title: Effects of fast walking on tibiofemoral bone water content in middle-aged adults.
abstract: Although it is believed that genu varum increases loading on the medial knee during locomotion, the acute effect of increased loading on bone stress has not been determined. This study aimed to examine the effects of locomotion and lower extremity alignment on bone water content in middle-aged adults without knee osteoarthritis.
  
  
  
  Five males and 5 females participated. Lower extremity alignment was defined as the angle between the midpoint of the anterior mid-thigh and the midpoint of the patellar tendon using the center of the patella as the fulcrum. A chemical-shift-encoded water-fat magnetic resonance imaging protocol was used to assess bone water content before and after a 30-minute fast walking session. Bone stress response was determined by quantifying water content within the weight-bearing regions of the medial and lateral compartments of the tibiofemoral joint. Paired t-tests were used to compare bone water content before and after fast walking. Pearson correlation coefficients were used to determine the associations between lower extremity alignment and changes in water content post-walking.
  
  
  
  The paired t-tests revealed no changes in water content after fast walking within medial and lateral femur/tibia (P>0.05). Pearson correlation analyses revealed a significant moderate correlation between increased bone water content of the medial femur and increased varus alignment (R=0.688, P=0.028).
  
  
  
  Although there was no significant change in bone water content following locomotion, knee varus was associated with signs of bone stress in the medial femur.
authors.affiliation: Department of Physical Therapy, University of Nevada, Las Vegas, Las Vegas, NV, USA. Electronic address: kaiyu.ho@unlv.edu.
authors.forename: Kai-Yu
authors.initials: KY
authors.lastname: Ho
authors.affiliation: Department of Physical Therapy, University of Nevada, Las Vegas, Las Vegas, NV, USA.
authors.forename: Alexa
authors.initials: A
authors.lastname: Standerfer
authors.affiliation: Department of Physical Therapy, University of Nevada, Las Vegas, Las Vegas, NV, USA.
authors.forename: Suzenna
authors.initials: S
authors.lastname: Ngo
authors.affiliation: Department of Physical Therapy, University of Nevada, Las Vegas, Las Vegas, NV, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Daun
authors.affiliation: Department of Physical Therapy, University of Nevada, Las Vegas, Las Vegas, NV, USA.
authors.forename: Szu-Ping
authors.initials: SP
authors.lastname: Lee
mesh_terms: D005260:Female; D005269:Femur / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D035002:Lower Extremity; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery; D013312:Stress, Physiological / Q000502:physiology*; D013977:Tibia / Q000502:physiology*; D016138:Walking / Q000502:physiology*; D014867:Water / Q000032:analysis*; D016474:Weight-Bearing / Q000502:physiology
chemical_list: D014867:Water
keywords: Alignment; Bone water content; Knee osteoarthritis