Impact of Mobility Aid on Base of Support

The base of support corresponds to the delimited surface by the projection of the various points of support of a person and their technical walking aid (TWA).

The mobility aid therefore directly influences the base of support. Depending on the type of TWA, its mode of use, and the objectives pursued, the base of support varies throughout the gait cycle. Walkers and walking frames (one-handed, two-handed) are the only mobility aids that modify the base of support throughout the entire gait cycle. This is why they are particularly useful in cases of significant balance disorders.

General Principles

• Surface and stability: The larger and more extended the base of support, the greater the stability.
• Orientation: The orientation of the surface must correspond to the axis in which balance is sought. Fragile individuals often prefer an oblique orientation, offering both lateral and anterior-posterior stability.
• Variation during gait: The base of support alternates between phases of large surface (multiple supports) and phases of small surface (single-leg support). This variation is reduced for certain TWAs (walker) and more significant for others (canes).
• Rules according to objectives:
  • For weight-bearing relief: The size of the surface is less important. Supports are often close to the body.
  • For “balance: The supports (feet and TWA) are more spread out, thus increasing the size of the base of support. It’s not the force exerted on the TWA that provides” balance, but its contribution to the overall configuration of supports.

Examples of Bases of Support with Different Mobility Aids

Quad Cane – 2-Point Gait

Alternation between a large rectangular surface (double support) and a small surface (single-leg support). To adopt a 2-point gait, sufficient stability is required. The weakest individuals will spontaneously adopt a 3-point gait (see below).

1 Crutch – 2-Point Gait

Alternation between a large triangular surface (double support) and a small surface (single-leg support).

Two Crutches for Partial Weight-Bearing Relief

Alternation between a triple support (laterally spread surface) and a single-leg support. This gait offers good lateral stability but is less stable anteroposteriorly. The primary objective is weight-bearing relief.

Two Crutches for Complete Weight-Bearing Relief

Alternation between support on both crutches (complete replacement of foot support) and single-leg support. This gait, focused on weight-bearing relief, is very stable laterally but remains limited in anteroposterior stability, allowing the body to move forward.

Two Crutches with Alternating Supports

Alternation between double supports (one crutch and the opposite foot). This gait ensures symmetrical weight-bearing relief and stability for people with bilateral deficits. Each foot support is doubled by a crutch support. The Wheeleo® one-handed walker also allows doubling of each support while freeing one hand.

Two Walking Poles with Alternating Supports

Alternation between double supports (one pole and the opposite foot). This gait improves balance throughout the entire gait cycle. The handles are placed in a high position (bent elbows) because the goal is not to push hard but to benefit from the change in the base of support by taking one or two additional ground supports.

Quad Cane – 3-Point Gait

Three distinct phases:

• Double support on both feet while moving the cane.
• Double support cane/adjacent foot.
• Double support cane/opposite foot.

This approach allows for maintaining a large base of support throughout the cycle, without a single-leg support phase. It is used to compensate for situations of great instability. Unfortunately, this compensation to eliminate the effect of lifting the cane has an impact on the gait.

The Wheeleo® one-handed walker provides stability (always two points of support, thus a large base of support) without altering the natural walking pattern.

Wheeleo® – Two-Step Gait

Alternation between a double support of Wheeleo®/opposite foot and a double support of Wheeleo®/adjacent foot. The use of Wheeleo® improves stability without disrupting the natural walking pattern, offering an effective solution in many situations.

This article demonstrates how the base of support is a fundamental concept in the selection and use of walking aids. Understanding these principles allows for optimizing safety, stability, and gait quality for each patient.