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

Biochemistry of Sports
Patterns of Biochemical Adaptation in Sports Training
Sequence of Adaptive Changes During Training

Adaptive changes in individual Organs and their Functions, observed in response to applied forms of interval training, occur heterochronously—that is, asynchronously, at varying rates and with different degrees of intensity. The phenomenon of heterochronism in adaptive restructuring within the body is clearly evident in the indicators of both acute and cumulative training effects.

As noted above, in METABOLISM/26.html">Energy Metabolism, the most pronounced and rapid changes during interval loads occur in the alactacid anaerobic process (ATP + PCr), followed by Glycolysis, and lastly in aerobic metabolism processes. During the recovery period following the completion of a workout, intramuscular PCr content is the first to reach supercompensation, followed by Glycogen and fat levels, and finally the Proteins that perform catalytic functions and form the Subcellular structures of Muscle fibers. Given this, by adjusting the duration of the recovery period between repeated loads, one can selectively target a specific aspect of muscle metabolism and, consequently, The Development of certain physical qualities.

This is even more pronounced during the accumulation of training effects. In this case, at the initial stages, the development of adaptive Changes in the body in response to systematic physical loads occurs through the improvement of bioenergetic power indicators, followed by bioenergetic capacity indicators, and only at The final stage of adaptation through the enhancement of bioenergetic efficiency. Deadaptation following the cessation of training develops in reverse order: indicators of bioenergetic efficiency decline first, followed by bioenergetic capacity, and lastly, bioenergetic power.

The adaptation of individual bioenergetic systems of the body during training also occurs asynchronously: the capacities of the aerobic energy production system and the glycogen content in working Muscles increase most rapidly, followed by the capacity and intensity of the anaerobic glycolytic process, and lastly by the creatine phosphate content and creatine phosphate kinase activity in muscles. Following the cessation of training during the period of deadaptation, creatine phosphate content returns to baseline first, followed by the intensity of glycolysis and glycogen content in working muscles, and finally, the capacities for aerobic ATP resynthesis decline.

Thus, as evidenced by biochemical research, during the training process, bioenergetic indicators characterizing endurance for prolonged work—namely, an athlete's aerobic capacity—exhibit the highest rates of development and maintain a maximally high level for the longest duration. Bioenergetic indicators characterizing speed-strength qualities and speed endurance develop significantly slower and are maintained at a peak level for a much shorter time.

In sports practice, the patterns of sequential adaptation induced by interval training are clearly traceable in The Structure of seasonal preparation. In the preparatory phase of training, especially at its early stages, the bulk of the training volume is performed in the mode of interval and continuous long-duration work aimed at developing the athlete's aerobic capabilities. Once the required level of aerobic qualities is achieved (typically taking 1.5–3.0 months of preparation), the volume of applied training means is reduced to a minimum, while simultaneously, in the pre-competition period, There is a sharp increase in The Use of training Methods that promote the development of speed-strength qualities and the anaerobic component of the athlete's special endurance.