The relationship between ankle dorsiflexion range of motion and reactive postural control mechanisms in response to anterior perturbations

Adequate ankle dorsiflexion range of motion (DF-ROM) is essential for generating sufficient corrective torque during an ankle strategy; however, limitations in dorsiflexion may mechanically constrain this response, potentially leading to earlier reliance on hip or stepping strategies. Although indirect evidence links dorsiflexion capacity to dynamic balance performance, it remains unclear whether restricted dorsiflexion influences the selection of reactive postural control strategies in healthy young adults. Twenty active male participants were recruited for this study. Ankle DF-ROM was measured via the weight-bearing lunge test and categorized as either normal (≥20°) or restricted (<20°). Reactive postural control was assessed in response to a single unexpected anterior perturbation administered by a custom-engineered movable platform, with the perturbation load normalized to participants’ body mass. Sagittal-plane kinematics were recorded at 60 Hz and independently evaluated by two blinded raters to classify the initial balance recovery response into ankle, hip, or stepping strategies based on established criteria. Statistical analysis revealed no significant association between ankle DF-ROM category and the type of reactive postural control strategy employed following anterior perturbations. Pearson’s chi-square test indicated no significant relationship between dorsiflexion status and balance strategy selection ( χ 2 (2) = 0.826, p = 0.662). Due to low expected cell counts, Fisher’s exact test was also conducted, corroborating the absence of a significant association (two-sided p = 0.835). The distribution of postural strategies did not differ substantially between participants with normal and restricted dorsiflexion. In healthy young adults exposed to a standardized anterior perturbation, ankle DF-ROM was not independently associated with reactive postural strategy selection. These findings suggest that the postural demands imposed by the perturbation may have contributed to the predominance of stepping responses and may have reduced the sensitivity to detect an influence of ankle mobility on strategy selection.