Avaltroni Priscilla, Sylos-Labini Francesca, Villani Margherita, Cappellini Germana, Lacquaniti Francesco, Ivanenko Yury
Laboratory of Neuromotor Physiology, Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Santa Lucia, Rome, Italy.
Department of Systems Medicine and Center of Space Biomedicine, University of Rome Tor Vergata, Rome, Italy.
Front Bioeng Biotechnol. 2025 Aug 11;13:1622083. doi: 10.3389/fbioe.2025.1622083. eCollection 2025.
Understanding how haptic interaction supports interpersonal coordination during locomotion is important to develop assistive technologies when necessary. While significant work has been done on haptic interactions during adult locomotion, little is known about how children interact between each other or with an adult during walking. Here, we studied haptic-guided locomotion in children and adults.
We examined 11 pairs (adult-adult, child-child [6-8 years old], and adult-child) walking side by side with hand contact toward targets, with one participant leading and one blindfolded follower. The walking path was either straight or curved. We recorded and analysed upper limb muscle electromyography, kinematics, and haptic interaction forces.
All dyads (adult-adult, child-child, adult-child) showed relatively small interaction forces (around 3 N), which presumably function primarily as communicative cues rather than as direct mechanical drivers of movement of the partner. Gait initiation involved compliant interaction in all dyads, with frequent anterior deltoid shortening reactions aiding arm elevation and movement onset, particularly prominent in adult-child pairs. During curved locomotion, small direction-specific adjustments in force (2-3 N) and arm elevation (3-4) conveyed effective haptic cues across ages. In addition, we found clear age-related features in the haptic interaction. Adults reduced upper-limb compliance when guiding children as compared with guiding another adult. However, children were systematically more compliant when interacting with adults, irrespective of their role, leader or follower. We interpret this difference as indicating that adults emphasize precise control and interaction stability, whereas children display more variable and reactive motor behaviour. The latter behaviour may reflect the need of children to learn and explore while walking in tandem. However, it may also reflect a compliance control that is different from that of adults.
The sample size and children age range were limited. Moreover, we only included female adults.
了解触觉互动如何在运动过程中支持人际协调对于在必要时开发辅助技术至关重要。虽然在成人运动过程中的触觉互动方面已经开展了大量工作，但对于儿童在行走过程中彼此之间或与成人之间如何互动却知之甚少。在此，我们研究了儿童和成人的触觉引导运动。
我们观察了11对（成人-成人、儿童-儿童[6至8岁]以及成人-儿童）并排行走且手部接触以朝向目标前进的情况，其中一名参与者为引导者，一名被蒙住眼睛的跟随者。行走路径要么是直的，要么是弯曲的。我们记录并分析了上肢肌肉肌电图、运动学以及触觉相互作用力。
所有配对（成人-成人、儿童-儿童、成人-儿童）均表现出相对较小的相互作用力（约3牛顿），这些力大概主要起到交流线索的作用，而非作为伙伴运动的直接机械驱动力。在所有配对中，步态启动都涉及顺应性互动，前三角肌频繁的缩短反应有助于手臂抬起和运动开始，这在成人-儿童配对中尤为明显。在弯曲运动过程中，力（2至3牛顿）和手臂抬高（3至4）方面的小幅度特定方向调整在各年龄段都传达了有效的触觉线索。此外，我们在触觉互动中发现了明显的年龄相关特征。与引导另一名成人相比，成人在引导儿童时会降低上肢的顺应性。然而，儿童在与成人互动时，无论其角色是引导者还是跟随者，系统性地表现得更具顺应性。我们将这种差异解释为表明成人强调精确控制和互动稳定性，而儿童则表现出更多可变且反应性的运动行为。后一种行为可能反映了儿童在并排行走时学习和探索的需求。然而，这也可能反映了一种与成人不同的顺应性控制。
样本量和儿童年龄范围有限。此外，我们仅纳入了成年女性。
