Basic Axis of Movement

‘X’ axis (coronal axis) describes pitch rotation and lateral motion.

‘Y’ axis (sagittal axis) describes roll rotation and anterior & posterior motion.

‘Z’ axis (vertical axis) describes upward and downward motion

In any given movement (eg walking), the body is moving through each axis in varying proportions simultaneously.

Note:

Therefore a lower limb ‘biomechanics’ assessment without taking into account whole body movement is a ridiculous concept and completely unreliable. It is not a biomechanics assessment at all, but merely some form of professional guess work at best.

Laws of Motion

Inertia the resistance of the body to change its state of motion. This becomes important when examining the forces to change the state of motion (eg. tackled by an opponent & wind direction). The weights held by the lifter in the diagram below is in a state of inertia, until force due to muscle contraction results in a push upward changing its state of motion.

Acceleration is comprised of the relationships of: force, mass and acceleration, which in-turn is linked to momentum.

Action & Reaction the factor of force working in pairs. The term every action, has an equal and opposite reaction is not exactly true. Eg. When you land from a jump, you exert a force onto the ground on which you land...BUT the force returning up your body is not equal but greater, because the earth beneath you is far larger and heavier. Therefore, optimizing the appropriate resistive muscle groups, and utility of correct techniques and equipment become pertinent points for consideration. Inertia

The essential co-factors – for efficient motion & performance

 Balance & Stability

 Translation of gravity

 Mass

 Energetics (force production and translation)

Balance & Stability

This has a direct effect on each individual's motion pattern and ability to perform. Balance and stability is an essential asset for high-performance athletes across every sporting discipline. It is pertinent for control, where the loss of control can affect factors such as force production, endurance and accuracy.

Components of balance & stability are:

 posture

 base of support

 static balance

 dynamic balance

In my opinion balance and stability conditioning must come before strengthening.

Consider this: from greatest buildings, ships, supercars, airplanes and rockets, the lack of stability will be disastrous regardless of their magnitude and power. Effective human motion is no different at all levels of moment, where greater need for balance is required at high-performance levels.

Translation of Gravity

Much has been focused on the centre of gravity, and rightfully so. However this is meaningless if this centre is ineffectively transferred or translated. The centre of gravity shifts with movement and can be inside or outside of the body depending on the movement pattern. In some sports, the centre of gravity shifts very rapidly. Wherever the given centre of gravity may be, drawing an imaginary line from that point straight down to ground level is considered as being the ‘line of gravity’. In order to effectively adapt to these gravitational translations, balance becomes the key as emphasised previously.

Point to consider: Besides the ‘central’ centre of gravity within the human body, individual body parts, such as limbs, also have their own centres of gravity.

Centre of Gravity