FOOT ARCH DYNAMICS IS RELATED TO DYNAMIC POSTURAL STABILITY AFTER LANDING IN ADOLESCENT COMPETITIVE ATHLETES

N. Maeda¹, Y. Ikuta^2,3, M. Komiya¹, T. Tashiro¹, S. Tsutsumi¹, K. Kaneda¹, S. Arima¹, H. Ishihara¹, T. Nakasa^2,4, Y. Mikami³, N. Adachi^2,3, Y. Urabe¹

¹Hiroshima University, Department of Sports Rehabilitation, Graduate School of Biomedical and Health Sciences, Hiroshima, Japan, ²Hiroshima University, Department of Orthopaedic Surgery, Graduate School of Biomedical and Health Sciences, Hiroshima, Japan, ³Hiroshima University Hospital, Department of Rehabilitation, Hiroshima, Japan, ⁴Hiroshima University Hospital, Medical Center for Translational and Clinical Research, Hiroshima, Japan

Background: The human foot has competent mechanisms for supporting weight and adapting movement to various surfaces; in particular, the toe flexor muscles aid in supporting the foot arches and may be important contributors to postural stability. However, the role of intrinsic foot muscle (IFM) morphology and structure in the postural control system remains unclear, and the relationship between them is not well known in adolescent competitive athletes.

Purpose: This study aimed to investigate whether foot arch dynamics, IFM morphology, and toe flexor strength are related to dynamic postural stability after jump-landing and repetitive rebound jump in adolescent competitive athletes.

Methods: Fifty adolescent competitive athletes (28 boys and 22 girls) participated in this study. The exclusion criteria were as follows: any injury within the past 3 months that required taking a break from sporting activities, any error during any of the measurements, any neurological disorder that might have affected balance ability, and any lower extremity injury. All participants were classified based on their foot arch dynamics (which were calculated from the relative change in foot arch height in the sitting and standing positions) into three groups: the stiff, normal, and flexible groups. Foot arch dynamics were calculated using the following equation for relative change in Foot arch height (FAH) in the sitting position without weight and in the standing position with approximately 50% of the body weight applied to each foot: Foot arch dynamics = (FAH sitting – FAH standing) / FAH sitting・100. Foot arch dynamics were classified into the stiff, normal, and flexible groups based on their mean and standard deviation values. IFM morphology, including the thickness and cross-sectional area (CSA) of the abductor hallucis, flexor hallucis brevis, and flexor digitorum brevis muscles, was measured by ultrasonography (HI Vision Avius; Hitachi, Japan) with an 8-MHz linear array probe. During dynamic postural stability assessment, the participants jumped and landed with their right leg on a force plate as a measure of dynamic postural stability index (DPSI). Repetitive rebound jumping performance was assessed using jump height and the reactive jump index. A one-factor ANOVA was used to investigate differences in the morphological characteristics of the foot, thickness and CSA of the IFMs, DPSI index, and repetitive rebound jump values. The relationship between foot arch dynamics and DPSI was examined using multiple linear regression with forced entry.

Results: The stiff group showed significantly higher DPSI and Vertical Stability Index scores than the normal group and a significantly higher Anterior-Posterior Stability Index (APSI) score than the flexible group. Only APSI score was correlated with foot-arch dynamics. In the post hoc power analysis, the multivariate regression models for the association between APSI and foot arch dynamics showed adequate power (β=-0.45, p=0.001, 95% confidence interval=-50.175 – -13.502, 1 err prob = 0.912).

Conclusions: The results showed that foot arch dynamics play an important role in dynamic postural control in the anterior and posterior directions among in adolescent competitive athletes.

Implications: Increased stiffness of the foot arch can adversely affect dynamic balance during jump landings, leading to decreased performance in in adolescent competitive athletes.

Funding acknowledgements: We have no funding acknowledgement in this study.

Keywords:
Foot arch dynamics
Intrinsic foot muscle
Dynamic postural stability

Topics:
Sport & sports injuries
Musculoskeletal: lower limb
Education: methods of teaching & learning

Did this work require ethics approval? Yes

Institution: Ethical Committee for Epidemiology

Committee: Hiroshima University

Ethics number: E-941