Stretching exercises aim at improving flexibility of the entire body. Flexibility is a capability of realizing maximum range of motion. The goal should be optimal (not maximal) range of movement. Range of movement depends on the built of the joints, respective bones, as well as on flexibility of ligaments, tendons and muscles.
By stretching during the warm-up phase, we prepare muscles and joints for the upcoming effort. By stretching at the end of the training, we relax muscles and joints and enhance post-training recovery. Large numbers of top athletes dedicate full training sessions to stretching. As we age, flexibility diminishes. To maintain flexibility, it is important to constantly maintain it.