ECSS Paris 2023: OP-BM12
INTRODUCTION: Maintaining balance in an upright stance is a fundamental movement skill. Balance control relies on sensory feedback from visual, vestibular, and proprioceptive systems [1]. Previous research has shown that the relative contribution of each sensory system changes depending on environmental conditions, a process referred to as sensory reweighting [2]. However, the effects of balance training (BT) on sensory integration are currently unresolved. This study aimed to investigate the effects of virtual reality-based BT (BT+VR) versus conventional BT on sensory integration during bipedal stance in young adults. METHODS: Twenty-two participants aged 22.9±1.1y were randomly allocated to a BT or a BT+VR group. BT participants received conventional BT, while BT+VR participants additionally received visual input manipulations in the form of a tilting visual scene during the performance of BT exercises. Both training protocols were conducted for four weeks with two weekly sessions. To investigate the visual sensory contribution, participants were exposed to two stimulus conditions. The visual scene tilted in pseudo random sequences with peak-to-peak amplitudes of 1° or 4° (pp1 and pp4) while postural sway was recorded in bipedal stance using a force plate. The independent-channel model was applied to estimate the visual contribution to balance [3], i.e., the visual weight (Wv), together with parameters characterizing the dynamics of the feedback system. Specifically, the proportional and derivative feedback-loop gains represent the strength of muscle contraction relative to the deviation from the desired upright position and postural sway velocity. Three-way rmANOVAs were performed with the factors group (BT vs BT+VR), time (pre vs post), and stimulus condition (pp1 vs pp4). RESULTS: Results revealed a significant main effect of condition (p<0.001, part. eta squared effect size [ES]=0.97), with higher Wv observed in pp1 compared to pp4. A significant condition-by-time interaction (p=0.003, ES=0.38) was found, with a 15% pre to post decrease in Wv in pp1. However, no significant group-by-time interactions were found. For the proportional and derivative feedback-loop gains, significant main effects of time were observed (p=0.004, ES=0.28; p=0.044, ES=0.35, respectively). CONCLUSION: This study demonstrates that both BT and BT+VR can induce adaptations in sensory reweighting by reducing the visual contribution to balance. While neural adaptations following BT have been extensively studied, this study provides novel evidence of adaptations in the feedback system of balance control after BT and BT+VR in healthy young adults. These findings may have clinical implications for patients (e.g., with Parkinson disease) or older adults who often have increased visual dependence during balance control. References [1] Pasma et al., Neuroscience, 2014 [2] Peterka, J Neurophysiol, 2002 [3] Assländer et al., Sci Rep, 2023
Read CV Jakob KettererECSS Paris 2023: OP-BM12
INTRODUCTION: Aging results in a progressive decline of motor control, affecting static and dynamic balance (1). Balance training programs for elderly individuals typically involve exercises targeting various factors, such as visual input, surface type, or foot positioning (2), but rarely incorporate specific stimulation of the neuromuscular system to enhance the training effects. While previous studies have focused on techniques like vibration or electrical stimulation (3,4), the combination of both remains largely unexplored. This study aims to investigate the effects of four balance training interventions that integrate balance exercises and neuromuscular stimulation. METHODS: Seventy-four healthy older adults (75-87 years old) completed a 6-month protocol that included 8 weeks of tailored balance training consisting of either 40-min session of balance exercises alone (CON group) or combined with concurrent application of electrical stimulation (TENS group), vibration (LV group) or both (LV+TENS group). Four evaluations were conducted: 8 weeks before the training (T1), 1-7 days before the training (T2), 1-7 days after the training period (T3), and after an 8-week retention period with no training (T4). The assessment included the 10-Meter Walking Test (10MWT), 6-Minute Walking Test (6MWT), Timed Up and Go (TUG), Berg Balance Scale (BBS), and Short Physical Performance Battery (SPPB). Linear mixed model (fixed effect: evaluation and group, random effect: participants) were