ECSS Paris 2023: OP-BM15
INTRODUCTION: Chronic ankle instability (CAI) has been associated with altered sensorimotor control, particularly when postural tasks are challenged by sensory deprivation or cognitive load. The purpose of this study was to examine how cognitive dual-tasking and visual conditions modulate the relationship between postural sway (center of pressure; COP) and cortical hemodynamics (concentration of oxyhemoglobin (HbO), de-oxyhemoglobin (HbR), total hemoglobin (HbT)) in individuals with CAI, copers (i.e., history of ankle sprain with full recovery), and healthy controls during single-leg standing. METHODS: Eighteen individuals with CAI (26.5±6 y/o, 9M9F), 13 copers (27±6.9 y/o, 5M8F), and 12 healthy controls (24.4±4.6 y/o, 5M7F) participated. Participants performed single-leg standing under four conditions: eyes-open (EO), eyes-closed (EC), EO with cognitive dual-task, and EC with cognitive dual-task. COP metrics (anterior-posterior (AP)/medial-lateral (ML) maximal displacement, variability and total trajectory) were recorded using a forceplate. Mean cortical hemodynamics were measured via fNIRS over bilateral prefrontal (PF), premotor (PM), primary motor (M1), and somatosensory (S1) cortices. Spearman correlations were calculated between COP variables and cortical hemodynamics within each group and condition. Statistical significance was set at p<0.05. RESULTS: COP-cortical coupling was condition- and group-specific. During EO single-task, copers showed positive COP-HbO coupling in sensorimotor regions (M1 r=0.582; S1 r=0.676), whereas healthy controls demonstrated negative associations between sway and HbO/HbT (e.g., ML displacement vs M1 HbO r=-0.671; total trajectory vs M1 HbO r=-0.713). During EC single-task, CAI exhibited positive correlations between total trajectory and HbO in premotor and motor cortices (r=0.470-0.496), while copers showed positive associations between AP sway variability and prefrontal HbO (r=0.577-0.593). Under EO dual-task, CAI and healthy control demonstrated negative sway, HbT/HbO coupling (CAI r=-0.585 to -0.513; HC r=-0.685 to -0.748). In contrast, during EC dual-task, copers displayed widespread positive coupling across sensorimotor regions (S1 HbO r=0.615-0.748; M1/S1 HbT r=0.650-0.699), with additional positive associations between HbT and AP sway variability (r=0.615-0.678). CONCLUSION: The relationship between postural sway and cortical hemodynamics during single-leg standing is highly task-dependent and differs among CAI, copers, and healthy controls. Sensory deprivation and cognitive dual-tasking reveal distinct cortical-postural control strategies. Copers demonstrate robust and widespread positive sensorimotor coupling under the most challenging condition (EC dual-task), suggesting adaptive cortical engagement, whereas CAI and healthy controls exhibit different or region-specific coupling patterns.
