Muscle strength and flexibility characteristics of people displaying excessive medial knee displacement

Arch Phys Med Rehabil. 2008 Jul;89(7):1323-8. doi: 10.1016/j.apmr.2007.11.048.


Objective: To determine differences in strength and range of motion (ROM) between participants who exhibit medial knee displacement (MKD) during a squat that is corrected by a heel lift and those who do not.

Design: Case control.

Setting: Sports medicine research laboratory.

Participants: Thirty-seven healthy subjects (control, 19; MKD, 18) with no lower-extremity injury in the past 6 months volunteered to participate.

Interventions: Not applicable.

Main outcome measures: Peak force was measured in newtons using a hand-held dynamometer and passive ROM was measured in degrees with a goniometer. Separate multivariate analyses of variance were used to determine differences in strength and ROM between groups. Post hoc testing was used to elucidate differences between groups.

Results: The MKD group had the following: greater hip external rotation strength (P=.03), increased hip extension strength (P=.01), less plantarflexion strength (P=.007), and increased hip external rotation ROM (P=.008).

Conclusions: The MKD group exhibited tight and weak ankle musculature. Interventions focusing on improving strength and ROM of the ankle may improve kinematics during a squat.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ankle Joint / physiopathology
  • Case-Control Studies
  • Exercise / physiology
  • Hip Joint / physiopathology*
  • Humans
  • Joint Instability / physiopathology*
  • Knee Joint / physiopathology*
  • Muscle Strength Dynamometer
  • Muscle Strength*
  • Muscle, Skeletal / physiopathology
  • Range of Motion, Articular*
  • Rotation