Sports Nutrition Bible

[ono]

Creatine

So i talked about Phosphocreatine earlier on. I explained that PC consisted of a phosphagen molecule and creatine. So,although most of you have probably supplemented or at least heard of creatine, i'd like to give you a brief breakdown of what the compound actually is.

So....What is Creatine?

It's basically a compound that's made naturally in our bodies to supply energy. It's mainly produced in the liver from 3 amino acids:- glycine, arginine and methionine. From the liver it's transported in the blood to the muscle cells where it is combined with phosphate to make phosphocreatine. Just like magic.

The muscle cells turn over around 2-3g of creatine a day. Once PC is broken down into ATP (energy, remember) it can be recycled into PC or converted into a naother substance called creatinine, which is then removed via the kidney in the urine (pee )

Creatine is typically obtained (in diet) from beef, fish and pork. The typical person stores around 120g of creatine. 60-70% is stored as PC while the remainder is sotred as free creatine.

Supplementation

While i'm on the subject, i might aswell go into the supplementation of creatine. I'm sure most of you have tried creatine monohydrate before, or CEE maybe...Probably with decent results.

The most common course of action is to saturate your muscles with a loading phase of creatine, followed by a maintenance phase. This method is effective, but it's not actually the best way of doing things. In fact it's quite a costly way of getting creatine into your muscles.

What should i do then?

Seen as though around two-thirds of this creatine (20g per day) actually ends up in your urine (wee) with only the remaining one-third ending up in your muscle cells.

To reape maximum benefits of creatine supplementation, a better idea would be to take smaller doses spaced throughout the day. The key is to try to slow down the absorption from the gut. This gives the maximum chance of all the creatine ending up in your muscle cells and not in your urine. To do this, try taking only 6g daily (instead of the 20g - for the loading phase), but instead of consuming it at once, in shake format, sprinkle it on your food. Sprinkle 1g at a time over the course of 6 meals which would give you a total of 6g per day. This will actually produce effects equivalent to taking 20g a day. After that, maintenance should only be 2g per day.

Not only will this method save you money, it will also produce less water retention which can only be a good thing. This loading strategy can be repeated every 8-12 weeks.

Cycle length

The maximum effectiveness, it's proposed that creatine is best taken is cycles lasting 3-5 months, followed by one month off cycle.

[ono]

Lactic Acid - The Lactic Acid Shuttle

Contrary to popular belief, lactic acid produced by the muscles is not a wasted by-product. Infact it constitutes a valuable fuel (once exercise intensity is reduced).

Once intensity is reduced or stopped completely, lactic acid has two possible fates. Some may be converted into pyruvic acid, when then can be broken down into ATP (in the presence of oxygen). So basically lactic acid produces ATP and can be a valuable fuel for aerobic exercise.

The other fate is....

lactic acid may carried away from the muscle (in the bloodstream) to the liver where it can be converted back into glucose, released back into the bloodstream or stored as gylcogen in the liver. This mechanism for removing lactic acid from the muscle is called the lactic acid shuttle

This also explains why the muscle soreness brought on by hard training is not due to lactic acid. In fact, the lactic acid is usually cleared within 15 minutes of exercise.

[ono]

When i initially started this thread i was originally going to dive straight in at the deep end and explain the importance of carbohydrates, protein and fat. In the end i decided to give my best explanation of how the body's energy system works. This hopefully will give you a better understanding of why nutrients are important.

So now i think i have pretty much covered everything i wanted to go through so i'll move on to talk about carbohydrates. I get a feeling this chapter is going to be quite long so i'll try complete it in stages...

to be continued......

[Salty]

I think you've got the lactate shuttle a little wrong mate, the way I understood it worked was...

1. Pyruvate (pyruvic acid) is formed when glycogen and glucose are being broken down at high rates in your muscles (called glycolysis which is the conversion of these into pyruvate). Pyruvate is then converted to Lactate (lactic acid) as it increases in the muscles.
2. Lactate is now formed and transported away from the muscle cells into surrounding tissue and blood. This allows glycolysis to persist and thus continuing the supply of energy to our muscles.
3. The muscle cells which the lactate is transported to can cause the lactate to be broken down to fuel (mainly ATP) or can be used to build glycogen.

[ono]

Yeah sorry i missed out how pyruvic acid accumulates. Anyways i'll give it a go...

When pyruvic acid accumulates in our muscles (which normally occurs after a slight increase in exercise intensity) lactic dehydrogenase(spelling) converts it into lactate. Under moderate-to-high exercise intensity, lactate is converted back to pyruvic acid, which then can be broken into ATP (in the presence of oxygen, of course).

As far as i am aware, pyruvic acid does convert to lactate, but lactate can also be converted back into pyruvic acid.

I hope that explains it a little better...i was rushed for time trying to finish the chapter before my dinner ended at work :-)

[ono]

Carbohydrates

In a an age where low carb-high protein diets are 'the shit' one can be forgiven for not realising that carbohydrates play an essential part in everyday nutrition. The scary thing is, they play an even more important part in sports nutrition.

I say scary because an awful lot of fitness magazines give you allsorts of crazy advice about carbohydrates...

