Impact of height-induced postural threat and arm movement strategies while performing a semi-static balance task: comparison of postural control and emotional state outcomes between children and young adultsRunning head: Postural threat and arm movem

Previous evidence suggests that children compared to young adults show a potentially ineffective postural adaptation strategy in response to a height-induced threat during quite standing. However, it is unknown whether this behavior is also evident in a more difficult (semi-static) balance task and how this is altered by the applied arm movement strategy. This work compared the effects of different arm movement strategies on subjective and objective indicators related to performing a semi-static balance task at or above ground-level in children versus young adults. Twenty-five children [mean (SD) age: 11.7 (0.5) years] and 23 young adults [mean (SD) age: 21.8 (3.4) years] performed a continuous contralateral leg swing whilst standing on one leg at both ground-level (no threat) and 80 cm above ground (threat). In both conditions, participants completed the task under free and restricted arm movements. Subjective indicators related to postural control—including balance confidence, fear of falling, perceived instability, and conscious balance processing—were assessed via self-report questionnaires. Objective measures related to the balance included sway amplitude and frequency. Children significantly differed from young adults in subjective and objective outcomes by showing more pronounced emotional responses (i.e., fear of falling, perceived instability, and conscious balance processing) and greater sway frequency (i.e., AP COP MPF) when standing at height, especially when arm movements were restricted. The findings complement previous research related to postural threat and arm restriction while using a more difficult semi-static balance task. Future studies should examine when the transition from a child to an adult-like pattern in balance control during height-induced postural threat occurs. • Effect of arm movement on height-induced postural threat while standing was tested. • Standing at height with restricted arms worsened balance in children and adults. • Children exhibited stronger emotional responses to height than young adults.