Adaptations to endurance training
Different level of physical adaptations to regular endurance training
Level I: movement optimization
The main symptom of this adaptation level is a decrease of heart rate at a given workload. Reason for this first physiologic adaptation is an improvement of co-ordination and control of movement performed. Dispensable movements are reduced, making it more economic.
Level II: Energy storage
At level II gylcogen storage is increased. Glycogen (=animal starch) serves as storage form of glucose (sugar) within our organism, an important energy reserve of muscle cells (circ. 300g). Increased muscle glycogen storage enables the athlete to sustain high intensive workouts.
Level III: System optimization
Due to an improved collaboration of different body parts and their adaptations to chronically increased requirements the athlete reaches the next level of performance.
Level IV: central support
At the fourth level, the local muscular adaptations are supported by hormonal (adrenalin, noradrenalin, cortisol) and autonomic changes.
(Neumann, Pfützner, Berbalk, 2007)