State University of Tocantins, Faculty of Medicine, Augustinópolis, Brazil.
Biomechanics and Motor Control Lab, School of Physical Education and Sport of Ribeirao Preto, University of Sao Paulo, Brazil.
Exp Gerontol. 2022 May;161:111716. doi: 10.1016/j.exger.2022.111716. Epub 2022 Jan 30.
Walking in a daily life context requires constant adaptations to meet the environment's requirements for successful locomotion. We investigated the walking adaptations of younger and older adults when dealing with holes of different lengths in the pathway (60-cm long and 1.3 times foot length [critical point] conditions). We used the critical point condition to increase the demand for accuracy as it reduces the safety margin between the foot and the borders of the hole. Fifteen younger and fifteen older adults walked barefoot on a wooden walkway in three conditions: no-hole, 60-cm hole (length: 0.60 m | width: 0.80 m | depth: 0.095 m), and critical point hole (length: participant's foot length × 1.3 | width: 0.80 m | depth: 0.095 m). Participants stepped into the hole with only one foot. We assessed the impulses based on the ground reaction forces, trunk and lower limb joint angles, stride speed, and the margin of stability based on the concept of the extrapolated center of mass in the sagittal plane. Across walking conditions, older adults exhibited a larger margin of stability than younger adults. Before the hole, both age groups increased the braking impulse and adopted a more flexed posture of the lower limbs to help to lower the body in the subsequent step. Only older adults increased the vertical braking impulse and markedly reduced stride speed when stepping into both holes. Both age groups adopted a more vertically oriented trunk posture as a strategy to contribute to stability control when stepping into the hole. The two age groups showed a larger margin of stability and a more flexed trunk posture after the hole than the no-hole condition. Older adults were able to control body stability adequately and even better than younger adults. Younger and older adults used the same anticipatory and compensatory locomotor adjustments before and after the hole. These adjustments resulted in improved stability control. The differences between younger and older adults were confined to the moment of stepping into the hole. Older adults used a more cautious strategy that ensured task accuracy and gait progression.
在日常生活中行走需要不断适应以满足成功行走对环境的要求。我们研究了年轻人和老年人在处理路径中不同长度的孔（60 厘米长和 1.3 倍足长[关键点]条件）时的行走适应。我们使用关键点条件来增加准确性的要求，因为它减少了脚和孔的边界之间的安全裕度。15 名年轻人和 15 名老年人在三种条件下赤脚走在木制步道上：无孔、60 厘米孔（长度：0.60 米|宽度：0.80 米|深度：0.095 米）和关键点孔（长度：参与者的脚长×1.3|宽度：0.80 米|深度：0.095 米）。参与者只用一只脚进入孔中。我们根据地面反作用力、躯干和下肢关节角度、步速以及基于质心外推概念的稳定性余量来评估冲动。在所有行走条件下，老年人的稳定性余量均大于年轻人。在进入孔之前，两个年龄组都增加了制动冲量，并采取了更弯曲的下肢姿势，以帮助在后续步骤中降低身体。只有老年人在进入两个孔时增加了垂直制动冲量，并明显降低了步速。两个年龄组在进入孔时都采取了更垂直的躯干姿势，作为稳定控制的策略。与无孔条件相比，两个年龄组在进入孔后都具有更大的稳定性余量和更弯曲的躯干姿势。老年人能够充分控制身体稳定性，甚至比年轻人更好。年轻人和老年人在进入孔前后都使用相同的预期和补偿性运动调整。这些调整导致了更好的稳定性控制。年轻人和老年人之间的差异仅限于进入孔的那一刻。老年人使用更谨慎的策略，确保任务准确性和步态进展。