used for analysis. RESULTS: No significant differences were found between T1 and T2 for any test (p>0.05), without group differences either. No significant effects of training (p=0.138) or group (p=0.525) were observed for the 6mWT. However, an improvement in 10mWT (p=0.004), TUG (p<0.001), SPPB (p<0.001) and BBS (p<0.001) was observed from T2 to T3, without differences between groups. After the retention period, the scores returned to their initial values (as in T2) for the TUG, SPPB and BBS (p=0.002; p=0.049; p<0.001, respectively) without differences between groups (p>0.05). CONCLUSION: These findings suggest that tailored balance training significantly enhances clinical balance performance, underscoring its importance as a non-pharmacological intervention to combat age-related decline in balance capacity. However, the addition of LV and TENS did not give additional benefits compared to exercises alone. This suggests that while these modalities are often posited to enhance neuromuscular activation and proprioceptive feedback, their contribution to balance improvement may be limited, at least in the context of this study. One possible explanation could be that the balance exercises provided sufficient stimulus for adaptation, leaving little range for additional gains from LV or TENS. References 1.Steffen et al. (2002). Phys Ther 82, 128–137. 2.Martínez-Amat et al. (2013). J Strength Cond Res 27, 2180–2188. 3.Filippi et al. (2009). Arch Phys Med Rehabil 90, 2019–2025. 4.Park et al. (2014). Med Sci Monit 20, 1890–1896.
Read CV Anastasia TheodosiadouECSS Paris 2023: OP-BM12
INTRODUCTION: Perturbation-based balance training during locomotion is recognized as an effective physical intervention to enhance fall-resisting skills across diverse populations [1]. However, its transfer to real-world scenarios remains insufficiently investigated. Given that the generalization of adaptive locomotor stability responses is essential for fall prevention, this study examined whether balance recovery improvements gained either through mechanically or visually induced gait perturbations translate to real-world balance disturbances in high fall risk individuals. METHODS: 110 healthy young and middle-aged participants (aged 18–63 years, male and female) were randomly assigned to a control group (n=30, no perturbation training) or one of two perturbation training groups: mechanically induced (MEC, n=40) or visually induced (VR, n=40). All participants walked on a treadmill during training. The MEC group experienced posterior and medio-lateral gait perturbations via ankle and waist pulls using a pneumatically operated brake-and-release system. The VR group encountered visually induced perturbations through virtual environment rotations displayed in VR glasses. To assess potential transfer effects to real-world perturbation scenarios, participants completed walkway negotiation tasks before and after treadmill training, encountering tripping, slipping, and misstep elements. Based on pre-training anterior margin of stability (MoS) during trip, slip, and misstep perturbations, participants were classified as high (HIGH) or low performers (LOW) using a median split with a minimum 20% separation threshold. Balance improvements in simulated real-world scenarios were evaluated by analysing MoS pre- and post-training. RESULTS: For each perturbation type our analysis revealed a similar number of LOW and HIGH performer independent of the analyzed exercise groups. LOW showed an increase in MoS during tripping and slipping in both intervention groups (mean increment in MoS: VR-trip: +8.65 cm, VR-slip: +4.18 cm; MEC-trip: +9.71 cm, MEC-slip: +7.95 cm; p<0.05). In the misstep transfer task, a significant MoS increase was observed only in the MEC group (+3.88 cm; p<0.05). In contrast, HIGH and the control group showed no increase in MoS or any components of dynamic stability from pre- to post-testing during tripping, slipping, or missteps. CONCLUSION: Our findings show that healthy young and middle-aged adults with low fall-resisting skills can benefit from repeated exposure to unpredictable visual and mechanical induced gait perturbations enhancing their fall resilience during simulated real-world balance disturbances. Thus, implementing such perturbation-based exercise interventions in occupational and clinical settings might be an effective tool to decrease fall risk in various population groups. [1] Karamanidis et al. 2020 Exerc Sport Sci Rev
Read CV Anika WeberECSS Paris 2023: OP-BM12