Ishihara H., Ikuta Y., Maeda N., Tsutsumi S., Arima S., Komiya M., Tashiro T., Abekura T., Ushio K., Mikami Y., Araki T., Adachi N., Urabe Y. . Abnormal lateral malleolus morphology and its as2025 · 記述言語： 日本語 掲載種別： 研究論文（学術雑誌） 出版者・発行元： Gait and Posture Background: Avulsion fractures of the lateral malleolus, detected as abnormal lateral malleolus morphology (ALM), occur concomitantly with lateral ankle sprain (LAS) in children and adolescents. We hypothesized that structural changes in the ankle joint due to ALM may contribute to deterioration in dynamic balance function. Research question: What are the differences in physical function between competitive adolescent athletes with and without ALM, and what factors influence dynamic postural stability on landing, a critical physical function associated with LAS? Methods: This is the cross-sectional study. Among the participants enrolled, 134 feet were categorized into a non-ALM group, whereas 36 feet were assigned to the ALM group. Foot alignment including medial longitudinal arch and transvers arch, ankle dorsiflexion range of motion, intrinsic foot muscle and plantar fascia morphology, toe flexor strength, and dynamic postural stability index (DPSI) were compared between the two groups. Additionally, regression analysis was employed to identify parameters influencing the dynamic postural stability in each group. Results: The ALM group exhibited wider foot widths, more pronounced transverse arch spreads, reduced ankle dorsiflexion range of motion, thickened plantar fascia, lower toe flexor strength, and decreased dynamic postural stability (p < 0.05, respectively). Multiple regression analysis indicated that decreased ankle dorsiflexion angle was associated with DPSI in both groups, and the wider transverse arch of ALM group was related to DPSI (p < 0.05, respectively). Significance: The lowered transverse arch emerged as a specific feature of ALM group associated with their decreasing dynamic postural instability. Athletes with ALM may be at higher risk of LAS due to poor foot alignment and limited ankle joint range of motion, leading to reduced shock absorption during landing. This study provides crucial keys for the critical focus regarding the physical screening of athletes. DOI： 10.1016/j.gaitpost.2025.03.009 Scopus PubMed
Tashiro T., Maeda N., Tsutsumi S., Abekura T., Esaki H., Tsuchida K., Oda S., Komiya M., Ikuta Y., Urabe Y. . A quantitative assessment of the anterior tibiofibular gap with and without weight2024 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） 出版者・発行元： Journal of Orthopaedic Science Background: Difficulties in the accurate evaluation of tibiofibular clear space in plain radiographs are diagnostic problems in the clinical setting of syndesmosis injury. This study aimed to quantify the anterior tibiofibular gap (ATFG) with weight-bearing using ultrasonography. Methods: In total, 32 healthy adults (16 men and 16 women) with 64 feet participated in this cross-sectional study. The ATFG was measured along the anterior inferior tibiofibular ligament for a US assessment conducted in both sitting and standing postures. The ankle joint was set on the tilt table at four different angles as follows: plantar flexion, 20° (P20); neutral position (N); dorsiflexion, 20° (D20); and dorsiflexion, 20°+ external rotation, 30° (D20ER30). The ankle joint position, sex, and side-to-side values were compared with and without weight-bearing. Results: Under all ankle angle conditions, the ATFG was wider in the standing posture than in the sitting posture (p < 0.001). In both sitting and standing postures, the ATFG widened with increasing dorsiflexion angle, eventually reaching a maximum at D20ER30. The widening ratio (D20ER30/N) in the standing posture was higher in women than in men (p < 0.05). No statistical differences were identified side-to-side differences in the ATFG. Conclusions: Ultrasound measurements for identifying unphysiological increases in ATFG with weight bearing, especially given the side-to-side differences, may provide a means for quantitatively assessing syndesmosis injury in a clinical setting. Further research is warranted to clarify direct attribution as a clinical diagnostic utility of the ATFG measurements for syndesmosis injuries. DOI： 10.1016/j.jos.2024.01.008 Scopus PubMed
Arima S., Maeda N., Tsutsumi S., Ishihara H., Ikuta Y., Ushio K., Fujishita H., Kobayashi T., Komiya M., Morikawa M., Adachi N., Urabe Y. . Association of the intrinsic foot muscles and planta2022 · 記述言語： 日本語 掲載種別： 研究論文（学術雑誌） 出版者・発行元： Gait and Posture Background: The characteristics of foot structure in adolescents and adults are different, affecting sports performance and leading to the progression of foot and lower extremity disorders. Research question: This study aimed to investigate the relationship between the intrinsic foot muscles (IFM) and plantar fascia morphology and the repetitive rebound jumping and jump landing ability in adolescent athletes. Methods: A total of 60 adolescent athletes (35 boys and 25 girls) participated in this study. B-mode ultrasonography was used to obtain images of the IFM and plantar fascia morphology [thickness and cross-sectional area (CSA) of the abductor hallucis (AbH), flexor hallucis brevis (FHB), flexor digitorum brevis (FDB), and thickness of the plantar fascia]. The repetitive rebound jump performance was evaluated using the Optojump™ system. Participants were instructed to jump five times continuously with one leg, jumping as high as possible with minimal ground contact time. The jump landing was assessed by measuring the dynamic posture stability index (DPSI) using forward one-legged jump landings. Results: The thickness and CSA of the AbH and FDB were positively correlated with the jump height and reactive jump index. The DPSI score was significantly correlated with the thickness of the AbH, but not with other IFMs or plantar fascia. In the multiple regression analysis, only the thickness of the FDB was associated with the jump height and reactive jump index, indicating that FDB thickness might facilitate adolescent athletes to jump higher with minimal contact time in repetitive rebounding movements. Significance: The IFM (especially FDB) should be focused on when examining sports performance in adolescent athletes. DOI： 10.1016/j.gaitpost.2022.11.003 Scopus PubMed
