 5% glucose drink. The 15% drink also drained from the stomach as quickly as the 5% one, though many other studies have linked such concentrated drinks with a slowdown in water movement.
• A 6% “simple sugar” drink will empty from your stomach at about the same rate as a fancy 6% “glucose polymer” beverage, so do not fall for the idea that the latter can boost water absorption or enhance your performance more than the former, and don’t pay more for the glucose-polymer concoction.
• Contrary to what you have heard, cold drinks are not absorbed into your body more quickly than warm ones. However, cold drinks are often more palatable than warm ones during exercise, so if coldness helps you to drink large quantities of fluid while you exert yourself, then keep your drinks cool.
• Swilling drinks during exercise does NOT increase your risk of digestive-system problems. In actuality, most gut disorders that arise during exercise are caused by dehydration, not from taking in fluid. Dehydration induces nausea and discomfort by reducing blood flow to the digestive system, so keep drinking!

Water Intoxication

Intracellular fluid and interstitial fluid have the same osmotic pressures under normal circumstances. The principal cation inside the cell is K+ (Potassium), whereas the principal cation outside is Na+ (Sodium). When a fluid imbalance between these two compartments occurs, it is usually caused by a change in the Na+ or K+ concentration. Sodium balance in the body normally is controlled by aldosterone and ADH (antidiuretic hormone). ADH regulates extracellular fluid electrolyte concentration by adjusting the amount of water reabsorbed into the blood by the distal convoluted tubules and collecting tubules of the kidneys. Aldosterone regulates extracellular fluid volume by adjusting the amount of sodium reabsorbed by the blood from the kidneys that directly affects the amount of water reabsorbed from the filtrate.

Certain conditions, however, may result in an eventual decrease in the sodium concentration in interstitial fluid. For instance, during sweating the skin excretes sodium as well as water. Coupled with replacement of fluid volume with plain water, these conditions can quickly produce a sodium deficit. The decrease in sodium concentration in the interstitial fluid lowers the interstitial fluid osmotic pressure and establishes an effective water concentration gradient between the interstitial fluid and the intracellular fluid. Water moves from the interstitial fluid into the cells, producing two results that can be quite serious:

• The first result, an increase in intracellular water concentration, called over hydration, is particularly disruptive to nerve cell function. In fact, severe over hydration, or water intoxication, produces neurological symptoms ranging from disoriented behaviour to convulsions, coma, and even death.
• The second result of the fluid shift is a loss of interstitial fluid volume that leads to a decrease in the interstitial fluid hydrostatic pressure. As the interstitial hydrostatic pressure drops, water moves out of the plasma, resulting in a loss of blood volume that may lead to circulatory shock.

Alcohol

Alcohol is a high octane fuel but it cannot be metabolised to provide energy except in the liver and then only at a very slow constant rate. Energy provided by alcohol tends to be converted to fat and excessive consumption may cause liver damage. As a diuretic it will cause dehydration and evidence suggests that vitamin B and C may be depleted. Excessive alcohol will diminish aerobic capacity and impair motor function.

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Interval Training

Interval Training Involves the performance repeated exercise bouts, with brief recovery periods in between. The length and intensity of the work interval depends on what the athlete is trying to accomplish. For instance, a longer work interval requires a greater involvement of aerobic energy production, while a shorter, more intense interval provides greater participation of anerobic metabolism. Therefore, interval training that is designed to improve VO2 max should generally utilize intervals longer than 60 seconds to maximize the involvement of aerobic ATP production.

Further, it generally believed that high intensity intervals are more effective in improving aerobic power, and perhaps the lactate threshold, than low intensity intervals.

In planning an interval training session, the following variables need to be considered

• length of the work interval
• intensity of the effort
• duration of the rest interval
• number of interval set and
• the number of work repetitions

the length of work interval refers to the distance to be covered during the work effort. in training to improve aerobic power, the work interval should generally last longer than 60 seconds. The intensity of the work effort during interval training can be monitored using HR monitor or from a 10 second HR count upon completion of the interval (10 second HR count x 6=HR per min). In general, HRs should reach more than 85% of the maximal HR (220-Age=max HR) during interval training.

