Muscle weakness

Fatigue is a usually temporary ( reversible) reduction of physical and / or mental performance. It can be used as a subjective perception which occurs for example due to lack of sleep, as well as objective measures of fatigue, for example, as a result of physical stress, occur. A distinction between the mental fatigue of the central nervous system (CNS ) and the peripheral, physical fatigue of the muscles.

Physical fatigue

The peripheral or physical ( bodily ) Fatigue is the reduced force of one or more muscles in comparison to the otherwise expected, depending on the individual physical strength performance. It occurs mainly at a local stress and a poor physical condition. The reduced performance is reversible and can be partially compensated for by an increased use.

Mental fatigue

The central (CNS ) or psychological (mental ) fatigue can occur regardless of the muscular fatigue and shows up mostly by subjective sensations and a visible deterioration of motor coordination. It occurs especially when intricate and complex stresses. The reduction in performance is here Follow a disturbed central nervous control. A central position is occupied by the reticular formation, an area of the brain that inhibits the other motor systems of the central nervous system. The inhibitory processes affect, among other things in an impairment of recorded information ( sensory perception) and a slower forwarding of information and information processing. In the toleration of stress is psychologically a coping process.

Symptoms

From a sports medicine perspective can be observed in fatigue subjective and objective symptoms, which are used for an assessment or evaluation of the degree of fatigue. The correlation between the subjective complaints of fatigue and the objectively verifiable data is low and depend heavily on the state of training and the athletic experience of the person concerned from. To an untrained person is psychologically less workload tolerate than as a competitive athlete.

Subjective

• Feeling of exhaustion
• Flickering
• Ringing in the ears ( tinnitus)
• Shortness of breath (dyspnea )
• Nausea (feeling sick)
• Fatigue
• Apathy ( apathy ) to external stimuli
• Muscle pain ( myalgia)

Lenses

• Declining muscle strength
• Prolonged refractory
• Rising Threshold
• Decreased reflex responses
• Muscle trembling ( tremor)
• Incoordination
• Electrolyte shifts, increase in lactate, pH changes, Glykogenverarmung, hormone levels decrease
• Changes in brain wave activity (EEG )
• Concentration and attention impairment, deterioration of perception

Causes

Possible causes fatigue, especially with regard to endurance training are:

• Depletion of energy reserves ( creatine phosphate, glycogen)
• Accumulation of metabolic intermediates and end substances (lactate, urea )
• Enzyme inhibition by acidification or changes in concentration of the enzymes
• Electrolyte imbalance (potassium and calcium at the cell membrane )
• Depletion of hormones in constantly heavy load ( adrenaline and noradrenaline as a neurotransmitter, dopamine in the central nervous system )
• Changes in cell organelles ( mitochondria and the nucleus )
• Inhibitory processes in the central nervous system due to monotonic loads ( excessive demands by lower demand )
• Regulatory changes in the cellular area at the level of individual organ systems with respect to the integrated control center

Fatigue as a protective mechanism

As a normal regeneration phenomenon applies fatigue as a physiological protective mechanism for the maintenance of homeostasis and is called acute fatigue.

Fatigue resistance

Fatigue processes can be more or less compensated for a certain period. The so-called fatigue resistance is influenced by the following factors, some of which are particularly the state of training and motivation of importance:

• Initial position ( training status, age, health, gender)
• The previous load ( duration, intensity, type of training )
• Adjustment of athletes to load ( motivation, interest )
• Psychological resilience