Serkan Uzlasir

Stroboscopic vision (SV) is a novel modality that modulates visual input and can impair postural control due to the resulting visual occlusion. SV tools have multiple levels of visual occlusion (i.e. difficulty) but our understanding of how both instrumented and clinical measures of postural control are impacted by different modes of visual occlusion remain extremely limited. This study aimed to investigate the effects of different modes of SV on instrumented and clinical measures of static and dynamic balance. Three-dimensional ground reaction forces were recorded during both the jump and dominant single-leg balance tasks using a portable Kistler force plate (9286BA; Kistler Instrument Corp, Novi, MI) at a sampling rate of 1200 Hz. Thirty-four healthy individuals performed a single limb static balance task under six visual conditions: eyes open (EO), Mode A, Mode B, Mode C, and Mode D, and eyes closed (EC). SV operated in four modes: both lenses strobing (Mode A), left lens strobing with the right lens opaque (Mode B), right lens strobing with the left lens opaque (Mode C), and alternating strobing between lenses to disrupt binocular vision (Mode D). Static balance was assessed using force plate–derived center of pressure (COP) metrics, including COP velocity and 95% confidence ellipse area, whereas dynamic balance was quantified using the dynamic postural stability index (DPSI) and its directional components. All modes of SV resulted in significantly worse objective static postural control and velocity relative to the EO condition (p < .001). No differences were noted among levels of SV (p > .05) for dynamic postural control. All modes of visual occlusion impair static postural control, but the magnitude of the impairment depends on the outcome measure used. However, these modes did not impair dynamic postural control. In conclusion, it can be stated that different stroboscopic modes have distinct effects on static and dynamic postural control.

Basketball is an open-skill sport that requires rapid processing of visual information and appropriate motor responses in dynamic environments. Stroboscopi

This study investigated the effects of three different 6-week interventions—Sensory Targeted Ankle Rehabilitation Strategy (STARS) alone, balance training alone, and a sequentially integrated STARS and balance training on postural control, dorsiflexion range of motion, self-reported function, and kinesiophobia in athletes with chronic ankle instability. Thirty-five athletes were assigned to one of the three intervention groups. A 2 × 3 mixed repeated-measures analysis of variance revealed no significant Time × Group interactions and no significant group main effects for any outcome (all p > .05). However, significant time main effects were observed for all outcomes (all p < .001), indicating comparable improvements across all three intervention groups, with large effect sizes observed within each group for the majority of outcomes. STARS alone produced improvements comparable to balance training alone, and a sequentially integrated STARS and balance training across all measured outcomes associated with chronic ankle instability.

Stroboscopic visual training (SVT), a relatively new modality, temporarily limits visual input to enhance visuomotor processing and motor coordination. It

Background: Chronic ankle instability (CAI) is associated with impaired gait adaptability, and investigating time-dependent changes in step kinematics and variability—particularly step-to-step corrections—under visually-disruptive conditions compared to a control setting may offer valuable insights into the sensorimotor deficits underlying this condition. Methods: This cross-over investigation included nineteen participants (Age: 22±3 years, 5±3 sprains, 7±9 giving-way episodes, 23±6 IdFAI score). Inclusion criteria followed International Ankle Consortium guidelines. Participants completed two 15 min walking trials on an instrumented treadmill at 1.2 m/s surrounded by a speed-matched virtual hallway. Within each 15-minute assessment, participants walked normally without visual perturbations for the first (Pre-test) and last two minutes (Post-test). Between these assessments, participants were exposed to 10 min of either continuous mediolateral optical flow perturbations (OFP) or stroboscopic vision (SV) and a 1-minute active rest period. This window allowed us to capture early (first two minutes of exposure) and late (last two minutes of exposure) adaptation. Means and standard deviations of step widths (SW), step lengths (SL), and their respective variabilities (SWV, SLV) were calculated from consecutive heel positions. For each visual condition, separate repeated measures ANOVA were used. Results: We observed significant changes over time for both OFP and SV ( p ≤ 0.036). In early adaptation, for both OFP and SV, SL decreased, while SW and SWV increased ( p ≤ 0.009). In late adaptation for OFP, SL increased ( p = 0.012) while SLV decreased ( p = 0.002). During the same period for SV, SW decreased ( p = 0.002) while SL ( p = 0.008) increased. Post-test demonstrated reduced SW ( p ≤ 0.036) and increased SWV ( p ≤ 0.022) relative to Pre-test for OFP and SV. Conclusions: This study identified time-dependent changes in step kinematics and variability in response to OFP and SV among individuals with CAI. The observed changes indicate a reduction in anticipatory control and an increase in reactive control with prolonged exposure to visual perturbations. A short-term aftereffect of the step-to-step reactive control strategy was also observed.

Background: Chronic Ankle Instability (CAI) is associated with proprioceptive deficits and altered neuromuscular control, yet limited studies have examined these factors concurrently during functional tasks like jump-landing. Methods: A total of 44 participants, including 21 healthy individuals and 23 with CAI, participated in a crossover experimental study. An EMG system (Noraxon, USA) was used bilaterally to assess muscle activation of the key muscles involved in ankle movement during jump-landing activities. Specifically, medial gastrocnemius (MG) and tibialis anterior (TA) muscles were evaluated. To identify differences in The Ankle Inversion Discrimination Apparatus for Landing (AIDAL) parameters between groups, an independent samples t-test was conducted. Linear mixed modeling with repeated measures was performed to analyze muscle activation differences during jump-landing at different angles. Results: Individuals with CAI exhibited significantly lower AIDAL slope estimates compared to healthy controls, with a moderate effect size (p < 0.001, d = 0.78). In the EMG results, no statistically significant difference was observed between the CAI group and healthy controls (p = 0.431) for TA and (p = 0.699) for MG. Statistically significant differences were found in the activation of the MG muscle between 10^o and 14^o (p = 0.009), between 12^o and 16^o (p = 0.041) and between 14^o and 16^o (p = 0.005). Conclusion: This study indicates that individuals with CAI experience impaired proprioception compared to healthy individuals, while showing no notable differences in key muscle activation patterns. It highlights the necessity of rehabilitation strategies focused on proprioception.

