Rinaldi Natalia Madalena, Lim Jongil, Hamill Joseph, Van Emmerik Richard, Moraes Renato
Center of Physical Education and Sports, Department of Sports, Federal University of Espírito Santo, Brazil.
Biomechanics and Motor Control Laboratories, University of Massachusetts, USA; Department of Counseling, Health and Kinesiology, Texas A&M University, San Antonio, USA.
Gait Posture. 2018 Sep;65:1-7. doi: 10.1016/j.gaitpost.2018.06.167. Epub 2018 Jun 28.
Obstacle avoidance and object prehension occur regularly in real-world environments (walking up/down steps and opening a door). However, it is not known how walking and prehension change when there is an increase in the level of difficulty of the walking task.
We investigated the changes in walking and reach-tograsp when performing these two motor skills concomitantly in the presence of an obstacle on the ground positioned in different locations in relation to the object-to-be-grasped.
Fifteen young adults walked and grasped a dowel placed on a support with the obstacle positioned at the step before (N-1), during (N) and after (N + 1) the prehension task.
The prehension task did not affect leading limb obstacle negotiation. Toe clearance and maximum toe elevation were lesser at obstacle position N + 1 than at obstacle position N-1 when combining grasping and obstacle-crossing task for the trailing limb. Step width increased in the presence of the obstacle-crossing task independent of obstacle location. The correlation between foot position before the obstacle and toe clearance revealed that the addition of the prehension task disrupted the relationship between these variables for the trailing limb. Foot placement and limb elevation were unaffected by the prehension task. The reaching component was unaffected by the increased level of difficulty of the walking task. The grasping component was affected by the increased level of difficulty of the walking task, as the time to peak grip aperture occurred earlier in the presence of the obstacle at position N, and may indicate a cautious strategy to grasp the dowel successfully.
Our results showed that prospective control is affected after the prehension since the attention to grasping may have impaired the acquisition of visual information for planning the trailing limb elevation.
在现实环境中（上/下楼梯和开门），避障和物体抓握经常发生。然而，尚不清楚当行走任务难度增加时，行走和抓握会如何变化。
我们研究了在存在位于相对于待抓握物体不同位置的地面障碍物的情况下，同时执行这两种运动技能时行走和伸手抓握的变化。
15名年轻成年人行走并抓握放置在支架上的木钉，障碍物位于抓握任务前一步（N-1）、抓握任务期间（N）和抓握任务后一步（N + 1）。
抓握任务不影响主导肢体越过障碍物。对于非主导肢体，在将抓握和越过障碍物任务相结合时，在障碍物位置N + 1处的脚趾间隙和最大脚趾抬高比在障碍物位置N-1处小。在存在越过障碍物任务时，步宽增加，与障碍物位置无关。障碍物前足部位置与脚趾间隙之间的相关性表明，抓握任务的添加破坏了非主导肢体这些变量之间的关系。足部放置和肢体抬高不受抓握任务影响。伸手动作不受行走任务难度增加的影响。抓握动作受行走任务难度增加的影响，因为在障碍物位于位置N时，达到最大握距的时间更早出现，这可能表明是一种成功抓握木钉的谨慎策略。
我们的结果表明，抓握后前瞻性控制受到影响，因为对抓握的关注可能损害了用于规划非主导肢体抬高的视觉信息的获取。
