Flexibility

Flexibility is a component of physical fitness traditionally related to the range of motion available at a joint or group of joints. It depends particularly on the properties of muscles and other soft tissues surrounding the joint. Flexibility is highly specific to individual joints and movements, so being flexible at one joint does not necessarily imply similar flexibility elsewhere in the body .^1,2

The range of motion available at a joint is influenced by several factors. These include the extensibility and stiffness of muscles and other soft tissues, as well as joint structure and neural factors involved in controlling or tolerating movement. For this reason, flexibility is closely related to range of motion, but the two terms are not necessarily identical .^1,2

Terminology varies across exercise science. Flexibility has traditionally been defined in terms of the range of motion available at a joint. A more specific recent usage defines flexibility in terms of the extensibility of the soft tissues around a joint, treating it as one factor that contributes to overall range of motion. Under this distinction, range of motion is broader because it can also be influenced by factors such as bone and joint anatomy that flexibility training cannot substantially change .²

Flexibility is also distinct from stretching. Flexibility describes a physical characteristic or capacity, whereas stretching is an activity that can be used to influence flexibility and joint range of motion .^1,2