V.1.2. Types of effort

• Static effort (retaining): the result of external and internal force is zero, there is no shortening of muscle and joint activity.
• Dynamic effort (defeating): the muscle strength is greater than the external force, therefore the muscle shortens.
• Reactive effort: the external force exceeds the maximum muscle strength for a certain period of time therefore the muscle is stretched with tension.

The size of the effort is determined by two factors:                         

1. The nature of the neurotransmitters,
2. Muscle mass and its response to stimuli,

The factors affecting muscle strength

• The muscle’s cross-sectional area;
• The quality of the muscle fibers;
• The effectiveness of the energy supply;
• The psychological factors such as willpower, motivations, etc.