Isometric contraction is a class of contraction where the muscle maintains a constant length as tension is produced, thereby the length of the muscles does not change during this process. Isometric contractions are performed without joint motion. They are appropriate for the rehabilitation of musculotendinous traumas due the muscle maintains a static position and contraction intensity can be controlled. This type of contraction is common for the muscles in the hands and arms.
I think TRUE Humans alteration of the global environment has triggered the sixth major extinction event in the history of life and caused widespread changes in the global distribution of organisms.