Adenosine triphosphate (ATP) is the source of energy for all contractile muscles.
Energy is released when ATP breaks down into ADP + P (adenosine diphosphate and phosphorus). Maintaining the availability of energy from ATP for muscle is limited until all stores stored in skeletal muscle are exhausted. ATP reconstitution can be derived anaerobically (anaerobically) or aerobic (aerobic). The basic source of energy will therefore depend on the degree of muscle contraction.
The main sources of ATP in anaerobic processes are Phosphocreatine and glycolysis. Intramuscular phosphocreatine is used for quick and strong contractions but it lasts for less than 30 seconds and the restoration takes a few minutes. For example, phosphocreatine provides most of the energy for the sprint run at 100m. In addition, the ability to repeat contractions at the workplace is largely dependent on phosphocreatine sources. Creatine supplementation increases the concentration of phosphocreatine, which translates into better effectiveness of the work performed (according to the translation it would be possible to influence it, but we know that it affects).
Anaerobic glycolysis refers to the breakdown of glucose (glycolysis) to pyruvate, which in the absence of oxygen is converted to lactic acid. In muscle fibers, glucose is obtained from the breakdown of muscle glycogen. Anaerobic glycolysis is not dependent on the availability of glycogen; but, from the accumulation of lactic acid and other metabolic products. A high intensity of effort lasting 1-3 minutes (eg running at 800m) depends mainly on anaerobic glycolysis, causing the accumulation of lactic acid in large quantities.
Oxygen glycolysis occurs when oxygen is available for the breakdown of pyruvate, which is broken down by ATP in a chemical reaction occurring in the Krebs Cycle and in the Electric Transport System. As with anaerobic metabolism, glucose can be obtained from muscle glycogen. The source of glycogen is abundant, so exhaustion should only be feared by athletes whose efforts last more than 90 minutes or do exercises, interrupting them for a much longer time. For example, it is not unusual for athletes to end up using glycogen stores. In marathon runs, it means something like “hitting the walls. In order to reduce the risk of running out of glycogen stores during a marathon, athletes often “load carbohydrates” by the event. This includes manipulating the carbohydrate content of the diet to fully fill the glycogen source.
The most abundant source of energy available for muscle fibers is fat. The formation of ATP from the decay of fat is called lipolysis. When the supply of fatty acids is essentially inexhaustible, the lipolysis index that is present is the factor limiting the generation of ATP. Lipolysis is responsible for muscle nourishment at rest, but the contribution to supplying the total muscle energy will decrease as the strength of the muscle contraction increases. For example, glycogen depletion occurs when the lipolysis index is unable to meet muscle demand by the requirements of the exercise being performed and when glycolysis can not be obtained from glycolysis. After glycogen depletion, the intensity of the exercise is dramatically reduced. Nevertheless, a slight reduction in intensity (eg slower pace) in the early part of the exercise would prevent glycogen from running out. In order, the importance of facilitating lipolysis during endurance runs can not be exaggerated.
Adaptation for strength training
`Specific training that determines adaptation
`Strength training is under the nervous, biomechanical and physiological factors
Adaptation of the nervous system
`increased acquisition of new movement units
`reduced containment of movement units
`increased coordination of the nervous system
`Increase in fibril size due to hypertrophy (1 *) and hyperplasia (2 *)
`An increase in the size of both types of nerve fibers with a larger increase in type 2 fibrils
The (Olympic) strength training of squeezers can move certain amounts of myosin towards FTb fibers
`Bodybuilding training can move certain amounts of myosin towards ST-type fibers
`A higher level of testosterone in men partially explains the greater musculature
Comparison of strength in men and women
`There is a similar increase in strength in both sexes during short training sessions
`Men have greater total strength than women because they have more muscle mass
`Comparing strength with respect to a kilogram based on dry body weight, men are a little stronger in the upper body and women equal their strength in the lower parts
Exercises – inducing damage and muscle pains
Eccentric motion, generates the same strength as concentric motion, using fewer motor units as myofibrils develop greater intensity during elongation than shortening. Therefore, the intensity on the fiber is greater during eccentric movements.
They do not get used to exercise, mainly eccentric, in order
`initiation of inflammatory reactions and
`cause so-called DOMS – delayed-onsed muscular damage (Delayed skeletal muscle soreness)
The order in the exercises – causing damage and muscle pains
1. During exercise
`mechanical factors (eg high stress) cause
– sarcolemma damage
– damage to the sarcoplasmic reticulum
– myofibril damage
`metabolic factors that cause damage come from
– free radical production
– too high temperature
– pH drop
2. 0-3 days after the exercises
The inflow of Ca2 + from the sarcoplasmic reticulum and from the outside of myoblasts initiates many inflammatory reactions
`The production of phagocytic cells (eg monocytes, white blood cells) to remove damage and repair damaged tissue
`Myofibril damage lasts up to 3 days after training …
Ps. Damage to myofibrils lasts longer, point 2 includes reactions up to 3 days after training.
You can read also: Creatine – ATP and anabolism