title: Barefoot running and hip kinematics: good news for the knee?
abstract: OBJECTIVE
  Patellofemoral pain and iliotibial band syndromes are common running injuries. Excessive hip adduction (HADD), hip internal rotation (HIR), and contralateral pelvic drop (CLPD) during running have been suggested as causes of injury in female runners. This study compared these kinematic variables during barefoot and shod running.
  
  
  METHODS
  Three-dimensional gait analyses of 23 habitually shod, uninjured female recreational athletes running at 3.33 m·s while shod and barefoot were studied. Spatiotemporal and kinematic data at initial contact (IC), 10% of stance (corresponding to the vertical impact peak), and peak angles were collected from each participant for HADD, HIR, and CLPD, and differences were compared across footwear conditions.
  
  
  RESULTS
  Step rates when running barefoot were 178 ± 13 versus 172 ± 11 steps per minute when shod (P < 0.001). Foot-strike patterns changed from a group mean heel-toe latency indicating a rear-foot strike (20.8 ms) when shod, to one indicating a forefoot strike (-1.1 ms) when barefoot (P < 0.001). HADD was lower at IC and at 10% of stance when running barefoot (2.3° ± 3.6° vs. 3.9° ± 4.0°, P < 0.001 and 2.8° ± 3.5° vs. 3.8° ± 3.7°, P < 0.01), as was HIR (7.9° ± 6.1° vs. 10.8° ± 6.1°, P < 0.001 and 4.1° ± 6.3° vs. 7.0° ± 5.8°, P < 0.01) and CLPD (0.4° ± 2.4° vs. -0.4° ± 2.3°, P < 0.01 and 0.8° ± 2.7° vs. 0.3° ± 2.5°, P < 0.05). There were no significant differences detected in peak data for hip kinematics.
  
  
  CONCLUSIONS
  Barefoot running resulted in lower HADD, HIR, and CLPD when compared to being shod at both IC and 10% of stance, where the body's kinetic energy is absorbed by the lower limb. Because excessive HADD, HIR, and CLPD have been associated with knee injuries in female runners, barefoot running could have potential for injury prevention or treatment in this cohort.
authors.affiliation: 1Departments of Anatomy and Physiology, Trinity College Dublin, IRELAND; 2Department of Kinesiology, Recreation and Sport, Indiana State University, Terre Haute, IN; and 3School of Sport Science, Exercise and Health, University of Western Australia, Crawley, AUSTRALIA.
authors.forename: Colm
authors.initials: C
authors.lastname: McCarthy
authors.forename: Neil
authors.initials: N
authors.lastname: Fleming
authors.forename: Bernard
authors.initials: B
authors.lastname: Donne
authors.forename: Brian
authors.initials: B
authors.lastname: Blanksby
mesh_terms: D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology*; D006615:Hip / Q000502:physiology*; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology / Q000517:prevention & control*; D008297:Male; D010388:Pelvis / Q000502:physiology; D012307:Risk Factors; D012420:Running / Q000293:injuries / Q000502:physiology*; D012775:Shoes