Validity and reliability of 2-dimensional trunk, hip, and knee frontal plane kinematics during single-leg squat, drop jump, and single-leg hop in females with patellofemoral pain

Phys Ther Sport. 2020 Sep;45:181-187. doi: 10.1016/j.ptsp.2020.07.006. Epub 2020 Jul 25.


Objectives: To investigate validity and between-session reliability of frontal plane trunk, hip, and knee kinematics during three functional tasks in females with patellofemoral pain (PFP).

Design: Observational.

Setting: Research Laboratory.

Participants: 20 females with PFP (22.7 ± 3.2 years, 69.9 ± 9.2 kg, 167.7 ± 9.6 cm).

Main outcome measures: Trunk, hip, and knee frontal plane peak angles during the single leg squat (SLS), drop vertical jump (DVJ), and single leg hop (SLH) kinematics were evaluated using 2-dimensional (2D) and 3-dimensional (3D) motion capture. Participants returned to the lab one week later and competed a second 2D analysis of the functional tasks. Concurrent validity was assessed by evaluating relationship between 2D and 3D frontal plane kinematics with Pearson correlations. Between-session reliability was assessed by evaluating 2D kinematics with intraclass correlation coefficients by a single assessor.

Results: Moderate to strong correlations (r = 0.55-0.76, p < .05) were found for frontal plane hip kinematics during all three tasks and the trunk during the SLH. Frontal plane kinematics demonstrated good to excellent test-retest reliability for each of the three tasks, (ICC (2,1) = 0.70-0.90).

Conclusion: 2D hip joint angles during the three functional tasks were the only valid frontal plane angles. Trunk, hip, and knee 2D frontal plane kinematics ranged between good-excellent reliability.

Keywords: Anterior knee pain; Biomechanics; Functional tests; Two-dimensional video analysis.

Publication types

  • Observational Study

MeSH terms

  • Biomechanical Phenomena
  • Female
  • Hip Joint / physiopathology*
  • Humans
  • Knee Joint / physiopathology*
  • Leg / physiopathology*
  • Patellofemoral Pain Syndrome / physiopathology*
  • Posture / physiology*
  • Reproducibility of Results
  • Torso / physiopathology*
  • Young Adult