Bottom-up kinetic chain in drop landing among university athletes with normal dynamic knee valgus

• Main Authors: Jamaludin, Nazatul Izzati, Sahabuddin, Farhah Nadhirah Aiman, Raja Ahmad Najib, Raja Khairul Mustaqim, Shamshul Bahari, Muhamad Lutfi Hanif, Shaharudin, Shazlin
• Format: Article
• Published: MDPI 2020
• Subjects: R Medicine (General); RC1200 Sports Medicine
• Online Access: http://eprints.um.edu.my/36650/
• Institution: Universiti Malaya

The study investigated the influence of ankle strength and its range of motion (ROM) on knee kinematics during drop landing. Fifteen male and fifteen female university athletes with a normal range of dynamic knee valgus (DKV) (knee frontal plane projection angle: men = 3 degrees to 8 degrees, females = 7 degrees to 13 degrees) were recruited. They performed drop landing at height 30 cm and 45 cm with three-dimensional motion capture and analysis. Knee angles were compared at specific landing phases. Isokinetic ankle strength was tested at 60 degrees/s angular velocity while the weight-bearing lunge test was conducted to evaluate ankle ROM. For males, strength for both plantarflexors and dorsiflexors were associated with knee kinematics at both heights (30 cm: r = -0.50,p= 0.03; 45 cm: r = -0.45,p= 0.05) during maximum vertical ground reaction force (MVGRF) phase. For females, ankle invertor strength and knee kinematics were associated at both 30cm (r = 0.53;p= 0.02,) and 45 cm landing heights (r = 0.49,p= 0.03), while plantarflexor strength and knee kinematics showed a significant association during initial contact (r = 0.70,p< 0.01) and MVGRF (r = 0.55,p= 0.02) phases at height 30 cm only. Male and female athletes with normal range of DKV showed a significant relationship between ankle strength and knee kinematics at specific landing phases. These relationships varied with increased landing height.