Read CV Chia-Wei LinECSS Paris 2023: OP-BM15
INTRODUCTION: Football is a sport with a high risk of ankle sprains. More than 40% of players experience recurrent sprains or giving way, known as chronic ankle instability (CAI). Single-leg balance (SLB), bipedal landing (BL), and single-leg landing (SLL) tests are effective assessment methods for determining the presence of CAI. However, current SLB research mainly compares football athletes of different performance levels. Existing SLL and BL studies largely focus on landing time. Therefore, the purpose of this study was to compare biomechanical parameters between football players with and without CAI during SLB, BL, and SLL tests. METHODS: 36 male soccer athletes were recruited and divided into CAI (n = 16) and non-CAI (n = 20) groups. Basic parameters were obtained through questionnaire. A Kinvent V3 force plate was used to collect data. The SLB test required participants to maintain a 10-second stance under both eyes-open (EO) and eyes-closed (EC) conditions. For the BL and SLL tests, participants were instructed to step off a 30 cm box and land on the force plate in accordance with the test protocol. RESULTS: Compared with the non-CAI group, athletes with CAI demonstrated significantly greater bilateral asymmetry and overall postural sway across single-leg tasks. Specifically, during both SLB-EO and SLB-EC tests, the CAI group exhibited significantly larger COP ellipse area. Under the SLB-EC condition, additional significant increases were observed in medial-lateral length, medial-lateral velocity. No significant between-group differences were identified during the BL test. However, during the more demanding SLL test, the CAI group demonstrated significantly bigger time to stabilisation and COP ellipse area. CONCLUSION: CAI is associated with impaired dynamic postural control and increased bilateral asymmetry, particularly during single-leg tasks. Athletes with CAI exhibited greater postural sway during SLB test, which was further exacerbated under EC conditions, particularly in the medial-lateral direction. This may be related to compromised subtalar joint function affecting inversion-eversion stability, consistent with previous single-leg balance findings [1]. No significant differences were observed in the BL test, possibly because greater energy absorption occurred at the hip (35.0%) and knee (35.3%) [2]. In contrast, deficits became evident during the single-leg landing task, where greater demands were placed on the ankle joint. These findings have practical implications for injury prevention and provide reference criteria for assessing functional recovery in athletes with CAI. References 1. Liu N, Yang C, Song Q, et al. J Frontiers in Human Neuroscience, 2024. 2. Yeow CH, Lee PVS, Goh JCH. Hum Mov Sci 2011;30:624-635.
Read CV Qi WangECSS Paris 2023: OP-BM15
INTRODUCTION: Previous research has shown that, compared to young adults, children did not adopt a postural “stiffening” response when confronted with a height-induced threat during quite bipedal standing [1, 2, 3]. However, it remains unclear whether this maladaptive behaviour is also evident in a more difficult (semi-static) balance task and how this is influenced by the different arm movement strategies. The objective of this study was to compare the effects of arm movement strategies on balance and emotional state outcomes during a semi-static task performed on ground level and at height in children versus young adults. METHODS: Children (n=25, age: 11.7 ± 0.5 years) and young adults (n=23, age: 21.8 ± 3.4 years) executed a continuous contralateral leg swing for 30 s during unipedal stance at both ground-level (no threat) and 80 cm above ground (threat). In both conditions, the task was performed with free and restricted arm movements. Subjective balance-related indicators—including fear of falling, perceived instability, and conscious balance processing—were assessed using self-report questionnaires. Objective balance-related parameters comprised sway amplitude and frequency. Statistical analyses were conducted using 2 (Group) × 2 (Threat) × 2 (Arm) ANOVAs (ηp²). RESULTS: Compared with young adults, children demonstrated significantly greater threat-related changes in both emotional state and balance outcomes. When standing above ground (threat), children exhibited more pronounced emotional and cognitive responses (Group × Threat: fear of falling, p = .033, ηp² = .10; perceived instability, p = .006, ηp² = .15; conscious balance processing, p = .039, ηp² = .09) as well as greater sway frequency, particularly during the restricted arm movement condition (Group × Threat × Arm: AP COP MPF, p = .032, ηp² = .10). CONCLUSION: The observation of an increased postural “stiffening” response (i.e., greater sway frequency) when standing at height with restricted arms in children contrasts with previous research [3] and requires further studies. References: 1. A.L. Adkin, M.G. Carpenter, New Insights on Emotional Contributions to Human Postural Control, Front. Neurol. 9 (2018) 789. 2. A.M. Wissmann, M. Hill, T. Muehlbauer, J. Lambrich, Arm movement strategies did not influence emotional state and static postural control during height-induced postural threat in children and young adults, Front. Hum. Neurosci. 19 (2025) 1635330. 3. M. Hill, L. Brayne, E. Hosseini, M. Duncan, T. Muehlbauer, S.R. Lord, T.J. Ellmers, The influence of fear of falling on the control of upright stance across the lifespan, Gait & Posture 109 (2024) 226–232.
Read CV Anna Maria WissmannECSS Paris 2023: OP-BM15