Fluid Coordination in Running, Dance, and Parkour: Emergent Patterns from Nonlinear Kinematic Analysis / Samantha Emanuel (2025)

Movement fluidity represents a critical parameter across sport, rehabilitation, and occupational health domains. Current research paradigms assume universal optimal coordination patterns—applying one-size-fits-all protocols across diverse populations—while overlooking individual coordination patterns. This study investigated coordination patterns during nonlinear movement tasks across participants with diverse athletic backgrounds, examining whether and how fluidity manifests through distinct coordination phenotypes. A cross-sectional case study design examined three participants (dancer, runner, parkour practitioner) using integrated 2D video analysis and 3D inertial measurement units (IMUs). Participants performed baseline countermovement jumps followed by two four-count coordination sequences (side-to-side and back-step patterns) synchronized to 120 BPM. A novel delta-based framework quantified coordination strategies through displacement, velocity modulation, acceleration, and rotational parameters. Direction adaptation ratios and absolute delta changes characterized individual movement signatures across task conditions. Distinct coordination phenotypes emerged across participants: the dancer demonstrated exceptional coordination robustness with consistent rotational patterns; the runner showed dramatic velocity adaptation with minimal rotational involvement; the parkour practitioner exhibited substantial multi-parameter adaptations. Baseline jump performance showed no predictive relationship with fluidity patterns across all participants, while negative fatigue indices (-0.8% to -9.0%) indicated performance enhancement rather than deterioration during assessment protocols. Movement fluidity emerges through distinct coordination strategies that vary across individuals. The delta-based assessment framework reveals that multiple pathways to fluidity exist, challenging traditional normative approaches and supporting individualized movement evaluation. The small sample size (n=3) and cross-sectional case study design limit causal inference about the origins of observed coordination patterns. Through further research, these findings could have significant implications for rehabilitation, training design, and movement assessment across diverse populations, particularly in dance medicine where artistic and athletic contexts require differentiated evaluation approaches. Key Points Delta-based fluidity assessment may enable practitioners to identify individual coordination phenotypes, supporting personalized rehabilitation and training interventions. This study demonstrates that movement fluidity can be systematically quantified across trained practitioners, with participants exhibiting three distinct coordination phenotypes that may or may not reflect their specific movement training backgrounds. Participants demonstrated performance improvements (0.8-9.0%) across CMRJ and Pogo protocols, challenging fatigue-based assumptions and suggesting phenotype-specific priming responses to different temporal demands.