Determinants of Gait

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The classic six basic determinants of gait were first described by John Saunders, Verne Inman and Howard Eberhart in their classic paper in 1953:

Saunders, J.; Inman, V.; Eberhart, H. (1953). “The major determinants in normal and pathological gait”. American Journal of Bone and Joint Surgery, 35, 543–558. (link)

They based this on the assumed strategies that the body uses in order to maintain the center of gravity in a horizontal plane, to decrease the vertical and lateral displacements of center of gravity, to increase the smoothness of the gait, to increase efficiency and to decrease energy expenditure. Sometimes you see it also stated that the 6 determinants of gait make the gait more ‘graceful’.

The authors claim that a gait without these six determinants would be characterized by excessive vertical excursion of the center of mass and be wasteful of energy. They called this gait a ‘compass gait’. This compass gait was described as how an individual would walk if the lower limbs were simple rigid levers that did not have feet, ankles or knees and was hinged at the hips.

A ‘determinant’ in this context could be defined as a movement that occurs in the body to maintain center of gravity of the body in a horizontal plane and ensure a smooth pathway of gait.

The Classic Six Determinants of Gait:
1. Pelvic rotation – the pelvis rotates in the transverse plane 4 degrees forward on the swing side and 4 degrees backward on the stance limb (total of 8 degrees); this decreases vertical displacement of the center of gravity by 9.5mm (3/8in).
2. Pelvic tilt – the pelvis tilts or drops down an average of 5 degrees in relation to the horizontal plane on the side opposite to that of the weightbearing limb during midstance; this decreases the vertical displacement of the center of gravity by an average of just over 3mm (1/8in).
3. Knee flexion after heel strike in the stance phase; at heel strike the knee is fully extended and at foot flat the knee is flexed 15-20 degrees; this absorbs shock and helps minimizes the displacement of the center of gravity.
4. Foot and ankle motion – at heel strike the foot is dorsiflexed and the center of rotation of the ankle is elevated. At foot flat the foot plantarflexes and the center of rotation on the ankle is lowered. At push off the heel lifts from the floor and the center of rotation of the ankle raises again.
5. Knee motion – at heel strike, when the center of rotation of the ankle is high, the knee joint begins to flex. During midstance when the ankle center is low the knee joint flexes a second time. The effects of this  relationship between the motions of the foot, ankle, and knee is to smooth the pathway of the center of gravity.
6. Lateral displacement of the pelvis – the center of gravity must shift over the stance foot to provide balance, otherwise the person will fall over the unsupported limb.

Commentary:

  • Saunders et al did not publish any kinematic data in their original paper to support their contention of the 6 determinants.
  • There is a lack of evidence linking a minimizing of the center of mass movement to a reduction in energy consumption.
  • There is substantial individual variability in pelvic movement
  • The first 3 determinants have been shown to only have a minor or insignificant impact on vertical displacement of the center of gravity.
  • Gard and Childress (2001), Kerrigan et al (2000) and Hayot et al (2013) showed that the heel rise in late stance is an important determinant of the movement of the center of mass.
  • Kirtley (2006) in his book on Clinical Gait Analysis (pg 164) stated that the ‘Determinants of gait’ have been “discredited”.

External Links:
Determinants of gait discredited? (Podiatry Arena)

Page last updated: Jun 9, 2022 @ 2:58 am

 
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