Near-gaze fixation promotes use of spin turns during walking: age-independent visuomotor effects with maladaptive behavioral consequences in older adults

Background: Older adults frequently rely on spin turns while walking, a turning strategy that is biomechanically less stable than step turns and has been associated with an increased risk of falls. Previous studies have suggested that increased gaze fixation toward the area near the feet may be related to this tendency; however, the determinants of increased spin-turn use, particularly the causal role of gaze fixation, remain unclear. The present study aimed to examine whether constraining gaze fixation to the near walking location increases the use of spin turns during walking in older adults. Methods: Fifteen older adults (73.5 ± 6.3 years) and 12 younger adults (24.8 ± 3.7 years) performed a double-target stepping walking task in which the turning strategy (step turn or spin turn) was determined by foot placement relative to a second target. Gaze fixation was experimentally constrained to either a near or a far-gaze condition before stepping onto the first target. Eye movements were recorded using a mobile eye-tracking system, and whole-body kinematics were collected using a three-dimensional motion analysis system. The proportion of spin turns, frequency of pivot switching, gaze behavior, and spatiotemporal gait parameters were analyzed using generalized linear mixed models. Results: The proportion of spin turns was significantly higher under the near-gaze condition than under the far-gaze condition across both age groups, with no statistically significant difference in the magnitude of this effect between older and younger adults. Increased use of spin turns was accompanied by reduced gaze fixation on the far area during the reaching phase, shorter step length, and increased step count. Notably, older adults exhibited unnecessary pivot switching even in conditions in which a strategy change was not required. In contrast, younger adults primarily adjusted their gait patterns according to pivot-switch demands and showed less pronounced effects of gaze condition during turning strategy selection. Conclusion: These findings identify gaze fixation as a key determinant of increased spin-turn use during turning in older adults, whereby constraining gaze to the near walking surface alters visual information available for step planning and promotes maladaptive turning strategy selection.