Effects of sport specific unplanned movements on ankle kinetics and kinematics in healthy athletes from systematic review with meta-analysis

Lower limb injuries are common in team sports, often occurring during athletic tasks with high cognitive demands, such as time-constrained decision-making. This systematic review and meta-analysis used robust variance estimation to compare ankle biomechanics during unplanned (time-constrained) versus pre-planned (no decision-making) tasks. Standardized mean differences (SMD) and 95% confidence intervals were pooled to assess differences in ankle kinematics and kinetics. A literature search was conducted in PubMed, Google Scholar, Cochrane Library, and ScienceDirect (until April 2025). Trials assessing ankle kinematics and/or kinetics during pre-planned and unplanned jump-landing or cutting tasks in healthy athletes were included. The GRADE approach was used to rate the certainty of evidence for each outcome as low, moderate, or high. Fifteen trials (162 men, 152 women) with fair to high methodological quality (modified Downs and Black checklist) were identified. In the sagittal plane, low to moderate certainty evidence indicated higher ankle plantarflexion angles during unplanned movement (SMD = 0.27, p = .017). Subgroup analyses showed this effect was most evident in run-and-cut tasks, at initial ground contact, and among elite athletes (SMD = 0.24 to 0.36, p = .017 to .045). Sensitivity analysis excluding outliers indicated low-certainty evidence of increased ankle dorsiflexion angles during unplanned tasks (SMD = 0.25, p = .044), predominantly during the stance phase. Unplanned sports movements may increase ankle plantar- and dorsiflexion, but their impact on injury risk remains uncertain, as these changes may also reflect performance or protective adaptations. Due to the limited number of studies, low certainty of the available evidence, small effect sizes in the sagittal plane, and limited findings in the frontal and transverse planes, further research is warranted to draw more specific conclusions. PROSPERO registration number: CRD42024598492 (date of registration: 18 October 2024).