Elsevier

Gait & Posture

Volume 57, Supplement 1, September 2017, Pages 282-283
Gait & Posture

P57: 2D video Frontal Plane Projection Angle and 3D inertial sensor based assessment of Dynamic Knee Valgus. A Comparison

https://doi.org/10.1016/j.gaitpost.2017.06.418Get rights and content

Introduction

Dynamic knee valgus (DKV) is one of the most discussed issues in recent applied biomechanical research [1]. It is the main parameter when predicting the risk of knee (re-)injuries concerning athletes who are about to return to sport. Recent research has focused on the evaluation of DKV using mobile sensor system suitable for field studies [2]. Therefore in this study two mobile systems, a 2D video analysis and 3D inertial sensor system were compared regarding their correlation in Lower Extremity (LE) kinematics during typical screening tasks of different dynamic.

Section snippets

Research Question

How does frontal and transversal plane kinematic data delivered from an inertial sensor system correlate with the common Frontal Plane Projection Angle [2] (FPPA) gained from 2D Video analysis during quasi static and dynamic screening tasks?

Methods

14 young and healthy soccer players (age 16.71 years) of a German Bundesliga club performed bilateral squat (FS) and vertical drop jump (DJ). 3D kinematic data was delivered from 7 inertial sensor measurement units (IMU) fixed to the segments of the LE and Pelvis. FPPA was calculated from 3 retroreflective markers placed on each leg according to Willson et al [2]. Coefficient of determination was calculated to quantify the association between 3D kinematic data and the FPPA.

Results

Coefficient of determination showed very strong relationship between the inertial kinematic data and FPPA in the FS task. The correlation found for the DJ task was slightly weaker ranging from r²=0.367 to 0.821. Results showed that a medial displacement of the Knee marker (negative FPPA) was strongly associated with Ankle Inversion in both tasks (see Fig.)

Discussion

The results indicate that there is a strong relationship between 3D kinematic data from an inertial sensor system and 2D FPPA in relatively static movements. With increasing speed of movement the association between 3D and 2D kinematic seems to decrease due to reasons not yet specified. Further the data suggests that there is an important correlation between Ankle Inversion and medial displacement of the Knee. More studies are needed to clarify the role of Ankle 3D kinematics in Dynamic Knee

References (2)

  • Hewett

    Am J Sports Med

    (2005)
  • Willson

    Journal of Orthopaedic & Sport Physical Therapy

    (2008)

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