Development and decline of upright gait stability

Abstract

Upright gait is a peculiar characteristic of humans that requires the ability to manage upper body dynamic balance while walking, despite the perturbations that are generated by movements of the lower limbs. Most of the studies on upright gait stability have compared young adults and the elderly to determine the effects of aging. In other studies, the comparison was between healthy subjects and patients to examine specific pathologies. Fewer researches have also investigated the development of upright gait stability in children. This review discusses these studies in order to provide an overview of this relevant aspect of human locomotion. A clear trend from development to decline of upright gait stability has been depicted across the entire lifespan, from toddlers at first steps to elderly. In old individuals, even if healthy, the deterioration of skeletal muscle, combined with sensorial and cognitive performance, reduces the ability to maintain an upright trunk during walking, increasing the instability and the risk of falls. Further, the pathological causes of altered development or of a sudden loss of gait stability, as well as the environmental influence are investigated. The last part of this review is focused on the control of upper body accelerations during walking, a particularly interesting topic for the recent development of low-cost wearable accelerometers.

Keywords: accelerometry; aging; balance; falls; locomotion; motor control; neuromuscular diseases; walking.

Figure 1

Upper body accelerations. Upper body accelerations along the antero-posterior direction in a child (data obtained for a 2-year-old female), an adult (35 years, female), and an elderly subject (69 years, female).

Figure 2

Walking speed and acceleration RMSs. Mean (±SD) of walking speed, AP, LL, and CC acceleration RMSs with respect to mean (±SD) age for the studies in Table 1. Regression lines (in blue) were obtained with a bi-exponential fit.

Figure 3

Stability and velocity of walking. Values of mean RMSs [along the antero-posterior (AP), latero-lateral, (LL) and cranio-caudal (CC) axes] and WS² for healthy subjects at various ages [(A), on the left] and for children with cerebral palsy and adults with stroke [(B), on the right]. In the latter graph, the large gray rhomboidal area is formed by joining the extremes of values of healthy subjects [reported in (A)], and blue–green rhomboidal area by joining the extremes of values of children with cerebral palsy.