title: Influence of trunk posture on lower extremity energetics during running.
abstract: OBJECTIVE
  This study aimed to examine the influence of sagittal plane trunk posture on lower extremity energetics during running.
  
  
  METHODS
  Forty asymptomatic recreational runners (20 males and 20 females) ran overground at a speed of 3.4 m·s(-1). Sagittal plane trunk kinematics and lower extremity kinematics and energetics during the stance phase of running were computed. Subjects were dichotomized into high flexion (HF) and low flexion (LF) groups on the basis of the mean trunk flexion angle.
  
  
  RESULTS
  The mean (±SD) trunk flexion angles of the HF and LF groups were 10.8° ± 2.2° and 3.6° ± 2.8°, respectively. When compared with the LF group, the HF group demonstrated significantly higher hip extensor energy generation (0.12 ± 0.06 vs 0.05 ± 0.04 J·kg(-1), P < 0.001) and lower knee extensor energy absorption (0.60 ± 0.14 vs 0.74 ± 0.09 J·kg(-1), P = 0.001) and generation (0.30 ± 0.05 vs 0.34 ± 0.06 J·kg(-1), P = 0.02). There was no significant group difference for the ankle plantarflexor energy absorption or generation (P > 0.05).
  
  
  CONCLUSIONS
  Sagittal plane trunk flexion has a significant influence on hip and knee energetics during running. Increasing forward trunk lean during running may be used as a strategy to reduce knee loading without increasing the biomechanical demand at the ankle plantarflexors.
authors.affiliation: Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA.
authors.forename: Hsiang-Ling
authors.initials: HL
authors.lastname: Teng
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Powers
mesh_terms: D000328:Adult; D000842:Ankle / Q000502:physiology; D001696:Biomechanical Phenomena; D005260:Female; D006615:Hip / Q000502:physiology; D006801:Humans; D007717:Knee / Q000502:physiology; D035002:Lower Extremity / Q000502:physiology*; D008297:Male; D011187:Posture; D012420:Running / Q000502:physiology*; D060726:Torso / Q000502:physiology*; D055815:Young Adult