Age and sex are two important factors in flexibility. Both are uncontrollable factors. Figure 1 illustrates how age affects flexibility. Flexibility is high in children, but it decreases as people become older.
One reason for the age-related decline in flexibility is maturation. Maturation causes changes in anatomical structure (e.g., ligaments, muscles, bones, and tendons) that reduce our range of motion. In children, girls are more flexible than boys because of anatomical differences, but over time the differences in flexibility between men and women become smaller. While age and sex are uncontrollable factors that affect flexibility, the decline in flexibility with age is also related to a controllable factor: lack of use! The decrease in range of motion that we see throughout the life span are also due to lack of use. A regular stretching routine can help everyone maintain a healthy level of flexibility.
