Edited by Dr. Umberto Miletto
Very brief notes on muscle physiology
Thanks to ATP, it is possible to perform any physiological activity, including muscle contraction.
Food oxidation - Energy - ATP - physiological work (muscle contraction)
ATP, adenosine triphosphate, is the chemical form with which energy is stored in all muscle cells, only through its demolition is it possible to obtain the energy with which the cells can perform their own specialized work.
ATP can be simplified, into a very complex component, adenosine, and into three less complicated parts called phosphate groups.
Structure of the ATP
ADENOSINE --- P --- P --- P
The bond existing between the two terminal phosphate groups is a highly energetic bond whose breakdown or hydrolysis releases energy (from 7 to 12 kilocalories) that can be readily used by the muscle cell to perform its work.
ATP <→ ADP + Pi + ENERGY
The process of cleavage of ATP is a reversible reaction and allows the restoration of the original molecule.
The stocks of ATP in muscle cells are very limited and must be continuously regenerated to ensure that our body can work for prolonged times.
"The" ATP stored in your muscles is the only fuel immediately available to give you energy, therefore the only fuel capable of generating one hundred percent maximal contraction.
You can store enough ATP for about 4-5 seconds of maximal contraction, enough to squat one repetition, throw a javelin, or run 50 meters. As 100m sprinters know, maximum muscle contraction cannot be maintained for more than 5 seconds, or so. After that the goal is to lose as little speed as possible until you are over the "finish" line. (Colgan, 2003)
After 4-5 seconds of maximal exercise it is possible to continue with an almost maximal contraction thanks to creatine-phosphate (CP). By adding the energy available with the stored ATP and the CP it is possible to carry out an effort at maximum intensity for a total of about 10-11 seconds, the time to perform 3-4 maximum repetitions or run 100 meters at maximum speed. . This energy production system is called the phosphate system or alactacid anaerobic system, uses ATP / CP stored in the muscles and does not use glycogen, glucose, fatty acids and amino acids.
"At the end of a muscle contraction, almost all of the free creatine and free phosphate molecules residing in the muscle come together again to generate creatine phosphate.
This process requires oxygen: so you have to stop anaerobic exercise to allow this to happen. During recovery half of the "off" creatine is regenerated into creatine-phosphate in 60 seconds; approximately 90% is regenerated over a period of 5 minutes The remaining 10% is eliminated by the muscles and appears, as a waste product, creatinine, in the urine.
This biochemical activity is critical to building muscle and strength because it tells you exactly how long to rest between sets for maximum growth.
Creatine-phosphate is the only means to regenerate the ADP spent in ATP and to allow the almost maximal muscle contraction to continue beyond 4-5 seconds. So you can understand the importance of having a creatine-phosphate load in every muscle.
Oral supplements with creatine increase muscle creatine and "strenuous exercise increases creatine use by approximately 50%" (Colgan, 2003).
The biochemistry of creatine only tells us what we might expect from supplementation.
In a recent study, Conrad Earnest and colleagues at Southwestern Texas Medical Center and the Cooper Clinic in Dallas gave advanced weightlifters 20 grams of creatine per day for 28 days. They measured performance with the 1 RM bench press. The mean weight gain was 8 kg, the improvement in potency by 6.5%.
Thanks to the use of creatine it is possible to prolong maximal exercise for longer, so as to allow harder workouts and create faster muscle growth processes.
In the overexposed strength study, Earnest found that reps on average at 70% of 1RM increased from 11 to 15.
Colgan identifies in the low repetitions the best training with overloads to generate muscle strength and hypertrophic increase. The more muscle overload is increased, the more conditioning muscle growth is stimulated. Over the span of a month Balsom recorded gains in lean mass of about 0.3 to 2 kg with an average of 1 kg. Conrad Earnest found even greater growth in his studies: after 28 days of 20 grams of creatine per day, his subjects had an average increase in lean mass of 1.6 kg.
Creatine Monohydrate is definitely one of the best supplements for muscle and strength gain.
High level and very experienced athletes, with four 8-week cycles per year, separated by 4-week rests, show an increase in strength in squat MRI of 15-20% more.
Some studies have shown that a single week of creatine monohydrate (20 g per day for 5 days) increases jumping power by 7-12% and running speed by 13% (Bosco, 1997).
How much creatine to take?
