title: A minimal limit-cycle model to profile movement patterns of individuals during agility drill performance: Effects of skill level.
abstract: Identification of control strategies during agility performance is significant in understanding movement behavior. This study aimed at providing a fundamental mathematical model for describing the motion of participants during an agility drill and to determine whether skill level constrained model components. Motion patterns of two groups of skilled and unskilled participants (n=8 in each) during performance of a forward/backward agility drill modeled as limit-cycles. Participant movements were recorded by motion capture of a reflective marker attached to the sacrum of each individual. Graphical and regression analyses of movement kinematics in Hooke's plane, phase plane and velocity profile were performed to determine components of the models. Results showed that the models of both skilled and unskilled groups had terms from Duffing stiffness as well as Van der Pol damping oscillators. Data also indicated that the proposed models captured on average 97% of the variance for both skilled and unskilled groups. Findings from this study revealed the movement patterning associated with skilled and unskilled performance in a typical forward/backward agility drill which might be helpful for trainers and physiotherapists in enhancing agility.
authors.affiliation: Biomechanics and Sports Engineering Groups, Biomedical Engineering Department, Amirkabir University of Technology, Tehran, Iran. Electronic address: s.mehdizadeh@aut.ac.ir.
authors.forename: Sina
authors.initials: S
authors.lastname: Mehdizadeh
authors.affiliation: Biomechanics and Sports Engineering Groups, Biomedical Engineering Department, Amirkabir University of Technology, Tehran, Iran. Electronic address: arshi@aut.ac.ir.
authors.forename: Ahmed Reza
authors.initials: AR
authors.lastname: Arshi
authors.affiliation: Centre for Sports Engineering Research, Sheffield Hallam University, A217, Collegiate Hall, Collegiate Crescent, Sheffield S10 2BP, UK; FiDiPro Programme, University of Jyväskylä, Finland. Electronic address: k.davids@shu.ac.uk.
authors.forename: Keith
authors.initials: K
authors.lastname: Davids
mesh_terms: D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D001696:Biomechanical Phenomena; D002138:Calibration; D003198:Computer Simulation; D006801:Humans; D008962:Models, Theoretical; D009038:Motion; D009068:Movement; D009991:Oscillometry; D010809:Physical Fitness / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D012044:Regression Analysis; D012420:Running / Q000502:physiology*; D012447:Sacrum / Q000502:physiology; D055815:Young Adult
keywords: Agility; Limit-cycle model; Motor processes; Nonlinear dynamics; Skill level