title: A kinematic analysis of high-speed treadmill sprinting over a range of velocities.
abstract: BACKGROUND
  The purpose of this study was to measure changes in stride characteristics and lower-extremity kinematics of the hip and knee as a function of increasing treadmill velocity, at velocities ranging from submaximal to near maximal.
  
  
  METHODS
  Six power/speed athletes experienced at sprinting on a treadmill performed trials at 70%, 80%, 90%, and 95% of their previous individual maximum velocity, with video data collected in the sagittal view at 60 Hz.
  
  
  RESULTS
  Significant differences were seen in stride frequency (70%, 80%, P < 0.01; 90%, P < 0.05), stance time (70%, 80%, P < 0.01; 90%, P < 0.05) flight time (70%, P < 0.01; 80%, P < 0.05), hip flexion angle (70%, P < 0.01), hip flexion angular velocity (70%, P < 0.01), hip extension angular velocity (70%, 80%, P < 0.01), knee flexion angular velocity (70%, 80%, P < 0.01), and knee extension angular velocity (70%, P < 0.01), as compared with the near maximum (95%) velocity. Coefficient of variation (CV) values showed that the positional variables at the hip and knee were more variable at faster test conditions, indicating that kinematic changes occur as a function of increased treadmill velocity.
  
  
  CONCLUSIONS
  The results indicated that at slower velocities, there were differences in the stride characteristics and lower-extremity kinematics while sprinting on a treadmill. As the velocity approached near maximum mechanical breakdown was seen, suggesting that velocities greater than 90% should be used selectively during treadmill training.
authors.affiliation: Sports Biomechanics Laboratory, Faculty of Physical Education, University of Alberta, Edmonton, Alberta, Canada, T6G 2H9. dkivi@ualberta.ca
authors.forename: Derek M R
authors.initials: DM
authors.lastname: Kivi
authors.forename: Brian K V
authors.initials: BK
authors.lastname: Maraj
authors.forename: Pierre
authors.initials: P
authors.lastname: Gervais
mesh_terms: D000054:Acceleration; D001696:Biomechanical Phenomena; D005080:Exercise Test; D005260:Female; D006615:Hip / Q000502:physiology; D006801:Humans; D007717:Knee / Q000502:physiology; D007866:Leg / Q000502:physiology; D008297:Male; D010809:Physical Fitness / Q000502:physiology; D012420:Running / Q000502:physiology*