title: Wrist kinematic coupling and performance during functional tasks: effects of constrained motion.
abstract: OBJECTIVE
  To quantify the coupled motion of the wrist during selected functional tasks and to determine the effects of constraining this coupled motion using a radial-ulnar deviation blocking splint on performance of these tasks.
  
  
  METHODS
  Ten healthy, right-handed men performed 15 trials during selected functional tasks with and without a splint, blocking radial and ulnar deviation. The following tasks were performed: dart throwing, hammering, basketball free-throw, overhand baseball and football throwing, clubbing, and pouring. Kinematic coupling parameters (coupling, kinematic path length, flexion-extension range of motion, radial-ulnar deviation range of motion, flexion-extension offset, and radial-ulnar deviation offset) and performance were determined for each functional task. A generalized estimation equation model was used to determine whether each kinematic coupling parameter was significantly different across tasks. A repeated-measures generalized estimation equation model was used to test for differences in performance and kinematic coupling parameters between the free and splinted conditions.
  
  
  RESULTS
  Wrist motion exhibited linear coupling between flexion-extension and radial-ulnar deviation, demonstrated by R(2) values from 0.70 to 0.99. Average wrist coupling and kinematic path lengths were significantly different among tasks. Coupling means and kinematic path lengths were different between free and splinted conditions across all tasks other than pouring. Performance was different between wrist conditions for dart throwing, hammering, basketball shooting, and pouring.
  
  
  CONCLUSIONS
  Wrist kinematic coupling parameters are task specific in healthy individuals. Functional performance is decreased when wrist coupling is constrained by an external splint.
  
  
  CONCLUSIONS
  Surgical procedures that restrict wrist coupling may have a detrimental effect on functional performance as defined in the study. Patients may benefit from surgical reconstructive procedures and wrist rehabilitation protocols designed to restore kinematic coupling.
authors.affiliation: Motion Analysis Laboratory and the Hand and Upper Extremity Service, Hospital for Special Surgery, New York, NY; Department of Orthopaedics, Brown University, Providence, RI.
authors.forename: Rohit
authors.initials: R
authors.lastname: Garg
authors.affiliation: Motion Analysis Laboratory and the Hand and Upper Extremity Service, Hospital for Special Surgery, New York, NY; Department of Orthopaedics, Brown University, Providence, RI.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Kraszewski
authors.affiliation: Motion Analysis Laboratory and the Hand and Upper Extremity Service, Hospital for Special Surgery, New York, NY; Department of Orthopaedics, Brown University, Providence, RI.
authors.forename: Holbrook H
authors.initials: HH
authors.lastname: Stoecklein
authors.affiliation: Motion Analysis Laboratory and the Hand and Upper Extremity Service, Hospital for Special Surgery, New York, NY; Department of Orthopaedics, Brown University, Providence, RI.
authors.forename: Grisha
authors.initials: G
authors.lastname: Syrkin
authors.affiliation: Motion Analysis Laboratory and the Hand and Upper Extremity Service, Hospital for Special Surgery, New York, NY; Department of Orthopaedics, Brown University, Providence, RI.
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Hillstrom
authors.affiliation: Motion Analysis Laboratory and the Hand and Upper Extremity Service, Hospital for Special Surgery, New York, NY; Department of Orthopaedics, Brown University, Providence, RI.
authors.forename: Sherry
authors.initials: S
authors.lastname: Backus
authors.affiliation: Motion Analysis Laboratory and the Hand and Upper Extremity Service, Hospital for Special Surgery, New York, NY; Department of Orthopaedics, Brown University, Providence, RI.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Lenhoff
authors.affiliation: Motion Analysis Laboratory and the Hand and Upper Extremity Service, Hospital for Special Surgery, New York, NY; Department of Orthopaedics, Brown University, Providence, RI.
authors.forename: Aviva L
authors.initials: AL
authors.lastname: Wolff
authors.affiliation: Motion Analysis Laboratory and the Hand and Upper Extremity Service, Hospital for Special Surgery, New York, NY; Department of Orthopaedics, Brown University, Providence, RI.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Crisco
authors.affiliation: Motion Analysis Laboratory and the Hand and Upper Extremity Service, Hospital for Special Surgery, New York, NY; Department of Orthopaedics, Brown University, Providence, RI. Electronic address: wolfes@hss.edu.
authors.forename: Scott W
authors.initials: SW
authors.lastname: Wolfe
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology*; D013165:Splints; D013647:Task Performance and Analysis; D014955:Wrist Joint / Q000502:physiology*; D055815:Young Adult
keywords: Function; kinematics; motion analysis; performance; wrist