The effect of cam FAI on hip and pelvic motion during maximum squat

Clin Orthop Relat Res. 2009 Mar;467(3):645-50. doi: 10.1007/s11999-008-0620-x. Epub 2008 Nov 26.


Femoroacetabular impingement (FAI) causes abnormal contact at the anterosuperior aspect of the acetabulum in activities requiring a large hip range of motion (ROM). We addressed the following questions in this study: (1) Does FAI affect the motions of the hip and pelvis during a maximal depth squat? (2) Does FAI decrease maximal normalized squat depth? We measured the effect of cam FAI on the 3-D motion of the hip and pelvis during a maximal depth squat as compared with a healthy control group. Fifteen participants diagnosed with cam FAI and 11 matched control participants performed unloaded squats while 3-D motion analysis was collected. Patients with FAI had no differences in hip motion during squatting but had decreased sagittal pelvic range of motion compared to the control group (14.7 +/- 8.4 degrees versus 24.2 +/- 6.8 degrees , respectively). The FAI group also could not squat as low as the control group (41.5 +/- 12.5% versus 32.3 +/- 6.8% of leg length, respectively), indicating the maximal depth squat may be useful as a diagnostic exercise. Limited sagittal pelvic ROM in FAI patients may contribute to their decreased squatting depth, and could represent a factor amongst others in the pathomechanics of FAI.

MeSH terms

  • Acetabulum / physiopathology*
  • Adult
  • Biomechanical Phenomena
  • Case-Control Studies
  • Disability Evaluation
  • Exercise*
  • Female
  • Femur / physiopathology*
  • Hip Joint / physiopathology*
  • Humans
  • Imaging, Three-Dimensional
  • Joint Diseases / diagnosis
  • Joint Diseases / physiopathology*
  • Male
  • Middle Aged
  • Pelvic Bones / physiopathology*
  • Range of Motion, Articular
  • Video Recording
  • Young Adult