Current application of continuous relative phase in running and jumping studies: A systematic review

Background: Continuous relative phase (CRP) has gained popularity to assess movement performances in recent decades. Research question: The application and interpretation of CRP in common movements such as running and jumping are still unclear. Methods: This systematic review summarized the current applications, methodology, parameters of interest, and interpretations of CRP variables in running and jumping. Reviewed articles were found in five databases from January 1999 to December 2020, and 1613 records were obtained. After applying selection criteria and analysis of study quality to titles, abstracts, and full texts, 38 articles were identified for subsequent review. Results: Twenty-eight reviewed articles relating to running were found to compare the coordination among pathological gait, footwear designs, running speed, gender, age, running level, fatigue state, and treadmill effect. In addition, ten reviewed articles relating to jumping were found to compare the coordination among different types of jump (e.g., squat jump coordination, countermovement jump, single leg jump) and insole effect. Significance: The CRP and its variability (CRPv) are two common variables to describe the changes and differences of coordination patterns, respectively. These reviewed articles suggest that CRP tools are effective to assess the coordination and performances in running and jumping, as these values are related to external (environment/equipment) and internal (self-biological) changes. In the future, studying higher-order analysis of movement patterns using CRP tools can provide meaningful interpretation of movement behavior.