# Lower Limb Joint Coordination and Coordination Variability During Landing: A Scoping Review
## 2 Methods  
This scoping review was conducted in accordance with the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews--Appendix A) guidelines [11]. **Protocol Registration:** Although no external registration was completed, an internal protocol was developed to guide the review process, including eligibility criteria, database selection, and charting strategy. At the time of writing, registration on PROSPERO was not feasible as it does not accept scoping reviews not focused on direct health outcomes. We acknowledge that the absence of protocol registration limits external reproducibility and transparency. **Search Strategy:** The following search strategy was used in PubMed and adapted for other databases (i.e., Web of Science, Scopus, SPORTDiscus) using equivalent field tags: **(\"joint coordination\" OR \"coordination variability\" OR \"inter-joint coordination\" OR \"movement coordination\") AND (landing OR \"drop jump\" OR \"jump landing\" OR \"landing mechanics\"). ** No restrictions were placed on publication year, and results were limited to peer-reviewed journal articles published in English. The final search was conducted in March 2024. **Inclusion Criteria:** We included peer-reviewed original research articles that (1) involved human participants and reported biomechanical measures of lower limb joint/segment coordination during a landing task, and (2) quantified coordination patterns and/or coordination variability. Both bilateral (two-leg) and unilateral (single-leg) landing tasks were considered (including drop landings, stop-jumps, drop vertical jumps, and similar deceleration/jump-landing tasks). Studies needed to report a coordination metric such as coupling angle analyses (vector coding (VC), continuous relative phase (CRP), and discrete relative phase (DRP)) or variability of coordination (standard deviation or angular dispersion of coupling angles across trials). We included studies examining healthy individuals as well as those focusing on specific groups (athletes with injury history, trained versus untrained, male versus female, and different age groups). There were no restrictions on the type of landing direction (vertical, diagonal, etc.) or height. We excluded studies that only analyzed temporal events or discrete joint angles without examining joint coupling relationships, as well as studies of gait or running (as opposed to landing) unless a landing component was explicitly analyzed. Only articles in English were included. **Study Selection:** Two reviewers independently screened titles and abstracts for relevance. Full texts of potentially relevant papers were then assessed against the inclusion criteria. Disagreements were resolved through discussion. A PRISMA flow diagram (Figure 1) was used to document the selection process, yielding a total of 18 studies that met the inclusion criteria. **Data Charting and Synthesis:** Data from included studies were charted using a standardized form. Extracted information included author/year, participant characteristics (sample size, population or group types such as ACL-injured, male/female, and age), landing task description (i.e., single-leg drop from 30 cm, double-leg drop jump with subsequent jump, and anticipated versus unanticipated conditions), coordination analysis methods (VC, CRP, and DRP), and key findings regarding coordination patterns and variability. Rather than conducting a meta-analysis (not appropriate due to the heterogeneity of methods and outcomes), we performed a descriptive synthesis. Consistent with scoping review objectives, we organized the results to map the evidence by thematic focus.