A normal walking gait pattern is based on numerous key biomechanical functions which are known as the determinants of gait. These 6 determinants of gait were initially published by Saunders et al in 1953, and still have been widely adopted with many variations and also small issues. All the determinants of gait are regarded as important as they facilitate a much more efficient movement by the minimizing the up and down centre of mass movement that leads to a decrease in the metabolic energy needed for motion. The rationale underpinning this is that the greater control of these types of determinants of gait brings about an increase in energy preservation and much more efficient movement. This model which does underpin these determinants of gait are in conflict with the ‘inverted pendulum’ model which views the static stance leg acting as a pendulum that tracks an arc. The biomechanics community continues to debate the benefit of the two approaches.
The 6 determinants of gait and the way they influence the centre of mass (abbreviated as COM) displacement as well as energy efficiency are:
1. Pelvic rotation: The pelvis rotates side to side during normal gait to assist in the progression of the contralateral side via decreased hip joint flexion and extension. This affects the lowering of metabolic energy and also the greater energy preservation by reducing the up and down COM displacement.
2. Pelvic tilt: Throughout regular gait there is a slanting of the swing period side of the pelvis that is governed by the hip joint abductor muscles. This muscle motion cuts down on the raising of the center of mass during the changeover from hip joint flexion to extension. This should lower the use of metabolic energy while increasing energy preservation by lessening vertical center of mass movements.
3. Knee joint flexion throughout the stance phase: The knee joint is extended at heel strike and then starts to flex when the foot is on the floor. The knee flexion will reduce the height of the up and down trajectory of the COM contributing to some energy preservation.
4. Motion in the foot and ankle: The ankle joint rockers at heel contact and mid-stance leads to a reduction in COM displacement through the shortening of the lower leg play a role by reduction of the COM vertical displacement.
5. Knee movements: The movement of the knee relates to those of the ankle and foot movements and leads to the lowering of the center of mass up and down movement and results in decreases in the COM movement and energy cost.
6. Lateral displacement of the body: the lateral movement with the pelvis or a relative adduction with the hip is mediated with the influence of the tibiofemoral angle and also relative adduction of the hip joint to reduce vertical COM movement. It's considered that this particular determinant plays a key part in ensuring the efficiency in normal gait.
These six determinants of gait are practically intriguing because they help us give attention to some key factors to hold the COM movement flat to improve the efficiency of walking. Nevertheless, some recent investigations questions if all or most of the determinants are really that critical in the general plan of the functions that occur throughout the walking cycle. Even though contemplating these kinds of determinants is fundamental in figuring out walking impairment.
