Patellofemoral Joint Loading in Forward Lunge With Step Length and Height Variations

Area of Science:

• Biomechanics
• Kinesiology
• Orthopedics

Background:

• Patellofemoral pain syndrome is common.
• Understanding joint loading during exercises like lunges is crucial for injury prevention and rehabilitation.

Purpose of the Study:

• To investigate the impact of step length and height on patellofemoral joint loads during forward lunges.
• To quantify changes in joint force and stress under varied lunge conditions.

Main Methods:

• Sixteen participants performed forward lunges with short and long steps on ground level and a 10-cm platform.
• Electromyography, ground reaction force, and 3D motion capture were utilized.
• Patellofemoral loads were calculated relative to knee flexion angles and analyzed using repeated-measures 2-way ANOVA.

Main Results:

• Longer steps increased patellofemoral loads at initial landing (10°-30° knee flexion) and push-off (10°-40°).
• Shorter steps resulted in higher loads during deep knee flexion (50°-100°).
• Lunging at ground level generated greater loads than on a 10-cm platform during descent (50°-100°) and ascent (40°-70°).

Conclusions:

• Patellofemoral loads are modulated by step length, step height, and knee flexion angle during lunges.
• Exercise progression for increasing patellofemoral loading should consider these variables.
• A specific sequence of increasing knee flexion, step length, and platform height can be used to gradually increase patellofemoral loads.