Movement analysis is the systematic study of human motion, focusing on how muscles, bones, and joints interact to produce specific actions. To analyse movement accurately, the body is mapped using three imaginary geometric planes and three corresponding axes of rotation. Every dynamic sporting action occurs within these planes and rotates around these axes, providing a standardised framework for sports scientists and coaches to break down technique, maximise mechanical efficiency, and reduce the risk of injury.
The sagittal plane divides the body vertically into left and right halves. Movements within this plane involve forward and backward motions. The primary joint actions seen here are flexion, which decreases the angle at a joint, and extension, which increases it. For example, a bicep curl, a running stride, and a front flip all take place in the sagittal plane. Any movement in the sagittal plane rotates around the frontal axis, which runs horizontally from hip to hip. When a gymnast performs a forward roll, their entire body rotates forward through the sagittal plane around this transverse hip-to-hip axis.
The frontal plane divides the body into front and back halves. Movements in this plane are lateral, or side-to-side. The key joint actions are abduction, which moves a limb away from the midline of the body, and adduction, which pulls a limb back toward the midline. Examples include a gymnast performing a cartwheel, a star jump, or a defender sliding sideways to block a pass. Movements within the frontal plane rotate around the sagittal axis, which passes horizontally through the body from front to back, like an arrow through the belly button. During a cartwheel, the body tilts sideways around this front-to-back axis.
The transverse plane divides the body into top and bottom halves, cutting horizontally across the midsection. Movements in this plane are rotational or twisting actions. Joint actions include internal and external rotation, as well as horizontal flexion and extension, such as the swinging motion of a bat. A figure skater spinning on ice, a discus thrower rotating in the circle, or a golfer twisting their torso during a swing all operate in the transverse plane. These rotational movements occur around the vertical axis, which runs straight down through the body from head to toe, acting as the central pivot line for the twist.
To complete a movement analysis, these planes and axes are combined with the concept of levers. The human skeletal system functions as a system of levers, where bones act as levers, joints act as fulcrums, muscles provide the effort, and the body weight or equipment acts as the load. The body utilises first, second, and third-class levers to balance force and speed. For instance, the calf raised push-off in running functions as a second-class lever, prioritising force to lift the body, while the bicep curl operates as a third-class lever, maximising speed and range of motion. By combining planes, axes, and levers, sports professionals can fully deconstruct any athletic skill.
