Relation between aerobic capacity and walking ability in older adults with a lower-limb amputation

Abstract

Objectives: To determine the relative aerobic load, walking speed, and walking economy of older adults with a lower-limb prosthesis, and to predict the effect of an increased aerobic capacity on their walking ability.

Design: Cross-sectional.

Setting: Human motion laboratory at a rehabilitation center.

Participants: Convenience sample of older adults (n=36) who underwent lower-limb amputation because of vascular deficiency or trauma and able-bodied controls (n=21).

Interventions: Not applicable.

Main outcome measures: Peak aerobic capacity and oxygen consumption while walking were determined. The relative aerobic load and walking economy were assessed as a function of walking speed, and a data-based model was constructed to predict the effect of an increased aerobic capacity on walking ability.

Results: People with a vascular amputation walked at a substantially higher (45.2%) relative aerobic load than people with an amputation because of trauma. The preferred walking speed in both groups of amputees was slower than that of able-bodied controls and below their most economical walking speed. We predicted that a 10% increase in peak aerobic capacity could potentially result in a reduction in the relative aerobic load of 9.1%, an increase in walking speed of 17.3% and 13.9%, and an improvement in the walking economy of 6.8% and 2.9%, for people after a vascular or traumatic amputation, respectively.

Conclusions: Current findings corroborate the notion that, especially in people with a vascular amputation, the peak aerobic capacity is an important determinant for walking ability. The data provide quantitative predictions on the effect of aerobic training; however, future research is needed to experimentally confirm these predictions.

Keywords: Amputation; Artificial limbs; C(pws); PWS; Physical exertion; Physical fitness; Rehabilitation; Walking; energy expenditure while walking (ml·kg(−1)·min(−1)); o(2)peak; o(2rel); o(2walking); oxygen cost (ie, the oxygen consumption per distance traveled at preferred walking speed) (ml·kg(−1)·m(−1)); peak oxygen consumption (ml·kg(−1)·min(−1)); preferred walking speed (m/s); relative aerobic load (eg, as the percentage of available peak oxygen consumption that was used when walking).