Biochemical Foundations of Human Vital Activity - Volkov, N.I., Nesen, E.N. 2000

Biochemistry of Sports
Biochemical Characteristics of Recovery Processes During Muscular Activity
Dynamics of Biochemical Recovery Processes After Muscular Work

During the post-exercise recovery period, the biochemical changes that occurred in the Muscles and other Organs during physical activity are gradually eliminated. The most pronounced changes are observed in METABOLISM/26.html">Energy Metabolism. During exercise, the content of energy substrates (PCr, Glycogen, and Lipids during prolonged exertion) decreases in muscles and other Tissues, while the concentration of intracellular metabolic products (ADP, AMP, H₃PO₄, lactic acid, Ketone Bodies, etc.) increases. The accumulation of "working" metabolic products and heightened hormonal activity stimulate oxidative processes in tissues during the post-exercise rest period, which facilitates the restoration of intramuscular energy stores, normalizes the body's Water-electrolyte balance, and ensures the inductive synthesis of Proteins in the organs subjected to the load.

As shown in Table 31, recovery processes during the post-exercise period proceed at varying rates and conclude at different times (The phenomenon of heterochronism). The O₂ and PCr reserves in the working muscles are restored the fastest, followed by intramuscular and Liver glycogen stores, and lastly, fat reserves and protein structures damaged during exercise.

The intensity of recovery processes and the timeframe for replenishing the body's energy stores depend on the extent of their depletion during exercise (Engelhardt's rule). The intensification of recovery processes leads to a point during rest where the reserves of energy substances exceed their pre-exercise levels. This phenomenon is termed supercompensation, or over-recovery (Fig. 156).

This phenomenon is transient: following the phase of a significant overshoot above baseline, the concentration of energy substances gradually returns to normal. The greater the Energy Expenditure during work, the faster the resynthesis of energy substances occurs and the more pronounced the overshoot in the supercompensation phase. It should be noted, however, that this rule applies only within certain limits. During excessively intense exercise associated with very high energy expenditure and the accumulation of breakdown products, The rate of recovery processes may decrease, and the supercompensation phase will be achieved later and to a lesser degree.

Class="center">TABLE 31 Time required to complete the recovery of biochemical processes during the post-exercise rest period after strenuous muscular work

The duration of the supercompensation phase depends on the overall duration of the work performed and the depth of the biochemical shifts it induces in the body. Following powerful, short-duration exercise, this phase occurs rapidly and concludes just as quickly. For example, during the restoration of intramuscular PCr stores, it is already detectable by the 3rd to 4th minute of rest and concludes 1.5–2 hours after the exercise ends; ATP restoration occurs even faster because it is powered by aerobic metabolism energy (Fig. 157). During prolonged exercises, when pronounced acidosis occurs due to enhanced Glycolysis in working muscles, PCr supercompensation only manifests 12 minutes after the end of exercise and persists for several hours (Fig. 158). The causes of supercompensation are related to an increase in the concentration of anabolic Hormones during post-exercise rest and their Induction of the synthesis of enzyme proteins that regulate the restoration of energy resources in skeletal muscles.

Fig. 156 Supercompensation during the recovery of energy resources in the post-exercise period following exhausting work:

1 — exhaustion phase; 2 — recovery phase; 3 — over-recovery phase; 4 — lost-state phase

Fig. 157 Restoration of intramuscular PCr stores after short-term high-intensity exercise

Fig. 158 Restoration of intramuscular PCr stores after short-term (1) and prolonged (2) high-intensity exercises accompanied by The Development of pronounced acidosis in working muscles: a, b — respectively, pH and intramuscular PCr concentration during the recovery period in highly qualified athletes