Last Updated24 May 2023

This chapter provides background information on the biomechanics most relevant to skiing. It outlines how the muscles and skeleton function as a system to create the movements of skiing by: describing the planes of movement and how these apply to skiing; describing the key bones, joints and muscles used in skiing; and describing how the body moves as this applies to skiing.

The Spine

The spine is one of the more complex parts of the skeleton. The spinal column provides the main support for the body, giving it strength and enabling a person to stand upright. It is also flexible, allowing the body to bend and twist in several planes while protecting the spinal cord from injury.

The spinal or vertebral column extends from the skull to the pelvis and is made up of 33 individual bones called vertebrae.

The vertebrae are numbered and divided into five regions: seven cervical, twelve thoracic, five lumbar, five sacral and four coccygeal. Only the top 24 vertebrae are movable; those of the sacrum and coccyx are fused. The vertebrae in each region have unique features that help them perform their main functions.

Cervical region – the main function of the cervical spine is to support the weight of the head. The cervical region has the greatest range of motion.

Thoracic region – the main function of the thoracic spine is to protect the organs of the chest by providing attachment for the rib cage. The range of motion in the thoracic spine is limited.

Lumbar region – the main function of the lumbar spine is to bear the weight of the body. These vertebrae are much larger in size due to their weight-bearing function. The lumbar region has the second largest range of motion.

Sacral region – the main function of the sacrum is to provide attachment for the iliac (hip) bones and protect the pelvic organs. The five sacral vertebrae are fused together. Together with the iliac bones, they form a ring called the pelvic girdle.

Coccyx region – the four fused bones of the coccyx or tailbone in conjunction with the two sit bones of the pelvis, function to provide triangular support for the body when sitting.

The range of movement between any two bones of the 24 bones that make up the cervical, thoracic and lumbar regions is very limited. However, when several of the vertebrae are involved, the spine as a unit moves significantly in all three planes of movement.

The spine can flex and extend, moving forward or backward in the sagittal plane, flex and extend laterally moving sideways in the frontal plane, and rotate, twisting left and right in the axial or horizontal plane. The spine can move along the planes of movement in any combination.

Spinal Curves

If the 33 vertebrae of the spine were merely a stack of bones, that structure would not be sound.

The spine has natural curves that form an S-shape. In an upright posture the spine is constantly being pulled forward by the weight of the body. Viewed from the side, the cervical and lumbar regions have a slight concave curve, and the thoracic and sacral regions have a gentle convex curve. The spine’s curves work like a coiled spring to absorb shock, maintain balance and allow the full range of movement throughout the spinal column. These natural curves are maintained by the muscles and connective tissues in the front and back of the torso (the core). Working in unison this results in a strong support and stability for the entire body.

For the spine to serve as the “backbone” of effective movements a skier should employ the strength of the core muscles in the torso. The spine needs to remain aligned in its most biomechanically effective stance to resist strong forces.

While the flexibility of the spine is an asset, it also means the ability to flex, extend and twist may move the spine into a weaker position. That is why a functionally strong core is vital to skiing. When a skier’s core muscles support the vertebrae and stabilise the core, then the limbs can move effectively in opposition to the spine.