OpenCap vs. LESS: Sport-Specific Profiling of Dynamic Knee Valgus

Area of Science:

• Biomechanics
• Sports Medicine
• Movement Analysis

Background:

• Knee valgus during landing is a risk factor for anterior cruciate ligament (ACL) injuries.
• Understanding the neuromuscular control of knee valgus is crucial for injury prevention strategies.

Purpose of the Study:

• To investigate the relationship between the Landing Error Scoring System (LESS), markerless 3D motion capture (OpenCap) of knee valgus, and hamstring/quadriceps muscle activity (EMG).
• To identify predictors of knee valgus during a drop-landing task.

Main Methods:

• Thirty-two healthy male university students performed a drop-landing task.
• Video analysis using the LESS, markerless 3D motion capture (OpenCap) for knee valgus, and surface EMG for rectus femoris (RF) and biceps femoris (BF) were employed.
• EMG data were normalized to peak dynamic activity.

Main Results:

• The LESS demonstrated a significant negative association with left knee valgus.
• Bilateral biceps femoris (BF) muscle activity during the acceleration phase predicted knee valgus.
• Athletes showed reduced rectus femoris (RF) activity during deceleration and less left-side knee valgus compared to non-athletes.

Conclusions:

• Hamstring muscle activation during the transition phase of landing is associated with knee alignment.
• Integrating LESS with markerless 3D motion capture provides complementary biomechanical data.
• Further research is needed to generalize findings due to sample size disparities between athletes and non-athletes.