'don't eat fruit, it's full of sugar'

'carbs before bed will make you fat'

In this chapter i'm going to try to explain the importance of carbohydrate. I'm going to try to explain proper glycogen replenishment and why it's vitally importance. I'm going to go into 'carb loading'

I'm also going to go into the GI index, as well as touch upon pre and post exercise carbohydrate.

Finally i'll explain how to work out, how much carbohydrate you need for your particular sport while hopefully dispelling a few myths along the way.

to be continued....


ps, my pc isn't available for me to use at home so this thread may be slow for a few days. Please be patient

[yvonne]

Some really good stuff there me freind.I'll be keeping tuned in!

[Trainer Monkey]

I think you've got the lactate shuttle a little wrong mate, the way I understood it worked was...

1. Pyruvate (pyruvic acid) is formed when glycogen and glucose are being broken down at high rates in your muscles (called glycolysis which is the conversion of these into pyruvate). Pyruvate is then converted to Lactate (lactic acid) as it increases in the muscles.
2. Lactate is now formed and transported away from the muscle cells into surrounding tissue and blood. This allows glycolysis to persist and thus continuing the supply of energy to our muscles.
3. The muscle cells which the lactate is transported to can cause the lactate to be broken down to fuel (mainly ATP) or can be used to build glycogen.

Everything Ive read says its Hydrogen,but keep in mind,those findings were only published a couple of years ago

[ono]

Post Exercise - carbohydrates



Glycogen Depletion

Intensive training severley depletes your body's glycogen stores. Just how much they're depleted depends very much on the intensity of the training session/event and the duration of it. Another factor that comes into it is - how full your glycogen stores were before exercise. For example, if you commenced training without adequately refuelling from the previous days exercise, you will reach glycogen depletion much more rapidly - as would a car that was running on half a fuel tank, as opposed to a car running on a full on. Simple.

The higher the intensity, the more glycogen you use. For example, explosive activities such as sprints, jumps or lifts and high intensity activities such as running will deplete glycogen stores much more quickly than low intensity exercise would.

The duration also has a bearing on how much glycogen is used. For example you would use more more glycogen running for one hour than you would if you ran at the same pace for only half an hour.

[ono]

Glycogen Replenishment and Muscle Damage

Certain activities which involve eccentric movements (heavy weight training, plyometrics or hard running) can cause muscle fibre damage. Muscle damage delays glycogen replenishment, so complete glycogen replenishment can take as long as 7-10 (when there is muscle damage).

Without muscle damage, glycogen replenishment takes around 20-22 hours provided you have an adequate nutrition plan

[Salty]

I think you've got the lactate shuttle a little wrong mate, the way I understood it worked was...

1. Pyruvate (pyruvic acid) is formed when glycogen and glucose are being broken down at high rates in your muscles (called glycolysis which is the conversion of these into pyruvate). Pyruvate is then converted to Lactate (lactic acid) as it increases in the muscles.
2. Lactate is now formed and transported away from the muscle cells into surrounding tissue and blood. This allows glycolysis to persist and thus continuing the supply of energy to our muscles.
3. The muscle cells which the lactate is transported to can cause the lactate to be broken down to fuel (mainly ATP) or can be used to build glycogen.

Everything Ive read says its Hydrogen,but keep in mind,those findings were only published a couple of years ago

You are right, although the definition of an acid is that it is a H+ donator. The strength of an acid is how easily it gives up a H+ ion, the stronger they are the more ions they give up. I think what you have read may be in regards to muscle failure where there is a drop in pH? Although I have read articles which say where the lactate is distributed depends on the concentration of the H+ however can't really remember too much.

[ono]

Carbohydrate Loading

For those that don't know, carbohydrate loading is a technique devised in the 1960's to increase the muscles' glycogen stores above normal levels. The idea behind it being...the more glycogen you have available, the longer and harder you can exercise. This is potentially advantageous in endurance events lasting longer than 90 minutes and events which involve multiple heats or several short matches.

It is unlikely to benefit you if your event lasts less than 90 minutes as muscle gylcogen depletion would not be a limiting factor to your performance.

It is believed that carbohydrate loading increases time to exhaustion by around 20% and improves performance by 2-3%.

The classical 6 day regimen involved 2 bouts of of glycogen depleting exercise seperated by 3 days of low carbohydrate intake and followed by 3 days of high carbohydrate intake and minimal exercise.

The theory behind this 2 phase regimen is that glycogen depletion stimulates the activity of glycogen synthetase, the key enzyme involved in glycogen storage...resulting in above normal levels of muscle gylcogen.


Drawbacks

Not only did it interfere with exercise tapering, but the low carbohydrate diets left the athletes feeling rather shitty - weak, tired etc...

Add that to the fact that a lot of athletes never ended up achieving above normal glycogen levels. So the object was defeated really.

The correct way

The carbohydrate depletion stage isn't really required. It does more damage than good generally. A better way of loading would be to taper training on 6 consecutive days while following a normal diet during the first 3, followed by a carbohydrate rich diet during the next 3. That would leave you going into competition with above normal levels of muscle glycogen.

A clever way

You can also reach the same state of glycogen saturation by following this protocal...

High levels of glycogen can be achieved by taking in 10g of carbohydrate/1kg of bodyweight over the course of a single day, following a 3 minute bout of high intensity exercise. The rate of glycogen storage is greatly increased after such a workout. The advantage of this regimen is that only 1 day is required instead of 6, and very little change to our usual programme needs to be made.