The time between work efforts is termed the rest interval and consists of light activity such as walking. The length of the rest interval is generally expressed as a ratio of the duration of the work interval. For example, if the work interval for running 400 meters was 75 seconds, a rest interval of 75 seconds would result 1:1 ratio of work to rest. Generally, the rest interval should be at least as long as the work interval. In planning an interval training program for athletes who are not already highly trained,  a work: rest ratio of 1:3 or 1:2 seems preferable. As a rule of thumb, the HR should drop to approximately 120 beats/min near the end of the recovery interval.

A set is a specified number of works efforts performed as a unit. For instance,  a set may consist of 8×400 meter runs with a prescribed rest interval between each run. The term repetition is the number is work efforts within one set. in the example just given, 8×400 meter run repetitions constitued one set. The number of repetitionsand sets performed per workout depends on the purpose of the particular training session and the fitness levels of the athletes involved

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To find the gender prediction, find the mother’s age (based on year born) at conception (across the top of the table) and then the month in which conception occurred. Follow the column and row to the intersecting point. The color of the box tells you what the prediction is. Blue = Boy and Pink = Girl

Woman’s Age at Conception
Month of Conception	18	19	20	21	22	23	24	25	26	27	28	29	30	31
January
February
March
April
May
June
July
August
September
October
November
December

Woman’s Age at Conception
Month of Conception	32	33	34	35	36	37	38	39	40	41	42	43	44	45
January
February
March
April
May
June
July
August
September
October
November
December

P/s: I tried, its accurate! you can try..

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Before Fasting……..

after 30 days………

Hopefully can get same…hehe..

i want to reduce my weight to 56kg

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click

(more…)

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Endurance training improves VO₂ max by increasing both maximal cardiac output and increasing the a-v O₂ difference (increase the muscle’s ability to extract O₂). Therefore, a training program designed to improve maximal aerobic power must overload the circulatory system and stress the oxidative capacities of skeletal muscles as well. As in all training regimens, specificity is critical. The athlete should stress the specific muscles to be used in his or her sport. In other words, runners should train by running, cyclist should train on the bicycle, swimmers should swim, and so forth.

There are three principal aerobic training methods used by athletes

• interval training
• long, slow distance (low intensity)
• high-intensity, continuous exercise

Controversy exists as to which of these training methods results in the greatest improvement in VO₂ max. Indeed, there does not appear to be a magic training formula for all athletes to follow. however, there is evidence that it is training intensity and not duration that is the most important factor in improving VO₂ max. Nonetheless, from a psychological stand point, it would appear that a mixing of all three methods would provide the needed variety to prevent the athlete from becoming bored with a single and rather monotonous training program.

Note that improvement of VO₂ max is only one variable related to endurance. Although a high VO₂ max is important for success in endurance events, both movement economy and the lactate threshold are also important variables. Therefore, training to improve endurance performance should not only be geared toward the improvement of VO₂ max, but should increase the lactate threshold and improve running economy.

p/s: will continue about discussion of various training methods…I’m tired
to write..

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Performance goals require much more time, effort, and risk of injury than fitness goals. what are the requirements for optimal performance? in order to answer the question we must ask another.

What kind of performance? it is clear that requirements for the best performance in the 400 meter run are different from those associated with the marathon

Figure below shows a diagram of factors influencing performance

source pic from Exercise Physiology 4th Edition (Powers and Howley)

Every performance requires a certain amount of strength, as well as the ’skill’ to aply that strength in the best way, Further, energy must be supplied in the manner needed or performance will suffer. Different activities require differing amounts of energy from aerobic and anaerobic processes. Both of environment (altitud and heat) and diet (carbohydrate and water intake) play a role in endurance performance. Lastly, best performances require a psycological commitment to ‘go for the gold’

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