Core stability refers to a person's ability to stabilise their core. Stability, in this context, should be considered as an ability to control the position and movement of the core. Thus, if a person has greater core stability, they have a greater level of control over the position and movement of this area of their body. The body's core is frequently involved in aiding other movements of the body, such as the limbs, and it is considered that by improving core stability a person's ability to perform these other movements may also be improved i.e. core stability training may help improve someone's running ability. The bodies core region is sometimes referred to as the torso or the trunk, although there are some differences in the muscles identified as constituting them. The major muscles involved in core stability include the pelvic floor muscles, transversus abdominis, multifidus, internal and external obliques, rectus abdominis, erector spinae (sacrospinalis) especially the longissimus thoracis, and the diaphragm. The minor muscles involved include the latissimus dorsi, gluteus maximus, and trapezius. Notably, breathing, including the action of the diaphragm, can significantly influence the posture and movement of the core; this is especially apparent in regard to extreme ranges of inhalation and exhalation. On this basis, how a person is breathing may influence their ability to control their core.
Some researchers have argued that the generation of intra-abdominal pressure, caused by the activation of the core muscles and especially the transversus abdominis, may serve to lend support to the lumbar spine.
Typically, the core is associated with the body's center of gravity, which is over the region of the second sacral vertebrae groups and stability is associated with isometric or static strength. In addition, it is the lumbar spine that is primarily responsible for posture and stability thus providing the strength needed for the stability especially utilized in dynamic sports.