OLIVE OILS AND HEALTH 120 physiological approach, a simple distinction can be made between dynamic and static exercise. In the former, muscle contraction is rhythmic with low strength development and usually employs large muscle groups. It is also called resistance or cardiorespiratory exercise and aerobic metabolism (oxygen need) is mainly employed. Aerobic metabolism generates energy (ATP) at low speed over extensive time periods and is, therefore, a key factor in endurance sports. In contrast, during static exercise (increasing tension in a muscle while keeping its length constant) and intense exercise sessions energy is obtained by anaerobic metabolism (without oxygen). Anaerobic metabolic pathways generate energy at high speed although only for short periods because muscular fatigue appears. As a result, they are crucial for sports involving strength and speed (Figure 9.1). A criticalfactor for sport performance is the way muscle obtains energy which is dependent on factors such as blood flow, energetic substrate mobilization, and glycogen muscle storage (glycogen is the way glucose is stored). In summary, metabolism conditions how the muscle works and is the basis for key performance concepts (aerobic capacity, oxygen debt, anaerobic threshold). Figure 9.1. Energy systems for muscle. The muscle uses different systems according to exercise intensity and duration. O2: oxygen. ATP: adenosine triphosphate. ATP Large ATP quantity generated at low speed ATP (and phosphagen system) Low ATP quantity generated at high speed Endurance Power
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