Influence of physical exercise after long-lasting hypodynamia on the morphological parameters of muscle fibers.

The purpose of this research was morphometric ultrastructure evaluation of the fibers in muscles taking part in the flight of pigeons forced to exercise after a long period of hypodynamia. It was found that following physical exercise, after 12 and 18 months of mobility limitation, there appeared marked qualitative and quantitative changes: a diminution of the volume fraction and number of mitochondria, increase of smooth sarcoplasmic reticulum and sarcoplasm, and a significant decrease of the number of glycogen granules as compared with those after 18 months hypodynamia. The above described changes were more pronounced in the supracoracoideus than in the pectoralis muscle.