Medio-lateral stability during walking turns in older adults

Abstract

IntroductionMedio-lateral stability during walking turns relies on the interaction between precise weight shifts of the body and changes in base of support by regulating step width. Although older adults and clinical populations often slow down while turning in order to compensate for balance impairments, little is known about the influence of walking speed on stability during turning.ObjectiveTo compare medio-lateral stability between walking turns and straight walking and to investigate whether walking speed affects medio-lateral stability during turning in healthy older adults.MethodsNineteen older adults walked straight or walked and turned 180° to the right and left at their comfortable speed and at a slow pace. The walking direction was visually cued before they started to walk (preplanned) or while walking straight (unplanned). As a proxy for medio-lateral stability, we calculated the absolute difference between pelvis lateral displacement and the lateral edge of the base of support during straight walking and turning.ResultsOverall, irrespective of turning condition, medio-lateral stability was enhanced during turning as the pelvis was further away from the boundary of the base of support resulting in a greater margin of stability compared to straight walking. Turning at a slow pace hampered medio-lateral stability as demonstrated by pelvis lateral displacement closer to the boundaries of the base of support resulting in reduced margins of stability. The reduction in stability was caused by a narrower step width during slow walking whereas pelvis lateral displacement was unaffected by turning speed.ConclusionIn older adults, medio-lateral stability was augmented during turning compared to straight walking, whereas turning at a slow pace hampered medio-lateral stability. These findings provide insights into the postural strategies used by older adults in order to adapt to the postural challenges of turning and straight walking.

Will We Do If We Can? Habitual Qualitative and Quantitative Physical Activity in Multi-Morbid, Older Persons with Cognitive Impairment

“…The present findings are coherent since turning while walking represents a more challenging movement for older persons as compared to straight walking [ 23 , 24 ] that places high demands on coordination and balance [ 68 , 69 ], as prerequisites for activity, and accounts for up to almost fifty percent of daily indoor activities [ 25 ], which is typical for multi-morbid, older persons.…”

“…Turning while walking stands out as a more demanding movement for older persons, compared to straight walking [ 23 , 24 ], and is required in many daily activities [ 25 ]. It reflects a high risk situation for serious falls that my lead to hip fractures [ 26 ] and has therefore been incorporated in established clinical tests, such as the Timed “Up & Go” Test.…”

Age-Related Changes in Mobility Evaluated by the Timed Up and Go Test Instrumented through a Single Sensor

“…Turning is a repeated and asymmetric task, requiring an accurate active control from the central nervous system because the progression of the center of mass is rapidly halted and redirected over the base of support. In fact, turning requires kinematics and force generation to rapidly reorient the head, trunk, and pelvis, with greater medial ground reaction impulses on the outside limb to lead the body center of mass upon the contralateral limb [37][38][39].…”

“…Enlarging the base of support along the medial-lateral axis is a postural adaptation adopted by elderly adults to guarantee appropriate postural reactions for greater safety in walking along a curved path [38,40,41]. On these bases, the slow down observed in elderly adults during mid turning may contribute to accomplish the medial-lateral expansion of the base of support, increasing the margins of stability while walking during turning.…”

Dynamic stability and spatiotemporal parameters during turning in healthy young adults

“…Based on the inverted pendulum model of balance, MoS can be used to assess gait stability for straight walking, for starting and stopping walking and for turning [ 22 ], and is much more convincing than the static method by considering both the relative position and velocity between CoM and BoS [ 18 ]. However, most studies investigating turning gait stability either assessed static stability, such as distance between the ankles [ 13 , 23 ], stride width [ 12 , 24 ] and distance between CoM and BoS [ 9 , 13 , 23 , 24 ], or did not compare dynamic stability between two turning strategies and straight walking [ 9 , 23 ]. For example, spin turns are generally considered less stable and demanding a higher biomechanical cost than step turns, mainly because Taylor et al [ 13 ] indicated that the spin turn had a narrow BoS leading to CoM outside displacement and required increased joint moments and power, compared to the step turn and straight gait.…”