Bu araştırmanın amacı sporcuların dikey sıçrama performansını ölçmek amacıyla kullanılan My Jump Lab (MJL) uygulamasının geçerlilik ve güvenirliğinin belirlenmesidir. Araştırmaya, amatör seviyede iki farklı branşta (futbol: 28; tenis: 12) düzenli olarak antrenman yapan 21 erkek ve 19 kadın olmak üzere toplam 40 gönüllü sporcu katılmıştır (yaş: 21,95±2,23 yıl; boy: 170,74±10,28 cm; vücut ağırlığı: 66,50±12,35 kg). Araştırma kapsamında sıçrama performansını değerlendirmek için dikey sıçrama (DS) testi kullanılmıştır. Her ölçüm öncesinde beş dakikalık standart bir ısınma protokolü uygulanmıştır. Her ölçüm için iki kez DS testi yaptırılmıştır. Ölçümler arasında iki dakikalık dinleme süresi verilmiş olup sporcuların en iyi performansı kaydedilmiştir. Bu esnada MJL uygulamasının geçerlik ve güvenirlik analizleri için akıllı bir cep telefonuna (14 Promax, Apple, ABD) kayıtlı MJL uygulaması ve Opto Jump fotoelektrik hücre sistemi (Opto Jump Next, Microgate, İtalya) kullanılmıştır. Bu iki sistemde eş zamanlı olarak çalıştırılmış ve kullanılmıştır. Ölçümler 3 farklı ölçüm gününde randomize bir şekilde 24 saat arayla gerçekleştirilmiştir. İstatistiki analiz yöntemlerinden, geçerliliği test etmek için ölçüt geçerliği tekniği esas alınırken, güvenirliği test etmek için test-tekrar test yöntemi kullanılmıştır. MJL uygulamasının güvenirlik testi için sınıf içi korelasyon katsayısı (ICC) kullanılırken ölçüt geçerliğini sınamak için Pearson korelasyon katsayısı incelenmiştir. Her iki ölçme aracı arasındaki test puanlarının farklılığı tespit etmek için ilişkili örneklemlerde t-testi kullanılmıştır. Son olarak, MJL uygulaması için iki ölçüm yöntemi arasındaki uyumu görsel olarak değerlendirmek amacıyla DS sıçrama yüksekliği değerleri Bland-Altman tekniği ile incelenmiştir. Araştırma bulgularına göre her iki uygulama için DS yüksekliği değerlerinin güvenirlik katsayısının yüksek düzeyde olduğu tespit edilmiştir. Her iki ölçüm yöntemi arasındaki farkın t-testi sonuçlarına göre anlamlı düzeyde olmadığı belirlenmiştir (p>0.05). Son olarak Bland-Altman analizi sonuçları da her iki ölçme yöntemi arasında sistematik bir hata olmadığını göstermiştir. Sonuç olarak MJL uygulaması üzerinde yapılan geçerlik analizleri, güvenilir ve kabul edilebilir nitelikte sonuçlar ortaya koyduğu tespit edilmiştir.

Clinical Scenario: Ankle sprains are highly common and can lead to chronic ankle instability (CAI). Individuals with CAI have a variety of sensorimotor impairments including poor postural control and altered sensory organization strategies. Visual occlusion modalities, if worn during neuromuscular control exercises, may facilitate greater postural control gains and a more appropriate sensory organization strategy. However, a cumulative review of the ability of visual occlusion modalities (e.g., stroboscopic goggles) to impair postural control and thus demonstrate the potential to facilitate greater postural gains has not yet been completed. Clinical Question: Does stroboscopic vision impair postural control in those with and without CAI, and if so, is the impairment comparable between the groups? Summary of Key Findings: Regardless of how postural control was assessed, stroboscopic vision impaired postural control relative to an eyes open (i.e., no goggles) condition. All studies demonstrated that those with and without CAI were impacted equally. Stroboscopic vision resulted in postural control impairments comparable to an eyes closed in some but not all studies. Clinical Bottom Line: Stroboscopic vision impairs postural control in both those with CAI and uninjured controls. Strength of Recommendation: There is moderate-quality evidence (Grade B) that stroboscopic vision impairs postural control in those with CAI and uninjured controls.

Clinical Scenario: Individuals with chronic ankle instability (CAI) typically complete balance training protocols to improve postural control and reduce recurrent injury risk. However, the presence of CAI persists after traditional balance training protocols suggesting that such programs may be missing elements that could be beneficial to patients. Visual occlusion modalities, such as stroboscopic goggles, may be able to augment balance training exercises to further enhance postural control gains in those with CAI. However, a cumulative review of the existing evidence has yet to be conducted. Focused Clinical Question: Does wearing stroboscopic goggles during balance training result in greater improvements to postural control than balance training alone in those with CAI? Summary of Key Findings: All 3 studies indicated that the stroboscopic goggles group had statistically significant improvements in either a measure of static or dynamic postural control relative to the standard balance training group. However, significant improvements were not consistent across all postural control outcomes assessed in the included studies. Clinical Bottom Line: Postural control may improve more in those with CAI when stroboscopic goggles were worn while completing balance training exercises relative to completing balance training exercises alone. Strength of Recommendation: Overall, consistent moderate- to high-quality evidence was present in the 3 studies, suggesting grade C evidence for the use of stroboscopic goggles during balance training in those with CAI.