add_frontal_plane_knee_angle: Calculate frontal plane knee kinematics in anatomical or...

In steenharsted/mocapr: Functions to import, plot, animate, and analyse motion capture data

Calculate frontal plane knee kinematics in anatomical or movement plane.

Description

Positive values of LFPKA and RFPKA reflect lateral deviation of the knee (knee varus).

Usage

add_frontal_plane_knee_angle(.data, plane = "anatomical")

Arguments

.data	A tibble containing knee and ankle spatial joint center positions. These can be created from global joint center positions using either project_full_body_to_AP() for anatomical projection or project_full_body_to_MP() for movement plane projection.
plane	A character string specifying which plane to use for angle calculation. Must be either "anatomical" (default) or "movement". When "anatomical", the angle is calculated using the anatomical frontal plane (Y-up, X-right). When "movement", the angle is calculated in the task-specific movement frontal plane (UP, RIGHT).

Value

The tibble supplied in .data, with added columns:

• LFPKA – Left Frontal Plane Knee Angle

• RFPKA – Right Frontal Plane Knee Angle

Equation

Figure

References

Stone EE, Butler M, McRuer A, Gray A, Marks J, Skubic M. Evaluation of the Microsoft Kinect for screening ACL injury. Conf Proc IEEE Eng Med Biol Soc. 2013;2013:4152-5.

Ortiz A, Rosario-Canales M, Rodriguez A, Seda A, Figueroa C, Venegas-Rios HL. Reliability and concurrent validity between two-dimensional and three-dimensional evaluations of knee valgus during drop jumps. Open access journal of sports medicine. 2016;7:65-73.

Harsted S, Holsgaard-Larsen A, Hestbaek L, Boyle E, Lauridsen HH. Concurrent validity of lower extremity kinematics and jump characteristics captured in pre-school children by a markerless 3D motion capture system. Chiropr Man Therap. 2019;27:39.

Examples

# Simulated example for anatomical frontal plane
df <- data.frame(
  LA_APR = c(10,5,0,-5,-10),
  LK_APR = c(0,0,0,0,0),
  LA_APU = c(0,0,0,0,0),
  LK_APU = c(10,10,10,10,10),
  RA_APR = c(20,15,10,5,0),
  RK_APR = c(10,10,10,10,10),
  RA_APU = c(0,0,0,0,0),
  RK_APU = c(10,10,10,10,10)
)

add_frontal_plane_knee_angle(df, plane = "anatomical")

steenharsted/mocapr documentation built on June 10, 2025, 11:55 a.m.